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Forests, Volume 8, Issue 4 (April 2017)

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Open AccessArticle An Ecologically Based System for Sustainable Agroforestry in Sub-Tropical and Tropical Forests
Forests 2017, 8(4), 102; doi:10.3390/f8040102
Received: 7 December 2016 / Revised: 20 March 2017 / Accepted: 21 March 2017 / Published: 29 March 2017
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Abstract
Forests in tropical and sub-tropical countries face severe pressures due to a combination of poverty and environment degradation. To be effective, measures to protect these forests must therefore consider both economic and ecological dimensions synergistically. The purpose of this paper was to synthesize
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Forests in tropical and sub-tropical countries face severe pressures due to a combination of poverty and environment degradation. To be effective, measures to protect these forests must therefore consider both economic and ecological dimensions synergistically. The purpose of this paper was to synthesize our long-term work (1994–2015) on a Ginkgo (Ginkgo biloba L.) agroforestry system and demonstrate its potential for achieving both goals, and discuss its wider application in tropical and sub-tropical countries. The performance of various ecological, economic, and social indicators was compared among five Ginkgo agroforestry systems. Two additional indicators, Harmony Degree (HD) and Development Degree (DD), were also used to show the integrated performance of these indicators. Ginkgo-Wheat-Peanut (G+W+P) and Ginkgo-Rapeseed-Peanut (G+R+P) are the best systems when compared to pure and mixed Ginkgo plantations, or pure agricultural crops. Results demonstrate that it is possible to achieve both economic development and environmental protection through implementation of sustainable agroforestry systems in sub-tropical regions. Full article
(This article belongs to the Special Issue Management Strategies for Forest Ecosystem Services)
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Open AccessArticle Biomass and Carbon Sequestration by Juglans regia Plantations in the Karst Regions of Southwest China
Forests 2017, 8(4), 103; doi:10.3390/f8040103
Received: 23 December 2016 / Revised: 23 March 2017 / Accepted: 24 March 2017 / Published: 29 March 2017
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Abstract
Abstract: To better understand carbon (C) sequestration by Juglans regia L. plantations in karst regions of southwest China, this study examined biomass increment and C storage in four different-aged J. regia stands, as well as the distribution of carbon stock among the
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Abstract: To better understand carbon (C) sequestration by Juglans regia L. plantations in karst regions of southwest China, this study examined biomass increment and C storage in four different-aged J. regia stands, as well as the distribution of carbon stock among the various ecosystem components. Tree and ecosystem biomass increased with stand age. Aboveground biomass (AGB) represented 64.79% of the total biomass, belowground tree biomass comprised 22.73%, and shrubs and herbs totaled 11.38%, whereas only a small amount (1.11%) was associated with soil litter. Soil organic C (SOC) content in the top soil of plantations aged 1, 5, 9, and 13 years was 33.37, 53.15, 33.56, and 49.78 mg ha−1, respectively. SOC content decreased continually with increasing soil depth. Ecosystem C storage amounted to 33.49, 54.21, 46.40, and 65.34 mg ha−1 for the 1-, 5-, 9-, and 13-year old plantations, respectively, with most (86.55%) of the ecosystem C being in the soil. Our results suggest that large-scale planting of J. regia has potential for not only vegetation restoration but also high C fixation capacity in the karst region of southwest China. Full article
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Open AccessArticle Simulated Summer Rainfall Variability Effects on Loblolly Pine (Pinus taeda) Seedling Physiology and Susceptibility to Root-Infecting Ophiostomatoid Fungi
Forests 2017, 8(4), 104; doi:10.3390/f8040104
Received: 26 January 2017 / Revised: 25 March 2017 / Accepted: 27 March 2017 / Published: 30 March 2017
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Abstract
Seedlings from four families of loblolly pine (Pinus taeda L.) were grown in capped open-top chambers and exposed to three different weekly moisture regimes for 13 weeks. Moisture regimes varied in intensity and frequency of simulated rainfall (irrigation) events; however, the total
