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  Subjects -> FORESTS AND FORESTRY (Total: 108 journals)
    - FORESTS AND FORESTRY (107 journals)
    - LUMBER AND WOOD (1 journals)

FORESTS AND FORESTRY (107 journals)                     

Showing 1 - 12 of 12 Journals sorted alphabetically
Acta Silvatica et Lignaria Hungarica     Open Access  
Advance in Forestry Research     Open Access   (Followers: 5)
Advances in Forestry Science     Open Access   (Followers: 3)
Agrociencia     Open Access   (Followers: 1)
Agroforestry Systems     Hybrid Journal   (Followers: 19)
Annals of Forest Research     Open Access  
Annals of Forest Science     Hybrid Journal   (Followers: 5)
Annals of Silvicultural Research     Open Access   (Followers: 1)
Appita Journal: Journal of the Technical Association of the Australian and New Zealand Pulp and Paper Industry     Full-text available via subscription   (Followers: 9)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (Followers: 7)
Arboriculture and Urban Forestry     Partially Free   (Followers: 7)
Australian Forest Grower     Full-text available via subscription   (Followers: 3)
Australian Forestry     Full-text available via subscription   (Followers: 2)
Balduinia     Open Access  
Banko Janakari     Open Access  
Bosque     Open Access   (Followers: 2)
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Horticulture     Open Access  
Canadian Journal of Forest Research     Hybrid Journal   (Followers: 26)
Canadian Journal of Plant Science     Full-text available via subscription   (Followers: 14)
Ciência Florestal     Open Access   (Followers: 2)
Ciencia forestal en México     Open Access  
Colombia Forestal     Open Access  
Current Forestry Reports     Hybrid Journal  
Dissertationes Forestales     Open Access  
East African Agricultural and Forestry Journal     Hybrid Journal  
European Journal of Forest Research     Hybrid Journal   (Followers: 7)
Expert Opinion on Environmental Biology     Hybrid Journal  
Floresta e Ambiente     Open Access   (Followers: 1)
Folia Forestalia Polonica     Open Access  
Forest Ecology and Management     Hybrid Journal   (Followers: 57)
Forest Ecosystems     Open Access   (Followers: 1)
Forest Pathology     Hybrid Journal   (Followers: 2)
Forest Phytophthoras     Open Access   (Followers: 2)
Forest Policy and Economics     Hybrid Journal   (Followers: 23)
Forest Research Papers     Open Access   (Followers: 3)
Forest Science     Full-text available via subscription   (Followers: 6)
Forest Science and Practice     Hybrid Journal   (Followers: 2)
Forest Science and Technology     Partially Free   (Followers: 1)
Forest Systems     Open Access   (Followers: 1)
Forest@ : Journal of Silviculture and Forest Ecology     Open Access   (Followers: 1)
Foresta Veracruzana     Open Access  
Forestry Chronicle     Full-text available via subscription   (Followers: 11)
Forestry Letters     Open Access   (Followers: 1)
Forestry Studies : Metsanduslikud Uurimused     Open Access  
Forestry: An International Journal of Forest Research     Hybrid Journal   (Followers: 16)
Forests     Open Access   (Followers: 4)
Forests, Trees and Livelihoods     Partially Free   (Followers: 5)
Ghana Journal of Forestry     Full-text available via subscription   (Followers: 2)
Holzforschung     Hybrid Journal   (Followers: 1)
iForest : Biogeosciences and Forestry     Open Access   (Followers: 3)
Indonesian Journal of Forestry Research     Open Access   (Followers: 2)
INNOTEC : Revista del Laboratorio Tecnológico del Uruguay     Open Access  
International Forestry Review     Full-text available via subscription   (Followers: 7)
International Journal of Agriculture and Forestry     Open Access   (Followers: 8)
International Journal of Forest Engineering     Hybrid Journal   (Followers: 1)
International Journal of Forestry Research     Open Access   (Followers: 4)
Irish Journal of Agricultural and Food Research     Open Access   (Followers: 1)
Journal of Agriculture, Forestry and the Social Sciences     Full-text available via subscription   (Followers: 3)
Journal of Biodiversity Management & Forestry     Hybrid Journal   (Followers: 3)
Journal of Environmental Extension     Full-text available via subscription  
Journal of Forest and Livelihood     Open Access  
Journal of Forest Economics     Hybrid Journal   (Followers: 6)
Journal of Forest Research     Hybrid Journal   (Followers: 3)
Journal of Forestry     Full-text available via subscription   (Followers: 15)
Journal of Forestry Research     Hybrid Journal   (Followers: 4)
Journal of Horticulture and Forestry     Open Access   (Followers: 5)
Journal of Natural Resources Policy Research     Hybrid Journal   (Followers: 13)
Journal of Research in Forestry, Wildlife and Environment     Open Access   (Followers: 4)
Journal of Sustainable Forestry     Hybrid Journal   (Followers: 7)
Journal of the Faculty of Forestry Istanbul University     Open Access  
Journal of Tropical Forestry and Environment     Open Access   (Followers: 1)
Journal of Wood Chemistry and Technology     Hybrid Journal   (Followers: 9)
Journal of Wood Science     Hybrid Journal   (Followers: 4)
Jurnal Ilmu Kehutanan     Open Access  
Jurnal Manajemen Hutan Tropika     Open Access   (Followers: 1)
Jurnal Penelitian Kehutanan Wallacea     Open Access  
La Calera     Open Access  
Landscapes     Hybrid Journal   (Followers: 18)
Lesnícky časopis     Open Access  
Maderas. Ciencia y tecnología     Open Access   (Followers: 1)
Mathematical and Computational Forestry & Natural-Resource Sciences     Free  
Natural Areas Journal     Full-text available via subscription   (Followers: 12)
New Forests     Hybrid Journal   (Followers: 2)
New Zealand Journal of Forestry Science     Open Access   (Followers: 1)
Open Journal of Forestry     Open Access   (Followers: 1)
Quebracho. Revista de Ciencias Forestales     Open Access  
Research Journal of Forestry     Open Access   (Followers: 4)
Revista Árvore     Open Access   (Followers: 1)
Revista Chapingo. Serie Ciencias Forestales y del Ambiente     Open Access  
Revista de Agricultura Neotropical     Open Access   (Followers: 1)
Revista Ecologia e Nutrição Florestal - ENFLO     Open Access  
Revista Verde de Agroecologia e Desenvolvimento Sustentável     Open Access   (Followers: 2)
Revue forestière française     Full-text available via subscription   (Followers: 4)
Rural Sustainability Research     Open Access   (Followers: 3)
Rwanda Journal     Full-text available via subscription  
Scandinavian Journal of Forest Research     Hybrid Journal   (Followers: 4)
Science, Technology and Arts Research Journal     Open Access   (Followers: 1)
Silva Lusitana     Open Access  
Small-scale Forestry     Hybrid Journal   (Followers: 2)
Southern African Forestry Journal     Full-text available via subscription   (Followers: 1)
Southern Forests : a Journal of Forest Science     Hybrid Journal   (Followers: 5)
Tanzania Journal of Forestry and Nature Conservation     Full-text available via subscription   (Followers: 2)
Trees     Hybrid Journal   (Followers: 5)
Urban Forestry & Urban Greening     Hybrid Journal   (Followers: 9)
Veld & Flora     Full-text available via subscription   (Followers: 2)
Wahana Forestra : Jurnal Kehutanan     Open Access  
Wood and Fiber Science     Full-text available via subscription   (Followers: 4)


Journal Cover Forests
  [SJR: 0.63]   [H-I: 16]   [4 followers]  Follow
  This is an Open Access Journal Open Access journal
   ISSN (Print) 1999-4907
   Published by MDPI Homepage  [156 journals]
  • Forests, Vol. 8, Pages 294: Age-Effect Radial Growth Responses of Picea
           schrenkiana to Climate Change in the Eastern Tianshan Mountains, Northwest

    • Authors: Liang Jiao, Yuan Jiang, Mingchang Wang, Wentao Zhang, Yiping Zhang
      First page: 294
      Abstract: The climate changed from warm-dry to warm-wet during the 1960s in northwest China. However, the effects of climate change on the response of radial growth from different age-class trees have been unclear. We assessed the age-effect radial growth responses in three age-classes (ml-old: ≥200 years, ml-middle: 100–200 years and ml-young: <100 years) of Schrenk spruce (Picea schrenkiana Fisch. et Mey.) in the eastern Tianshan Mountains. The primary conclusions were as follows: the developed chronologies of the three age-class trees contained significant climate information and exhibited high similarity as shown by calculating the statistical parameter characteristics and Gleichlaufigkeit index. The three age-class trees were consistent for annual variation trends of radial growth under climate change, showing similar fluctuations, tree-ring width chronology trends, time trends of cumulative radial growth, and basal area increment. In addition, the old and middle trees were found to be more sensitive to climate variability by analyzing Pearson correlations between radial growth from three age-class trees and climate factors. As a result, the drought caused by reduced total precipitation and higher mean temperature was a limiting factor of tree radial growth, and the trees with ages of up to 100 years were more suitable for studies on the growth-climate relationships. Thus, the studies on age-effect radial growth responses of Schrenk spruce can help not only in understanding the adaptive strategies of different-age trees to climate change, but also provide an accurate basis for climate reconstruction.
      Citation: Forests
      PubDate: 2017-08-26
      DOI: 10.3390/f8090294
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 302: Assessing and Monitoring Forest Degradation in
           a Deciduous Tropical Forest in Mexico via Remote Sensing Indicators

    • Authors: Martin Romero-Sanchez, Raul Ponce-Hernandez
      First page: 302
      Abstract: Assessing and monitoring forest degradation under national Monitoring, Verification and Reporting (MRV) systems in developing countries have been difficult to implement due to the lack of adequate technical and operational capacities. This study aims at providing methodological options for monitoring forest degradation in developing countries by using freely available remote sensing, forest inventory and ancillary data. We propose using Canopy Cover to separate, through a time series analysis approach using Landsat Imagery, forest areas with changes over time from sectors that report a “stable condition”. Above ground Biomass and Net Primary Productivity derived from remote sensing data were used to define thresholds for areas considered degraded. The approach was tested in a semi-deciduous tropical forest in the Southeast of Mexico. The results showed that higher rates of forest degradation, 1596 to 2865 ha year−1, occur in areas with high population densities. The results also showed that 43% of the forests of the study area remain with no evident signs of degradation, as determined by the indicators used. The approach and procedures followed allowed for the identification and mapping of the temporal and spatial distribution of forest degradation, based on the indicators selected, and they are expected to serve as the basis for operations of the Reduction of Emissions from Deforestation and Forest Degradation (REDD+) initiative in Mexico and other developing countries, provided appropriate adaptations of the methodology are made to the conditions of the area in turn.
      Citation: Forests
      PubDate: 2017-08-24
      DOI: 10.3390/f8090302
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 304: Edyn: Dynamic Signaling of Changes to Forests
           Using Exponentially Weighted Moving Average Charts

    • Authors: Evan Brooks, Zhiqiang Yang, Valerie Thomas, Randolph Wynne
      First page: 304
      Abstract: Remote detection of forest disturbance remains a key area of interest for scientists and land managers. Subtle disturbances such as drought, disease, insect activity, and thinning harvests have a significant impact on carbon budgeting and forest productivity, but current change detection algorithms struggle to accurately identify them, especially over decadal timeframes. We introduce an algorithm called Edyn, which inputs a time series of residuals from harmonic regression into a control chart to signal low-magnitude, consistent deviations from the curve as disturbances. After signaling, Edyn retrains a new baseline curve. We compared Edyn with its parent algorithm (EWMACD—Exponentially Weighted Moving Average Change Detection) on over 3500 visually interpreted Landsat pixels from across the contiguous USA, with reference data for timing and type of disturbance. For disturbed forested pixels, Edyn had a mean per-pixel commission error of 31.1% and omission error of 70.0%, while commission and omission errors for EWMACD were 39.9% and 65.2%, respectively. Edyn had significantly less overall error than EWMACD (F1 = 0.19 versus F1 = 0.13). These patterns generally held for all of the reference data, including a direct comparison to other contemporary change detection algorithms, wherein Edyn and EWMACD were found to have lower omission error rates for a category of subtle changes over long periods.
      Citation: Forests
      PubDate: 2017-08-24
      DOI: 10.3390/f8090304
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 305: Can Biomass Quality Be Preserved through
           Tarping Comminuted Roadside Biomass Piles'

    • Authors: Suzanne Wetzel, Sylvain Volpe, Janet Damianopoulos, Sally Krigstin
      First page: 305
      Abstract: Storage conditions play a vital role in maintaining biomass quality as a suitable bioenergy feedstock. Research has shown that biomass undergoes significant changes under different storage conditions and that these may influence its suitability for various biorefining and bioenergy opportunities. This study explores the effects of different tarp covers on the properties of stored-comminuted forest harvest residue from the Great Lakes St. Lawrence Forest. Characteristics of the biomass were evaluated upon harvesting and after one year in storage. The physical state of the different tarps used for pile coverage was monitored onsite. Results indicated that tarp material considerably affects micro-climatic conditions inside piles, yielding variation in the characteristics of stored biomass over the storage period. While plastic based tarps were easier to work with and lasted longer than paper-based tarps, the paper-based tarps were more breathable and resulted in less degradation of biomass. However, the paper-based tarps did not maintain their structural integrity for the full duration of the storage period. Moisture content of original biomass (48.99%) increased to a maximum of 65.25% under plastic cover after 1 year of storage. This negatively influenced the net heating value of the biomass, causing it to decrease from 8.58 MJ/kg to 4.06 MJ/kg. Overall, the use of covers was not considered successful in preserving the original quality of biomass but may enhance its quality for other biorefinery opportunities.
      Citation: Forests
      PubDate: 2017-08-23
      DOI: 10.3390/f8090305
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 306: Early Stage Forest Windthrow Estimation Based
           on Unmanned Aircraft System Imagery

    • Authors: Martin Mokroš, Jozef Výbošťok, Ján Merganič, Markus Hollaus, Iván Barton, Milan Koreň, Julián Tomaštík, Juraj Čerňava
      First page: 306
      Abstract: Strong wind disturbances can affect large forested areas and often occur irregularly within a forest. Due to this, identifying damaged sites and estimating the extent of these losses are crucial for the harvesting management of salvage logging. Furthermore, the location should be surveyed as soon as possible after the disturbance to prevent the degradation of fallen trees. A fixed-wing type of unmanned aircraft system (UAS) with a compact digital camera was used in this study. The imagery was acquired on approximately 200 hectares where five large windthrow areas had occurred. The objective of the study was to determine the location of the windthrow areas using a semi-automatic approach based on the UAS imagery, and on the combination of UAS imagery with airborne laser scanning (ALS). The results were compared with reference data measured by global navigation satellite system (GNSS) devices. At the same time, windthrow areas were derived from Landsat imagery to investigate whether the UAS imagery would have significantly more accurate results. GNSS measurements and Landsat imagery are currently used in forestry on an operational level. The salvage logging was estimated for each forest stand based on the estimated areas and volume per hectare obtained from the forest management plan. The results from the UAS (25.09 ha) and the combined UAS/ALS (25.56 ha) methods were statistically similar to the reference GNSS measurements (25.39 ha). The result from Landsat, at 19.8 ha, was not statistically similar to the reference GNSS measurements or to the UAS and UAS/ALS methods. The estimate of salvage logging for the whole area, from UAS imagery and the forest management plan, overestimated the actual salvage logging measured by foresters by 4.93% (525 m3), when only the most represented tree species were considered. The UAS/ALS combination improved the preliminary results of determining windthrow areas which lead to decreased editing time for all operators. The UAS imagery shows potential for application to early-stage surveys of windthrow areas in forests. The advantages of this method are that it provides the ability to conduct flights immediately after the disturbance, the foresters do not need to walk within the affected areas which decreases the risk of injury, and allows flights to be conducted on cloudy days. The orthomosaic of the windthrow areas, as a by-product of data processing in combination with forest maps and forest road maps, can be used as a tool to plan salvage logging.
      Citation: Forests
      PubDate: 2017-08-23
      DOI: 10.3390/f8090306
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 307: A Markov Chain Model for Simulating Wood
           Supply from Any-Aged Forest Management Based on National Forest Inventory
           (NFI) Data

    • Authors: Jari Vauhkonen, Tuula Packalen
      First page: 307
      Abstract: Markov chain models have been applied for a long time to simulate forest dynamics based on transitions in matrices of tree diameter classes or areas of forest size and structure types. To date, area-based matrix models have been applied assuming either even-aged or uneven-aged forest management. However, both management systems may be applied simultaneously due to land-use constraints or the rationality of combining the systems, which is called any-aged management. We integrated two different Markov chain models, one for even-aged and another for uneven-aged forest management, in an area-based approach to analyze wood supply from any-aged forest management. We evaluate the impacts of parameterizing the model based on available data sets, namely permanent and temporary Finnish National Forest Inventory (NFI) sample plots and a plot-level simulator to determine transitions due to different types of thinning treatments, and present recommendations for the related methodological choices. Our overall observation is that the combined modelling chain simulated the development of both the even- and uneven-aged forest structures realistically. Due to the flexibility of the implementation, the approach is very well suited for situations where scenario assumptions need to be varied according to expected changes in silvicultural practices or land-use constraints, for example.
      Citation: Forests
      PubDate: 2017-08-23
      DOI: 10.3390/f8090307
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 308: Development of Sessile Oak and European
           Hornbeam Sprouts after Thinning

    • Authors: Zdeněk Adamec, Jan Kadavý, Barbora Fedorová, Robert Knott, Michal Kneifl, Karel Drápela
      First page: 308
      Abstract: We observed the growth of juvenile sprouts at stool level in an oak-hornbeam selective coppice after selective thinning. We tested the relations of sprouting probability, number and height of new sprouts, and stool biometric characteristics with thinning intensity and light conditions. We compared the results between the two species. The sprouting probability, number of new sprouts, and height of new sprouts were modelled using different types of regression (logistic, generalized linear, and multiple linear regression) evaluated from 84 sessile oak (Quercus petraea Matt. Liebl.) and 139 European hornbeam (Carpinus betulus L.) stools with the same site conditions. There were no significant relations between sprouting probability and the tested parameters because nearly all stools re-sprouted. The growth (number and height) of new sprouts depended on the stool basal area before thinning and on thinning intensity. Light conditions (indirect site factor) only influenced the number of new European hornbeam sprouts in 2016 and the height of new sessile oak sprouts. The number of new sprouts in European hornbeam was higher than in sessile oak.
      Citation: Forests
      PubDate: 2017-08-24
      DOI: 10.3390/f8090308
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 309: Allometric Equations for Estimating
           Compartment Biomass and Stem Volume in Mature Hybrid Poplars: General or

    • Authors: Julien Fortier, Benoit Truax, Daniel Gagnon, France Lambert
      First page: 309
      Abstract: We evaluated the extent to which general or site-specific allometric equations, using diameter at breast height (DBH) as a predictor, are more accurate for estimating stem volume, stem biomass, branch biomass, aboveground woody biomass, and coarse root biomass in 14 year-old plantations of Populus canadensis × Populus maximowiczii (clone DN × M-915508) located along an environmental gradient in southern Québec (eastern Canada). The effect of tree size and site on stem wood basic density, moisture content, and proportion of branch biomass was also evaluated. For stem volume, stem biomass, and aboveground biomass, site-specific and general models had comparable fit and accuracy, but lower Akaike’s Information Criterion (AICc) values were observed for the general models. For the branch and coarse root biomass, higher fit and accuracy and lower AICc values were observed for the site-specific models. Allometric trajectory changes (plastic allometry) across sites were mainly observed for coarse root biomass, branch biomass, and stem volume. On the low fertility site, allocation was increased to coarse roots and decreased to stem volume. Site-specific tradeoffs between tree architecture and stem wood density explained the relatively invariant allometry for the whole aboveground woody biomass across the plantation sites. On the high fertility sites, basic wood density was the lowest and declined as tree DBH increased. At all sites, stem wood moisture content and the proportion of branch biomass increased with DBH. Overall, this study showed that biomass allometry, tree architecture, and biomass quality are a function of both tree size and plantation environment in hybrid poplar. Allometric model selection (site-specific or general) should depend on the objective pursued (evaluation of yield, nutrient budget, carbon stocks).
      Citation: Forests
      PubDate: 2017-08-24
      DOI: 10.3390/f8090309
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 310: The Effect of Silver and Copper Nanoparticles
           on the Condition of English Oak (Quercus robur L.) Seedlings in a
           Container Nursery Experiment

