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Forests, Volume 7, Issue 8 (August 2016) – 31 articles

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1901 KiB  
Article
Analysis of the Mechanism Hindering Sustainable Forestry Operations: A Case Study of Japanese Forest Management
by Yukari Fuchigami, Keishiro Hara, Michinori Uwasu and Shuji Kurimoto
Forests 2016, 7(8), 182; https://doi.org/10.3390/f7080182 - 22 Aug 2016
Cited by 20 | Viewed by 6780
Abstract
We investigated local forest management practices in Osaka, Japan aiming to clarify mechanisms that hinder long-term, sustainable forestry operation by carrying out forest surveys and interview surveys. Because mountain districts in Japan now face declining and aging populations, forestry work has shifted to [...] Read more.
We investigated local forest management practices in Osaka, Japan aiming to clarify mechanisms that hinder long-term, sustainable forestry operation by carrying out forest surveys and interview surveys. Because mountain districts in Japan now face declining and aging populations, forestry work has shifted to forest owners’ associations, with efficient forest management being required on an ad hoc basis as a result of the subsidy system. We found that the forest management plan for the study site utilized only one-seventh of the economic value of the forest, mainly due to the local forestry structure and an inefficient subsidy system that requires efficiency. The income yielded by timber undergoing such forest management and distribution processes is too low to permit forest owners to carry out sufficient forest cultivation. To effectively utilize the wood, a subsidy system that takes a long-term view and a timber market that puts an appropriate price on wood are needed. We argue that it is important to bolster the management position of the Japanese Forest Owners’ Associations for design an institutional scheme that enables to practice forestry management from a long-term perspective. Full article
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3188 KiB  
Article
C Stocks in Forest Floor and Mineral Soil of Two Mediterranean Beech Forests
by Anna De Marco, Antonietta Fioretto, Maria Giordano, Michele Innangi, Cristina Menta, Stefania Papa and Amalia Virzo De Santo
Forests 2016, 7(8), 181; https://doi.org/10.3390/f7080181 - 22 Aug 2016
Cited by 27 | Viewed by 5527
Abstract
This study focuses on two Mediterranean beech forests located in northern and southern Italy and therefore subjected to different environmental conditions. The research goal was to understand C storage in the forest floor and mineral soil and the major determinants. Relative to the [...] Read more.
This study focuses on two Mediterranean beech forests located in northern and southern Italy and therefore subjected to different environmental conditions. The research goal was to understand C storage in the forest floor and mineral soil and the major determinants. Relative to the northern forest (NF), the southern forest (SF) was found to produce higher amounts of litterfall (4.3 vs. 2.5 Mg·ha−1) and to store less C in the forest floor (~8 vs. ~12 Mg·ha−1) but more C in the mineral soil (~148 vs. ~72 Mg·ha−1). Newly-shed litter of NF had lower P (0.4 vs. 0.6 mg·g−1) but higher N concentration (13 vs. 10 mg·g−1) than SF. Despite its lower Mn concentration (0.06 vs. 0.18 mg·g−1), SF litter produces a Mn-richer humus (0.32 vs. 0.16 mg·g−1) that is less stable. The data suggest that decomposition in the NF forest floor is limited by the shorter growing season (178 days vs. 238 days) and the higher N concentrations in newly shed litter and forest floor. Differences in C stock in the mineral soil reflect differences in ecosystem productivity and long-term organic-matter accumulation. The vertical gradient of soluble and microbial fractions in the soil profile of SF was consistent with a faster turnover of organic matter in the forest floor and greater C accumulation in mineral soil relative to NF. With reference to regional-scale estimates from Italian National Forest Inventory data, the C stock in the mineral soil and the basal area of Italian beech forests were found to be significantly related, whereas C stock in the forest floor and C stock in the mineral soil were not. Full article
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2458 KiB  
Article
Allometric Equations for Estimating Tree Aboveground Biomass in Tropical Dipterocarp Forests of Vietnam
by Bao Huy, Krishna P. Poudel, Karin Kralicek, Nguyen Dinh Hung, Phung Van Khoa, Vu Tan Phương and Hailemariam Temesgen
Forests 2016, 7(8), 180; https://doi.org/10.3390/f7080180 - 22 Aug 2016
Cited by 30 | Viewed by 7467
Abstract
There are few allometric equations available for dipterocarp forests, despite the fact that this forest type covers extensive areas in tropical Southeast Asia. This study aims to develop a set of equations to estimate tree aboveground biomass (AGB) in dipterocarp forests in Vietnam [...] Read more.
There are few allometric equations available for dipterocarp forests, despite the fact that this forest type covers extensive areas in tropical Southeast Asia. This study aims to develop a set of equations to estimate tree aboveground biomass (AGB) in dipterocarp forests in Vietnam and to validate and compare their predictive performance with allometric equations used for dipterocarps in Indonesia and pantropical areas. Diameter at breast height (DBH), total tree height (H), and wood density (WD) were used as input variables of the nonlinear weighted least square models. Akaike information criterion (AIC) and residual plots were used to select the best models; while percent bias, root mean square percentage error, and mean absolute percent error were used to compare their performance to published models. For mixed-species, the best equation was AGB = 0.06203 × DBH 2.26430 × H 0.51415 × WD 0.79456 . When applied to a random independent validation dataset, the predicted values from the generic equations and the dipterocarp equations in Indonesia overestimated the AGB for different sites, indicating the need for region-specific equations. At the genus level, the selected equations were AGB = 0.03713 × DBH 2.73813 and AGB = 0.07483 × DBH 2.54496 for two genera, Dipterocarpus and Shorea, respectively, in Vietnam. Compared to the mixed-species equations, the genus-specific equations improved the accuracy of the AGB estimates. Additionally, the genus-specific equations showed no significant differences in predictive performance in different regions (e.g., Indonesia, Vietnam) of Southeast Asia. Full article
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1827 KiB  
Article
Cellulose Dynamics during Foliar Litter Decomposition in an Alpine Forest Meta-Ecosystem
by Kai Yue, Fuzhong Wu, Wanqin Yang, Chuan Zhang, Yan Peng, Bo Tan, Zhenfeng Xu and Chunping Huang
Forests 2016, 7(8), 176; https://doi.org/10.3390/f7080176 - 19 Aug 2016
Cited by 18 | Viewed by 5619
Abstract
To investigate the dynamics and relative drivers of cellulose degradation during litter decomposition, a field experiment was conducted in three individual ecosystems (i.e., forest floor, stream, and riparian zone) of an alpine forest meta-ecosystem on the eastern Tibetan Plateau. Four litter species (i.e., [...] Read more.