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Seedlings from four families of loblolly pine (Pinus taeda L.) were grown in capped open-top chambers and exposed to three different weekly moisture regimes for 13 weeks. Moisture regimes varied in intensity and frequency of simulated rainfall (irrigation) events; however, the total amounts were comparable. These simulated treatments were chosen to simulate expected changes in rainfall variability associated with climate change. Seedlings were inoculated with two root-infecting ophiostomatoid fungi associated with Southern Pine Decline. We found susceptibility of loblolly pine was not affected by water stress; however, one family that was most sensitive to inoculation was also most sensitive to changes in moisture availability. Many studies have examined the effects of drought (well-watered vs. dry conditions) on pine physiology and host-pathogen interactions but little is known about variability in moisture supply. This study aimed to elucidate the effects of variability in water availability, pathogen inoculation and their interaction on physiology of loblolly pine seedlings. Full article
(This article belongs to the Special Issue Forest Pathology and Plant Health)
Open AccessArticle Mixed-Species Effects on Soil C and N Stocks, C/N Ratio and pH Using a Transboundary Approach in Adjacent Common Garden Douglas-Fir and Beech Stands
Forests 2017, 8(4), 95; doi:10.3390/f8040095
Received: 25 February 2017 / Revised: 17 March 2017 / Accepted: 20 March 2017 / Published: 23 March 2017
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Abstract
Mixed forest of Douglas-fir and beech has been suggested as one of the possible future forest types in Northwest Europe but the effects of this mixed forest on soil properties relative to monoculture stands are unknown. In a transboundary investigation of adjacent common
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Mixed forest of Douglas-fir and beech has been suggested as one of the possible future forest types in Northwest Europe but the effects of this mixed forest on soil properties relative to monoculture stands are unknown. In a transboundary investigation of adjacent common garden Douglas-fir and beech stands, we determined the effects on topsoil properties. However, responses of C and N stocks, the C/N ratio and pH were site- and soil layer-specific and were mainly single-sided and without synergistic effects. Beech reduced the soil C and N stocks in Douglas-fir at the nutrient-poor site, caused an increase in the C/N ratio in the forest floor and mineral soil at both nutrient-poor and -rich sites, and reduced the acidifying effect of Douglas-fir at the nutrient-poor site. These results do not support the hypothesis that mixture effects would be consistent across sites and soil layers. The lack of synergistic effects may be attributed to the relatively similar litter quality or rooting depth that prevented any larger niche differentiation and complementarity. The results indicate that the transboundary approach within a mature common garden proved useful as a platform to test tree species interactions, and this approach could be explored in soil studies until dedicated mixed-species common gardens reach maturity. Full article
(This article belongs to the Special Issue Tree Species, as Major Drivers of Forest Ecosystems Functioning)
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Open AccessArticle On the Effect of Thinning on Tree Growth and Stand Structure of White Birch (Betula platyphylla Sukaczev) and Siberian Larch (Larix sibirica Ledeb.) in Mongolia
Forests 2017, 8(4), 105; doi:10.3390/f8040105
Received: 13 February 2017 / Revised: 15 March 2017 / Accepted: 23 March 2017 / Published: 31 March 2017
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Abstract
The forests of North Mongolia are largely dominated either by larch (Larix sibirica Ledeb.) or birch (Betula platyphylla Sukaczev). The increasing demand for timber and firewood is currently met by removal of wood from these forest stands. Therefore, silvicultural approaches that
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The forests of North Mongolia are largely dominated either by larch (Larix sibirica Ledeb.) or birch (Betula platyphylla Sukaczev). The increasing demand for timber and firewood is currently met by removal of wood from these forest stands. Therefore, silvicultural approaches that account for both utilization and protection are needed. Thinning trials were established in the research area Altansumber, in the mountain forest steppe west of the town of Darkhan. We analyzed the response of non-spatial and spatial structure and growth of birch and larch stands on thinning. Before thinning, spatial tree distribution was largely clumped. Thinning promoted regular tree distribution. Ingrowth of new stems after thinning tended to redirect stand structure towards clumping. Both relative and absolute tree growth and competition were evaluated before, directly after, and three years after the thinning. Competition played a significant role in tree growth before thinning. A reduction in competition after thinning triggered significantly increased growth of both birch and larch. The observed positive growth response was valid in absolute and relative terms. A methodically based forest management strategy, including thinning operations and selective cuttings, could be established, even under the harsh Mongolian conditions. Our findings could initiate the development of broader forest management guidelines for the light-taiga dominated stands. Full article
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Open AccessArticle Multiple Trait Selection Index for Simultaneous Improvement of Wood Properties and Growth Traits in Pinus kesiya Royle ex Gordon in Malawi