    • Authors: Jacek Olchowik, Roman Bzdyk, Marcin Studnicki, Magdalena Bederska-Błaszczyk, Alexander Urban, Marta Aleksandrowicz-Trzcińska
      First page: 310
      Abstract: Some studies indicate that metal nanoparticles can be used in plant cultivation as fungicides and growth stimulators. The aim of this study was to evaluate the effect of silver (AgNPs) and copper nanoparticles (CuNPs) on the growth parameters, on the extent of leaves infected by powdery mildew and on spontaneous ectomycorrhizal colonization of English oak (Quercus robur L.) seedlings growing in containers. Nanoparticles were applied to foliage four times during one vegetation season, at four concentrations: 0, 5, 25 and 50 ppm. The adsorption of NPs to leaves was observed by microscopical imaging (TEM). The tested concentrations of AgNPs and CuNPs did not have any significant effect on the growth parameters of the oak seedlings. TEM results showed disturbances in the shape of plastids, plastoglobules and the starch content of oak leaves treated with 50 ppm Cu- and AgNPs, while no changes in the ultrastructure of stems and roots of oak plants treated with NPs were observed. No significant difference in powdery mildew disease intensity was observed after NP foliar app lication. Four ectomycorrhizal taxa were detected on oak roots (Sphaerosporella brunnea, Thelephora terrestris, Paxillus involutus and Laccaria proxima). Oak seedlings treated (foliar) with CuNPs and AgNPs at 25 ppm were characterised by the highest degree of mycorrhization (respectively, 37.1% and 37.5%) among all treatments including the control treatment. None of the tested NPs manifested phytotoxicity in the examined Q. robur seedlings under container nursery conditions.
      Citation: Forests
      PubDate: 2017-08-25
      DOI: 10.3390/f8090310
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 311: Lianas Abundance is Positively Related with
           the Avian Acoustic Community in Tropical Dry Forests

    • Authors: Branko Hilje, Shauna Stack, Arturo Sánchez-Azofeifa
      First page: 311
      Abstract: Dry forests are important sources of biodiversity where lianas are highly abundant given their ability to grow during times of drought and as a result of secondary growth processes. Lianas provide food and shelter for fauna such as birds, but there are no studies assessing the influence of liana abundance on birds in dry forests. Here we evaluate the influence of liana abundance on the avian acoustic community in the dry forests of Costa Rica at Santa Rosa National Park. We selected forest sites with different levels of liana abundance and set up automated sound recorders for data collection, analysis and estimation of the avian acoustic community. When the number of lianas increases, the avian acoustic community becomes more complex. Lianas could provide important direct and indirect resources for birds such as structure for shelter, protection, nesting and roosting, and food. The positive relationship that lianas have with birds is particularly important in dry forests where lianas are becoming highly abundant due to the level of forest disturbance and climate change, especially for some bird species that are restricted to this ecosystem. By validating the number of bird species detected in the recordings with the acoustic complexity index, we found that a higher acoustic complexity means higher species richness.
      Citation: Forests
      PubDate: 2017-08-25
      DOI: 10.3390/f8090311
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 312: Effective Seed Dispersal and Fecundity
           Variation in a Small and Marginal Population of Pinus pinaster Ait.
           Growing in a Harsh Environment: Implications for Conservation of Forest
           Genetic Resources

    • Authors: Jesús Charco, Martin Venturas, Luis Gil, Nikos Nanos
      First page: 312
      Abstract: Small-size, relict and marginal tree-species populations are a priority for conservation of forest genetic resources. In-situ conservation of these populations relies on adequate forest management planning based on knowledge and understanding of both ecological (i.e., recruitment or dispersal dynamics) and population-genetic processes (i.e., female reproductive success, gene flow or inbreeding). Here, we estimate the fecundity (or female reproductive success) of adult trees (i.e., the number of successfully established offspring/adult tree) and the effective dispersal distance distribution in the pine forest of Fuencaliente (southern Spain), a small-sized, marginal and relict population of maritime pine growing on a steep, craggy hill with just 312 reproductively active individuals. Previous studies have shown the population to present reduced allelic richness and suffer from genetic introgression from nearby exotic plantations of unknown origin. Between 2003 and 2004, we surveyed all adults and recruits and we measured several adult-specific covariates, including the number of cones of all adults. The population was found to be distributed into two nuclei with 268 (Stand 1) and 44 adults (Stand 2). We used inverse modeling to adjust several dispersal-and-fecundity models including a model with random variation in fecundity among adults (Unrestricted Fecundity or UF model). Results show that: (i) the average fecundity is 2.5–3.2 recruits/adult; (ii) the mean effective dispersal distance is restricted to 13–24 m and (iii) fecundity is most likely controlled by the spatial location of adult trees in Stand ,1 but it should be considered randomly distributed in Stand 2 (in this stand five adults mothered 80% of recruits). We conclude that the low fecundity in Stand 1 and the unequal fecundity in Stand 2 may decrease the population genetic diversity and lead to lower effective population size while the low average dispersal distance may reduce the probability of this population expanding to adjacent areas. In light of the results, we define the management priorities for in-situ conservation of this population.
      Citation: Forests
      PubDate: 2017-08-26
      DOI: 10.3390/f8090312
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 313: Spatio-Temporal Linkages between Declining
           Arctic Sea-Ice Extent and Increasing Wildfire Activity in the Western
           United States

    • Authors: Paul Knapp, Peter Soulé
      First page: 313
      Abstract: We examined relationships between monthly Arctic sea-ice extent (ASIE) and annual wildfire activity for seven regions in the western United States during 1980–2015 to determine if spatio-temporal linkages exist between ASIE, upper-level flow, and surface climatic conditions conducive to western U.S. wildfire activity. Winter ASIE had significant (p < 0.05) negative relationships with annual wildfire area burned (rs = −0.391 − −0.683), with the strongest relationship occurring in the Northern Rockies. We explored spatial linkages between ASIE and 300-hPa flow (+), temperature (+), precipitation (−), and soil moisture (+) using monthly values of ASIE and gridded values for the climatic parameters. Relationships were best expressed between January ASIE and conditions in the current-year July over the Pacific Northwest and Northern Rockies. Reduced wintertime ASIE is teleconnected with increased ridging in summertime 300-hPa flow over the western U.S., resulting in warmer and drier conditions during peak fire season. Our findings suggest that reductions in ASIE are one of the driving forces behind the increasing annual trend (>36,000 ha) in area burned in the western U.S. since 1980.
      Citation: Forests
      PubDate: 2017-08-26
      DOI: 10.3390/f8090313
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 314: Seasonal Dynamics of Litterfall in a
           Sub-Alpine Spruce-Fir Forest on the Eastern Tibetan Plateau: Allometric
           Scaling Relationships Based on One Year of Observations

    • Authors: Changkun Fu, Wanqin Yang, Bo Tan, Zhenfeng Xu, Yu Zhang, Jiaping Yang, Xiangyin Ni, Fuzhong Wu
      First page: 314
      Abstract: Litterfall is the primary source of carbon and nutrients that determine soil fertility in forest ecosystems. Most current studies have focused on foliar litter, but the seasonal dynamics and allometric scaling relationships among different litter components (e.g., foliar litter, woody litter, reproductive litter, and epiphytic litter) are poorly understood. Here, we investigated the litter production of various litter components in a sub-alpine spruce-fir forest on the eastern Tibetan Plateau based on one year of observations (from August 2015 to July 2016). Our results showed that total litter production (LT) was 2380 kg·ha−1·year−1 (3% of the aboveground forest biomass), of which 73.6% was foliar litter (LF), 15.6% was woody litter (LW), 3.0% was reproductive litter (LR), 1.3% was epiphytic litter (LE), and 6.5% was miscellaneous material (LM). The total litterfall was bimodal (with peaks occurring in April and October) and was dominated by tree species (85.4% of LT, whereas shrubs accounted for 6.8% of LT). The litter production of evergreen species (68.4% of LT) was higher than that of deciduous species (23.8% of LT). Isometric relationships were observed between litter components and the total litter (i.e., LF∝LT0.99≈1 and LR∝LT0.98≈1), and allometric relationships were also found (i.e., LW∝LT1.40>1 and LM∝LT0.82<1). However, because some components did not exhibit obvious seasonal dynamics (i.e., LE), some relationships could not be expressed using allometric equations (i.e., LE versus LT, LF versus LE, LW versus LE, and LE versus LM). Thus, the different litter components showed different seasonal dynamics, and the total litter dynamics were primarily determined by the variation in foliar litter. In addition, the allometric relationships of the forest litterfall varied with the litter components, functional types (evergreen versus deciduous) and vertical structures (tree versus shrub). This study provides basic data and a new insight for future plant litter studies.
      Citation: Forests
      PubDate: 2017-08-26
      DOI: 10.3390/f8090314
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 315: Climate Response of Larch and Birch Forests
           across an Elevational Transect and Hemisphere-Wide Comparisons, Kamchatka
           Peninsula, Russian Far East

    • Authors: Clara Deck, Gregory Wiles, Sarah Frederick, Vladimir Matsovsky, Tatiana Kuderina, Rosanna D’Arrigo, Olga Solomina, Nicholas Wiesenberg
      First page: 315
      Abstract: Kamchatka’s forests span across the peninsula’s diverse topography and provide a wide range of physiographic and elevational settings that can be used to investigate how forests are responding to climate change and to anticipate future response. Birch (Betula ermanii Cham.) and larch (Larix gmelinii (Rupr.) Kuzen) were sampled at eight new sites and together with previous collections were compared with monthly temperature and precipitation records to identify their climate response. Comparisons show that tree-ring widths in both species are primarily influenced by May through August temperatures of the current growth year, and that there is a general increase in temperature sensitivity with altitude. The ring-width data for each species were also combined into regional chronologies. The resulting composite larch chronology shows a strong resemblance to a Northern Hemisphere (NH) tree-ring based temperature reconstruction with the larch series tracking NH temperatures closely through the past 300 years. The composite birch ring-width series more closely reflects the Pacific regional coastal late summer temperatures. These new data improve our understanding of the response of forests to climate and show the low frequency warming noted in other, more continental records from high latitudes of the Northern Hemisphere. Also evident in the ring-width record is that the larch and birch forests continue to track the strong warming of interior Kamchatka.
      Citation: Forests
      PubDate: 2017-08-27
      DOI: 10.3390/f8090315
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 316: Changes of Scots Pine Phyllosphere and Soil
           Fungal Communities during Outbreaks of Defoliating Insects

    • Authors: Lukas Beule, Maren Grüning, Petr Karlovsky, Anne l-M-Arnold
      First page: 316
      Abstract: Outbreaks of forest pests increase with climate change, and thereby may affect microbial communities and ecosystem functioning. We investigated the structure of phyllosphere and soil microbial communities during defoliation by the nun moth (Lymantria monacha L.) (80% defoliation) and the pine tree lappet (Dendrolimus pini L.) (50% defoliation) in Scots pine forests (Pinus sylvestris L.) in Germany. Ribosomal RNA genes of fungi and bacteria were amplified by polymerase chain reaction (PCR), separated by denaturing gradient gel electrophoresis (DGGE), and subsequently sequenced for taxonomic assignments. Defoliation by both pests changed the structure of the dominant fungal (but not bacterial) taxa of the phyllosphere and the soil. The highly abundant ectomycorrhizal fungal taxon (Russula sp.) in soils declined, which may be attributed to insufficient carbohydrate supply by the host trees and increased root mortality. In contrast, potentially pathogenic fungal taxa in the phyllosphere increased during pest outbreaks. Our results suggest that defoliation of pines by insect pest, change the structure of fungal communities, and thereby indirectly may be contributing to aggravation of tree health.
      Citation: Forests
      PubDate: 2017-08-28
      DOI: 10.3390/f8090316
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 317: Forest Structure and Composition Affect Bats
           in a Tropical Evergreen Broadleaf Forest

    • Authors: Emma Willcox, William Giuliano, Lauren Watine, Daniel Mills, Michael Andreu
      First page: 317
      Abstract: The lack of knowledge regarding many aerial insectivorous bats and their relationships with forest characteristics limits conservation decision-making for tropical rainforests and for this important bat group. Therefore, our objective was to understand the effects of forest structure and composition on these bats in the Neotropical evergreen broadleaf forest of Belize, Central America. We conducted bat monitoring and quantified 51 forest characteristics at 24 locations in the Chiquibul Forest Reserve (CFR) from May–July 2014. Simple linear and backward stepwise multiple regression analyses were used to examine relationships between bat richness and activity and forest characteristics. Bat genus richness and total activity were directly related to overstory canopy depth and inversely related to ≤4 structural characteristics. Lasiurus, Myotis, Promops, and Pteronotus spp. were affected by ≤7 forest characteristics; the responses were explained by preferences for less-cluttered, open space for flying and foraging and species-specific food and cover requirements. However, bat richness and activity were often unaffected by forest structure and composition in the CFR, suggesting that at this taxonomic level, bats may not be very sensitive to variation in forest characteristics, may not be very useful indicators of alteration, and may have some tolerance for disturbance and change.
      Citation: Forests
      PubDate: 2017-08-29
      DOI: 10.3390/f8090317
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 318: Susceptibility of Several Northeastern
           Conifers to Fusarium circinatum and Strategies for Biocontrol

    • Authors: Jorge Martín-García, Marius Paraschiv, Juan Flores-Pacheco, Danut Chira, Julio Diez, Mercedes Fernández
      First page: 318
      Abstract: Fusarium circinatum, the causal of pine pitch canker disease (PPC), is now considered among the most important pathogens of Pinaceae in the world. Although in Europe PPC is only established in the Iberian Peninsula, the potential endangered areas cover over 10 million hectares under the current host distribution and climatic conditions. It is therefore a priority to test the susceptibility of those species and their provenances, within Central and Northern Europe and find biological control agents (BCAs) against the disease. In this study, the susceptibility of Pinus sylvestris, P. mugo and Picea abies Romanian provenances to F. circinatum was tested using three inoculum doses. In parallel, the potential use of Trichoderma atroviride and Trichoderma viride as BCAs against F. circinatum was also tested. This study has demonstrated, for the first time, the susceptibility of P. mugo to F. circinatum. Likewise, the susceptibility of P. abies was also confirmed. The fact that the Romanian provenance of P. sylvestris has not been susceptible to F. circinatum suggests genetic resistance as a potential tool to manage the disease. This, together with the apparent effectiveness of Trichoderma species as BCAs, seems to indicate that an integrated management of the disease might be feasible.
      Citation: Forests
      PubDate: 2017-08-30
      DOI: 10.3390/f8090318
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 319: Improved Outbreak Prediction for Common Pine
           Sawfly (Diprion pini L.) by Analyzing Floating ‘Climatic Windows’ as
           Keys for Changes in Voltinism

    • Authors: Katrin Möller, Rainer Hentschel, Aline Wenning, Jens Schröder
      First page: 319
      Abstract: The biology and population dynamics of pine sawfly Diprion pini L. are extremely complex and variable. Among other factors, climatic conditions determine the potential for mass outbreaks of the species. In this paper, we investigate this influence and describe a statistical approach to identify responsible climatic variables in floating time windows, thus identifying the factors responsible for the transition from latency to outbreak events. Analyses were built upon a data base comprising outbreak events and fine-scaled climatic data for the period 2002–2016 for a model region in the state of Brandenburg, Germany. By applying Random Forest statistic classification analyses, we isolated a set of four variables. They cover precipitation, temperature, and potential evapotranspiration in distinct periods during the current and the previous year. These periods are not fixed in their position but attached to the floating phenological date of bud burst of the host species Pinus sylvestris L. The complete set of variables was able to distinguish forests likely to be defoliated from those not threatened at high probabilities (95% true-positive rate, 98% true-negative rate). Theidentified climatic windows offer insights into population dynamics in the study region, support adjustments in current monitoring algorithms, and indicate starting points for further investigations covering other regions or different years.
      Citation: Forests
      PubDate: 2017-08-30
      DOI: 10.3390/f8090319
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 320: Effects of the Antiozonant Ethylenediurea
           (EDU) on Fraxinus ornus L.: The Role of Drought

    • Authors: Elisabetta Salvatori, Lina Fusaro, Fausto Manes
      First page: 320
      Abstract: Ethylenediurea (EDU) is a synthetic chemical known to protect plants from the phytotoxic effects of tropospheric ozone (O3). Although many studies have proposed the use of EDU for studying the O3 effects under field conditions, its mechanism of action is not fully understood, and it is unclear whether it exerts a specific antiozonant action, or if it may also interact with other oxidative stresses. The aim of this work was to evaluate the effect of EDU on forest species in a Mediterranean environment where, during summer, vegetation is exposed to multiple oxidative stresses, such as O3 and drought. The experiment was conducted on Fraxinus ornus L. (Manna ash) plants growing in six mesocosms, three maintained under full irrigation, while the other three were subjected to drought for 84 days. In each mesocosm, three plants were sprayed every 15 days with 450 ppm EDU. Gas exchange and chlorophyll “a” fluorescence measurements carried out through the experimental period highlighted that EDU did not affect stomatal conductance and had an ameliorative effect on the functionality of drought-stressed plants, thus suggesting that it may act as a generic antioxidant. The implications of these findings for the applicability of EDU in field studies are discussed.
      Citation: Forests
      PubDate: 2017-08-30
      DOI: 10.3390/f8090320
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 321: Integrating Climate Change and Land Use
           Impacts to Explore Forest Conservation Policy

    • Authors: Hyeyeong Choe, James H. Thorne
      First page: 321
      Abstract: This study uses a scenario-based approach to ask what are the varying impacts to forest extent and biodiversity from sixteen climate change and forest conversion scenario combinations, and what do they suggest about future forest conservation policy directions' We projected these combinations onto existing forests in South Korea and grouped them into four forest categories. We used species distribution models for 1031 climate vulnerable plant species as a biodiversity index, and found that species richness loss due to forest conversion could be reduced significantly by deploying the scenarios which preserve forest areas that are climatically suitable for these species. Climate-suitable forest areas declined sharply and moved northward as future temperatures increase, and climate-suitable areas lost the highest proportion of forest extent under the current trend of forest conversion. We suggest climate refugia, defined as existing forests with suitable future climates, be protected from land use conversion as a way to preserve forest biodiversity. These spatially explicit results can be used for developing forest conservation policies, and the methods may be applicable to other forested regions. However, planners should consider the assumptions and uncertainties of climate projections, species distribution models, and land use trends when addressing forest biodiversity conservation.
      Citation: Forests
      PubDate: 2017-08-30
      DOI: 10.3390/f8090321
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 322: Prediction of Forest Canopy and Surface Fuels
           from Lidar and Satellite Time Series Data in a Bark Beetle-Affected Forest