To investigate the dynamics and relative drivers of cellulose degradation during litter decomposition, a field experiment was conducted in three individual ecosystems (i.e., forest floor, stream, and riparian zone) of an alpine forest meta-ecosystem on the eastern Tibetan Plateau. Four litter species (i.e., willow: Salix paraplesia, azalea: Rhododendron lapponicum, cypress: Sabina saltuaria, and larch: Larix mastersiana) that had varying initial litter chemical traits were placed separately in litterbags and then incubated on the soil surface of forest floor plots or in the water of the stream and riparian zone plots. Litterbags were retrieved five times each year during the two-year experiment, with nine replicates each time for each treatment. The results suggested that foliar litter lost 32.2%–89.2% of the initial dry mass depending on litter species and ecosystem type after two-year’s incubation. The cellulose lost 60.1%–96.8% of the initial mass with degradation rate in the order of stream > riparian zone > forest floor. Substantial cellulose degradation occurred at the very beginning (i.e., in the first pre-freezing period) of litter decomposition. Litter initial concentrations of phosphorus (P) and lignin were found to be the dominant chemical traits controlling cellulose degradation regardless of ecosystems type. The local-scale environmental factors such as temperature, pH, and nutrient availability were important moderators of cellulose degradation rate. Although the effects of common litter chemical traits (e.g., P and lignin concentrations) on cellulose degradation across different individual ecosystems were identified, local-scale environmental factors such as temperature and nutrient availability were found to be of great importance for cellulose degradation. These results indicated that local-scale environmental factors should be considered apart from litter quality for generating a reliable predictive framework for the drivers of cellulose degradation and further on litter decomposition at a global scale. Full article
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2126 KiB  
Article
Variation in Mountain Vegetation Composition between the East and the West Sides of Southern Taiwan
by Yi-Shin Chian, Ching-Long Yeh and Chih-Chiang Wang
Forests 2016, 7(8), 179; https://doi.org/10.3390/f7080179 - 18 Aug 2016
Cited by 7 | Viewed by 4182
Abstract
In this study, we classified twenty associations, 179 families, 810 genera, 1897 species, and identified 291 rare species. The vegetation units were named following floristic-sociological approach. A cocktail determination key was used to classify the following vegetation units of association. More of the [...] Read more.
In this study, we classified twenty associations, 179 families, 810 genera, 1897 species, and identified 291 rare species. The vegetation units were named following floristic-sociological approach. A cocktail determination key was used to classify the following vegetation units of association. More of the west side than the east side of the study area was at a higher altitude, and the vegetation experienced significant compression. Follow the result of detrended correspondence analysis (DCA), winter rainfall and average January temperature were the main environmental factors affecting variation in vegetation distribution by elevation gradient in this area. The particular association type on the eastern side of the study area is attributable to the northeast monsoon experienced year-round in this area, which causes relatively low temperature and humidity and wind rush, as well as the compression of the elevation range in each forest. The monsoon deciduous vegetation area exists only on the west of the low altitude mountains. Full article
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5424 KiB  
Article
Reproductive Success and Inbreeding Differ in Fragmented Populations of Pinus rzedowskii and Pinus ayacahuite var. veitchii, Two Endemic Mexican Pines under Threat
by Paty Castilleja Sánchez, Patricia Delgado Valerio, Cuauhtémoc Sáenz-Romero and Yvonne Herrerías Diego
Forests 2016, 7(8), 178; https://doi.org/10.3390/f7080178 - 18 Aug 2016
Cited by 10 | Viewed by 6101
Abstract
Seed production, quality, germination and seedling establishment are indicators of reproductive success in conifers. Monitoring of these parameters is essential to determine the viability of populations for the purposes of conservation. We analyze cone and seed traits as indicators of reproductive success in [...] Read more.
Seed production, quality, germination and seedling establishment are indicators of reproductive success in conifers. Monitoring of these parameters is essential to determine the viability of populations for the purposes of conservation. We analyze cone and seed traits as indicators of reproductive success in the endangered Rzedowski´s pine (Pinus rzedowskii (Madrigal et Caballero) and near-threatened veitchii pine (Pinus ayacahuite var. veitchii (Shaw)) in west-central Michoacán, Mexico. These traits were systematically quantified and their variation assessed using Generalized Linear Mixed Models (GLMMs). We found that the reproductive success of Rzedowski’s pine seems to be critical, presenting low seed efficiency (17.10%), germination (5.0%) and seedling establishment (27.7%), with high levels of inbreeding (0.79). In contrast, veitchii pine presents moderate seed efficiency (54.9%), high germination (71.5%) and seedling establishment (84%–97%) and low inbreeding (0.33). Reproductive indicators differed significantly among zones and populations for each species, where fragment sizes mainly affected seed production and efficiency. This result indicates that fragmentation has played a more important role in the reproductive success of Rzedowski’s pine than in veitchii pine, perhaps by limiting pollen flow among zones and populations and producing higher levels of inbreeding and lower seed efficiency in the former species. We propose a conservation strategy for these important pine species in order to increase their long-term genetic viability. Full article
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5230 KiB  
Article
Diameter Growth, Biological Rotation Age and Biomass of Chinese Fir in Burning and Clearing Site Preparations in Subtropical China
by Hua Zhou, Shengwang Meng and Qijing Liu
Forests 2016, 7(8), 177; https://doi.org/10.3390/f7080177 - 18 Aug 2016
Cited by 10 | Viewed by 6089
Abstract
Sustained forest management of Cunninghamia lanceolata (Chinese fir) plantations in subtropical China is restricted by the limited availability of quantitative data. This study combines inventory data and tree-ring analysis of Chinese fir from natural and plantation forests that were subjected to controlled burning [...] Read more.
Sustained forest management of Cunninghamia lanceolata (Chinese fir) plantations in subtropical China is restricted by the limited availability of quantitative data. This study combines inventory data and tree-ring analysis of Chinese fir from natural and plantation forests that were subjected to controlled burning or brush clearing site preparations. Inter-annual variation of Chinese fir tree-ring widths were measured for the controlled burning, brush clearing and natural forest sites. The mean annual diametric growth of Chinese fir was 0.56 cm·year−1 for the natural forest, 0.80 cm·year−1 for the brush clearing site and 1.10 cm·year−1 for the controlled burning site. The time needed to reach the minimum cutting/logging diameter of 15 cm was 14 years in the controlled burning site, 19 years in the brush clearing site and >40 years in the natural forest. The biological rotation ages for the burning, cutting and natural forest sites were 15, 26 and >100 years, respectively. The total aboveground biomasses for the burning and clearing sites were 269.8 t·ha−1 and 252 t·ha−1, respectively. These results suggest that the current 25-year cutting cycle greatly underestimates the growth rate of Chinese fir plantations. Full article
(This article belongs to the Special Issue Forest Growth Response to Environmental Stress)
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3442 KiB  
Article
Optimum Vegetation Conditions for Successful Establishment of Planted Eastern White Pine (Pinus strobus L.)
by Douglas G. Pitt, Michael K. Hoepting, William C. Parker, Andrée E. Morneault, Len Lanteigne, Al Stinson and James C. G. Farrell
Forests 2016, 7(8), 175; https://doi.org/10.3390/f7080175 - 13 Aug 2016
Cited by 4 | Viewed by 5259
Abstract
The 10th-growing season performance of planted eastern white pine (Pinus strobus L.) seedlings was evaluated in response to herbaceous and woody vegetation control treatments within a clearcut and two variants of the uniform shelterwood regeneration system (single vs. multiple future removal cuts). [...] Read more.