Forests 2017, 8(4), 96; doi:10.3390/f8040096
Received: 10 January 2017 / Revised: 15 March 2017 / Accepted: 23 March 2017 / Published: 25 March 2017
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Abstract
Tree breeders face the problem of negative correlations between wood properties and growth traits. It is necessary to overcome this difficulty in order to obtain promising genotypes. The selection index is one of the helpful tools in this process, because it allows multiple
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Tree breeders face the problem of negative correlations between wood properties and growth traits. It is necessary to overcome this difficulty in order to obtain promising genotypes. The selection index is one of the helpful tools in this process, because it allows multiple features of interest to be selected. In this study, a multiple trait selection index for Khasi pine (Pinus kesiya Royle ex Gordon) grown in Malawi was developed. Data on wood properties and growth traits were collected from six families of P. kesiya at the age of 30 years. The breeding objective was defined in terms of wood stiffness, wood strength and volume. Selection traits included in the index were wood stiffness (MoE), wood strength (MoR), volume (Vol.), wood density (WD), and diameter at breast height (DBH). The index was termed as I T = 80.36 M o E 14.60 M o R + 132.07 V o l . + 4858.09 W D 7.56 D B H . The accuracy of the index was 98.8% and the correlation between the index and the aggregate breeding objective was 0.994. A genetic gain of 16.7% for volume, 14.8% for wood stiffness and 13.2% for wood strength would be expected from a standardized 10% selection intensity. Therefore, application of the developed selection index is necessary in order to increase the efficiency of the Pinus kesiya breeding programme in Malawi. Full article
Open AccessArticle Biophysical and Economic Analysis of Black Spruce Regeneration in Eastern Canada Using Global Climate Model Productivity Outputs
Forests 2017, 8(4), 106; doi:10.3390/f8040106
Received: 11 October 2016 / Revised: 22 March 2017 / Accepted: 27 March 2017 / Published: 31 March 2017
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Abstract
We explore the biophysical potential and economic attractiveness of black spruce (Picea mariana) regeneration in eastern Canada under the high greenhouse gas emission scenario (RCP 8.5) of the Intergovernmental Panel on Climate Change (IPCC). The study integrates net primary productivity and
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We explore the biophysical potential and economic attractiveness of black spruce (Picea mariana) regeneration in eastern Canada under the high greenhouse gas emission scenario (RCP 8.5) of the Intergovernmental Panel on Climate Change (IPCC). The study integrates net primary productivity and net ecosystem productivity estimates from three major global climate models (GCMs), growth and yield equations specific to black spruce, and economic analyses to determine spatially varying investment values of black spruce regeneration—both including and excluding carbon sequestration benefits. Net present value (NPV) was used to represent financial attractiveness. It was assumed that stands would not be harvested at volumes less than 80 m3·ha−1. A baseline case with the stumpage price set to $20 m−3, stand establishment cost $500 ha−1, and the discount rate 4%, was used with wide-ranging sensitivity analyses conducted around these assumptions. These values represent the wide range of choices and outcomes possible with black spruce regeneration investments. The results indicated a latitudinal gradient in economic attractiveness, with higher forest productivity and NPVs in the southern portion of the study area; however, black spruce regeneration was not economically attractive unless regeneration costs were very low (representing something closer to a natural regeneration type scenario) and/or carbon sequestration benefits of at least $5 ton−1 CO2 were realized. In general, the optimal harvest rotation age increased with increasing carbon price by approximately 9 to 18 years. Results of this study highlight the importance of future price and yield expectations and establishment costs in evaluating forest investments. Full article
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Open AccessArticle Dynamics of Wood Pulp Production: Evidence from OECD Countries
Forests 2017, 8(4), 107; doi:10.3390/f8040107
Received: 4 January 2017 / Revised: 23 March 2017 / Accepted: 27 March 2017 / Published: 1 April 2017
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Abstract
This paper investigates whether shocks to pulp for paper production for 17 Organisation for Economic Co-Operation and Development (OECD) members over the period 1980–2012 are transitory or permanent. A variety of univariate and panel data unit root tests are employed. The presence of