    • Authors: Benjamin Bright, Andrew Hudak, Arjan Meddens, Todd Hawbaker, Jennifer Briggs, Robert Kennedy
      First page: 322
      Abstract: Wildfire behavior depends on the type, quantity, and condition of fuels, and the effect that bark beetle outbreaks have on fuels is a topic of current research and debate. Remote sensing can provide estimates of fuels across landscapes, although few studies have estimated surface fuels from remote sensing data. Here we predicted and mapped field-measured canopy and surface fuels from light detection and ranging (lidar) and Landsat time series explanatory variables via random forest (RF) modeling across a coniferous montane forest in Colorado, USA, which was affected by mountain pine beetles (Dendroctonus ponderosae Hopkins) approximately six years prior. We examined relationships between mapped fuels and the severity of tree mortality with correlation tests. RF models explained 59%, 48%, 35%, and 70% of the variation in available canopy fuel, canopy bulk density, canopy base height, and canopy height, respectively (percent root-mean-square error (%RMSE) = 12–54%). Surface fuels were predicted less accurately, with models explaining 24%, 28%, 32%, and 30% of the variation in litter and duff, 1 to 100-h, 1000-h, and total surface fuels, respectively (%RMSE = 37–98%). Fuel metrics were negatively correlated with the severity of tree mortality, except canopy base height, which increased with greater tree mortality. Our results showed how bark beetle-caused tree mortality significantly reduced canopy fuels in our study area. We demonstrated that lidar and Landsat time series data contain substantial information about canopy and surface fuels and can be used for large-scale efforts to monitor and map fuel loads for fire behavior modeling at a landscape scale.
      Citation: Forests
      PubDate: 2017-08-30
      DOI: 10.3390/f8090322
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 323: Differential Responses in Non-structural
           Carbohydrates of Machilus ichangensis Rehd. et Wils. and Taxus wallichiana
           Zucc. Var. chinensis (Pilg.) Florin Seedlings to Elevated Ozone

    • Authors: Jixin Cao, Zhan Chen, Hao Yu, He Shang
      First page: 323
      Abstract: Tropospheric ozone (O3) enrichment could change the carbon (C) metabolism and decrease the C stock for tree species. To assess the differences in response of non-structural carbohydrates (NSCs) between Machilus ichangensis Rehd. et Wils. (M. ichangensis) and Taxus wallichiana Zucc. var. chinensis (Pilg.) Florin (T. wallichiana) with elevated O3, one-year-old container seedlings of the two species were grown with ambient air (AA), 100 ppb (elevated O3 treatment 1, E1-O3), and 150 ppb (elevated O3 treatment 2, E2-O3) treatments using open top chambers. During the experiment, net photosynthetic rate (Pn) of M. ichangensis and T. wallichiana were examined once each month from April to October. At the end of experiment, plants were harvested to examine the NSC concentrations and tissue C stocks. Results suggest elevated O3 significantly decreased Pn and total C stock for both M. ichangensis and T. wallichiana, while it also significantly decreased the NSC concentrations in the foliage of the two species, and the roots of T. wallichiana. However, the concentrations of NSCs and their components in other tissues did not change obviously. Significant increases in the ratio of soluble sugars to starch were observed in the foliage of M. ichangensis and the roots of T. wallichiana. For M. ichangensis, Pn was significantly and positively correlated with NSCs and their components only in foliage. In contrast, NSCs in both foliage and roots were significantly and positively correlated with Pn for T. wallichiana. Based on the results for Pn, total C stock, and NSC concentrations, M. ichangensis appeared more sensitive to elevated O3 than T. wallichiana. It is suggested that the strategies of C allocation in the two species are different with elevated O3.
      Citation: Forests
      PubDate: 2017-08-31
      DOI: 10.3390/f8090323
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 324: Functional Response Trait Analysis Improves
           Climate Sensitivity Estimation in Beech Forests at a Trailing Edge

    • Authors: Éva Salamon-Albert, Gallusz Abaligeti, Adrienne Ortmann-Ajkai
      First page: 324
      Abstract: Functional response traits influence the ability of species to colonize and thrive in a habitat and to persist under environmental challenges. Functional traits can be used to evaluate environment-related processes and phenomena. They also help to interpret distribution patterns, especially under limiting ecological conditions. In this study, we investigate landscape-scale functional distribution responses of beech forests in a climatic transitional zone in Europe. We construct empirical density distribution responses for beech forests by applying coping-resilience-failure climatic traits based on 27 bioclimatic variables, resulting in prevalence-decay-exclusion distribution response patterns. We also perform multivariate exploratory cluster analysis to reveal significant sets of response patterns from the resilience and adaptation aspects. Temperature-related distribution responses presented a prevalence-dominated functional pattern, with Annual mean temperature indicating the most favorable adaptation function. Precipitation indices showed climate-limited response patterns with the dominance of extinction function. Considering regional site-specific climate change projections, these continental beech forests could regress moderately due to temperature increase in the near future. Our results also suggest that both summer and winter precipitation could play a pivotal role in successful resilience. Functions and variables that indicate climate sensitivity can serve as a useful starting point to develop adaptation measures for regional forest management.
      Citation: Forests
      PubDate: 2017-08-31
      DOI: 10.3390/f8090324
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 325: Effects of Cycle Length and Plot Density on
           Estimators for a National-Scale Forest Monitoring Sample Design

    • Authors: Francis Roesch, Todd Schroeder, James Vogt
      First page: 325
      Abstract: The resilience of a National Forest Inventory and Monitoring sample design can sometimes depend upon the degree to which it can adapt to fluctuations in funding. If a budget reduction necessitates the observation of fewer plots per year, some practitioners weigh the problem as a tradeoff between reducing the total number of plots and measuring the original number of plots over a greater number of years. Here, we explore some of the effects of differing plot intensities and cycle lengths on variants of three general classes of estimators for annual cubic meter per hectare volume, using a simulated population and appropriately-graduated sampling simulations. The simulations showed that an increase in cycle length yielded quite dramatic effects while differences due to a simulated reduction in plot intensity had more subtle effects.
      Citation: Forests
      PubDate: 2017-09-01
      DOI: 10.3390/f8090325
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 326: Development of Northern White-Cedar (Thuja
           occidentalis L.) Plantations within and outside Deer Yards

    • Authors: Olivier Villemaire-Côté, Jean-Claude Ruel, Luc Sirois
      First page: 326
      Abstract: Regional surveys done over the last decades show a clear decline in abundance of Northern white-cedar (Thuja occidentalis L.) throughout its range. A lack of seed trees, difficulties in the establishment of natural regeneration and high browsing pressure caused by increasing deer populations have been identified as plausible causes. Current silvicultural strategies for cedar restoration recommend partial cutting to promote and release natural regeneration, but there is also a need to restore the species in areas where it became absent. Yet, little attention has been given to cedar plantations. This study provides a first characterisation of the effects of competition, silvicultural treatments and deer, moose and hare browsing on planted cedar growth, survival, and stem form. Pure and mixed cedar plantations aged 5–27 years located in Eastern Québec were sampled. Both inside and outside deer yards, planted cedars showed high survival rates and were generally subject to low browsing pressure, but 45% were forked. Cedars showed high growth rates and strong reaction to stand opening. Results suggest that at reduced competition levels, a 9-year browser exclusion could be sufficient to establish safe-from-browsing cedar stands of >3 m in height.
      Citation: Forests
      PubDate: 2017-09-01
      DOI: 10.3390/f8090326
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 327: New Allometric Equations to Support
           Sustainable Plantation Management of Rosewood (Aniba rosaeodora Ducke) in
           the Central Amazon

    • Authors: Pedro Krainovic, Danilo Almeida, Paulo Sampaio
      First page: 327
      Abstract: Rosewood (Aniba rosaeodora Ducke) is an endangered Amazonian tree species which produces one of the most valuable essential oils in the world. The species is used in silvicultural systems which are seen as a means to reducing the pressure of exploitation of natural rosewood populations. There are no specific equations for rosewood plantations, and therefore generalized equations are inappropriate for the species in commercial systems. This study presents allometric equations from 144 trees sampled in different rosewood plantations of Central Amazonia. The equations generated were compared with an equation used in forest management to estimate wood volume and another one recommended by law for rosewood biomass. The equation suggested by current legislation underestimates the actual values by more than 70% making the viable use of this equation impossible in commercial plantations. The equations generated to estimate the volume and biomass serve as an alternative to the need to develop specific equations for each area and age of the plant. The generic equation for the species is consistent for fresh mass management, with a generalized R2 of 0.80 and an underestimation of 0.33%. The equation for crown fresh mass estimation presented a generalized R2 of 0.32 and an underestimation of 0.24%. The underestimation of the mass production by rosewood plantations represents a serious impediment to this forest activity. The allometric equations developed are highly applicable under different conditions and management options and should be suggested by the legal provisions regulating rosewood-related activity in Central Amazonia.
      Citation: Forests
      PubDate: 2017-09-04
      DOI: 10.3390/f8090327
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 328: Allometric Models to Predict Aboveground Woody
           Biomass of Black Locust (Robinia pseudoacacia L.) in Short Rotation
           Coppice in Previous Mining and Agricultural Areas in Germany

    • Authors: Christin Carl, Peter Biber, Dirk Landgraf, Allan Buras, Hans Pretzsch
      First page: 328
      Abstract: Black locust is a drought-resistant tree species with high biomass productivity during juvenility; it is able to thrive on wastelands, such as former brown coal fields and dry agricultural areas. However, research conducted on this species in such areas is limited. This paper aims to provide a basis for predicting tree woody biomass for black locust based on tree, competition, and site variables at 14 sites in northeast Germany that were previously utilized for mining or agriculture. The study areas, which are located in an area covering 320 km × 280 km, are characterized by a variety of climatic and soil conditions. Influential variables, including tree parameters, competition, and climatic parameters were considered. Allometric biomass models were employed. The findings show that the most important parameters are tree and competition variables. Different former land utilizations, such as mining or agriculture, as well as growth by cores or stumps, significantly influenced aboveground woody biomass production. The new biomass models developed as part of this study can be applied to calculate woody biomass production and carbon sequestration of Robinia pseudoacacia L. in short rotation coppices in previous mining and agricultural areas.
      Citation: Forests
      PubDate: 2017-09-07
      DOI: 10.3390/f8090328
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 329: Differentiating Structural and Compositional
           Attributes across Successional Stages in Chilean Temperate Rainforests

    • Authors: Diego Ponce, Pablo Donoso, Christian Salas-Eljatib
      First page: 329
      Abstract: The landscape in the lowlands of south-central Chile is dominated by agricultural lands and forestry plantations of exotic species. Natural forests are restricted to successional forests, while old-growth forests are nearly absent. The lack of old-growth forests may deprive society from some ecosystem services. Both successional and old forests differ in their ecological functions and in the ecosystem services they can provide. To promote old-growth characteristics in successional forests, it becomes necessary to know which compositional and structural attributes differentiate forests along succession. We aim at identifying the differential attributes among successional and old-growth forests in the lowlands in the northern portion of the Valdivian Rainforests. We analyzed 19 variables in seven different forests and found statistically significant differences in 13 of them. A subset of these variables illustrated major patterns that differentiate successional stages, of which a few could be more easily controlled through management. The latter include lowering tree densities (from >3000 to <1500 trees per hectare), increasing volume of large trees, especially of shade-tolerant species, and structural heterogeneity (a Gini coefficient >0.7 represents older forests). While successional forest show a rapid recovery, forest managers would need to focus in controlling these attributes to increase their old-growth characteristics.
      Citation: Forests
      PubDate: 2017-09-06
      DOI: 10.3390/f8090329
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 330: The Potential of Juniperus thurifera to
           Sequester Carbon in Semi-Arid Forest Soil in Spain

    • Authors: Elena Charro, Amelia Moyano, Raquel Cabezón
      First page: 330
      Abstract: The main purpose of this work is to show the influence of vegetation in the storage and stabilisation of organic carbon in semi-arid Juniperus thurifera (J. thurifera) forest soil in central Spain. The variability of the organic matter storage with factors such as sex, trunk diameter and the protection of the canopy of the tree has been analysed. The distribution of the soil organic carbon (SOC) into different fractions has also been determined, in order to estimate the stability of the organic matter. The results show that the SOC concentration has no dependence on the sex of the tree, but it increases with the diameter of the trunk and under the protection of the tree canopy. This study found that the organic matter of the J. thurifera forest soil has a high proportion of recalcitrant organic fraction, humin, which suggests that, given its organic matter stability, J. thurifera forest soils could be a real carbon sink. Consequently, the conservation of this type of old forest ecosystem is important for promoting carbon sequestration.
      Citation: Forests
      PubDate: 2017-09-06
      DOI: 10.3390/f8090330
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 331: Forestry Best Management Practices
           Relationships with Aquatic and Riparian Fauna: A Review

    • Authors: Brooke Warrington, W. Aust, Scott Barrett, W. Ford, C. Dolloff, Erik Schilling, T. Wigley, M. Bolding
      First page: 331
      Abstract: Forestry best management practices (BMPs) were developed to minimize water pollution from forestry operations by primarily addressing sediment and sediment transport, which is the leading source of pollution from silviculture. Implementation of water quality BMPs may also benefit riparian and aquatic wildlife, although wildlife benefits were not driving forces for BMP development. Therefore, we reviewed literature regarding potential contributions of sediment-reducing BMPs to conservation of riparian and aquatic wildlife, while realizing that BMPs also minimize thermal, nutrient, and chemical pollution. We reached five important conclusions: (1) a significant body of research confirms that forestry BMPs contribute to the protection of water quality and riparian forest structure; (2) data-specific relationships between forestry BMPs and reviewed species are limited; (3) forestry BMPs for forest road construction and maintenance, skid trails, stream crossings, and streamside management zones (SMZs) are important particularly for protection of water quality and aquatic species; (4) stream crossings should be carefully selected and installed to minimize sediment inputs and stream channel alterations; and (5) SMZs promote retention of older-age riparian habitat with benefits extending from water bodies to surrounding uplands. Overall, BMPs developed for protection of water quality should benefit a variety of riparian and aquatic species that are sensitive to changes in water quality or forest structure.
      Citation: Forests
      PubDate: 2017-09-07
      DOI: 10.3390/f8090331
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 332: Effects of Drought on Xylem Anatomy and
           Water-Use Efficiency of Two Co-Occurring Pine Species

    • Authors: Dario Martin-Benito, Kevin Anchukaitis, Michael Evans, Miren del Río, Hans Beeckman, Isabel Cañellas
      First page: 332
      Abstract: Exploring how drought influences growth, performance, and survival in different species is crucial to understanding the impacts of climate change on forest ecosystems. Here, we investigate the responses of two co-occurring pines (Pinus nigra and Pinus sylvestris) to interannual drought in east-central Spain by dendrochronological and wood anatomical features integrated with isotopic ratios of carbon (δ13C) and oxygen (δ18O) in tree rings. Our results showed that drought induces both species to allocate less carbon to build tracheid cell-walls but increases tracheid lumen diameters, particularly in the transition wood between early and latewood, potentially maximizing hydraulic conductivity but reducing resistance to embolism at a critical phase during the growing season. The thicker cell-wall-to-lumen ratio in P. nigra could imply that its xylem may be more resistant to bending stress and drought-induced cavitation than P. sylvestris. In contrast, the higher intrinsic water-use efficiency (iWUE) in P. sylvestris suggests that it relies more on a water-saving strategy. Our results suggest that narrower cell-walls and reduced growth under drought are not necessarily linked to increased iWUE. At our site P. nigra showed a higher growth plasticity, grew faster and was more competitive than P. sylvestris. In the long term, these sustained differences in iWUE and anatomical characters could affect forest species performance and composition, particularly under increased drought stress.
      Citation: Forests
      PubDate: 2017-09-08
      DOI: 10.3390/f8090332
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 333: Changes in Soil Quality and Hydrological
           Connectivity Caused by the Abandonment of Terraces in a Mediterranean
           Burned Catchment

    • Authors: Aleix Calsamiglia, Manuel Esteban Lucas-Borja, Josep Fortesa, Julián García-Comendador, Joan Estrany
      First page: 333
      Abstract: Wildfires and agricultural activities are relevant factors affecting soil quality, hydrological cycle and sedimentary dynamics. Land abandonment leads to afforestation, which increases fire risk and land degradation. However, no studies have yet evaluated the effect of combining the two factors, which occur frequently in Mediterranean ecosystems. This study assessed the changes in soil quality caused by the abandonment of terraces in two microcatchments (<2.5 ha) affected distinctly by wildfires (once and twice burned) and in an unburned control microcatchment by analyzing soil quality parameters, biochemical indices and spatial patterns of hydrological and sediment connectivity. Soil samples were collected in thirty-six plots (25 m2) representing terraced and non-terraced areas within these microcatchments. Unburned non-terraced plots had higher organic matter content and higher microbiological and enzymatic activities than other plots. Plots in abandoned terraces had lower soil quality indices, regardless of the fire effect. Land abandonment induced changes in the spatial patterns of hydrological connectivity, leading to concentrated runoff, enhanced erosion and soil degradation. Fire also negatively affected soil quality in both terraced and non-terraced plots. However, microbiological communities had different positive post-fire recovery strategies (growth and activity), depending on the previous soil conditions and land uses, which is indicative of the resilience of Mediterranean soil ecosystems.
      Citation: Forests
      PubDate: 2017-09-08
      DOI: 10.3390/f8090333
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 334: Climatic Factors Shape the Spatial
           Distribution of Concentrations of Triterpenoids in Barks of White Birch
           (Betula Platyphylla Suk.) Trees in Northeast China

    • Authors: Shenglei Guo, Dehui Zhang, Huanyong Wei, Yinan Zhao, Yibo Cao, Tao Yu, Yang Wang, Xiufeng Yan
      First page: 334
      Abstract: Betulin, betulinic acid and lupeol are naturally occurring pentacyclic triterpenoids with significant medicinal values. Great amounts of triterpenoids are found in the bark of white birch (Betula platyphylla Suk.) trees, which can be affected by climatic factors along the geographical gradients. In this study, site-based data of triterpenoids’ (betulin, betulinic acid and lupeol) concentrations were determined in barks of white birch trees from 48 sites in Northeast China. Triterpenoid concentration in white birch tree barks did not change in response to any geographical gradients along latitudes, longitudes or elevations. Instead, concentrations of betulin and lupeol in birch tree barks increased with the increase of temperature and precipitation but declined with the increase of relative humidity. As a result, betulin concentration was higher in birch trees in the northeastern and southwestern parts of the study area, and lower in the central part of the study area in Northeast China. Although betulinic acid concentration did not change with climatic factors, its distribution pattern was similar to betulin concentration. Lupeol concentration was highest in the north-eastern part and along the southern and eastern boundaries in the study area. Our results can supply information for precondition of triterpenoids’ extraction for industrial production, which can be an available approach to solve the issue of bark waste processing of white birch.
      Citation: Forests
      PubDate: 2017-09-10
      DOI: 10.3390/f8090334
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 335: The Impact of Assumed Uncertainty on Long-Term
           Decisions in Forest Spatial Harvest Scheduling as a Part of Sustainable

    • Authors: Jan Kašpar, Robert Hlavatý, Karel Kuželka, Róbert Marušák
      First page: 335
      Abstract: The paper shows how the aspects of uncertainty in spatial harvest scheduling can be embedded into a harvest optimization model. We introduce an approach based on robust optimization that secures better scheduling schematics of the decision maker while eliminating a significant portion of uncertainty in the decisions. The robust programming approach presented in this paper was applied in a real management area of Central Europe. The basic harvest scheduling model with harvest-flow constraints was created. The uncertainty that is assessed here is due to forest inventory errors and growth prediction errors of stand volume. The modelled results were compared with randomly simulated errors of stand volume. The effects of different levels of robustness and uncertainty on harvest-flow were analyzed. The analysis confirmed that using the robust approach for harvest decisions always ensures significantly better solutions in terms of the harvested volume than the worst-case scenarios created under the same constraints. The construction of a mathematical model as well as the methodology of simulations are described in detail. The observed results confirmed obvious advantages of robust optimization. However, many problems with its application in forest management must still be solved. This study helps to address the need to develop and explore methods for decision-making under different kinds of uncertainty in forest management.
      Citation: Forests
      PubDate: 2017-09-08
      DOI: 10.3390/f8090335
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 336: Tree Growth Rings in Tropical Peat Swamp
           Forests of Kalimantan, Indonesia