The 10th-growing season performance of planted eastern white pine (Pinus strobus L.) seedlings was evaluated in response to herbaceous and woody vegetation control treatments within a clearcut and two variants of the uniform shelterwood regeneration system (single vs. multiple future removal cuts). Herbaceous vegetation control involved the suppression of grasses, forbs, ferns and low shrubs for the first 2 or 4 growing seasons after planting. Deciduous woody vegetation control treatments, conducted in combination with the herbaceous treatments within a response-surface design, involved the permanent removal of all tall shrubs and deciduous trees at the time of planting, at the end of the 2nd or 5th growing seasons, or not at all. In general, the average size of planted pine was related positively to the duration of herbaceous vegetation control and negatively to delays in woody control. White pine weevil (Pissodes strobi Peck) altered these trends, reducing the height of pine on plots with little or no overtopping deciduous woody vegetation or mature tree cover. Where natural pine regeneration occurred on these plots, growth was similar but subordinate to the planted pine. Data from the three sites indicate that at least 60% of planted pine may be expected to reach an age-10 height target of 2.5 m when overtopping cover (residual overstory + regenerating deciduous) is managed at approximately 65% ± 10%, and total herbaceous cover is suppressed to levels not exceeding 50% in the first five years. On productive sites, this combination may be difficult to achieve in a clearcut, and requires fairly rigorous vegetation management in shelterwood regeneration systems. Currently, synthetic herbicides offer the only affordable and effective means of achieving such vegetation control. Full article
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3387 KiB  
Article
Major Changes in Growth Rate and Growth Variability of Beech (Fagus sylvatica L.) Related to Soil Alteration and Climate Change in Belgium
by Nicolas Latte, Jérôme Perin, Vincent Kint, François Lebourgeois and Hugues Claessens
Forests 2016, 7(8), 174; https://doi.org/10.3390/f7080174 - 8 Aug 2016
Cited by 16 | Viewed by 5622
Abstract
Global change—particularly climate change, forest management, and atmospheric deposition—has significantly altered forest growing conditions in Europe. The influences of these changes on beech growth (Fagus sylvatica L.) were investigated for the past 80 years in Belgium, using non-linear mixed effects models on [...] Read more.
Global change—particularly climate change, forest management, and atmospheric deposition—has significantly altered forest growing conditions in Europe. The influences of these changes on beech growth (Fagus sylvatica L.) were investigated for the past 80 years in Belgium, using non-linear mixed effects models on ring-width chronologies of 149 mature and dominant beech trees (87–186 years old). The effects of the developmental stage (i.e., increasing tree size) were filtered out in order to focus on time-dependent growth changes. Beech radial growth was divided into a low-frequency signal (=growth rate), mainly influenced by forest management and atmospheric deposition, and into a high-frequency variability (≈mean sensitivity), mainly influenced by climate change. Between 1930 and 2008, major long-term and time-dependent changes were highlighted. The beech growth rate has decreased by about 38% since the 1950–1960s, and growth variability has increased by about 45% since the 1970–1980s. Our results indicate that (1) before the 1980s, beech growth rate was not predominantly impacted by climate change but rather by soil alteration (i.e., soil compaction and/or nitrogen deposition); and (2) since the 1980s, climate change induced more frequent and intense yearly growth reductions that amplified the growth rate decrease. The highlighted changes were similar in the two ecoregions of Belgium, although more pronounced in the lowlands than in the uplands. Full article
(This article belongs to the Special Issue Forest Growth Response to Environmental Stress)
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4017 KiB  
Article
Forest Biomass and Net Primary Productivity in Southwestern China: A Meta-Analysis Focusing on Environmental Driving Factors
by Li Bin Liu, Hua Mei Yang, Yue Xu, Yin Ming Guo and Jian Ni
Forests 2016, 7(8), 173; https://doi.org/10.3390/f7080173 - 6 Aug 2016
Cited by 16 | Viewed by 8191
Abstract
Biomass and net primary productivity (NPP) are important factors for studying terrestrial carbon storage and the carbon cycle. Using data from existing literature, this study synthesized and analyzed a comprehensive database of direct field observations of forest biomass and NPP for Southwestern China. [...] Read more.
Biomass and net primary productivity (NPP) are important factors for studying terrestrial carbon storage and the carbon cycle. Using data from existing literature, this study synthesized and analyzed a comprehensive database of direct field observations of forest biomass and NPP for Southwestern China. The biomass of mature natural forests and mature planted forests range from 81.2 Mg·ha−1 to 692.6 Mg·ha−1 (mean = 288.1 Mg·ha−1) and from 76.8 Mg·ha−1 to 670.1 Mg·ha−1 (mean = 181.5 Mg·ha−1), respectively. Mature natural forests have higher biomass than mature planted ones. The NPP values of natural and planted forests range from 1.4 Mg·ha−1·year−1 to 29.6 Mg·ha−1·year−1 (mean = 13.6 Mg·ha−1·year−1) and from 0.6 Mg·ha−1·year−1 to 26.5 Mg·ha−1·year−1 (mean = 9.9 Mg·ha−1·year−1), respectively. Correlations among biomass, NPP, and environmental factors show that NPP significantly decreases with latitude and increases with mean annual temperature, mean annual precipitation, growing degree-days on a 0 °C base, and mean annual drought index, whereas biomass positively correlates with stand age and leaf area index strongly. Karst forests exhibit almost the same NPP as non-karst forests, but the former have significantly lower biomass compared to the latter. Comprehensive regional data synthesis and analysis based on direct field observations of forest biomass and NPP are important for benchmarking global and regional vegetation and carbon models, estimating regional carbon content, restoring vegetation, and mitigating climate change. Full article
(This article belongs to the Collection Forests Carbon Fluxes and Sequestration)
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3912 KiB  
Article
Baseline Mortality Analysis Reveals Legacy of Contrasting Land Use Practices on the Structural Sustainability of Endangered Moroccan and Spanish Mountain Forests
by John D. Castello, Jonathan A. Cale, Cortney M. D’Angelo and Juan Carlos Linares
Forests 2016, 7(8), 172; https://doi.org/10.3390/f7080172 - 5 Aug 2016
Cited by 3 | Viewed by 5606
Abstract
Disturbances can affect forest health and are important modulating factors of tree responses to environmental changes. However, standard methods are needed to assess and elucidate the relative effects of disturbance legacies on forest health among species. Here, structural sustainability was used to evaluate [...] Read more.