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This paper investigates whether shocks to pulp for paper production for 17 Organisation for Economic Co-Operation and Development (OECD) members over the period 1980–2012 are transitory or permanent. A variety of univariate and panel data unit root tests are employed. The presence of structural breaks is taken into account when performing those tests. Based on the Narayan-Popp univariate unit root test, wood production series for approximately 64.71% of countries is found to follow a non-stationary process. However, univariate unit root tests tend to have low power when the time span is relatively short. Consequently, three generations of panel unit root tests are considered. Cross-sectional dependence is detected. The first generation of unit roots do not effectively control for cross-sectional dependence, while the second and third generations do. The third generation accounts mainly for cross-sectional co-integration. As a confirmatory analysis, both unit root tests that tests for the null of non-stationarity and stationarity are considered. Most of the panel unit root tests point towards a non-stationary process. Hence, while these shocks can be transmitted to other economic sectors, past behaviours of wood production cannot be used for forecasting purposes. Forest conservation policies can have a permanent impact on pulp for paper production. Full article
Open AccessArticle How Similar Are Forest Disturbance Maps Derived from Different Landsat Time Series Algorithms?
Forests 2017, 8(4), 98; doi:10.3390/f8040098
Received: 5 February 2017 / Revised: 16 March 2017 / Accepted: 23 March 2017 / Published: 26 March 2017
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Abstract
Disturbance is a critical ecological process in forested systems, and disturbance maps are important for understanding forest dynamics. Landsat data are a key remote sensing dataset for monitoring forest disturbance and there recently has been major growth in the development of disturbance mapping
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Disturbance is a critical ecological process in forested systems, and disturbance maps are important for understanding forest dynamics. Landsat data are a key remote sensing dataset for monitoring forest disturbance and there recently has been major growth in the development of disturbance mapping algorithms. Many of these algorithms take advantage of the high temporal data volume to mine subtle signals in Landsat time series, but as those signals become subtler, they are more likely to be mixed with noise in Landsat data. This study examines the similarity among seven different algorithms in their ability to map the full range of magnitudes of forest disturbance over six different Landsat scenes distributed across the conterminous US. The maps agreed very well in terms of the amount of undisturbed forest over time; however, for the ~30% of forest mapped as disturbed in a given year by at least one algorithm, there was little agreement about which pixels were affected. Algorithms that targeted higher-magnitude disturbances exhibited higher omission errors but lower commission errors than those targeting a broader range of disturbance magnitudes. These results suggest that a user of any given forest disturbance map should understand the map’s strengths and weaknesses (in terms of omission and commission error rates), with respect to the disturbance targets of interest. Full article
(This article belongs to the Special Issue Remote Sensing of Forest Disturbance)
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Open AccessArticle The Dynamics of Deforestation in the Wet and Dry Tropics: A Comparison with Policy Implications
Forests 2017, 8(4), 108; doi:10.3390/f8040108
Received: 4 March 2017 / Revised: 28 March 2017 / Accepted: 1 April 2017 / Published: 5 April 2017
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Abstract
Forests in the dry tropics differ significantly from forests in the humid tropics in their biomass and in their socio-ecological contexts, so it might be reasonable to assume that the dynamics that drive deforestation in these two settings would also differ. Until recently,
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Forests in the dry tropics differ significantly from forests in the humid tropics in their biomass and in their socio-ecological contexts, so it might be reasonable to assume that the dynamics that drive deforestation in these two settings would also differ. Until recently, difficulties in measuring the extent of dry tropical forests have made it difficult to investigate this claim empirically. The release of high resolution LANDSAT satellite imagery in 2013 has removed this impediment, making it possible to identify variations in the extent of wet and dry forests within countries by measuring variations in the canopy cover of their forests. These metrics have in turn made it possible to investigate human differences in the dynamics of deforestation between dry forested and wet forested nations in the tropics. Cross-national analyses suggest that international trade in agricultural commodities plays a more important role in driving deforestation in the wet tropics than it does in the dry tropics. The variable salience of international trade as a driver has important implications, described here, for the success of policies designed to slow deforestation in the dry tropics and the wet tropics. Curbing dry forest losses, in particular, would appear to require locally focused and administered policies. Full article