    • Authors: Martin Worbes, Hety Herawati, Christopher Martius
      First page: 336
      Abstract: Tree growth rings are signs of the seasonality of tree growth and indicate how tree productivity relates to environmental factors. We studied the periodicity of tree growth ring formation in seasonally inundated peatlands of Central Kalimantan (southern Borneo), Indonesia. We collected samples from 47 individuals encompassing 27 tree species. About 40% of these species form distinct growth zones, 30% form indistinct ones, and the others were classified as in between. Radiocarbon age datings of single distinct growth zones (or “rings”) of two species showing very distinct rings, Horsfieldia crassifolia and Diospyros evena, confirm annual growth periodicity for the former; the latter forms rings in intervals of more than one year. The differences can be explained with species-specific sensitivity to the variable intensity of dry periods. The anatomical feature behind annual rings in Horsfieldia is the formation of marginal parenchyma bands. Tree ring curves of other investigated species with the same anatomical feature from the site show a good congruence with the curves from H. crassifolia. They can therefore be used as indicator species for growth rate estimations in environments with weak seasonality. The investigated peatland species show low annual growth increments compared to other tropical forests.
      Citation: Forests
      PubDate: 2017-09-09
      DOI: 10.3390/f8090336
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 337: Vertical Ozone Gradients above Forests.
           Comparison of Different Calculation Options with Direct Ozone Measurements
           above a Mature Forest and Consequences for Ozone Risk Assessment

    • Authors: Giacomo Gerosa, Riccardo Marzuoli, Beatrice Monteleone, Maria Chiesa, Angelo Finco
      First page: 337
      Abstract: The estimation of the ozone (O3) stomatal dose absorbed by a forest is a crucial step for O3 risk assessment. For this purpose, data on O3 concentrations at the forest top-canopy are needed. However, O3 is barely measured at that height, while more often it is measured at a lower height above a different surface, typically a grassland near to the forest edge. The DO3SE model for O3 stomatal flux calculation estimates the top-canopy O3 concentration in near neutral stability conditions. However, near-neutrality is quite rare in the field, particularly in southern Europe. In this work, we present a modification of the DO3SE gradient calculation scheme to include the atmospheric stability. The performance of the new calculation scheme was tested against the direct measurements above a mature forest. Different gradient estimation options were also tested and evaluated. These options include simplified gradient calculation schemes and the techniques of the tabulated gradients described in the UN/ECE Mapping Manual for O3 risk assessment. The results highlight that the inclusion of the atmospheric stability in the DO3SE model greatly improves the accuracy of the stomatal dose estimation. However, the simpler technique of the tabulated gradients had the best performance on a whole-season time frame.
      Citation: Forests
      PubDate: 2017-09-09
      DOI: 10.3390/f8090337
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 338: Updating Bark Proportions for the Estimation
           of Tropical Timber Volumes by Indigenous Community-Based Forest
           Enterprises in Quintana Roo, Mexico

    • Authors: Julieta Rosell, Christian Wehenkel, Abraham Pérez-Martínez, José Arreola Palacios, Sandra García-Jácome, Marcela Olguín
      First page: 338
      Abstract: Sustainable management of tropical forests is essential for conserving the ecosystem services they provide and protecting the livelihoods of the millions of people who depend on these forests. Community-based forest management in Quintana Roo, Mexico, has shown that conserving forests while generating economic benefits is achievable in the tropics. However, this management is carried out with technical gaps that jeopardize sustainable use of these resources. Crucial among these gaps is a lack of equations for precise calculations of logged timber volumes. Current equations employ a proportion of bark volume (PBV) of 0.14 for mahogany and a flat 0.10 for species with dense woods, despite their wide variation in bark thickness. Here, using Meyer’s method, we calculated species-specific PBVs for the most commercially-important species in the Felipe Carrillo Puerto community-based logging operation. For most species, the new PBVs were smaller, indicating that wood volumes are currently underestimated. However, for two species, PBVs were higher. New values could influence the profits of the local enterprise and on the management of some of the most commercially-important species of Mexico’s tropical forests through changes in the numbers of individuals felled.
      Citation: Forests
      PubDate: 2017-09-10
      DOI: 10.3390/f8090338
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 339: Traits and Resource Use of Co-Occurring
           Introduced and Native Trees in a Tropical Novel Forest

    • Authors: Jéssica Fonseca da Silva, Ernesto Medina, Ariel Lugo
      First page: 339
      Abstract: Novel forests are naturally regenerating forests that have established on degraded lands and have a species composition strongly influenced by introduced species. We studied ecophysiological traits of an introduced species (Castilla elastica Sessé) and several native species growing side by side in novel forests dominated by C. elastica in Puerto Rico. We hypothesized that C. elastica has higher photosynthetic capacity and makes more efficient use of resources than co-occurring native species. Using light response curves, we found that the photosynthetic capacity of C. elastica is similar to that of native species, and that different parameters of the curves reflected mostly sun light variation across the forest strata. However, photosynthetic nitrogen use-efficiency as well as leaf area/mass ratios were higher for C. elastica, and both the amount of C and N per unit area were lower, highlighting the different ecological strategies of the introduced and native plants. Presumably, those traits support C. elastica’s dominance over native plants in the study area. We provide empirical data on the ecophysiology of co-occurring plants in a novel forest, and show evidence that different resource-investment strategies co-occur in this type of ecosystem.
      Citation: Forests
      PubDate: 2017-09-12
      DOI: 10.3390/f8090339
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 340: Individual Tree Detection from Unmanned Aerial
           Vehicle (UAV) Derived Canopy Height Model in an Open Canopy Mixed Conifer

    • Authors: Midhun Mohan, Carlos Silva, Carine Klauberg, Prahlad Jat, Glenn Catts, Adrián Cardil, Andrew Hudak, Mahendra Dia
      First page: 340
      Abstract: Advances in Unmanned Aerial Vehicle (UAV) technology and data processing capabilities have made it feasible to obtain high-resolution imagery and three dimensional (3D) data which can be used for forest monitoring and assessing tree attributes. This study evaluates the applicability of low consumer grade cameras attached to UAVs and structure-from-motion (SfM) algorithm for automatic individual tree detection (ITD) using a local-maxima based algorithm on UAV-derived Canopy Height Models (CHMs). This study was conducted in a private forest at Cache Creek located east of Jackson city, Wyoming. Based on the UAV-imagery, we allocated 30 field plots of 20 m × 20 m. For each plot, the number of trees was counted manually using the UAV-derived orthomosaic for reference. A total of 367 reference trees were counted as part of this study and the algorithm detected 312 trees resulting in an accuracy higher than 85% (F-score of 0.86). Overall, the algorithm missed 55 trees (omission errors), and falsely detected 46 trees (commission errors) resulting in a total count of 358 trees. We further determined the impact of fixed tree window sizes (FWS) and fixed smoothing window sizes (SWS) on the ITD accuracy, and detected an inverse relationship between tree density and FWS. From our results, it can be concluded that ITD can be performed with an acceptable accuracy (F > 0.80) from UAV-derived CHMs in an open canopy forest, and has the potential to supplement future research directed towards estimation of above ground biomass and stem volume from UAV-imagery.
      Citation: Forests
      PubDate: 2017-09-11
      DOI: 10.3390/f8090340
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 341: Excessive Accumulation of Chinese Fir Litter
           Inhibits Its Own Seedling Emergence and Early Growth—A Greenhouse

    • Authors: Bo Liu, Stefani Daryanto, Lixin Wang, Yanjuan Li, Qingqing Liu, Chong Zhao, Zhengning Wang
      First page: 341
      Abstract: Litter accumulation can strongly influence plants’ natural regeneration via both physical and chemical mechanisms, but the relative influence of each mechanism on seedling establishment remains to be elucidated. Chinese fir (Cunninghamia lanceolata) is one of the most important commercial plantations in southern China, but its natural regeneration is poor, possibly due to its thick leaf litter accumulation. We used natural and plastic litter to study the effects of Chinese fir litter on its own seedling emergence and early growth, as well as to assess whether the effect is physical or chemical in nature. Results showed that high litter amount (800 g·m−2) significantly reduced seedling emergence and the survival rate for both natural and plastic litter. Low litter amount (200 g·m−2) exerted a slightly positive effect on root mass, leaf mass, and total mass, while high litter amount significantly inhibited root mass, leaf mass, and total mass for both natural and plastic litter. Root-mass ratio was significantly lower, and leaf-mass ratio was significantly greater under high litter cover than under control for both natural and plastic litter. Although the root/shoot ratio decreased with increasing litter amount, such effect was only significant for high litter treatment for both natural and plastic litter. Seedling robustness (aboveground biomass divided by seedling height) decreased with increasing litter amount, with high litter treatment generating the least robust seedlings. Because plastic and natural litter did not differ in their effects on seedling emergence and growth, the litter layer’s short-term influence is primarily physical. These data indicated that as litter cover increased, the initial slightly positive effects on seedling emergence and early growth could shift to inhibitory effects. Furthermore, to penetrate the thick litter layer, Chinese fir seedlings allocated more resources towards stems and aboveground growth at the expense of their roots. This study provided experimental evidence of litter amount as a key ecological factor affecting seedling development and subsequent natural regeneration of Chinese fir.
      Citation: Forests
      PubDate: 2017-09-11
      DOI: 10.3390/f8090341
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 342: Proximate Causes of Land-Use and Land-Cover
           Change in Bannerghatta National Park: A Spatial Statistical Model

    • Authors: Sanchayeeta Adhikari, Timothy Fik, Puneet Dwivedi
      First page: 342
      Abstract: Land change modeling has become increasingly important in evaluating the unique driving factors and proximate causes that underlie a particular geographical location. In this article, a binary logistic regression analysis was employed to identify the factors influencing deforestation and simultaneous plantation driven reforestation in Bannerghatta National Park, located at the periphery of one of the fastest growing cities in India, i.e., Bangalore. Methodologically, this study explores the inclusion of different sub-regions and statistical population to address spatial autocorrelation in land change modeling. The results show negative relationship between deforestation and protected area status and edge of previous forest clearing. In addition, the deforestation models found differences in the processes that are affecting forest clearing in our two sub-periods of 1973–1992 and 1992–2007. The plantation driven reforestation in the region were attributed to distance to major towns, Bangalore city, rural centers and major and minor roads suggesting the importance of accessibility to market for heavy cash crops such as coconut palm and eucalyptus. Finally, the inclusion of different sub-regions and statistical population facilitated a better understanding of varying driving factors in different zones within the overall landscape.
      Citation: Forests
      PubDate: 2017-09-12
      DOI: 10.3390/f8090342
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 343: Forest Structure Estimation from a UAV-Based
           Photogrammetric Point Cloud in Managed Temperate Coniferous Forests

    • Authors: Tetsuji Ota, Miyuki Ogawa, Nobuya Mizoue, Keiko Fukumoto, Shigejiro Yoshida
      First page: 343
      Abstract: Here, we investigated the capabilities of a lightweight unmanned aerial vehicle (UAV) photogrammetric point cloud for estimating forest biophysical properties in managed temperate coniferous forests in Japan, and the importance of spectral information for the estimation. We estimated four biophysical properties: stand volume (V), Lorey’s mean height (HL), mean height (HA), and max height (HM). We developed three independent variable sets, which included a height variable, a spectral variable, and a combined height and spectral variable. The addition of a dominant tree type to the above data sets was also tested. The model including a height variable and dominant tree type was the best for all biophysical property estimations. The root-mean-square errors (RMSEs) for the best model for V, HL, HA, and HM, were 118.30, 1.13, 1.24, and 1.24, respectively. The model including a height variable alone yielded the second highest accuracy. The respective RMSEs were 131.74, 1.21, 1.31, and 1.32. The model including a spectral variable alone yielded much lower estimation accuracy than that including a height variable. Thus, a lightweight UAV photogrammetric point cloud could accurately estimate forest biophysical properties, and a spectral variable was not necessarily required for the estimation. The dominant tree type improved estimation accuracy.
      Citation: Forests
      PubDate: 2017-09-13
      DOI: 10.3390/f8090343
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 344: Relationships between Plant Species Richness
           and Terrain in Middle Sub-Tropical Eastern China

    • Authors: Chuangye Song, Mingchang Cao
      First page: 344
      Abstract: The objective of this research was to study the relation between species richness and topography in the middle sub-tropical area of Eastern China. A species richness survey was conducted along altitude in Kaihua County, Zhejiang Province, Eastern China. Topographic variables, such as altitude, slope, aspect, terrain roughness, relief degree and the topographical wetness index, were extracted from the digital elevation model. The Generalized Additive Model (GAM), the linear model and the quadratic model were used to fit response curves of species richness to topographic variables. The results indicated that altitude and the topographical wetness index have a significant relation to species richness. Species richness has a unimodal response to altitude and a linear response to the topographical wetness index. However, no significant correlations were observed between slope, aspect and species richness. The predicted species richness by GAM is significantly correlated with the observed species richness, whereas the prediction error tends to increase with the increment of species richness. This study furthered insights into the relationship between topography and plants’ diversity in the middle sub-tropical area of Eastern China.
      Citation: Forests
      PubDate: 2017-09-14
      DOI: 10.3390/f8090344
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 345: Towards a Theoretical Construct for Modelling
           Smallholders’ Forestland-Use Decisions: What Can We Learn from
           Agriculture and Forest Economics'

    • Authors: Kahlil Baker, Gary Bull, Kathy Baylis, Richard Barichello
      First page: 345
      Abstract: Academic research on smallholders’ forestland-use decisions is regularly addressed in different streams of literature using different theoretical constructs that are independently incomplete. In this article, we propose a theoretical construct for modelling smallholders’ forestland-use decisions intended to serve in the guidance and operationalization of future models for quantitative analysis. Our construct is inspired by the sub-disciplines of forestry and agricultural economics with a crosscutting theme of how transaction costs drive separability between consumption and production decisions. Our results help explain why exogenous variables proposed in the existing literature are insufficient at explaining smallholders’ forestland-use decisions, and provide theoretical context for endogenizing characteristics of the household, farm and landscape. Smallholders’ forestland-use decisions are best understood in an agricultural context of competing uses for household assets and interdependent consumption and production decisions. Forest production strategies range from natural regeneration to intensive management of the forest resource to co-jointly produce market and non-market values. Due to transaction costs, decision prices are best represented by their shadow as opposed to market prices. Shadow prices are shaped by endogenous smallholder-specific preferences for leisure, non-market values, time, risk, and uncertainty. Our proposed construct is intended to provide a theoretical basis to assist modellers in the selection of variables for quantitative analysis.
      Citation: Forests
      PubDate: 2017-09-14
      DOI: 10.3390/f8090345
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 346: Patterns of Early Postfire Succession of
           Alpine, Subalpine and Lichen-Woodland Vegetation: 21 Years of Monitoring
           from Permanent Plots

    • Authors: François Girard, Serge Payette, Ann Delwaide
      First page: 346
      Abstract: Field observations using chronosequences are helpful to study vegetation succession. This method allows to establish comparisons based on soil composition, stand structure, micro- and macrofossil remains from sites of different ages but on similar edaphic and topographic conditions. In the boreal forest, post-fire succession through time is triggered by climate, disturbance history (insect epidemics, fire and logging), latitude and altitude. The main objective of this research is to identify the main patterns of early post-fire succession, including similarities and differences in vegetation composition and attributes, of three contrasted ecosystems distributed along an altitudinal gradient. To do so, we have monitored the successional development of the alpine, subalpine and boreal lichen-woodland sites during the first 21 years (1991 to 2011) of post-fire sequence in eastern Canada 1991 to 2011. Each site was characterized by a different functional group that became established following fire. A rapid resurgence of ericaceous shrubs and lichens was observed in the lichen woodland and subalpine sites. Bryophyte and lichen species were not an important component of vegetation communities during the earlier stages of post-fire succession. For all three sites monitored, lichens were the last functional group to establish in the chronosequences. Herbs and mosses characterized the post-fire succession in alpine areas, the latter functional group established late in the chronosequence to cover >25% of the site after 15 years. Post-fire chronosequences in the three contrasted environments indicate that plant succession is a repetitive process often involving similar resilient plant assemblages.
      Citation: Forests
      PubDate: 2017-09-15
      DOI: 10.3390/f8090346
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 347: Rapid Shifts in Soil Nutrients and
           Decomposition Enzyme Activity in Early Succession Following Forest Fire

    • Authors: Joseph Knelman, Emily Graham, Scott Ferrenberg, Aurélien Lecoeuvre, Amanda Labrado, John Darcy, Diana Nemergut, Steven Schmidt
      First page: 347
      Abstract: While past research has studied forest succession on decadal timescales, ecosystem responses to rapid shifts in nutrient dynamics within the first months to years of succession after fire (e.g., carbon (C) burn-off, a pulse in inorganic nitrogen (N), accumulation of organic matter, etc.) have been less well documented. This work reveals how rapid shifts in nutrient availability associated with fire disturbance may drive changes in soil enzyme activity on short timescales in forest secondary succession. In this study, we evaluate soil chemistry and decomposition extracellular enzyme activity (EEA) across time to determine whether rapid shifts in nutrient availability (1–29 months after fire) might control microbial enzyme activity. We found that, with advancing succession, soil nutrients correlate with C-targeting β-1,4-glucosidase (BG) EEA four months after the fire, and with N-targeting β-1,4-N-acetylglucosaminidase (NAG) EEA at 29 months after the fire, indicating shifting nutrient limitation and decomposition dynamics. We also observed increases in BG:NAG ratios over 29 months in these recently burned soils, suggesting relative increases in microbial activity around C-cycling and C-acquisition. These successional dynamics were unique from seasonal changes we observed in unburned, forested reference soils. Our work demonstrates how EEA may shift even within the first months to years of ecosystem succession alongside common patterns of post-fire nutrient availability. Thus, this work emphasizes that nutrient dynamics in the earliest stages of forest secondary succession are important for understanding rates of C and N cycling and ecosystem development.
      Citation: Forests
      PubDate: 2017-09-15
      DOI: 10.3390/f8090347
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 348: Long Non-Coding RNAs Responsive to Witches’
           Broom Disease in Paulownia tomentosa

    • Authors: Zhe Wang, Xiaoqiao Zhai, Yabing Cao, Yanpeng Dong, Guoqiang Fan
      First page: 348
      Abstract: Paulownia witches’ broom (PaWB) disease caused by phytoplasmas is a fatal disease that leads to considerable economic losses. Long non-coding RNAs (lncRNAs) have been demonstrated to play critical regulatory roles in posttranscriptional and transcriptional regulation. However, lncRNAs and their functional roles remain poorly characterized in Paulownia. To identify lncRNAs and investigate their roles in the response to PaWB phytoplasmas, RNA sequencing was performed for healthy Paulownia tomentosa, PaWB-infected P. tomentosa, and for healthy and PaWB-infected P. tomentosa treated with 100 mg L−1 rifampicin. A total of 28,614 unique mRNAs and 3693 potential lncRNAs were identified. Comparisons between lncRNAs and coding genes indicated that lncRNAs tended to have shorter transcripts and fewer exon numbers, and displayed significant expression specificity. Based on our comparison scheme, 1063 PaWB-related mRNAs and 110 PaWB-related lncRNAs were identified; among them, 12 PaWB-related candidate target genes that were regulated by nine PaWB-related lncRNAs were characterized. This study provides the first catalog of lncRNAs expressed in Paulownia and gives a revealing insight into the molecular mechanism responsible for PaWB.
      Citation: Forests
      PubDate: 2017-09-15
      DOI: 10.3390/f8090348
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 349: Structure and Composition of a Dry
           Mixed-Conifer Forest in Absence of Contemporary Treatments, Southwest, USA