Disturbances can affect forest health and are important modulating factors of tree responses to environmental changes. However, standard methods are needed to assess and elucidate the relative effects of disturbance legacies on forest health among species. Here, structural sustainability was used to evaluate and to compare the impacts of contrasting disturbances on the health of Quercus ilex, Cedrus atlantica, and Abies pinsapo forest stands in Morocco and Spain. Disturbance effects on structural sustainability were related to type, severity, and land-use history, and showed inter-regional variability. Cedrus atlantica was structurally sustainable in its core distribution in Morocco, but not at its southern and northernmost geographical range limits. Quercus ilex was structurally sustainable in Morocco. Abies pinsapo was structurally sustainable at optimal elevation sites in Morocco (Rif Mts.), but considering the whole A. pinsapo dataset including Morocco and Spain, the species is structurally unsustainable due to excessive mortality. However, at the lower elevation plots in Spain, unsustainability was due to insufficient mortality. Although some forests were structurally sustainable, none of them were deemed healthy because none met their management objectives. Results also support the key role of disturbance regimes as drivers of forest structural sustainability and adaptive capacity. Full article
(This article belongs to the Special Issue Forest Growth Response to Environmental Stress)
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1595 KiB  
Review
Aftermath of Mountain Pine Beetle Outbreak in British Columbia: Stand Dynamics, Management Response and Ecosystem Resilience
by Amalesh Dhar, Lael Parrott and Christopher D.B. Hawkins
Forests 2016, 7(8), 171; https://doi.org/10.3390/f7080171 - 5 Aug 2016
Cited by 48 | Viewed by 11223
Abstract
The mountain pine beetle (Dendroctonus ponderosae Hopkins) (MPB) has infested and killed millions of hectares of lodgepole pine (Pinus contorta var. latifolia Engelm) forests in British Columbia, Canada, over the past decade. It is now spreading out of its native [...] Read more.
The mountain pine beetle (Dendroctonus ponderosae Hopkins) (MPB) has infested and killed millions of hectares of lodgepole pine (Pinus contorta var. latifolia Engelm) forests in British Columbia, Canada, over the past decade. It is now spreading out of its native range into the Canadian boreal forest, with unknown social, economic and ecological consequences. This review explores the ramifications of the MPB epidemic with respect to mid-term timber supply, forest growth, structure and composition, vegetation diversity, forest fire, climate change, and ecosystem resilience. Research confirms that, in British Columbia, all of these variables are more significantly impacted when salvage logging is used as management response to the outbreak. We conclude that appropriate management in response to MPB is essential to ensuring ecologically resilient future forests and reliable mid-term timber supplies for affected human communities. We highlight knowledge gaps and avenues for research to advance our understanding in support of sustainable post-disturbance forest management policies in British Columbia and elsewhere. Full article
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2975 KiB  
Review
The Place of Community Forest Management in the REDD+ Landscape
by Johanne Pelletier, Nancy Gélinas and Margaret Skutsch
Forests 2016, 7(8), 170; https://doi.org/10.3390/f7080170 - 4 Aug 2016
Cited by 48 | Viewed by 17471
Abstract
Community forest management (CFM) is identified by many actors as a core strategy for reducing emissions from deforestation and forest degradation in developing countries (REDD+). Others however see REDD+ as a danger to CFM. In response to these contrasting views, we carried out [...] Read more.
Community forest management (CFM) is identified by many actors as a core strategy for reducing emissions from deforestation and forest degradation in developing countries (REDD+). Others however see REDD+ as a danger to CFM. In response to these contrasting views, we carried out a systematic review of CFM case studies to look at CFM’s potential role in achieving forest carbon benefits and social co-benefits for forest communities. We evaluated the potential impacts of REDD+ on CFM. Our review showed that there is strong evidence of CFM’s role in reducing degradation and stabilizing forested landscapes; however, the review also showed less evidence about the role of CFM in reducing deforestation. For social benefits, we found that CFM contributes to livelihoods, but its effect on poverty reduction may be limited. Also, CFM may not deal adequately with the distribution of benefits within communities or user groups. These insights are important for CFM-based REDD+ intervention; measures should be adopted to overcome these gaps. Innovative incentive structures to existing CFM are discussed. The recognition of rights for forest communities is one first step identified in promoting CFM. We call for sound empirical impact evaluations that analyze CFM and CFM-based REDD+ interventions by looking at both biophysical and social outcomes. Full article
(This article belongs to the Special Issue REDD+ Crossroads Post Paris: Politics, Lessons and Interplays)
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3751 KiB  
Article
Improved Multi-Sensor Satellite-Based Aboveground Biomass Estimation by Selecting Temporally Stable Forest Inventory Plots Using NDVI Time Series
by Mikhail Urbazaev, Christian Thiel, Mirco Migliavacca, Markus Reichstein, Pedro Rodriguez-Veiga and Christiane Schmullius
Forests 2016, 7(8), 169; https://doi.org/10.3390/f7080169 - 4 Aug 2016
Cited by 14 | Viewed by 5674
Abstract
Accurate estimates of aboveground biomass (AGB) are crucial to assess terrestrial C-stocks and C-emissions as well as to develop sustainable forest management strategies. In this study we used Synthetic Aperture Radar (SAR) data acquired at L-band and the Landsat tree cover product together [...] Read more.
Accurate estimates of aboveground biomass (AGB) are crucial to assess terrestrial C-stocks and C-emissions as well as to develop sustainable forest management strategies. In this study we used Synthetic Aperture Radar (SAR) data acquired at L-band and the Landsat tree cover product together with Moderate Resolution Image Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) time series data to improve AGB estimations over two study areas in southern Mexico. We used Mexican National Forest Inventory (INFyS) data collected between 2005 and 2011 to calibrate AGB models as well as to validate the derived AGB products. We applied MODIS NDVI time series data analysis to exclude field plots in which abrupt changes were detected. For this, we used Breaks For Additive Seasonal and Trend analysis (BFAST). We modelled AGB using an original field dataset and BFAST-filtered data. The results show higher accuracies of AGB estimations using BFAST-filtered data than using original field data in terms of R2 and root mean square error (RMSE) for both dry and humid tropical forests of southern Mexico. The best results were found in areas with high deforestation rates where the AGB models based on the BFAST-filtered data substantially outperformed those based on original field data (R2BFAST = 0.62 vs. R2orig = 0.45; RMSEBFAST = 28.4 t/ha vs. RMSEorig = 33.8 t/ha). We conclude that the presented method shows great potential to improve AGB estimations and can be easily and automatically implemented over large areas. Full article
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1649 KiB  
Article
Physical, Chemical, and Biological Properties of Soil under Decaying Wood in a Tropical Wet Forest in Puerto Rico
by Marcela Zalamea, Grizelle González and Deborah Jean Lodge
Forests 2016, 7(8), 168; https://doi.org/10.3390/f7080168 - 4 Aug 2016
Cited by 30 | Viewed by 7989
Abstract
Decaying wood is related to nutrient cycling through its role as either a sink or source of nutrients. However, at micro scales, what is the effect of decaying logs on the physical, chemical, and biotic characteristics of the soil underneath? We took samples [...] Read more.