(This article belongs to the Special Issue Tropical Forest Ecology and Management for the Anthropocene)
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Open AccessArticle The Coupling of Treeline Elevation and Temperature is Mediated by Non-Thermal Factors on the Tibetan Plateau
Forests 2017, 8(4), 109; doi:10.3390/f8040109
Received: 21 December 2016 / Revised: 7 March 2017 / Accepted: 31 March 2017 / Published: 5 April 2017
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Abstract
Little is known about the relationships between treeline elevation and climate at regional and local scales. It is compelling to fill this research gap with data from the Tibetan Plateau where some of the highest alpine treelines in the world are found. This
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Little is known about the relationships between treeline elevation and climate at regional and local scales. It is compelling to fill this research gap with data from the Tibetan Plateau where some of the highest alpine treelines in the world are found. This research question partially results from the lack of in situ temperature data at treeline sites. Herein, treeline variables (e.g., elevation, topography, tree species) and temperature data were collected from published investigations performed during this decade on the Tibetan Plateau. Temperature conditions near treeline sites were estimated using global databases and these estimates were corrected by using in situ air temperature measurements. Correlation analyses and generalized linear models were used to evaluate the effects of different variables on treeline elevation including thermal (growing-season air temperatures) and non-thermal (latitude, longitude, elevation, tree species, precipitation, radiation) factors. The commonality analysis model was applied to explore how several variables (July mean temperature, elevation of mountain peak, latitude) were related to treeline elevation. July mean temperature was the most significant predictor of treeline elevation, explaining 55% of the variance in treeline elevation across the Tibetan Plateau, whereas latitude, tree species, and mountain elevation (mass-elevation effect) explained 30% of the variance in treeline elevation. After considering the multicollinearity among predictors, July mean temperature (largely due to the influence of minimum temperature) still showed the strongest association with treeline elevation. We conclude that the coupling of treeline elevation and July temperature at a regional scale is modulated by non-thermal factors probably acting at local scales. Our results contribute towards explaining the decoupling between climate warming and treeline dynamics. Full article
(This article belongs to the Special Issue Treeline Ecotone Dynamics)
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Open AccessArticle Estimating Large Area Forest Carbon Stocks—A Pragmatic Design Based Strategy
Forests 2017, 8(4), 99; doi:10.3390/f8040099
Received: 17 January 2017 / Revised: 8 March 2017 / Accepted: 20 March 2017 / Published: 26 March 2017
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Abstract
Reducing uncertainty in forest carbon estimates at local and regional scales has become increasingly important due to the centrality of the terrestrial carbon cycle in issues of climate change. In Victoria, Australia, public natural forests extend over 7.2 M ha and constitute a
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Reducing uncertainty in forest carbon estimates at local and regional scales has become increasingly important due to the centrality of the terrestrial carbon cycle in issues of climate change. In Victoria, Australia, public natural forests extend over 7.2 M ha and constitute a significant and important carbon stock. Recently, a wide range of approaches to estimate carbon stocks within these forests have been developed and applied. However, there are a number of data and estimation limitations associated with these studies. In response, over the last five years, the State of Victoria has implemented a pragmatic plot-based design consisting of pre-stratified permanent observational units located on a state-wide grid. Using the ground sampling grid, we estimated aboveground and belowground carbon stocks (including soil to 0.3 m depth) in both National Parks and State Forests, across a wide range of bioregions. Estimates of carbon stocks and associated uncertainty were conducted using simple design based estimators. We detected significantly more carbon in total aboveground and belowground components in State Forests (408.9 t ha−1, 95% confidence interval 388.8–428.9 t ha−1) than National Parks (267.6 t ha−1, 251.9–283.3 t ha−1). We were also able to estimate forest carbon stocks (and associated uncertainty) for 21 strata that represent all of Victoria’s bioregions and public tenures. It is anticipated that the lessons learnt from this study may support the discussion on planning and implementing low cost large area forest carbon stock sampling in other jurisdictions. Full article