    • Authors: Douglas Cram, Pradip Saud, Terrell Baker
      First page: 349
      Abstract: Dry mixed-conifer forests in the Southwest occupy an important ecological and hydrological role in upper watersheds. In the absence of reoccurring fire and silvicultural treatments over the last 50 years, we quantified forest structure and composition on prevailing north and south aspects of a dry mixed-conifer forest in southcentral New Mexico using mixed models and ordination analysis in preparation for an experiment in ecological restoration. Results indicated overstory and midstory were dominated by Douglas-fir (Pseudotsuga menziesii) and shade tolerant/fire intolerant white fir (Abies concolor) with interspersed mature aspen on north aspects, and Douglas-fir and Southwestern white pine (Pinus strobiformis) on south aspects. Ponderosa pine (Pinus ponderosa), which was historically co-dominant with Douglas-fir on north and south aspects, was subdominant on south aspects and almost entirely absent on north aspects. Regeneration was dominated by white fir saplings and seedlings on north aspects while ponderosa pine was completely absent. South aspect saplings and seedlings were characterized by Douglas-fir and Southwestern white pine, but almost no ponderosa pine. Ordination analysis characterized the effect of aspect on species composition. Understanding contemporary forest structure and composition is important when planning for desired future conditions that are to be achieved through ecological restoration using silvicultural techniques designed to foster resilience.
      Citation: Forests
      PubDate: 2017-09-16
      DOI: 10.3390/f8090349
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 350: How Reliable Are Heat Pulse Velocity Methods
           for Estimating Tree Transpiration'

    • Authors: Michael Forster
      First page: 350
      Abstract: Transpiration is a significant component of the hydrologic cycle and its accurate quantification is critical for modelling, industry, and policy decisions. Sap flow sensors provide a low cost and practical method to measure transpiration. Various methods to measure sap flow are available and a popular family of methods is known as heat pulse velocity (HPV). Theory on thermal conductance and convection, that underpins HPV methods, suggests transpiration can be directly estimated from sensor measurements without the need for laborious calibrations. To test this accuracy, transpiration estimated from HPV sensors is compared with an independent measure of plant water use such as a weighing lysimeter. A meta-analysis of the literature that explicitly tested the accuracy of a HPV sensors against an independent measure of transpiration was conducted. Data from linear regression analysis was collated where an R2 of 1 indicates perfect precision and a slope of 1 of the linear regression curve indicates perfect accuracy. The average R2 and slope from all studies was 0.822 and 0.860, respectively. However, the overall error, or deviation from real transpiration values, was 34.706%. The results indicate that HPV sensors are precise in correlating heat velocity with rates of transpiration, but poor in quantifying transpiration. Various sources of error in converting heat velocity into sap velocity and sap flow are discussed including probe misalignment, wound corrections, thermal diffusivity, stem water content, placement of sensors in sapwood, and scaling of point measurements to whole plants. Where whole plant water use or transpiration is required in a study, it is recommended that all sap flow sensors are calibrated against an independent measure of transpiration.
      Citation: Forests
      PubDate: 2017-09-18
      DOI: 10.3390/f8090350
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 351: Revisiting Wildland Fire Fuel Quantification
           Methods: The Challenge of Understanding a Dynamic, Biotic Entity

    • Authors: Thomas Duff, Robert Keane, Trent Penman, Kevin Tolhurst
      First page: 351
      Abstract: Wildland fires are a function of properties of the fuels that sustain them. These fuels are themselves a function of vegetation, and share the complexity and dynamics of natural systems. Worldwide, the requirement for solutions to the threat of fire to human values has resulted in the development of systems for predicting fire behaviour. To date, regional differences in vegetation and independent fire model development has resulted a variety of approaches being used to describe, measure and map fuels. As a result, widely different systems have been adopted, resulting in incompatibilities that pose challenges to applying research findings and fire models outside their development domains. As combustion is a fundamental process, the same relationships between fuel and fire behaviour occur universally. Consequently, there is potential for developing novel fuel assessment methods that are more broadly applicable and allow fire research to be leveraged worldwide. Such a movement would require broad cooperation between researchers and would most likely necessitate a focus on universal properties of fuel. However, to truly understand fuel dynamics, the complex biotic nature of fuel would also need to remain a consideration—particularly when looking to understand the effects of altered fire regimes or changing climate.
      Citation: Forests
      PubDate: 2017-09-18
      DOI: 10.3390/f8090351
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 352: Environmental Performance of Eastern Canadian
           Wood Pellets as Measured Through Life Cycle Assessment

    • Authors: Alejandro Padilla-Rivera, Julie Barrette, Pierre Blanchet, Evelyne Thiffault
      First page: 352
      Abstract: Global demand for renewable energy has increased drastically over the last decade due to new climate change policies implemented in many jurisdictions. Wood pellets made from primary wood processing mill residues represent an attractive source of renewable energy that can be used in the environmental global challenge. However, the environmental impacts involved in their manufacture must be considered to measure the real benefits they can provide to the atmosphere. The general aim of this study was to evaluate the environmental impacts of wood pellet production at two Quebec plants using the Life Cycle Assessment (LCA) methodology and considering a gate-to-gate approach. The paper focuses on the different stages involved in wood pellet production; from the recovery of mill residues, through the pelletization process, to pellet bagging. The paper further expands to a cradle-to-grave analysis comparing the environmental footprints of producing and combusting 1 GJ of energy from wood pellets, natural gas and fossil fuel oil. The analysis suggested that the drying and the pelletizing stages were the largest negative factors affecting the environmental performance of wood pellet production. The comparison demonstrated the environmental advantage of using renewable rather than fossil sources of energy. Considering the growing interest in renewable energy, biomass in particular, and the lack of environmental information on wood pellets, this study could be useful not only for forest sector-related industries but also for the energy sector and policymakers.
      Citation: Forests
      PubDate: 2017-09-19
      DOI: 10.3390/f8090352
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 353: Direct Seeding of Pinus halepensis Mill. for
           Recovery of Burned Semi-Arid Forests: Implications for Post-Fire
           Management for Improving Natural Regeneration

    • Authors: Francisco García-Morote, Eduardo Martínez-García, Manuela Andrés-Abellán, Eva Caballero, Heli Miettinen, Francisco López-Serrano
      First page: 353
      Abstract: Background: In order to maximize the resiliency of Pinus halepensis in semiarid forests, we analyzed direct seeding methods to recover burned stands by simulating post-fire soil treatments. Methods: Seeding was done by installing spot seeding (100 seeds in a 50 × 50 cm plot), using five methods: (1) covering seeding with wood chips; (2) seeding in branch piles; (3) seeding along trunks on contour-felled logs (on the shaded side); (4) seeding next to grass (Stipa tenacissima); and (5) seeding on the bare ground (control). The experiment was replicated according to aspect (northern and southern aspects). The response variables were seed germination (%), and seedling survival after the summer (measured in autumn 2015 and 2016). Direct seeding was carried out in 32 plots with 160-spot seeding, and data were analyzed using general linear models, including nested random effects. Results: Wood chips as a surface-covering material represented the only treatment that significantly improved seed germination and seedling survival (by 12.4%, and 17.4 seedlings m−2 in year 2, respectively) compared with the control in the two topographic aspects. Conclusions: Covering seeding with wood chips, and thus chipping wood within the burned stand, form a recommended post-fire treatment to improve regeneration in Pinus halepensis semiarid stands.
      Citation: Forests
      PubDate: 2017-09-20
      DOI: 10.3390/f8090353
      Issue No: Vol. 8, No. 9 (2017)
  • Forests, Vol. 8, Pages 292: Differential Effects of Coarse Woody Debris on
           Microbial and Soil Properties in Pinus densiflora Sieb. et Zucc. Forests

    • Authors: Seongjun Kim, Guanlin Li, Seung Hyun Han, Hanna Chang, Hyun-Jun Kim, Yowhan Son
      First page: 292
      Abstract: Although coarse woody debris (CWD) is important for soil functioning, the mechanism which affects soil properties beneath CWD are unclear. Here, initial changes in microbial and soil properties were studied using homogenous CWD samples in eight Korean red pine (Pinus densiflora Sieb. et Zucc.) forests. For each forest, CWD samples (diameter: 11.1 ± 0.1 cm; length: 10.2 ± 0.0 cm) from similarly aged Korean red pine trees were laid on the mineral soil surface from May to June, 2016, and soils were sampled at points beneath CWD and at a distance of 1 m from the CWD after 1 year. Soils beneath the CWD had higher moisture but lower inorganic nitrogen (N) and a higher microbial biomass C (carbon)/N ratio than those sampled 1 m from the CWD. No differences in total C and N, labile C, pH, and C substrate utilization between the soils were significant. The difference in inorganic N between the soils decreased with increasing CWD decomposition, whereas that for microbial biomass fraction in total C and N increased correspondingly. Our results showed that soil microbial affinity for retaining N might become higher than that for retaining C under the presence of CWD, which possibly alters N availability and generates a spatial heterogeneity in forest soils.
      Citation: Forests
      PubDate: 2017-08-11
      DOI: 10.3390/f8080292
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 293: Environmental Factors Driving the Recovery of
           Bay Laurels from Phytophthora ramorum Infections: An Application of
           Numerical Ecology to Citizen Science

    • Authors: Guglielmo Lione, Paolo Gonthier, Matteo Garbelotto
      First page: 293
      Abstract: Phytophthora ramorum is an alien and invasive plant pathogen threatening forest ecosystems in Western North America, where it can cause both lethal and non-lethal diseases. While the mechanisms underlying the establishment and spread of P. ramorum have been elucidated, this is the first attempt to investigate the environmental factors driving the recovery of bay laurel, the main transmissive host of the pathogen. Based on a large dataset gathered from a citizen science program, an algorithm was designed, tested, and run to detect and geolocate recovered trees. Approximately 32% of infected bay laurels recovered in the time period between 2005 and 2015. Monte Carlo simulations pointed out the robustness of such estimates, and the algorithm achieved an 85% average rate of correct classification. The association between recovery and climatic, topographic, and ecological factors was assessed through a numerical ecology approach mostly based on binary logistic regressions. Significant (p < 0.05) coefficients and the information criteria of the models showed that the probability of bay laurel recovery increases in association with high temperatures and low precipitation levels, mostly in flat areas. Results suggest that aridity might be a key driver boosting the recovery of bay laurels from P. ramorum infections.
      Citation: Forests
      PubDate: 2017-08-13
      DOI: 10.3390/f8080293
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 295: A Review of Carbon Forest Development in China

    • Authors: Wei Zhou, Peichen Gong, Lan Gao
      First page: 295
      Abstract: This paper provides an overview of China’s climate mitigation policy related to the forestry sector, with a special focus on the development of carbon forests which are established to mitigate climate change. A total of 3.5 million ha of carbon forest were planted in the past decade. In recent years, the number of Voluntary Emission Reduction forest carbon projects has increased rapidly. The main challenges for future development of carbon forests under market mechanisms include increasing costs, uncertainty in the future supply and demand for China-certified emission reduction, and potential disputes between households and project developers.
      Citation: Forests
      PubDate: 2017-08-13
      DOI: 10.3390/f8080295
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 296: Air Curtain Burners: A Tool for Disposal of
           Forest Residues

    • Authors: Eunjai Lee, Han-Sup Han
      First page: 296
      Abstract: Open pile burning (OPB) forest residues have been limited due to several concerns, including atmospheric pollution, risk of fire spread, and weather conditions restrictions. Air Curtain Burner (ACB) systems could be an alternative to OPB and can avoid some of the negative effects that may result from OPB. The main objective was to compare the burning consumption rates and costs of two types of ACB machines, the S-220 and BurnBoss. In addition, we tested a hand-pile burning (HPB) consumption rate for a comparison with BurnBoss unit. The S-220’s burning consumption rates ranged between 5.7 and 6.8 green metric ton (GmT)/scheduled machine hour (SMH) at a cost between US $12.8 and US $10.8/GmT, respectively. Costs were 70% higher when using the BurnBoss unit. Burning residue consumption rates and cost of disposal were considerably different: they were highly dependent on machine size, species, and fuel age of forest residues. Particularly, BurnBoss test burned over 40% more than HPB method and produced clean burn by airflow. The results from this study suggest that ACBs can be a useful tool to dispose of forest residues piled in many forests areas with less concerns of air quality and fire escape risks.
      Citation: Forests
      PubDate: 2017-08-14
      DOI: 10.3390/f8080296
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 297: Comparison of Heat Transfer and Soil Impacts
           of Air Curtain Burner Burning and Slash Pile Burning

    • Authors: Woongsoon Jang, Deborah Page-Dumroese, Han-Sup Han
      First page: 297
      Abstract: We measured soil heating and subsequent changes in soil properties between two forest residue disposal methods: slash pile burning (SPB) and air curtain burner (ACB). The ACB consumes fuels more efficiently and safely via blowing air into a burning container. Five burning trials with different fuel sizes were implemented in northern California, USA. Soil temperature was measured at 1, 2, 3, 4, 6, and 8 cm depth. Immediately after burning, soil samples from two depths (0–10 and 10–20 cm) and ash samples were collected for analyzing organic matter; carbon and nitrogen content; and calcium, magnesium, and potassium concentrations. The highest temperature observed was 389 °C at 1 cm depth under the SPB. Mean peak temperatures were 133.2 °C and 162.2 °C for ACB and SPB, respectively. However, there were no significant differences in peak temperatures and duration of lethal soil temperatures (total minutes over 60 °C) between ACB and SPB. Heat transfer decreased rapidly as the soil depth increased. There is little evidence that any subsequent changes in soil chemical properties occurred, concluding that these small-scale burns had few negative impacts at our study site. Therefore, given the lack of extreme soil heating and more efficient and safer woody residue reduction, the ACB may be more effective than open SPB, especially where fire escape or long-term fire damage to soils are of concern.
      Citation: Forests
      PubDate: 2017-08-16
      DOI: 10.3390/f8080297
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 298: How Climate Change Will Affect Forest
           Composition and Forest Operations in Baden-Württemberg—A GIS-Based Case
           Study Approach

    • Authors: Ferréol Berendt, Mathieu Fortin, Dirk Jaeger, Janine Schweier
      First page: 298
      Abstract: In order to accommodate foreseen climate change in European forests, the following are recommended: (i) to increase the number of tree species and the structural diversity; (ii) to replace unsuitable species by native broadleaved tree species, and (iii) to apply close-to-nature silviculture. The state forest department of Baden-Württemberg (BW) currently follows the concept of Forest Development Types (FDTs). However, future climatic conditions will have an impact on these types of forest as well as timber harvesting operations. This Geographic Information System (GIS)-based analysis identified appropriate locations for main FDTs and timber harvesting and extraction methods through the use of species suitability maps, topography, and soil sensitivity data. Based on our findings, the most common FDT in the state forest of BW is expected to be coniferous-beech mixed forests with 29.0% of the total forest area, followed by beech-coniferous (20.5%) and beech-broadleaved (15.4%) mixed forests. Where access for fully mechanized systems is not possible, the main harvesting and extraction methods would be motor manual felling and cable yarding (29.1%). High proportions of large dimensioned trees will require timber extraction using forestry tractors, and these will need to be operated from tractor roads on sensitive soils (23.0%), and from skid trails on insensitive soils (18.4%).
      Citation: Forests
      PubDate: 2017-08-16
      DOI: 10.3390/f8080298
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 299: The Impact of Water Content on Sources of
           Heterotrophic Soil Respiration

    • Authors: Kristin M. McElligott, John R. Seiler, Brian D. Strahm
      First page: 299
      Abstract: Heterotrophic respiration (RH) is a major flux of CO2 from forest ecosystems and represents a large source of uncertainty in estimating net ecosystem productivity (NEP) using regional soil respiration (RS) models. RH from leaf litter (RHL) may contribute greatly to annual RH estimates, but its contribution may be misrepresented due to the logistical and technical challenges associated with chamber-based field measurements of RHL. The purpose of this study was to evaluate the sensitivity of sources of RH (mineral soil-derived heterotrophic respiration [RHM] and leaf litter-derived heterotrophic respiration [RHL]) of a loblolly pine plantation (Pinus taeda L.) to varying soil and litter water content over the course of a dry down event. Additionally, we investigated whether fertilization influenced RHL and RHM to understand how forest nutrient management may impact forest soil carbon (C) dynamics. RHL was measured under dry conditions and at field capacity to evaluate water content controls on RHL, determine the duration of increased CO2 release following wetting, and evaluate the potential contribution to total RH. We also measured RHM inside collars that excluded plant roots and litter inputs, from field capacity until near-zero RHM rates were attained. We found that RHL was more sensitive to water content than RHM, and increased linearly with increasing litter water content (R2 = 0.89). The contribution of RHL to RH was greatest immediately following the wetting event, and decreased rapidly to near-zero rates between 3 and 10 days. RHM also had a strong relationship with soil water content (R2 = 0.62), but took between 200 and 233 days to attain near-zero RHM rates. Fertilization had no effect on RHM (p = 0.657), but significantly suppressed RHL rates after the wetting event (p < 0.009). These results demonstrate that there is great temporal variability in both CO2 released and the water content of differing sources of RH, and forest fertilization may largely impact forest floor C stocks. This variability may not be captured reliably using conventional weekly to monthly chamber-based field sampling efforts and could lead to over- or underestimation of RH. In the context of climate change, changes in the frequency and intensity of wetting and drying events will likely alter RHL and its contribution to RS. Separate consideration of RH sources and controls, along with increased field sampling frequency using chamber-based methodology under a broader range of specific environmental conditions, are likely needed to reduce variability in RH estimates and improve the accuracy of forest NEP predictions.
      Citation: Forests
      PubDate: 2017-08-16
      DOI: 10.3390/f8080299
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 300: Use of Multi-Temporal UAV-Derived Imagery for
           Estimating Individual Tree Growth in Pinus pinea Stands

    • Authors: Juan Guerra-Hernández, Eduardo González-Ferreiro, Vicente Monleón, Sonia Faias, Margarida Tomé, Ramón Díaz-Varela
      First page: 300
      Abstract: High spatial resolution imagery provided by unmanned aerial vehicles (UAVs) can yield accurate and efficient estimation of tree dimensions and canopy structural variables at the local scale. We flew a low-cost, lightweight UAV over an experimental Pinus pinea L. plantation (290 trees distributed over 16 ha with different fertirrigation treatments) to determine the tree positions and to estimate individual tree height (h), diameter (d), biomass (wa), as well as changes in these variables between 2015 and 2017. We used Structure from Motion (SfM) and 3D point cloud filtering techniques to generate the canopy height model and object-based image analysis to delineate individual tree crowns (ITC). ITC results were validated using accurate field measurements over a subsample of 50 trees. Comparison between SfM-derived and field-measured h yielded an R2 value of 0.96. Regressions using SfM-derived variables as explanatory variables described 79% and 86–87% of the variability in d and wa, respectively. The height and biomass growth estimates across the entire study area for the period 2015–2017 were 0.45 m ± 0.12 m and 198.7 ± 93.9 kg, respectively. Significant differences (t-test) in height and biomass were observed at the end of the study period. The findings indicate that the proposed method could be used to derive individual-tree variables and to detect spatio-temporal changes, highlighting the potential role of UAV-derived imagery as a forest management tool.
      Citation: Forests
      PubDate: 2017-08-18
      DOI: 10.3390/f8080300
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 301: Climate-Induced Northerly Expansion of
           Siberian Silkmoth Range