Decaying wood is related to nutrient cycling through its role as either a sink or source of nutrients. However, at micro scales, what is the effect of decaying logs on the physical, chemical, and biotic characteristics of the soil underneath? We took samples from a 0 to 5 cm depth under and a 50 cm distance away from decaying logs (Dacryodes excelsa and Swietenia macrophylla) at 2 stages of decay, and measured soil temperature, total and available nutrients, and root length in a tropical wet forest. We found decaying wood affected physical, chemical, and biotic properties of the underlying soil. Soil temperature was less variable under the decaying logs than away from the logs. Soil under the decaying wood had fewer roots, and lower NO3 and Mg2+ availability than samples collected a distance of 50 cm away from the logs. Tree species and decay stage were important factors defining the effect of decaying wood on the distribution of available nutrients. Ca2+, Mg2+, and K+ levels were higher in the soil associated with the youngest logs, and were higher near S. macrophylla logs. Heavy metals were also higher in the soil located near the younger logs independent of the species; other metal ions such as Al3+ and Fe3+ were higher in the soil associated with D. excelsa and the oldest logs. These results indicate decaying wood can contribute to and generate spatial heterogeneity of soil properties. Full article
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1301 KiB  
Article
Towards Harmonizing Leaf Litter Decomposition Studies Using Standard Tea Bags—A Field Study and Model Application
by Markus Didion, Anna Repo, Jari Liski, Martin Forsius, Michael Bierbaumer and Ika Djukic
Forests 2016, 7(8), 167; https://doi.org/10.3390/f7080167 - 1 Aug 2016
Cited by 54 | Viewed by 9465
Abstract
Decomposition of plant litter is a key process for the transfer of carbon and nutrients in ecosystems. Carbon contained in the decaying biomass is released to the atmosphere as respired CO2, and may contribute to global warming. Litterbag studies have been [...] Read more.
Decomposition of plant litter is a key process for the transfer of carbon and nutrients in ecosystems. Carbon contained in the decaying biomass is released to the atmosphere as respired CO2, and may contribute to global warming. Litterbag studies have been used to improve our knowledge of the drivers of litter decomposition, but they lack comparability because litter quality is plant species-specific. The use of commercial tea bags as a standard substrate was suggested in order to harmonize studies, where green tea and rooibos represent more labile and more recalcitrant C compounds as surrogates of local litter. Here we examine the potential of the use of standardized material for improving our understanding of litter decomposition across climate regions, and to further develop pertinent models. We measured the decomposition of incubated local and standard litters over two years along an elevation gradient in the Austrian Limestone Alps. The similar response to changes in temperature and precipitation of the pairs of local and standard litter—i.e., Fagus sylvatica and green tea, and Pinus nigra and rooibos tea, respectively—suggests the suitability of the standard litters for further examining the role of environmental drivers of decomposition. Harmonized data obtained from standardized litter experiments would provide a key prerequisite for further developing simulation models for the estimation of the C balance of ecosystem litter pools. Full article
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3052 KiB  
Article
Estimates of Wildfire Emissions in Boreal Forests of China
by Kunpeng Yi and Yulong Bao
Forests 2016, 7(8), 158; https://doi.org/10.3390/f7080158 - 1 Aug 2016
Cited by 11 | Viewed by 6151
Abstract
Wildfire emissions in the boreal forests yield an important contribution to the chemical budget of the troposphere. To assess the contribution of wildfire to the emissions of atmospheric trace species in the Great Xing’an Mountains (GXM), which is also the most severe fire-prone [...] Read more.
Wildfire emissions in the boreal forests yield an important contribution to the chemical budget of the troposphere. To assess the contribution of wildfire to the emissions of atmospheric trace species in the Great Xing’an Mountains (GXM), which is also the most severe fire-prone boreal forest region in China, we estimated various wildfire activities by combining explicit spatio-temporal remote sensing data with fire-induced emission models. We observed 9998 fire scars with 46,096 km2 in the GXM between the years 1986 and 2010. The years 1987 and 2003 contributed 33.2% and 22.9%, respectively, in burned area during the 25 years. Fire activity is the strongest in May. Most large fires occurred in the north region of the GXM between 50° N and 54° N latitude due to much drier weather and higher fire danger in the northern region than in the southern region of the study domain. Evergreen and deciduous needleleaf forest and deciduous broadleaf forest are the main sources of emissions, accounting for 84%, 81%, 84%, 87%, 89%, 86%, 85% and 74% of the total annual CO2, CH4, CO, PM10, PM2.5, SO2, BC and NOx emissions, respectively. Wildfire emissions from shrub, grassland and cropland only account for a small fraction of the total emissions level (approximately 4%–11%). Comparisons of our results with other published estimates of wildfire emissions show reasonable agreement. Full article
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9653 KiB  
Article
Forest Stand Inventory Based on Combined Aerial and Terrestrial Close-Range Photogrammetry
by Tomáš Mikita, Přemysl Janata and Peter Surový
Forests 2016, 7(8), 165; https://doi.org/10.3390/f7080165 - 30 Jul 2016
Cited by 111 | Viewed by 13518
Abstract
In this article we introduce a new method for forest management inventories especially suitable for highly-valued timber where the precise estimation of stem parameters (diameter, form, and tapper) plays the key role for market purposes. The unmanned aerial system (UAS)-based photogrammetry is combined [...] Read more.
In this article we introduce a new method for forest management inventories especially suitable for highly-valued timber where the precise estimation of stem parameters (diameter, form, and tapper) plays the key role for market purposes. The unmanned aerial system (UAS)-based photogrammetry is combined with terrestrial photogrammetry executed by walking inside the stand and the individual tree parameters are estimated. We compare two automatic methods for processing of the point clouds and the delineation of stem circumference at breast height. The error of the diameter estimation was observed to be under 1 cm root mean square error (RMSE) and the height estimation error was 1 m. Apart from the mentioned accuracy, the main advantage of the proposed work is shorter time demand for field measurement; we could complete both inventories of 1 hectare forest stand in less than 2 h of field work. Full article
(This article belongs to the Special Issue Forest Ground Observations through Terrestrial Point Clouds)
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1387 KiB  
Article
Functional Diversity of Small and Large Trees along Secondary Succession in a Tropical Dry Forest
by Lucía Sanaphre-Villanueva, Juan Manuel Dupuy, José Luis Andrade, Casandra Reyes-García, Horacio Paz and Paula C. Jackson
Forests 2016, 7(8), 163; https://doi.org/10.3390/f7080163 - 30 Jul 2016
Cited by 22 | Viewed by 5706
Abstract
Functional Diversity is considered an important driver of community assembly in environmental and successional gradients. To understand tree assembly processes in a semideciduous tropical forest, we analyzed the variation of Functional Richness (FRic), Functional Divergence (FDiv), and Functional Evenness (FEve) of small vs. [...] Read more.