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Open AccessArticle An Assessment of Carbon Storage in China’s Arboreal Forests
Forests 2017, 8(4), 110; doi:10.3390/f8040110
Received: 27 February 2017 / Revised: 27 March 2017 / Accepted: 4 April 2017 / Published: 6 April 2017
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Abstract
In the years 2009–2013, China carried out its eighth national survey of forest resources. Based on the survey data, this paper used a biomass conversion function method to evaluate the carbon stores and carbon density of China’s arboreal forests. The results showed that:
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In the years 2009–2013, China carried out its eighth national survey of forest resources. Based on the survey data, this paper used a biomass conversion function method to evaluate the carbon stores and carbon density of China’s arboreal forests. The results showed that: (1) By age group, the largest portion of carbon stores in China’s arboreal forests are in middle-aged forests. Over-mature forests have the least carbon storage; (2) By origin, natural forests of all age groups have higher carbon storage and carbon density than man-made forest plantations. The carbon density of natural forests and forest plantations increases gradually with the age of the trees; (3) By type (dominant tree species), the 18 most abundant types of arboreal forest in China account for approximately 94% of the nation’s total arboreal forest biomass and carbon storage. Among these, broadleaf mixed and Quercus spp. form the two largest portions. Taxus spp. forests, while comprising a very small portion of China’s forested area, have very high carbon density; (4) By region, the overall arboreal forest carbon storage is highest in the southwest part of China, and lowest in the northwest. However, because of differences in land use and forest coverage ratios, regions with arboreal forests of high carbon density are not necessarily the same regions that have high overall carbon storage; (5) By province, Heilongjiang, Yunnan, Tibet, Sichuan, Inner Mongolia, and Jilin have rather high carbon storage. The arboreal forests in Tibet, Jilin, Xinjiang, Sichuan, Yunnan, and Hainan have a rather high carbon density. This paper’s evaluation of carbon storage in China’s arboreal forests is a valuable reference for interpreting the role and function of Chinese ecosystems in coping with global climate change. Full article
(This article belongs to the Special Issue Soil Carbon Sequestration in Forests)
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Open AccessArticle Combining Airborne and Terrestrial Laser Scanning Technologies to Measure Forest Understorey Volume
Forests 2017, 8(4), 111; doi:10.3390/f8040111
Received: 17 January 2017 / Revised: 25 March 2017 / Accepted: 1 April 2017 / Published: 6 April 2017
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Abstract
A critical component of the forest ecosystem, the understorey supports the vast majority of wildlife habitat and total ecosystem floristic diversity. Remote sensing data have been developed to provide information at different scales for surveys of forest ecosystems, but obtaining information about the
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A critical component of the forest ecosystem, the understorey supports the vast majority of wildlife habitat and total ecosystem floristic diversity. Remote sensing data have been developed to provide information at different scales for surveys of forest ecosystems, but obtaining information about the understorey remains a challenge. As rapid and efficient tools for forest structure attribute estimation, Airborne Laser Scanning (ALS) and Terrestrial Laser Scanning (TLS) have attracted much attention. We examine the relationship between ALS and TLS data and detect changes in the forest understorey caused by forest-tending events in the study area. We conducted trials in five plots within a young Khasi pine (Pinus kesiya Royle ex Gord.) plantation in Yunnan province, China, before and after forest tending. We collected bi-temporal ALS data in this area and TLS data from 10 scanning stations. Canopy height profiles were retrieved from ALS and TLS data, and understorey material volume retrieved from filled TLS voxels volume agreed well with the understorey point clouds percentile distribution (PD) obtained from ALS data. The PD value for the understorey from ALS multiplied by the percentage of ALS return points in the overstorey had a stronger correlation (R2 = 0.90) with the TLS-derived understorey material volume than did the ALS PD value for the understorey only (R2 = 0.71). Taking the effect of the overstorey into consideration will improve evaluations of forest understorey parameters from ALS data. This study confirmed the potential of TLS as a validation tool to assess the accuracy of forest understorey material volume estimation at large scales using ALS data. Full article
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Open AccessArticle Prescribed Burning and Erosion Potential in Mixed Hardwood Forests of Southern Illinois