    • Authors: Viacheslav I. Kharuk, Sergei T. Im, Kenneth J. Ranson, Mikhail N. Yagunov
      First page: 301
      Abstract: Siberian silkmoth (Dendrolimus sibiricus Tschetv.) is a dangerous pest that has affected nearly 2.5 × 106 ha of “dark taiga” stands (composed of Abies sibirica, Pinus sibirica and Picea obovata) within the latitude range of 52°–59° N. Here we describe a current silkmoth outbreak that is occurring about half degree northward of its formerly documented outbreak range. This outbreak has covered an area of about 800 thousand ha with mortality of conifer stands within an area of about 300 thousand ha. The primary outbreak originated in the year 2014 within stands located on gentle relatively dry southwest slopes at elevations up to 200 m above sea level (a.s.l.) Then the outbreak spread to the mesic areas including northern slopes and the low-elevation forest belts along the Yenisei ridge. Within the outbreak area, the northern Siberian silkmoth population has reduced generation length from two to one year. Our study showed that the outbreak was promoted by droughts in prior years, an increase of the sum of daily temperatures (t > +10 °C), and a decrease in ground cover moisture. Within the outbreak area, secondary pests were also active, including the aggressive Polygraphus proximus bark borer beetle. The outbreak considered here is part of the wide-spread (panzonal) Siberian silkmoth outbreak that originated during 2014–2015 with a range of up to 1000 km in southern Siberia. Our work concludes that observed climate warming opens opportunities for Siberian silkmoth migration into historically outbreak free northern “dark taiga” stands.
      Citation: Forests
      PubDate: 2017-08-16
      DOI: 10.3390/f8080301
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 303: Land-Use Redistribution Compensated for
           Ecosystem Service Losses Derived from Agriculture Expansion, with Mixed
           Effects on Biodiversity in a NW Argentina Watershed

    • Authors: Ana Nanni, Héctor Grau
      First page: 303
      Abstract: Areas of land abandonment and agriculture expansion usually differ in location and associated environmental characteristics; thus, land-use redistribution affects the provision of ecosystem services and biodiversity conservation. In a subtropical region undergoing land redistribution patterns characteristic of Latin America, we estimated 20-year changes in food production, above-ground carbon stocks and soil erosion due to land cover change, and the potential effects of such redistribution of forests on the diversity of birds and mammals. Between 1986 and 2006, despite only 0.3% of net forest cover change, 7% of the total area (ca. 280,000 has) switched between forest and non-forest covers. Food production increased by 46%, while the estimated ecosystem services changed by less than 10%. Forest carbon remained stable, with gains in montane humid forests compensating for losses in lowlands. Modeled soil erosion increased, but sediment accumulation at the watershed bottom remained stable. The responses of birds and mammals to forest redistribution differed and were stronger in birds. Due to the strong responses of birds to forest loss, lowland bird communities might be especially threatened by current land-use trends. Results suggest that land redistribution associated with the adjustment of agriculture towards soils suitable for mechanized agriculture can help mitigate associated losses in ecosystem services and biodiversity, but species and supporting services depending on easily-converted ecosystems require appropriate landscape management practices.
      Citation: Forests
      PubDate: 2017-08-18
      DOI: 10.3390/f8080303
      Issue No: Vol. 8, No. 8 (2017)
  • Forests, Vol. 8, Pages 354: Variability in Larch (Larix Decidua Mill.)
           Tree-Ring Growth Response to Climate in the Polish Carpathian Mountains

    • Authors: Małgorzata Danek, Monika Chuchro, Adam Walanus
      First page: 354
      Abstract: The climate–growth relationship of larch (Larix decidua Mill.) in the Polish Carpathian Mountains was studied. We explored the spatial variability of the common signal observed in larch tree-ring growth, distinguished regions with uniform tree-ring growth patterns (dendrochronological signal), and determined the climatic factors that are particularly important for the growth of larch in this area. Uniformity in the growth reaction across the analyzed area was found in the positive response to May temperatures (significant correlation values range from 0.21 to 0.48); this indicates that the warm beginning of the growing season is important for larch growth across the study area. The signal variability from west to east found in the principal components analysis (PCA) results and differences in climate response between analyzed sites suggest their relation to increasing influence of the continental climate to the east. However, the observed relationship is not stable and does not occur systematically. Although the climate–growth response of larch at lower elevations is highly variable, a positive influence of July precipitation and a negative influence of April precipitation, and previous May and July temperature can be observed. The growth of larch from the highest study sites (Tatra Mountains, above 950 m a.s.l.) is related to temperature. This is manifested by a strong positive correlation with temperature during late spring, early summer, and the end of the previous growing season, and a negative or no response to late spring/summer precipitation. No relation between the observed correlations and slope aspect was found.
      Citation: Forests
      PubDate: 2017-09-21
      DOI: 10.3390/f8100354
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 355: Does the Slope of the Self-thinning Line
           Remain a Constant Value across Different Site Qualities'—An
           Implication for Plantation Density Management

    • Authors: Fangxing Ge, Weisheng Zeng, Wu Ma, Jinghui Meng
      First page: 355
      Abstract: The self-thinning rule is regarded as one of the most important principles in plantation management. This rule, involving the assumption of a constant slope coefficient, has been universally applied when regulating stand density. In this study, we hypothesized that the slope coefficient can change significantly with changes in site quality. To test this hypothesis, we first grouped forest plots into 5 categories based on site index. Second, we produced the self-thinning line represented by the Reineke function for each of the 5 site categories, selecting fully stocked plots using reduced major axis regression. Third, the slope coefficients for the different categories were tested for significant differences. The results indicated that in general, the slope was significantly different with different site quality. In addition, we observed that the slope of the self-thinning line exhibited a steeper trend for sites of lower quality, which indicated increased self-thinning or reduced self-tolerance. Finally, we concluded that it is imperative to produce specific self-thinning lines for different site quality categories.
      Citation: Forests
      PubDate: 2017-09-21
      DOI: 10.3390/f8100355
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 356: Population Spatial Dynamics of Larix potaninii
           in Alpine Treeline Ecotone in the Eastern Margin of the Tibetan Plateau,

    • Authors: Jia’nan Cui, Jihong Qin, Hui Sun
      First page: 356
      Abstract: The high-altitude treeline is known to be sensitive to climate variability, and is thus considered as a bio-monitoring indicator of climate change. However, our understanding of the population dynamics and the cumulative climate-change effects on the alpine treeline ecotone in recent decades is limited. Here, we investigated the population dynamics of Larix potainii on the south- and north-facing slopes in the alpine treeline ecotone in the eastern margin of the Tibetan Plateau, China, including treeline position, population density, and tree recruitment. Results showed that on both south- and north-facing slopes, the treeline did not show a significant advancement in the past four decades. The population was dominated by young individuals, which tend to be established in the lower areas. Larix, here, tends to be clustered, especially in the upper areas. However, population density increased dramatically only on north-facing slopes. Larix here suffer from the stressful environment, but the warmer winter due to climate warming could facilitate the vertical growth of seedlings and saplings. Aggregated spatial patterns also provide a positive feedback in ameliorating the harsh environment. The slope-climate-moisture interactions have a pronounced impact on tree recruitment, including snow-limited tree establishment on the north-facing slopes and moisture-limited tree establishment on the south-facing slopes.
      Citation: Forests
      PubDate: 2017-09-22
      DOI: 10.3390/f8100356
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 357: Characterizing Rigging Crew Proximity to
           Hazards on Cable Logging Operations Using GNSS-RF: Effect of GNSS
           Positioning Error on Worker Safety Status

    • Authors: Ann Wempe, Robert Keefe
      First page: 357
      Abstract: Logging continues to rank among the most lethal occupations in the United States. Though the hazards associated with fatalities are well-documented and safe distances from hazards is a common theme in safety education, positional relationships between workers and hazards have not been quantified previously. Using GNSS-RF (Global Navigation Satellite System-Radio Frequency) transponders that allow real-time monitoring of personnel, we collected positioning data for rigging crew workers and three common cable logging hazards: a log loader, skyline carriage, and snag. We summarized distances between all ground workers and each hazard on three active operations and estimated the proportion of time crew occupied higher-risk areas, as represented by geofences. We then assessed the extent to which positioning error associated with different stand conditions affected perceived worker safety status by applying error sampled in a separate, controlled field experiment to the operational data. Root mean squared error was estimated at 11.08 m in mature stands and 3.37 m in clearcuts. Simulated error expected for mature stands altered safety status in six of nine treatment combinations, whereas error expected for clearcuts affected only one. Our results show that canopy-associated GNSS error affects real-time geofence safety applications when using single-constellation American Global Positioning System transponders.
      Citation: Forests
      PubDate: 2017-09-23
      DOI: 10.3390/f8100357
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 358: Available Nutrients Can Accumulate in
           Permanent Skid Trails

    • Authors: Kenton Stutz, Helmer Schack-Kirchner, Gerald Kändler, Lea Landes, Martin Linz, Hannes Warlo, Friederike Lang
      First page: 358
      Abstract: Forest harvesting removes and redistributes nutrients through felling and forwarding. Substantial quantities of nutrients can accumulate in brash mats on permanent skid trails, but their availability and uptake after multiple thinnings on soils susceptible to leaching are unknown. In this study, we modeled the deposition of base cations and phosphorus on a permanent skid trail after five thinnings of a Picea abies (L.) Karst. stand, and measured the resulting nutrient stocks in both the forest floor and mineral soil. An estimated 35%, 44%, 41%, and 61% of harvested Ca, K, Mg, and P, respectively, were redistributed to the skid trail. Of those deposited stocks, 32–65% of nutrients remained in decomposed brash material on the skid trail. Mineral soil stocks for Ca, K, and P were significantly higher in the skid trail than in the stand, which included minor increases in bioavailable pools. Skid trail root densities were not lower than the stand while bulk densities were only partially higher. Both would not limit nutrient uptake. There were no significant relations between needle nutrient concentrations and distance to the skid trail. Altogether, these results indicate that nutrient uptake from the skid trail was minimal despite their accumulation, chemical availability, and physical accessibility. This suggests that other factors such as liming and frequent thinning disturbances can repress uptake of available nutrients on skid trails.
      Citation: Forests
      PubDate: 2017-09-23
      DOI: 10.3390/f8100358
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 359: Climate-Induced Tree Growth Variations under
           the RCP 2.6 Scenario: A Case Study on the Southeastern Tibetan Plateau

    • Authors: Xianliang Zhang, Fenghua Zou, Zhenju Chen
      First page: 359
      Abstract: The relationship between climate and radial tree growth is traditionally used to reconstruct past climate conditions based on interannual tree-ring variations. However, few studies have used these climate-growth relationships to model the radial tree growth based on future climate projections. To detect the future forest dynamics, the climate-induced tree growth from 2006 to 2100 was projected using temperature changes under representative concentration pathway (RCP) 2.6 for the southeastern Tibetan Plateau. Radial tree growth was mainly controlled by annual mean temperature in this region. Based on the relationship between regional annual mean temperature and radial tree growth, a regression model was built that explained 62.5% of variance in the observed temperature record over the period 1911–2005. A period of unprecedented radial tree growth was found after 1998 when compared with the tree growth in the past 700 years. We found that radial tree growth would increase in the period 2006–2045 and decline after that period due to the projected temperature decrease. As forest productivity and biomass are expected to increase with the increased tree growth, these results suggest that temperature-limited systems could see future increases in productivity as growth limitations are lessened. The results of this research could be used to predict regional forest dynamics in the future.
      Citation: Forests
      PubDate: 2017-09-23
      DOI: 10.3390/f8100359
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 360: The Effect of Customer–Contractor Alignment
           in Forest Harvesting Services on Contractor Profitability and the Risk for
           Relationship Breakdown

    • Authors: Mattias Eriksson, Luc LeBel, Ola Lindroos
      First page: 360
      Abstract: In forest operations, the interface between forest companies and harvesting contractors is of special importance, considering that it is the first link in the forest industry’s supply chains. Supply operations account for a significant share of the final costs of wood products (up to 50%). This study investigates the effect of customer–contractor alignment on contractors’ profit margins and on the risk for business relationship breakdown. Alignment is empirically measured for a Swedish forest company and 74 of its harvesting contractors, who were monitored during a four-year period. Two measures of alignment are employed: (1) the customer-perceived value of the contractors’ services; and (2) the contractors’ perceived alignment with the forest company expectations. Results indicate that the two measures of alignment are largely independent from each other, and that customer-perceived value affects both contractor profitability and the risk of relationship breakdown. Conflict between the two parties and lack of trust for the customer were found to be common complaints among contractors who ceased working for the studied forest company. Consequently, customer–contractor alignment should be considered a key objective by contractors who strive for business success, and also by forest companies who wish to improve their supply chain performance.
      Citation: Forests
      PubDate: 2017-09-25
      DOI: 10.3390/f8100360
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 361: Nonlinear Variations of Net Primary
           Productivity and Its Relationship with Climate and Vegetation Phenology,

    • Authors: Jian Yang, Xin Zhang, Zhao Luo, Xi Yu
      First page: 361
      Abstract: Net primary productivity (NPP) is an important component of the terrestrial carbon cycle. In this study, NPP was estimated based on two models and Moderate Resolution Imaging Spaectroradiometer (MODIS) data. The spatiotemporal patterns of NPP and the correlations with climate factors and vegetation phenology were then analyzed. Our results showed that NPP derived from MODIS performed well in China. Spatially, NPP decreased from the southeast toward the northwest. Temporally, NPP showed a nonlinear increasing trend at a national scale, but the magnitude became slow after 2004. At a regional scale, NPP in Northern China and the Tibetan Plateau showed a nonlinear increasing trend, while the NPP decreased in most areas of Southern China. The decreases in NPP were more than offset by the increases. At the biome level, all vegetation types displayed an increasing trend, except for shrub and evergreen broad forests (EBF). Moreover, a turning point year occurred for all vegetation types, except for EBF. Generally, climatic factors and Length of Season were all positively correlated with the NPP, while the relationships were much more diverse at a regional level. The direct effect of solar radiation on the NPP was larger (0.31) than precipitation (0.25) and temperature (0.07). Our results indicated that China could mitigate climate warming at a regional and/or global scale to some extent during the time period of 2001–2014.
      Citation: Forests
      PubDate: 2017-09-25
      DOI: 10.3390/f8100361
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 363: Tree Species Selection in the Face of Drought
           Risk—Uncertainty in Forest Planning

    • Authors: Matthias Albert, Ralf-Volker Nagel, Robert Nuske, Johannes Sutmöller, Hermann Spellmann
      First page: 363
      Abstract: Rapid climate change leads to significant shifts in the site-productivity relationship of tree species and alters abiotic and biotic risks well beyond classical rotation ages on many forest sites worldwide. Forest conversion may be an adequate measure to counter possible negative effects of climate change. Unfortunately, climate-driven changes in abiotic and biotic risks bear a significant source of intrinsic uncertainty inherent in climate projections. It is our goal to appraise uncertainty in species selection under drought stress, one of the most important risk factors for many forests. We derive a method to assess drought restrictions and demonstrate the uncertainty in the process of species selection by applying three climate scenarios. Furthermore, we interpret the consequences of climate uncertainty in the light of different management goals, i.e., a business-as-usual silviculture, a climate protection strategy favoring CO2 sequestration and a biodiversity strategy increasing diversity. The methods are applied to two representative regions in the North German Plain. The results clearly show the strong need for adaptive planning when drought restrictions are considered. However, different silvicultural management objectives may alter the extent of adaptive planning. The uncertainty in the planning process arising from different underlying climate projections strongly depends on the regional site characteristics and on forest management strategy. In conclusion, it is most important in forest planning to clearly state the management goals and to carefully explore if the goals can be met under climate change and if the uncertainty due to climate projections significantly affects the results of species selection.
      Citation: Forests
      PubDate: 2017-09-26
      DOI: 10.3390/f8100363
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 364: Forest Certification Perspectives in the Wood
           Products Supply Chain in Virginia, U.S.A.

    • Authors: John Munsell, Adrian Ares, Scott Barrett, Brian Bond, Jennifer Gagnon
      First page: 364
      Abstract: Participation among private forest owners, logging contractors, and wood products manufacturers in the forest certification sector remains low. Those that enroll are mainly large-acreage owners and specialized manufacturers. Little is known about certification perspectives across the supply chain and how they relate. Comparing what owners, contractors, and manufacturers think about certification would increase insight regarding sector growth. In this study, 2741 private forest owners, logging contractors, and wood products manufacturers in Virginia, U.S.A. were surveyed about their beliefs regarding the impact of certification on economic opportunities and image and the extent to which they think it positively affects the forestry sector and understand how to certify forestland. Co-orientation was used to map alignment and predictions between respondents. Owner and contractor responses were similar and predictions about each other mostly accurate, but manufacturer responses and predictions were largely incongruent. Manufacturers generally aligned more so with contractors than owners but contractors identified slightly more with owners. Owners and contractors shared perspectives and a discernable identity, whereas manufacturers viewed certification in a less positive light. Implications for participation in forest certification focus largely on interrelationships of actor perspectives regardless of scale and emphasize the roles each can play in the forest certification sector.
      Citation: Forests
      PubDate: 2017-09-26
      DOI: 10.3390/f8100364
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 365: Monitoring Changes in Water Use Efficiency to
           Understand Drought Induced Tree Mortality

    • Authors: Sparkle Malone
      First page: 365
      Abstract: Forests are becoming increasingly vulnerable to rising tree mortality rates in response to warming and drought. In California, the most severe drought on record occurred from 2012–2016 and high tree mortality rates were observed in response to this prolonged drought. Differences in satellite-derived estimates of water-use efficiency (WUE) under normal (i.e., WUEBASELINE) and drought conditions (ΔWUE = WUE2014 − WUEBASELINE) captured variation in drought resilience, and is used here to understand patterns in tree mortality. Across California forests, a low WUEBASELINE under normal conditions was indicative of a low drought resilience and was associated with increasing tree mortality rates. Forested areas with high drought frequency in recent years (2002–2015) and lower WUEBASELINE were the most vulnerable to high post-drought tree mortality. Post drought tree mortality peaked in 2015 and tree mortality was detected in areas where bark beetles were active. Our results show that spatial and temporal changes in WUE can signal shifts in ecosystem resilience and that water-limited forests are sensitive to temperature- and precipitation-driven drought stress. Considering that forests with low resilience will be poised for dieback in the future if climates continue to feature rising temperatures without compensating increases in precipitation, it is becoming increasingly important that we understand drought vulnerability at the ecosystem level and how it changes over time with climate conditions.
      Citation: Forests
      PubDate: 2017-09-26
      DOI: 10.3390/f8100365
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 366: Correction: Schelfhout, S.; et al. Tree
           Species Identity Shapes Earthworm Communities. Forests 2017, 8, 85

    • Authors: Stephanie Schelfhout, Jan Mertens, Kris Verheyen, Lars Vesterdal, Lander Baeten, Bart Muys, An De Schrijver
      First page: 366
      Abstract: It has come to our attention that there was a mistake in this paper [1]:[...]
      Citation: Forests
      PubDate: 2017-09-27
      DOI: 10.3390/f8100366
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 367: Pine Nuts: A Review of Recent Sanitary
           Conditions and Market Development

    • Authors: Hafiz Awan, Davide Pettenella
      First page: 367
      Abstract: Pine nuts are non-wood forest products (NWFP) with a constantly growing market notwithstanding a series of phytosanitary issues and related trade problems. The aim of this paper is to review the literature on the relationship between phytosanitary problems and trade development. Production and trade of pine nuts in Mediterranean Europe have been negatively affected by the spreading of Diplodia sapinea (a fungus) associated with an adventive insect Leptoglossus occidentalis (fungal vector), with impacts on forest management, production and profitability and thus in value chain organization. Reduced availability of domestic production in markets with a growing demand has stimulated the import of pine nuts. China has become a leading exporter of pine nuts, but its export is affected by a symptom caused by the nuts of some pine species: ‘pine nut syndrome’ (PNS). Most of the studies mentioned in the literature review concern PNS occurrence associated with the nuts of Pinus armandii. We highlight the need for a comprehensive and interdisciplinary approach to the analysis of the pine nuts value chain organization, where research on food properties and clinical toxicology may be connected to breeding and forest management, forest pathology and entomology, and trade development.
      Citation: Forests
      PubDate: 2017-09-27
      DOI: 10.3390/f8100367
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 368: Seasonal Water Relations and Leaf Temperature
           in a Deciduous Dipterocarp Forest in Northeastern Thailand