Functional Diversity is considered an important driver of community assembly in environmental and successional gradients. To understand tree assembly processes in a semideciduous tropical forest, we analyzed the variation of Functional Richness (FRic), Functional Divergence (FDiv), and Functional Evenness (FEve) of small vs. large trees in relation to fallow age after slash-and-burn agriculture and topographical position (flat sites vs. hills). FRic of small trees was lower than null model predicted values across the successional gradient, and decreased unexpectedly in older successional ages. FRic of large trees was higher than null model predictions early in succession and lower in late-successional stands on hills. Dominant species were more similar (low FDiv) in early and intermediate successional stands for small trees, and on hills for large trees, suggesting that species that are best adapted to harsh conditions share similar traits. We also found evidence of competitive exclusion among similar species (high FEve) for small trees in early successional stands. Overall, our results indicate that community assembly of small trees is strongly affected by the changing biotic and abiotic conditions along the successional and topographical gradient. For large trees, hills may represent the most stressful conditions in this landscape. Full article
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4449 KiB  
Article
Small-Scale Effect of Pine Stand Pruning on Snowpack Distribution in the Pyrenees Observed with a Terrestrial Laser Scanner
by Jesús Revuelto, Juan-Ignacio López-Moreno, Cesar Azorin-Molina, Esteban Alonso-González and Alba Sanmiguel-Vallelado
Forests 2016, 7(8), 166; https://doi.org/10.3390/f7080166 - 29 Jul 2016
Cited by 7 | Viewed by 4861
Abstract
Forests in snow-dominated areas have substantial effects on the snowpack and its evolution over time. Such interactions have significant consequences for the hydrological response of mountain rivers. Thus, the impact of forest management actions on the snow distribution, and hence the storage of [...] Read more.
Forests in snow-dominated areas have substantial effects on the snowpack and its evolution over time. Such interactions have significant consequences for the hydrological response of mountain rivers. Thus, the impact of forest management actions on the snow distribution, and hence the storage of water in the form of snow during winter and spring, is a major concern. The results of this study provide the first detailed comparison of the small-scale effect of forest characteristics on the snowpack distribution, assessed prior to and following major modification of the structure of the canopy by pruning of the lower branches of the trees to 3 m above the ground. This is a common management practice aimed at reducing the spread of forest fires. The snowpack distribution was determined using terrestrial laser scanning (LiDAR technology) at a high spatial resolution (0.25 m) over a 1000 m2 study area during 23 survey dates over three snow seasons in a small study area in the central Pyrenees. The pruning was conducted during summer following the snow season in the second year of the study (i.e., the study duration encompassed two seasons prior to canopy pruning and one following). Principal component analysis (PCA) was used to identify recurring spatial patterns of snow distribution. The results showed that pruning reduced the average radius of the canopy of trees by 1.2 m, and increased the clearance around the trunks, as all the branches that formerly contacted the ground were removed. However, the impact on the snowpack was moderate. The PCA revealed that the spatial configuration of the snowpack did not change significantly, as the principal components included survey days from different periods of the snow season, and did not discriminate days surveyed prior to and following pruning. Nevertheless, removal of the lower branches reduced the area beneath the canopy by 36%, and led to an average increase in total snow depth of approximately 14%. Full article
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1033 KiB  
Article
Long-Term Forest Paired Catchment Studies: What Do They Tell Us That Landscape-Level Monitoring Does Not?
by Daniel G. Neary
Forests 2016, 7(8), 164; https://doi.org/10.3390/f7080164 - 29 Jul 2016
Cited by 33 | Viewed by 4831
Abstract
Forested catchments throughout the world are known for producing high quality water for human use. In the 20th Century, experimental forest catchment studies played a key role in studying the processes contributing to high water quality. The hydrologic processes investigated on these paired [...] Read more.
Forested catchments throughout the world are known for producing high quality water for human use. In the 20th Century, experimental forest catchment studies played a key role in studying the processes contributing to high water quality. The hydrologic processes investigated on these paired catchments have provided the science base for examining water quality responses to natural disturbances such as wildfire, insect outbreaks, and extreme hydrologic events, and human-induced disturbances such as timber harvesting, site preparation, prescribed fires, fertilizer applications, pesticide usage, rainfall acidification, and mining. This paper compares and contrasts the paired catchment approach with landscape-level water resource monitoring to highlight the information on hydrologic processes provided by the paired catchment approach that is not provided by the broad-brush landscape monitoring. Full article
(This article belongs to the Special Issue Forest Management and Water Resources in the Anthropocene)
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2210 KiB  
Article
Exploring Relationships between Socioeconomic Background and Urban Greenery in Portland, OR
by Lorien Nesbitt and Michael J. Meitner
Forests 2016, 7(8), 162; https://doi.org/10.3390/f7080162 - 29 Jul 2016
Cited by 40 | Viewed by 7606
Abstract
Do urban residents experience societal benefits derived from urban forests equitably? We conducted a broad-scale spatial analysis of the relationship between urban greenery and socioeconomic factors in the Portland metropolitan area. The Normalized Difference Vegetation Index was derived from National Agriculture Imagery Program [...] Read more.
Do urban residents experience societal benefits derived from urban forests equitably? We conducted a broad-scale spatial analysis of the relationship between urban greenery and socioeconomic factors in the Portland metropolitan area. The Normalized Difference Vegetation Index was derived from National Agriculture Imagery Program images to map urban vegetation cover, and Outdoor Recreation and Conservation Area data were used to identify green spaces. These measures of urban greenery were correlated with census data to identify socioeconomic factors associated with high levels of green inequity. Population density, house age, income, and race were strongly correlated with vegetation cover. However, the distribution of green spaces showed a much weaker relationship with socioeconomic factors. These results highlight the importance of different measures of access to urban greenery and suggest potential solutions to the problem of urban green inequity. Cities can use our methods to conduct targeted urban forest management to maximize urban forest benefits received by residents. Full article
(This article belongs to the Special Issue Urban and Periurban Forest Diversity and Ecosystem Services)
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2328 KiB  
Article
Diurnal Freeze-Thaw Cycles Modify Winter Soil Respiration in a Desert Shrub-Land Ecosystem
by Peng Liu, Tianshan Zha, Xin Jia, Ben Wang, Xiaonan Guo, Yuqing Zhang, Bin Wu, Qiang Yang and Heli Peltola
Forests 2016, 7(8), 161; https://doi.org/10.3390/f7080161 - 29 Jul 2016
Cited by 16 | Viewed by 5606
Abstract
Winter soil respiration (Rs) is becoming a significant component of annual carbon budgets with more warming in winter than summer. However, little is known about the controlling mechanisms of winter Rs in dryland. We made continuous measurements of Rs [...] Read more.