Forests 2017, 8(4), 112; doi:10.3390/f8040112
Received: 8 February 2017 / Revised: 24 March 2017 / Accepted: 4 April 2017 / Published: 7 April 2017
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Abstract
Prescribed fire has several benefits for managing forest ecosystems including reduction of fuel loading and invasive species and enhanced regeneration of desirable tree species. Along with these benefits there are some limitations like nutrient and sediment loss which have not been studied extensively
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Prescribed fire has several benefits for managing forest ecosystems including reduction of fuel loading and invasive species and enhanced regeneration of desirable tree species. Along with these benefits there are some limitations like nutrient and sediment loss which have not been studied extensively in mixed hardwood forests. The objective of our research was to quantify the amount of sediment movement occurring on a watershed scale due to prescribed fire in a southern Illinois mixed hardwood ecosystem. The research site was located at Trail of Tears State Forest in western Union county, IL, USA and included five watershed pairs. One watershed in each pair was randomly assigned the prescribed burn treatment and the other remained as control (i.e., unburned). The prescribed burn treatment significantly reduced the litter depth with 12.6%–31.5% litter remaining in the prescribed burn treatment watersheds. When data were combined across all watersheds, no significant differences were obtained between burn treatment and control watershed for total suspended solids and sediment concentrations or loads. The annual sediment losses varied from 1.41 to 90.54 kg·ha−1·year−1 in the four prescribed burn watersheds and 0.81 to 2.54 kg·ha−1·year−1 in the four control watersheds. Prescribed burn watershed 7 showed an average soil sediment loss of 4.2 mm, whereas control watershed 8 showed an average accumulation of sediments (9.9 mm), possibly due to steeper slopes. Prescribed burning did not cause a significant increase in soil erosion and sediment loss and can be considered acceptable in managing mixed hardwood forests of Ozark uplands and the Shawnee Hills physiographic regions of southern Illinois. Full article
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Open AccessArticle A Tree Species Effect on Soil That Is Consistent Across the Species’ Range: The Case of Aspen and Soil Carbon in North America
Forests 2017, 8(4), 113; doi:10.3390/f8040113
Received: 15 February 2017 / Revised: 31 March 2017 / Accepted: 5 April 2017 / Published: 8 April 2017
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Abstract
Trembling aspen covers a large geographic range in North America, and previous studies reported that a better understanding of its singular influence on soil properties and processes is of high relevance for global change questions. Here we investigate the potential impact of a
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Trembling aspen covers a large geographic range in North America, and previous studies reported that a better understanding of its singular influence on soil properties and processes is of high relevance for global change questions. Here we investigate the potential impact of a shift in aspen abundance on soil carbon sequestration and soil carbon stability at the continental scale by conducting a systematic literature review using 23 published studies. Our review shows that aspen’s effect on soil carbon is relatively consistent throughout the species range. Aspen stores less C in the forest floor but similar amounts in the mineral soil relative to conifers. However, a robust set of indicators of soil C stability, for example, degree of organo-mineral associations, proportion of readily-available or labile C estimated during long-term soil incubations or using hot-water extraction, pattern of soil C distribution, and temperature sensitivity of soil heterotrophic respiration, reveals that the soil organic carbon (SOC) stock under aspen is more stable, rendering it more protected against environmental changes and soil disturbances. Therefore, our continental-scale analysis highlights that an increase in the abundance of trembling aspen in North American forests may increase the resistance and resilience of soil C stocks against global changes. Full article
(This article belongs to the Special Issue Tree Species, as Major Drivers of Forest Ecosystems Functioning)
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Open AccessArticle Estimating Carbon Dynamics in an Intact Lowland Mixed Dipterocarp Forest Using a Forest Carbon Model
Forests 2017, 8(4), 114; doi:10.3390/f8040114
Received: 27 January 2017 / Revised: 29 March 2017 / Accepted: 6 April 2017 / Published: 8 April 2017
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Abstract
Intact dipterocarp forests in Asia act as crucial carbon (C) reservoirs, and it is therefore important to investigate the C dynamics in these forests. We estimated C dynamics, together with net ecosystem production (NEP), in an intact tropical dipterocarp forest of Brunei Darussalam.