    • Authors: Philip Rundel, Kansri Boonpragob, Mark Patterson
      First page: 368
      Abstract: Deciduous dipterocarp forests across mainland Southeast Asia are dominated by two families: the Dipterocarpaceae and Fabaceae. Monsoon conditions produce strong seasonal climates with a hot dry season of 5–7 months extending from late November or early December through April or early May. Seasonal measurements of stomatal conductance and plant water potential found important differences between members of the two families. Despite their long dry season, Shorea siamensis and S. obtusa (Dipterocarpaceae) showed little significant patterns of seasonal change in xylem water potentials, with midday potentials never dropping below −1.3 MPa. These species present a classic example of isohydric strategies of adaptation where stomatal regulation maintains a relatively stable minimum water potential over the course of the year. However, maximum rates of stomatal conductance dropped sharply in the late dry season as the leaves heated in full sun without significant transpirational cooling, reaching as high as 44–45 °C, making them potentially sensitive to global increases in extreme temperature. The woody legumes Xylia kerrii and Dalbergia oliveri present different patterns of seasonal water relations and leaf response to high temperatures. The legumes exhibit anisohydric behavior where water potential decreases over the dry season as evaporative demand increases. Dry season midday water potentials dropped from high wet season levels to −2.4 to −3.2 MPa, moderately lowering maximum stomatal conductance. The relatively small leaflets of these legumes responded to the high temperatures of the late dry season by temporarily wilting, reducing their exposure to solar radiation and taking advantage of convective cooling. Large leaf size of dipterocarps in this community may not be an adaptive trait but rather an ancestral condition compensated for with ecophysiological adaptations.
      Citation: Forests
      PubDate: 2017-09-28
      DOI: 10.3390/f8100368
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 369: Buying Time: Preliminary Assessment of
           Biocontrol in the Recovery of Native Forest Vegetation in the Aftermath of
           the Invasive Emerald Ash Borer

    • Authors: Elan Margulies, Leah Bauer, Inés Ibáñez
      First page: 369
      Abstract: Introduced forest pests have become one of the major threats to forests, and biological control is one of the few environmentally acceptable management practices. Assessing the impacts of a biocontrol program includes evaluating the establishment of biocontrol agents, the control of target pest, the impact on the affected organism, and the indirect impacts that the biocontrol agent may have on the whole community. We assessed the recovery of forest vegetation following the mortality of ash trees caused by the invasive emerald ash borer (EAB) pest in forest stands where biocontrol agents were released or not. We used a multilevel framework to evaluate potential indirect effects of the biocontrol agents on native forest seedlings. Our results showed a higher number of ash saplings where increasing numbers of the dominant EAB biocontrol agent were released, while the number of invasive and weedy saplings was negatively associated with the number of ash saplings, and the density of native seedlings was negatively associated with invasive and weedy saplings. The protection of ash saplings by the biocontrol agent may help native recruitment during forest transition by supporting the growth of native hardwood seedlings over invasive and weedy species. These results show that research on the efficacy of EAB biocontrol should include all ash size classes and the community dynamics of co-occurring species.
      Citation: Forests
      PubDate: 2017-09-28
      DOI: 10.3390/f8100369
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 370: Assessing Alternative Silvicultural
           Prescriptions for Mid-Rotation, Unthinned, Spruce-Fir Stands in Maine

    • Authors: Patrick Hiesl, Mindy Crandall, Aaron Weiskittel, Anil Kizha
      First page: 370
      Abstract: Determining the optimal timing and type of entry in mid-rotation, unthinned stands can be complicated by a variety of economic and biological factors. In this analysis, long-term data from the Commercial Thinning Research Network was used to project spruce-fir (Picea spp.—Abies balsamea (L.) Mill.) stand growth on six different sites across Maine following six alternative thinning treatments (33% and 50% relative density removal paired with low, crown, and dominant thinning methods). Results showed that the low-thinning treatment performed best in terms of maximum net present value, stand age at time of maximum net present value, and average merchantable stem size. Although the low-thinning resulted in a 10% mean reduction in maximum net present value when compared to the control, the average merchantable stem size more than doubled. Overall, results of this analysis indicate that it may be financially responsible to commercially thin these stands using a low-thinning method and a light removal intensity, as the average merchantable stems size was increased and a mid-rotation financial return provided.
      Citation: Forests
      PubDate: 2017-09-28
      DOI: 10.3390/f8100370
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 371: Temporal Change in Aboveground Culms Carbon
           Stocks in the Moso Bamboo Forests and Its Driving Factors in Zhejiang
           Province, China

    • Authors: Lin Xu, Yongjun Shi, Guomo Zhou, Xiaojun Xu, Enbing Liu, Yufeng Zhou, Chong Li, Huiyun Fang, Xu Deng
      First page: 371
      Abstract: Moso bamboo (Phyllostachys pubescens) has high carbon sequestration potential and plays an important role in terrestrial carbon cycling. Quantifying the temporal change in Moso bamboo forest carbon stocks is important for understanding forest dynamics and global climate change feedback capacity. In 2009, 168 Moso bamboo forest sample plots were established in Zhejiang Province using National Forest Continuous Inventory protocols and enhanced measurements. These plots were revisited and remeasured in 2014. By comparing the two years, culms number in age classes 2 and 4 increased by 12.3% and 82.5%, respectively, while that in age classes 1 and 3 decreased by 14.7% and 0.03%, respectively. The total aboveground culms carbon stocks increased by 2.95 Mg C ha−1 in the sample plots. On average, age classes 2 and 4 contributed 25.5% and 86.7% of the change in total carbon stocks, respectively. The carbon sequestrated by aboveground culms was 0.42 Tg C year−1, accounting for 1.55 Tg CO2 year−1 in Moso bamboo over an area of 0.78 million hectares in Zhejiang Province. The change in Moso bamboo carbon stocks did not correlate with environmental factors, but significantly increased with increasing culms number and average diameter at breast height (DBH). Our study helps contribute to improvements in Moso bamboo forest management strategies and promote carbon sequestration capacity.
      Citation: Forests
      PubDate: 2017-09-30
      DOI: 10.3390/f8100371
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 372: Environmental Influences on Forest Fire Regime
           in the Greater Hinggan Mountains, Northeast China

    • Authors: Qian Fan, Cuizhen Wang, Dongyou Zhang, Shuying Zang
      First page: 372
      Abstract: Fires are the major disturbances in the Greater Hinggan Mountains, the only boreal forest in Northeast China. A comprehensive understanding of the fire regimes and influencing environmental parameters driving them from small to large fires is critical for effective forest fire prevention and management. Assisted with satellite imagery, topographic data, and climatic records in this region, this study examines its fire regimes in terms of ignition causes, frequencies, seasonality, and burned sizes in the period of 1980–2005. We found an upward trend for fire occurrences and burned areas and an elongated fire season over the three decades. The dates of the first fire in a year did not vary largely but those of the last fire were significantly delayed. Topographically, spring fires were prevalent throughout the entire region, while summer fires mainly occurred at higher elevations under severe drought conditions. Fall fires were mostly human-caused in areas at lower elevations with gentle terrains. An ordinal logistic regression revealed temperature and elevation were both significant factors to the fire size severity in spring and summer. Other than that, environmental impacts were different. Precipitation in the preceding year greatly influenced spring fires, while summer fires were significantly affected by wind speed, fuel moisture, and human accessibility. An important message from this study is that distinct seasonal variability and a significantly increasing number of summer and fall fires since the mid-1990s suggest a changing fire regime of the boreal forests in the study area. The observed and modeled results could provide insights on establishing a sustainable, localized forest fire prevention strategy in a seasonal manner.
      Citation: Forests
      PubDate: 2017-09-30
      DOI: 10.3390/f8100372
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 373: Seasonal Variations in Carbon, Nitrogen and
           Phosphorus Concentrations and C:N:P Stoichiometry in the Leaves of
           Differently Aged Larix principis-rupprechtii Mayr. Plantations

    • Authors: Hailiang Li, M. Crabbe, Fuli Xu, Weiling Wang, Ruilong Niu, Xing Gao, Pei Zhang, Haikui Chen
      First page: 373
      Abstract: The concentrations and stoichiometry of certain elements (carbon, nitrogen and phosphorus) are critical to the maintenance of plant functional and environmental adaptation during plant growth. We explore how the concentrations of C, N and P and the ratios of C:N, C:P, and N:P in the leaves of differently aged Larix principis-rupprechtii Mayr. plantations changed with growing season and stand age from 2012 to 2015 in the Qinling Mountains, China. The results showed that the element concentration and stoichiometric ratios in leaves were significantly affected by sampling month, stand age and sampling year; and multiple correlations with stand age were observed in different growing seasons. Compared to global element concentrations and stoichiometry in plants, the leaves of larch stands in the study region had higher C and P concentrations and C:N and C:P ratios but lower N concentrations and N:P ratios than global levels. The leaf N:P ratios of all of the larch stands were generally less than 14, suggesting that the growth of larch stands was limited by N in the study region. Our study facilitates the management and restoration of forest plantation and provides a valuable contribution to the global pool of leaf nutrition and stoichiometry data.
      Citation: Forests
      PubDate: 2017-09-30
      DOI: 10.3390/f8100373
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 374: Transcriptome Sequencing and Comparative
           Analysis of Piptoporus betulinus in Response to Birch Sawdust Induction

    • Authors: Lixia Yang, Mu Peng, Syed Shah, Qiuyu Wang
      First page: 374
      Abstract: Piptoporus betulinus, a brown-rot parasitic fungus of birch trees (Betula species), has been used as a common anti-parasitic and antibacterial agent. The lack of genetic resource data for P. betulinus has limited the exploration of this species. In this present study, we used Illumina Hiseq 2500 technology to examine the transcriptome assembly of P. betulinus in response to birch sawdust induction. By de novo assembly, 21,882 non-redundant unigenes were yielded, and 21,255 (97.1%) were annotated with known gene sequences. A total of 340 responsive unigenes were highly homologous with putative lignocellulose-degrading enzyme candidates. Additionally, 86 unigenes might be involved in the chemical reaction in xenobiotics biodegradation and metabolism, which suggests that this fungus could convert xenobiotic materials and has the potential ability to clean up environmental pollutants. To our knowledge, this was the first study on transcriptome sequencing and comparative analysis of P. betulinus, which provided a better understanding of molecular mechanisms underlying birch sawdust induction and identified lignocelluloses degrading enzymes.
      Citation: Forests
      PubDate: 2017-10-07
      DOI: 10.3390/f8100374
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 375: Establishing Pine Monocultures and Mixed
           Pine-Hardwood Stands on Reclaimed Surface Mined Land in Eastern Kentucky:
           Implications for Forest Resilience in a Changing Climate

    • Authors: Geoffrey Bell, Kenton Sena, Christopher Barton, Michael French
      First page: 375
      Abstract: Surface mining and mine reclamation practices have caused significant forest loss and forest fragmentation in Appalachia. Shortleaf pine (Pinus echinata) is threatened by a variety of stresses, including diseases, pests, poor management, altered fire regimes, and climate change, and the species is the subject of a widescale restoration effort. Surface mines may present opportunity for shortleaf pine restoration; however, the survival and growth of shortleaf pine on these harsh sites has not been critically evaluated. This paper presents first-year survival and growth of native shortleaf pine planted on a reclaimed surface mine, compared to non-native loblolly pine (Pinus taeda), which has been highly successful in previous mined land reclamation plantings. Pine monoculture plots are also compared to pine-hardwood polyculture plots to evaluate effects of planting mix on tree growth and survival, as well as soil health. Initial survival of shortleaf pine is low (42%), but height growth is similar to that of loblolly pine. No differences in survival or growth were observed between monoculture and polyculture treatments. Additional surveys in coming years will address longer-term growth and survival patterns of these species, as well as changes to relevant soil health endpoints, such as soil carbon.
      Citation: Forests
      PubDate: 2017-10-04
      DOI: 10.3390/f8100375
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 376: Potential Impact of the REDD+ Program on
           Poverty Reduction in Nghe An Province, Vietnam

    • Authors: Nguyen Dinh Tien, Roberto Rañola, Pham Thu Thuy
      First page: 376
      Abstract: The REDD+ program provides a mechanism for providing financial rewards to forest owners and users who contribute to the reduction of carbon emissions from deforestation and forest degradation. This paper determines the potential impact of the REDD+ program on poverty reduction by comparing income and poverty rate between two household groups that were willing to participate in this study, but that will not participate in the REDD+. The results showed that carbon payment from forests is a significant contributor to the increase in household income of poor people. The average income of households participating in the program is VND 20.68 million in contrast to those not participating whose average income is VND 14.72 million. Results showed that the REDD+ program intervention helped reduce the poverty rate in the two communes by 6.40% (from 39.4% to 33%). The paper recommends that the REDD+ program should facilitate the distribution of land titles to provide security of tenure for individual households that are participating in the program. While the program can contribute to poverty reduction, the program payments can increase income inequality and conflicts between those involved and those not involved in the program and legal ownership of the lands. In addition, a comprehensive research study on the impact of the program on forest conservation and poverty reduction is necessary. Stakeholders of the program should recognize and acknowledge the trade-offs between conservation and economic development or poverty reduction. A comprehensive trade-off analysis of program implementation and a business-as-usual option of commodity production is needed, which could reveal the indirect economic, political, and social costs and benefits of the program.
      Citation: Forests
      PubDate: 2017-10-03
      DOI: 10.3390/f8100376
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 377: Variations of Climate-Growth Response of Major
           Conifers at Upper Distributional Limits in Shika Snow Mountain,
           Northwestern Yunnan Plateau, China

    • Authors: Yun Zhang, Dingcai Yin, Mei Sun, Hang Wang, Kun Tian, Derong Xiao, Weiguo Zhang
      First page: 377
      Abstract: Improved understanding of climate-growth relationships of multiple species is fundamental to understanding and predicting the response of forest growth to future climate change. Forests are mainly composed of conifers in Northwestern Yunnan Plateau, but variations of growth response to climate conditions among the species are not well understood. To detect the growth response of multiple species to climate change, we developed residual chronologies of four major conifers, i.e., George’s fir (Abies georgei Orr), Likiang spruce (Picea likiangensis (Franch.) E.Pritz.), Gaoshan pine (Pinus densata Mast.) and Chinese larch (Larix potaninii Batalin) at the upper distributional limits in Shika Snow Mountain. Using the dendroclimatology method, we analyzed correlations between the residual chronologies and climate variables. The results showed that conifer radial growth was influenced by both temperature and precipitation in Shika Snow Mountain. Previous November temperature, previous July temperature, and current May precipitation were the common climatic factors that had consistent influences on radial growth of the four species. Temperature in the previous post-growing season (September–October) and moisture conditions in the current growing season (June–August) were the common climatic factors that had divergent impacts on the radial growth of the four species. Based on the predictions of climate models and our understanding of the growth response of four species to climate variables, we may understand the growth response to climate change at the species level. It is difficult to predict future forest growth in the study area, since future climate change might cause both increases and decreases for the four species and indirect effects of climate change on forests should be considered.
      Citation: Forests
      PubDate: 2017-10-04
      DOI: 10.3390/f8100377
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 378: Challenges for Uneven-Aged Silviculture in
           Restoration of Post-Disturbance Forests in Central Europe: A Synthesis

    • Authors: Jurij Diaci, Dusan Rozenbergar, Gal Fidej, Thomas A. Nagel
      First page: 378
      Abstract: Forest managers are often required to restore forest stands following natural disturbances, a situation that may become more common and more challenging under global change. In parts of Central Europe, particularly in mountain regions dominated by mixed temperate forests, the use of relatively low intensity, uneven-aged silviculture is a common management approach. Because this type of management is based on mimicking less intense disturbances, the restoration of more severe disturbance patches within forested landscapes has received little attention. The goal of this paper is to synthesize research on the restoration of forests damaged by disturbances in temperate forests of Slovenia and neighbouring regions of Central Europe, where uneven-aged silviculture is practiced. Research indicates that active management aimed at favouring mixed uneven-aged forest reduces the risk of disturbance and improves the resilience of stands. Salvage logging may have positive or negative effects on regeneration, much of which is due to the method applied and the quality of work. The most prominent factors that negatively affect restoration are: lack of advanced regeneration and decomposed woody debris, high altitude, steep slopes, dense ground vegetation, and overbrowsing. Planting or sowing should be applied in post-disturbance forests where many negative factors interact and where a high demand for sustainability of forest ecosystem services is present.
      Citation: Forests
      PubDate: 2017-10-04
      DOI: 10.3390/f8100378
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 379: Carbon Dioxide Fluxes and Their Environmental
           Controls in a Riparian Forest within the Hyper-Arid Region of Northwest

    • Authors: Xiaohong Ma, Qi Feng, Tengfei Yu, Yonghong Su, Ravinesh Deo
      First page: 379
      Abstract: Hyper-arid regions are expected to undergo climatic change, but only a few research works have so far been conducted on the dynamics of carbon dioxide (CO2) fluxes and their consequent responses to various bioclimatic factors, which is mainly attributable to a limited set of flux observations. In this study, the CO2 fluxes exchanged between the forest and the atmosphere have been measured continuously by the eddy covariance approach from June 2013 to December 2016 in a riparian forest, which is a primary body of natural oases located within the lower reaches of inland rivers in China. The present results revealed that the climatic conditions characterized by relatively high mean air temperatures (Ta) with fluctuating annual precipitation (P) during the prescribed study periods were comparable to the historical mean value. The annual net ecosystem productivity (NEP) ranged from approximately 278 g C m−2 year−1 to 427 g C m−2 year−1, with a mean value of 334 g C m−2 year−1. The mean annual ecosystem respiration (Re) and the gross primary productivity (GPP) were found to be 558 and 892 g C m−2 year−1, respectively. The results also ascertained that the high inter-annual variations in NEP were attributable to Re rather than to GPP, and this result was driven primarily by Ta and the groundwater depth under similar eco-physiological processes. In addition, the CO2 fluxes were also strongly correlated with the soil temperature and photosynthetically active radiation for the present study site. In conclusion, the desert riparian forest is a considerably significant carbon sink, particularly in the hyper-arid regions.
      Citation: Forests
      PubDate: 2017-10-04
      DOI: 10.3390/f8100379
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 380: Acoustic-Based Non-Destructive Estimation of
           Wood Quality Attributes within Standing Red Pine Trees

    • Authors: Peter Newton
      First page: 380
      Abstract: The relationship between acoustic velocity (vd) and the dynamic modulus of elasticity (me), wood density (wd), microfibril angle, tracheid wall thickness (wt,), radial and tangential diameters, fibre coarseness (co) and specific surface area (sa), within standing red pine (Pinus resinosa Ait.) trees, was investigated. The data acquisition phase involved 3 basic steps: (1) random selection of 54 sample trees from 2 intensively-managed 80-year-old plantations in central Canada; (2) attainment of cardinal-based vd measurements transecting the breast-height position on each sample tree; and (3) felling, sectioning and obtaining cross-sectional samples from the first 5.3 m sawlog from which Silviscan-based area-weighted mean attribute estimates were determined. The data analysis phase consisted of applying graphical and correlation analyses to specify regression models for each of the 8 attribute-acoustic velocity relationships. Results indicated that viable relationships were obtained for me, wd, wt, co and sa based on a set of statistical measures: goodness-of-fit (42%, 14%, 45%, 27% and 43% of the variability explained, respectively), lack-of-fit (unbiasedness) and predictive precision (±12%, ±8%, ±7%, ±8% and ±6% error tolerance intervals, respectively). Non-destructive approaches for estimating the prerequisite wd value when deploying the analytical framework were also empirically evaluated. Collectively, the proposed approach and associated results provide the foundation for the development of a comprehensive and precise end-product segregation strategy for use in red pine management.
      Citation: Forests
      PubDate: 2017-10-04
      DOI: 10.3390/f8100380
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 381: Projecting Land Use Changes by Integrating
           Site Suitability Analysis with Historic Land Use Change Dynamics in the
           Context of Increasing Demand for Wood Pellets in the Southern United