Winter soil respiration (Rs) is becoming a significant component of annual carbon budgets with more warming in winter than summer. However, little is known about the controlling mechanisms of winter Rs in dryland. We made continuous measurements of Rs in four microsites (non-crust (BS), lichen (LC), moss (MC), and a mixture of moss and lichen (ML)) in a desert shrub-land ecosystem northern China, to investigate the causes of Rs dynamics in winter. The mean winter Rs ranged from 0.10 to 0.17 µmol CO2 m−2·s−1 across microsites, with the highest value in BS. Winter Q10 (known as the increase in respiration rate per 10 °C increase in temperature) values (2.8–19) were much higher than those from the growing season (1.5). Rs and Q10 were greatly enhanced in freeze-thaw cycles compared to frozen days. Diurnal patterns of Rs between freeze-thaw and frozen days differed. Although the freeze-thaw period was relatively short, its cumulative Rs contributed significantly to winter Rs. The presence of biocrust might induce lower temperature, thus having fewer freeze-thaw cycles relative to bare soil, leading to the lower Rs for microsites with biocrusts. In conclusion, winter Rs in drylands was sensitive to soil temperature (Ts) and Ts-induced freeze-thaw cycles. The temperature impact on Rs varied among soil cover types. Winter Rs in drylands may become more important as the climate is continuously getting warmer. Full article
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1862 KiB  
Article
Assessing the Genetic Diversity and Genealogical Reconstruction of Cypress (Cupressus funebris Endl.) Breeding Parents Using SSR Markers
by Hanbo Yang, Rui Zhang, Guoqing Jin, Zhongping Feng and Zhichun Zhou
Forests 2016, 7(8), 160; https://doi.org/10.3390/f7080160 - 28 Jul 2016
Cited by 16 | Viewed by 4765
Abstract
To identify genetic diversity, genetic structure and the relationship among accessions, and further establish a core collection for the long-term breeding of cypress (Cupressus funebris Endl.), the genealogy of breeding parents was reconstructed using simple sequence repeat (SSR) molecular markers. Seventeen SSR [...] Read more.
To identify genetic diversity, genetic structure and the relationship among accessions, and further establish a core collection for the long-term breeding of cypress (Cupressus funebris Endl.), the genealogy of breeding parents was reconstructed using simple sequence repeat (SSR) molecular markers. Seventeen SSR markers were used to detect molecular polymorphisms among 290 cypress accessions from five provinces and 53 accessions with unknown origin in China. A total of 92 alleles (Na) were detected with 5.412 alleles per locus and an average polymorphism information content (PIC) of 0.593. The haplotype diversity (H) ranged from 0.021 to 0.832, with an average of 0.406. The number of alleles (Na) and the effective number of alleles (Ne) ranged from 4.294 to 5.176 and from 2.488 to 2.817 among five populations, respectively. The pairwise population matrix of Nei’s genetic distance ranged from 0.008 to 0.023. Based on the results of unweighted pair group method average (UPGMA) cluster and population structure analyses, 343 breeding parents were divided into two major groups. Lower genetic differentiation coefficients and closer genetic relationships were observed among cypress breeding parents, suggesting that the genetic basis was narrow, and the genetic relationship was confused by frequent introduction and wide cultivation. Moreover, we reconstructed the genealogy between breeding parents and 30 accessions of breeding parents from an identified core collection. According to the present study, not only geographic origin but also the relationship of the individuals should be considered in future crossbreeding work. Full article
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2038 KiB  
Article
Soil Elements Influencing Community Structure in an Old-Growth Forest in Northeastern China
by Wei Xu, Minhui Hao, Juan Wang, Chunyu Zhang, Xiuhai Zhao and Klaus Von Gadow
Forests 2016, 7(8), 159; https://doi.org/10.3390/f7080159 - 28 Jul 2016
Cited by 3 | Viewed by 4450
Abstract
This study uses detailed soil and vegetation data collected in a 30-ha old-growth broad-leaved Korean pine forest to study the effect of soil properties on tree community structures. Spatial distribution patterns are simulated using a homogeneous Poisson process (HomP) and a homogeneous Thomas [...] Read more.
This study uses detailed soil and vegetation data collected in a 30-ha old-growth broad-leaved Korean pine forest to study the effect of soil properties on tree community structures. Spatial distribution patterns are simulated using a homogeneous Poisson process (HomP) and a homogeneous Thomas process (HomT). The simulated distributions are compared with the observed ones to explore correlations between certain tree species and several soil elements. The HomP model shows that all tested tree species are significantly correlated with at least one principal component in the upper-layer soil elements. The HomT model shows that only 36.4% of tree species are significantly correlated with the principal component of at least one upper-layer soil element. This result shows that the impact of dispersal limitation is greater than impact of environmental heterogeneity on species spatial distributions. The spatial autocorrelation of species induced by the dispersal limitation will largely conceal the plant-soil relationships caused by the heterogeneity of soil elements. An additional analysis shows that the elements in the upper soil layer which have the greatest impact on community niche structure are Pb, total phosphorus (TP), total nitrogen (TN), Cu, Cr, Zn and available nitrogen (AN). The corresponding elements in the lower soil layers are Pb, TP, Cu, organic carbon (OC), Mn, total potassium (TK) and AN. Different species seem to be complementary regarding the demands on the available soil resources. The results of this study show that the tree species in the different growth groups have different habitat preferences. Compared with subcanopy and shrub species, the canopy species have more significant correlations with the soil elements. Full article
(This article belongs to the Special Issue Nutrient Cycling and Plant Nutrition in Forest Ecosystems)
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7366 KiB  
Article
Spatial Variability of Soil Moisture in a Forest Catchment: Temporal Trend and Contributors
by Zhenyang Peng, Fuqiang Tian, Hongchang Hu, Sihan Zhao, Qiang Tie, Hao Sheng, Christophe Darnault and Hui Lu
Forests 2016, 7(8), 154; https://doi.org/10.3390/f7080154 - 28 Jul 2016
Cited by 8 | Viewed by 4645
Abstract
Understanding the spatio-temporal dynamic of soil moisture is critical in hydrological and other land surface related studies. Until recently, however, there have been controversies about the relationship between spatial mean and spatial variance of soil moisture and the contributions of each of these [...] Read more.
Understanding the spatio-temporal dynamic of soil moisture is critical in hydrological and other land surface related studies. Until recently, however, there have been controversies about the relationship between spatial mean and spatial variance of soil moisture and the contributions of each of these factors to spatial variability. Therefore, in this study, spatial variability of soil moisture in a 7 km2 forest catchment is analyzed by time-series data on soil moisture obtained at a total of 12 observation sites. Results showed that soil moisture spatial mean and spatial variance varied almost synchronously and in three cyclic patterns during the monitoring period from 1 April 2015 to 31 October 2015. The spatial mean-variance relationship during the ascending and descending periods of spatial mean could be well-fitted by upward and downward convex quadratic curves, respectively, indicating possible clockwise hysteresis of this relationship. It was found that all through the monitoring period, contributions of time-invariant factors on total spatial variance increased from 68.9% to 88.2% with depth, and temporally stable ranking of sites was obtained. Because of the high spatial variation of soil moisture in our study area, it should be noted that a large number of sample plots would be needed to adequately estimate the spatial variability of soil moisture. Full article
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4887 KiB  
Article
Mapping Local Effects of Forest Properties on Fire Risk across Canada
by Pierre Y. Bernier, Sylvie Gauthier, Pierre-Olivier Jean, Francis Manka, Yan Boulanger, André Beaudoin and Luc Guindon
Forests 2016, 7(8), 157; https://doi.org/10.3390/f7080157 - 27 Jul 2016
Cited by 61 | Viewed by 8289
Abstract
Fire is a dominant mechanism of forest renewal in most of Canada’s forests and its activity is predicted to increase over the coming decades. Individual fire events have been considered to be non-selective with regards to forest properties, but evidence now suggests otherwise. [...] Read more.
Fire is a dominant mechanism of forest renewal in most of Canada’s forests and its activity is predicted to increase over the coming decades. Individual fire events have been considered to be non-selective with regards to forest properties, but evidence now suggests otherwise. Our objective was therefore to quantify the effect of forest properties on fire selectivity or avoidance, evaluate the stability of these effects across varying burn rates, and use these results to map local fire risk across the forests of Canada. We used Canada-wide MODIS-based maps of annual fires and of forest properties to identify burned and unburned pixels for the 2002–2011 period and to bin them into classes of forest composition (% conifer and broadleaved deciduous), above-ground tree biomass and stand age. Logistic binomial regressions were then used to quantify fire selectivity by forest properties classes and by zones of homogeneous fire regime (HFR). Results suggest that fire exhibits a strong selectivity for conifer stands, but an even stronger avoidance of broadleaved stands. In terms of age classes, fire also shows a strong avoidance for young (0 to 29 year) stands. The large differences among regional burn rates do not significantly alter the overall preference and avoidance ratings. Finally, we combined these results on relative burn preference with regional burn rates to map local fire risks across Canada. Full article
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1757 KiB  
Article
Salinity Differentially Affects Growth and Ecophysiology of Two Mastic Tree (Pistacia lentiscus L.) Accessions
by Giuseppe Cristiano, Salvatore Camposeo, Mariano Fracchiolla, Gaetano Alessandro Vivaldi, Barbara De Lucia and Eugenio Cazzato
Forests 2016, 7(8), 156; https://doi.org/10.3390/f7080156 - 27 Jul 2016
Cited by 14 | Viewed by 6988
Abstract
Pistacia lentiscus (Anacardiaceae; mastic tree) is an evergreen sclerophyll species, largely distributed in dry areas of the Mediterranean basin and well-adapted to severe conditions of drought in very unfertile soils. In the present study, we evaluated the growing responses of two [...] Read more.
Pistacia lentiscus (Anacardiaceae; mastic tree) is an evergreen sclerophyll species, largely distributed in dry areas of the Mediterranean basin and well-adapted to severe conditions of drought in very unfertile soils. In the present study, we evaluated the growing responses of two accessions of P. lentiscus to three different levels of salinity under nursery conditions. The two mastic tree accessions (Manfredonia and Specchia) were collected from individual trees in two different sites in the Apulia region (Southern Italy) and subjected to three different levels of salinization by adding 0, 400, and 800 g of salts 100 L−1 of substrate, respectively. The following parameters were recorded: plant height; survival of plants and total root length; total biomass; number of leaves per plant and leaf area; as well as various ecophysiological traits. Salinity reduced the values of all the examined parameters, both morphological and physiological. Results suggested that P. lentiscus can tolerate and accumulate salt at high concentrations in nursery conditions. As a result, it is important to identify germplasm that is highly tolerant to salinity for the production of nursery seedlings that will be planted in saline soils. Full article
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9864 KiB  
Article
Swiss Needle Cast in Western Oregon Douglas-Fir Plantations: 20‐Year Monitoring Results
by Gabriela Ritóková, David C. Shaw, Greg Filip, Alan Kanaskie, John Browning and Danny Norlander
Forests 2016, 7(8), 155; https://doi.org/10.3390/f7080155 - 26 Jul 2016
Cited by 29 | Viewed by 7183
Abstract
Swiss needle cast (SNC), a foliar disease specific to Douglas-fir (Pseudotsuga menziesii), is caused by an endemic Ascomycete fungus (Phaeocryptopus gaeumannii). In the late 1980s and early 1990s significant symptoms began to appear in coastal Oregon, and these have [...] Read more.
Swiss needle cast (SNC), a foliar disease specific to Douglas-fir (Pseudotsuga menziesii), is caused by an endemic Ascomycete fungus (Phaeocryptopus gaeumannii). In the late 1980s and early 1990s significant symptoms began to appear in coastal Oregon, and these have been associated with the planting of Douglas-fir in the Sitka spruce zone, leaf wetness during potential spore dispersal in May–August, and mild winter temperature. The first annual aerial survey was initiated in 1996 and has continued through 2015, which indicates a significant increase in area of visible symptoms from the air, increasing from 53,050 ha in 1996 to 238,705 ha in 2015. Monitoring plots in the NW Oregon Coast Range verified impacts of SNC on tree growth and productivity, with growth reductions averaging about 23% in the epidemic area linked to needle retention. A series of monitoring plots was set up in the western Cascade Mountains of Oregon and 590 10–23-year old Douglas-fir trees in 59 stands were tracked for 10 years, measured in 2001, 2006, and 2011. No measureable growth impacts were noted in this region of Oregon. A new plot network is being installed throughout the Oregon and southwest Washington coastal ranges as a means of monitoring future disease impact and providing framework for additional studies. Full article
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2603 KiB  
Article
Soil Respiration at Different Stand Ages (5, 10, and 20/30 Years) in Coniferous (Pinus tabulaeformis Carrière) and Deciduous (Populus davidiana Dode) Plantations in a Sandstorm Source Area
by Xin Zhao, Fadong Li, Wanjun Zhang, Zhipin Ai, Huitao Shen, Xiuping Liu, Jiansheng Cao and Kiril Manevski
Forests 2016, 7(8), 153; https://doi.org/10.3390/f7080153 - 25 Jul 2016
Cited by 23 | Viewed by 6828
Abstract
Understanding the effects of stand age and forest type on soil respiration is crucial for predicting the potential of soil carbon sequestration. Thus far, however, there is no consensus regarding the variations in soil respiration caused by stand age and forest type. This [...] Read more.
Understanding the effects of stand age and forest type on soil respiration is crucial for predicting the potential of soil carbon sequestration. Thus far, however, there is no consensus regarding the variations in soil respiration caused by stand age and forest type. This study investigated soil respiration and its temperature sensitivity at three stand ages (5, 10, and 20 or 30 years) in two plantations of coniferous (Pinus tabulaeformis Carrière) and deciduous (Populus davidiana Dode) species using an automated chamber system in 2013 in the Beijing-Tianjin sandstorm source area. Results showed that mean soil respiration in the 5-, 10-, and 20/30-year-old plantations was 3.37, 3.17, and 2.99 μmol·m−2·s−1 for P. tabulaeformis and 2.92, 2.85, and 2.57 μmol·m−2·s−1 for P. davidiana, respectively. Soil respiration decreased with stand age for both species. There was no significant difference in soil respiration between the two plantation species at ages 5 and 10 years (p > 0.05). Temperature sensitivity of soil respiration, which ranged from 1.85–1.99 in P. tabulaeformis and 2.20–2.46 in P. davidiana plantations, was found to increase with stand age. Temperature sensitivity was also significantly higher in P. davidiana plantations and when the soil water content was below 12.8%. Temperature sensitivity incorporated a combined response of soil respiration to soil temperature, soil water content, soil organic carbon, and fine root biomass and, thus, provided an ecological metric for comparing forest carbon dynamics of these species. Full article
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