    • Authors: Surendra Shrestha, Puneet Dwivedi
      First page: 381
      Abstract: Rising export of wood pellets from southern United States would bring more land under loblolly pine (Pinus taeda L.) at the expense of other competitive land uses. We developed an approach to project potential changes in existing land uses by integrating site suitability analysis with historical land use dynamics in a watershed located within Oconee River Basin, Georgia, United States. We developed a GIS-based site suitability model to classify land into three categories (High, Medium, and Low) for loblolly pine. Then, we calculated historical rates of land use changes in the selected watershed. Finally, we integrated the output of suitability analysis with the projected rates of land use changes under the two scenarios of wood pellet demand (High and Low) to determine an increase in area under loblolly pine for 2016, 2021, and 2026 in a spatially explicit manner. Relative to 2011, the combined changes in the shrubland and evergreen forest land cover categories under High Demand scenario were 7.6, 14.6, and 21.1% and under Low Demand scenario were 3.8, 7.5, and 11.1% for the years 2016, 2021, and 2026, respectively. The developed approach could be applied in a relatively short time at modest spatial scales. The outputs of this study can also be used to determine the environmental implications of land use changes for ensuring the overall sustainability of wood-based bioenergy development in the United States and beyond.
      Citation: Forests
      PubDate: 2017-10-05
      DOI: 10.3390/f8100381
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 382: Intra-Annual Variation of Stem Radius of Larix
           principis-rupprechtii and Its Response to Environmental Factors in Liupan
           Mountains of Northwest China

    • Authors: Zebin Liu, Yanhui Wang, Ao Tian, Pengtao Yu, Wei Xiong, Lihong Xu, Yarui Wang
      First page: 382
      Abstract: Fine-resolution studies on the stem radius variation at short timescale can provide useful information about the tree growth process and the major environmental variables that trigger and drive stem radius variation. This study investigated the stem radius variation of Larix principis-rupprechtii Mayr growing in the semi-humid Liupan Mountains of Northwest China at daily and seasonal scales using high-resolution automatic band dendrometers from May to October in 2015. The results showed that the stem radius variation of Larix principis-rupprechtii has a clear diurnal pattern which can be divided into contraction, recovery, and increment phases; and also a seasonal pattern which can be divided into three stages: (1) the rapid growth stage in spring (stage 1) with the radius increment of 94.0% of the total in the entire growing period; (2) the persistent shrinkage stage in the dry summer (stage 2) with a negative diurnal radius increment for most days, and a significantly larger amplitude of stem contraction and recovery than other stages; (3) the minimal growth stage in autumn (stage 3), mainly caused by the lowering temperature and leaf area. The amplitude of stem contraction was significantly correlated with air temperature (both the mean and highest value) in all three stages: vapor pressure deficit (VPD) in stage 1; relative humidity (RH), VPD and soil moisture (Ms) in stage 2; and soil temperature (Ts) in stage 3. This indicates that the stem radius contraction was mainly controlled by the factors influencing tree transpiration rate in spring and autumn stages, but jointly controlled by the factors influencing both the tree transpiration rate and the soil moisture availability in the dry summer stage. The factors controlling the stem radius recovery was similar to the stem contraction. The amplitude of stem increment was significantly correlated with the rainfall amount and air temperature (both the mean and highest value) in stage 1 and 3, Ms in stage 2, and the lowest air temperature and Ts in stage 3. This indicates that temperature and precipitation were the key factors controlling the stem radius increment in the spring and autumn stages, and soil moisture was the main factor limiting the stem radius increment in the dry summer stage at the study site with semi-humid climate in Northwest China.
      Citation: Forests
      PubDate: 2017-10-07
      DOI: 10.3390/f8100382
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 383: Forest Harvest Patterns on Private Lands in
           the Cascade Mountains, Washington, USA

    • Authors: Christopher Soulard, Jessica Walker, Glenn Griffith
      First page: 383
      Abstract: Forests in Washington State generate substantial economic revenue from commercial timber harvesting on private lands. To investigate the rates, causes, and spatial and temporal patterns of forest harvest on private tracts throughout the Cascade Mountains, we relied on a new generation of annual land-use/land-cover (LULC) products created from the application of the Continuous Change Detection and Classification (CCDC) algorithm to Landsat satellite imagery collected from 1985 to 2014. We calculated metrics of landscape pattern using patches of intact and harvested forest in each annual layer to identify changes throughout the time series. Patch dynamics revealed four distinct eras of logging trends that align with prevailing regulations and economic conditions. We used multiple logistic regression to determine the biophysical and anthropogenic factors that influence fine-scale selection of harvest stands in each time period. Results show that private lands forest cover became significantly reduced and more fragmented from 1985 to 2014. Variables linked to parameters of site conditions, location, climate, and vegetation greenness consistently distinguished harvest selection for each distinct era. This study demonstrates the utility of annual LULC data for investigating the underlying factors that influence land cover change.
      Citation: Forests
      PubDate: 2017-10-07
      DOI: 10.3390/f8100383
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 384: Mapping of Shorea robusta Forest Using Time
           Series MODIS Data

    • Authors: Bhoj Ghimire, Masahiko Nagai, Nitin Tripathi, Apichon Witayangkurn, Bhogendra Mishara, Nophea Sasaki
      First page: 384
      Abstract: Mapping forest types in a natural heterogeneous forest environment using remote sensing data is a long-standing challenge due to similar spectral reflectance from different tree species and significant time and resources are required for acquiring and processing the remote sensing data. The purpose of this research was to determine the optimum number of remote sensing images and map the Sal forest through the analysis of Vegetation Index (VI) signatures. We analyzed the eight days’ composite moderate resolution imaging spectroradiometer (MODIS) time series normalized differential vegetation index (NDVI), and enhanced vegetation index (EVI) for the whole year of 2015. Jeffries-Matusita (J-M) distance was used for the separability index. Performance of EVI and NDVI was tested using random forest (RF) and support vector machine (SVM) classifiers. Boruta algorithm and statistical analysis were performed to identify the optimum set of imageries. We also performed data level five-fold cross validation of the model and field level accuracy assessment of the classification map. The finding confirmed that EVI with SVM (F-score of Sal 0.88) performed better than NDVI with either SVM or RF. The optimum 12 images during growing and post monsoon season significantly decreased processing time (to one-fourth) without much deteriorating accuracy. Accordingly, we were able to map the Sal forest whose area is accounted for about 36% of the 82% forest cover in the study area. The proposed methodology can be extended to produce a temporal forest type classification map in any other location.
      Citation: Forests
      PubDate: 2017-10-07
      DOI: 10.3390/f8100384
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 385: The Effect of Re-Planting Trees on Soil
           Microbial Communities in a Wildfire-Induced Subalpine Grassland

    • Authors: Ed-Haun Chang, Guanglong Tian, Chih-Yu Chiu
      First page: 385
      Abstract: Wildfire often causes tremendous changes in ecosystems, particularly in subalpine and alpine areas, which are vulnerable due to severe climate conditions such as cold temperature and strong wind. This study aimed to clarify the effect of tree re-planting on ecosystem services such as the soil microbial community after several decades. We compared the re-planted forest and grassland with the mature forest as a reference in terms of soil microbial biomass C and N (Cmic and Nmic), enzyme activities, phospholipid fatty acids (PLFA) composition, and denaturing gradient gel electrophoresis (DGGE). The Cmic and Nmic did not differ among the grassland, re-planted forest and mature forest soil; however, ratios of Cmic/Corg and Nmic/Ntot decreased from the grassland to re-planted forest and mature forest soil. The total PLFAs and those attributed to bacteria and Gram-positive and Gram-negative bacteria did not differ between the re-planted forest and grassland soil. Principle component analysis of the PLFA content separated the grassland from re-planted forest and mature forest soil. Similarly, DGGE analysis revealed changes in both bacterial and fungal community structures with changes in vegetation. Our results suggest that the microbial community structure changes with the re-planting of trees after a fire event in this subalpine area. Recovery of the soil microbial community to the original state in a fire-damaged site in a subalpine area may require decades, even under a re-planted forest.
      Citation: Forests
      PubDate: 2017-10-07
      DOI: 10.3390/f8100385
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 386: Assessment of the Response of Photosynthetic
           Activity of Mediterranean Evergreen Oaks to Enhanced Drought Stress and
           Recovery by Using PRI and R690/R630

    • Authors: Chao Zhang, Catherine Preece, Iolanda Filella, Gerard Farré-Armengol, Josep Peñuelas
      First page: 386
      Abstract: The photochemical reflectance index (PRI) and red-edge region of the spectrum are known to be sensitive to plant physiological processes, and through measurement of these optical signals it is possible to use non-invasive remote sensing to monitor the plant photosynthetic status in response to environmental stresses such as drought. We conducted a greenhouse experiment using Quercus ilex, a Mediterranean evergreen oak species, to investigate the links between leaf-level PRI and the red-edge based reflectance ratio (R690/R630) with CO2 assimilation rates (A), and photochemical efficiency (FV/FM and Yield) in response to a gradient of mild to extreme drought treatments (nine progressively enhanced drought levels) and corresponding recovery. PRI and R690/R630 both decreased under enhanced drought stress, and had significant correlations with A, FV/FM and Yield. The differential values between recovery and drought treatments of PRI (ΔPRIrecovery) and R690/R630 (ΔR690/R630recovery) increased with the enhanced drought levels, and significantly correlated with the increases of ΔArecovery, ΔFV/FMrecovery and ΔYieldrecovery. We concluded that both PRI and R690/R630 were not only sensitive to enhanced drought stresses, but also highly sensitive to photosynthetic recovery. Our study makes important progress for remotely monitoring the effect of drought and recovery on photosynthetic regulation using the simple physiological indices of PRI and R690/R630.
      Citation: Forests
      PubDate: 2017-10-10
      DOI: 10.3390/f8100386
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 387: Influence of Container Type and Growth Medium
           on Seedling Growth and Root Morphology of Cyclocarya paliurus during
           Nursery Culture

    • Authors: Ning Tian, Shengzuo Fang, Wanxia Yang, Xulan Shang, Xiangxiang Fu
      First page: 387
      Abstract: As a multiple function tree species, Cyclocarya paliurus (Batal) Iljinskaja is mainly planted and managed for timber production and medical use. To improve the seed use efficiency and outplanting performance of C. paliurus, the effects of container types and growth medium on the seedling growth and root morphology of C. paliurus were investigated by using a completely randomized block experimental design with a 4 × 3 factorial arrangement during nursery culture. Both container type and growth medium significantly affected the growth, biomass, and root morphological indexes of C. paliurus seedlings, but container size had a greater effect on the seedling quality of C. paliurus than the growth medium formula. The root-collar diameter and height of the seedlings were positively and significantly correlated with the biomass variables and root morphological variables, and could be considered essential attributes for evaluating seedling quality. Based on the results from this study, the management regime used here in C. paliurus seedling production is suggested to ensure good quality seedling delivery. Our study provides not only valuable insights into the container seedling culture of C. paliurus, it also enables nursery managers to optimize seedling production.
      Citation: Forests
      PubDate: 2017-10-10
      DOI: 10.3390/f8100387
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 388: Growth and Physiology of Senegalia senegal
           (L.) Britton Seedlings as Influenced by Seed Origin and Salinity and
           Fertility Treatments

    • Authors: Mame Sarr, John Seiler, Jay Sullivan
      First page: 388
      Abstract: Multipurpose trees such as Senegalia senegal are widespread in arid and semi-arid lands that have natural or induced saline soils and poor soil fertility. Such environmental problems impact growth and have the potential to influence plant physiological adaptations. Identifying superior genotypes better adapted to these environmental stresses will be of great importance for tree selection for reclamation of degraded drylands. The main objective of this study was to examine the growth performance, and physiological and morphological adaptations to salinity, and fertility treatments of different Senegalia senegal families. We used five families (DB16, DB14, K4B19, K17B19, NB1) selected from 60 families of a Senegalia senegal progeny trial in Dahra, Senegal. Seedlings were grown under greenhouse conditions by watering all plants for three weeks and then stopping all watering for three more weeks. In a randomized complete block design, a two-level factorial combination was used for salinity (zero and 183.1 mM NaCl added) and fertility (zero and 100 kg/ha N-P-K added) treatments. A significant family × salt × fertilizer interaction was found for all biomass parameters (leaf dry matter, stem dry matter, root dry matter, and leaf area). The fertilizer application resulted in a significant increase of total biomass of all families, ranging from 63% to 237% for NB1 and K17B19, respectively. In contrast, salt only decreased total biomass of NB1 and K17B19 increased growth. Despite similar net photosynthetic rates before treatment started, fertilizer and salinity induced different effects between families. Prior to drought stress, fertilizer did not affect photosynthesis of DB16, while salt significantly decreased stomatal conductance of all families. DB16 and N1B1, despite significant differences of stomata size and density, significantly decreased transpiration, and thereby increased their intrinsic water use efficiency. Under drought, relative growth rate was significantly decreased. Given that genotype differences were found, these families and salinity and fertilizer treatments need to be explored in field trials.
      Citation: Forests
      PubDate: 2017-10-11
      DOI: 10.3390/f8100388
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 389: Assessing Forest Cover Dynamics and Forest
           Perception in the Atlantic Forest of Paraguay, Combining Remote Sensing
           and Household Level Data

    • Authors: Emmanuel Da Ponte, Benjamin Mack, Christian Wohlfart, Oscar Rodas, Martina Fleckenstein, Natascha Oppelt, Stefan Dech, Claudia Kuenzer
      First page: 389
      Abstract: The Upper Parana Atlantic Forest (BAAPA) in Paraguay is one of the most threatened tropical forests in the world. The rapid growth of deforestation has resulted in the loss of 91% of its original cover. Numerous efforts have been made to halt deforestation activities, however farmers’ perception towards the forest and its benefits has not been considered either in studies conducted so far or by policy makers. This research provides the first multi-temporal analysis of the dynamics of the forest within the BAAPA region on the one hand, and assesses the way farmers perceive the forest and how this influences forest conservation at the farm level on the other. Remote sensing data acquired from Landsat images from 1999 to 2016 were used to measure the extent of the forest cover and deforestation rates over 17 years. Farmers’ influence on the dynamics of the forest was evaluated by combining earth observation data and household survey results conducted in the BAAPA region in 2016. Outcomes obtained in this study demonstrate a total loss in forest cover of 7500 km2. Deforestation rates in protected areas were determined by management regimes. The combination of household level and remote sensing data demonstrated that forest dynamics at the farm level is influenced by farm type, the level of dependency/use of forest benefits and the level of education of forest owners. An understanding of the social value awarded to the forest is a relevant contribution towards preserving natural resources.
      Citation: Forests
      PubDate: 2017-10-11
      DOI: 10.3390/f8100389
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 390: Taxonomic and Functional Diversity of a
           Quercus pyrenaica Willd. Rhizospheric Microbiome in the Mediterranean

    • Authors: José Cobo-Díaz, Antonio Fernández-González, Pablo Villadas, Nicolás Toro, Susannah Tringe, Manuel Fernández-López
      First page: 390
      Abstract: Altitude significantly affects vegetation growth and distribution, including the developmental stages of a forest. We used shotgun Illumina sequencing to analyze microbial community composition and functional potential in melojo-oak (Quercus pyrenaica Willd.) rhizospheric soil for three different development stages along an altitudinal gradient: (a) a low altitude, non-optimal site for forest maintenance; (b) an intermediate altitude, optimal site for a forest; and (c) a high altitude, expansion site with isolated trees but without a real forest canopy. We observed that, at each altitude, the same microbial taxa appear both in the taxonomic analysis of the whole metagenome and in the functional analysis of the methane, sulfur and nitrogen metabolisms. Although there were no major differences at the functional level, there were significant differences in the abundance of each taxon at the phylogenetic level between the rhizospheres of the forest (low and intermediate altitudes) and the expansion site. Proteobacteria and Actinobacteria were the most differentially abundant phyla in forest soils compared to the expansion site rhizosphere. Moreover, Verrucomicrobia, Bacteroidetes and Nitrospirae phyla were more highly represented in the non-forest rhizosphere. Our study suggests that rhizospheric microbial communities of the same tree species may be affected by development stage and forest canopy cover via changes in soil pH and the C/N ratio.
      Citation: Forests
      PubDate: 2017-10-12
      DOI: 10.3390/f8100390
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 391: Tree Regeneration Spatial Patterns in
           Ponderosa Pine Forests Following Stand-Replacing Fire: Influence of
           Topography and Neighbors

    • Authors: Justin Ziegler, Chad Hoffman, Paula Fornwalt, Carolyn Sieg, Mike Battaglia, Marin Chambers, Jose Iniguez
      First page: 391
      Abstract: Shifting fire regimes alter forest structure assembly in ponderosa pine forests and may produce structural heterogeneity following stand-replacing fire due, in part, to fine-scale variability in growing environments. We mapped tree regeneration in eighteen plots 11 to 15 years after stand-replacing fire in Colorado and South Dakota, USA. We used point pattern analyses to examine the spatial pattern of tree locations and heights as well as the influence of tree interactions and topography on tree patterns. In these sparse, early-seral forests, we found that all species were spatially aggregated, partly attributable to the influence of (1) aspect and slope on conifers; (2) topographic position on quaking aspen; and (3) interspecific attraction between ponderosa pine and other species. Specifically, tree interactions were related to finer-scale patterns whereas topographic effects influenced coarse-scale patterns. Spatial structures of heights revealed conspecific size hierarchies with taller trees in denser neighborhoods. Topography and heterospecific tree interactions had nominal effect on tree height spatial structure. Our results demonstrate how stand-replacing fires create heterogeneous forest structures and suggest that scale-dependent, and often facilitatory, rather than competitive, processes act on regenerating trees. These early-seral processes will establish potential pathways of stand development, affecting future forest dynamics and management options.
      Citation: Forests
      PubDate: 2017-10-14
      DOI: 10.3390/f8100391
      Issue No: Vol. 8, No. 10 (2017)
  • Forests, Vol. 8, Pages 392: Estimation of Vegetation Cover Using Digital
           Photography in a Regional Survey of Central Mexico

    • Authors: Víctor Salas-Aguilar, Cristóbal Sánchez-Sánchez, Fabiola Rojas-García, Fernando Paz-Pellat, J. Valdez-Lazalde, Carmelo Pinedo-Alvarez
      First page: 392
      Abstract: The methods for measuring vegetation cover in Mexican forest surveys are subjective and imprecise. The objectives of this research were to compare the sampling designs used to measure the vegetation cover and estimate the over and understory cover in different land uses, using digital photography. The study was carried out in 754 circular sampling sites in central Mexico. Four spatial sampling designs were evaluated in three spatial distribution patterns of the trees. The sampling designs with photographic captures in diagonal form had lower values of mean absolute error (MAE < 0.12) and less variation in random and grouped patterns. The Carbon and Biomass Sampling Plot (CBSP) design was chosen due to its smaller error in the different spatial tree patterns. The image processing was performed using threshold segmentation techniques and was automated through an application developed in the Python language. The two proposed methods to estimate vegetation cover through digital photographs were robust and replicable in all sampling plots with different land uses and different illumination conditions. The automation of the process avoided human estimation errors and ensured the reproducibility of the results. This method is working for regional surveys and could be used in national surveys due to its functionality.
      Citation: Forests
      PubDate: 2017-10-15
      DOI: 10.3390/f8100392
      Issue No: Vol. 8, No. 10 (2017)
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