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Intact dipterocarp forests in Asia act as crucial carbon (C) reservoirs, and it is therefore important to investigate the C dynamics in these forests. We estimated C dynamics, together with net ecosystem production (NEP), in an intact tropical dipterocarp forest of Brunei Darussalam. Fifty-four simulation units (plots; 20 m × 20 m) were established and initial C stocks were determined via direct field measurement. The C dynamics were annually simulated with a regression model and the Forest Biomass and Dead organic matter Carbon (FBDC) model. The initial C stock (Mg C·ha−1) of biomass, litter, dead wood and mineral soil were 213.1 ± 104.8, 2.0 ± 0.8, 31.3 ± 38.8, and 80.7 ± 15.5, respectively. Their annual changes (Mg C·ha−1·year−1) were 3.2 ± 1.1, 0.2 ± 0.2, −3.7 ± 6.1, and −0.3 ± 1.1, respectively. NEP was −0.6 ± 6.1 Mg C·ha−1·year−1, showing large heterogeneity among the plots. The initial C stocks of biomass and dead wood, biomass turnover rates and dead wood decay rates were elucidated as dominant factors determining NEP in a sensitivity analysis. Accordingly, investigation on those input data can constrain an uncertainty in determining NEP in the intact tropical forests. Full article
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Open AccessArticle The Plight of Migrant Birds Wintering in the Caribbean: Rainfall Effects in the Annual Cycle
Forests 2017, 8(4), 115; doi:10.3390/f8040115
Received: 27 January 2017 / Revised: 24 March 2017 / Accepted: 1 April 2017 / Published: 8 April 2017
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Abstract
Here, we summarize results of migrant bird research in the Caribbean as part of a 75th Anniversary Symposium on research of the United States Department of Agriculture Forest Service, International Institute of Tropical Forestry (IITF). The fate of migratory birds has been a
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Here, we summarize results of migrant bird research in the Caribbean as part of a 75th Anniversary Symposium on research of the United States Department of Agriculture Forest Service, International Institute of Tropical Forestry (IITF). The fate of migratory birds has been a concern stimulating research over the past 40 years in response to population declines documented in long-term studies including those of the IITF and collaborators in Puerto Rico’s Guánica dry forest. Various studies indicate that in addition to forest loss or fragmentation, some migrant declines may be due to rainfall variation, the consequences of which may carry over from one stage of a migrant’s annual cycle to another. For example, the Guánica studies indicate that rainfall extremes on either the temperate breeding or tropical wintering grounds affect migrant abundance and survival differently depending on the species. In contrast, IITF’s collaborative studies of the migrant Kirtland’s Warbler (Setophaga kirtlandii) in the Bahamas found that late winter droughts affect its annual survival and breeding success in Michigan. We review these IITF migrant studies and relate them to other studies, which have improved our understanding of migrant ecology of relevance to conservation. Particularly important is the advent of the full annual cycle (FAC) approach. The FAC will facilitate future identification and mitigation of limiting factors contributing to migrant population declines, which for some species, may be exacerbated by global climate change. Full article
(This article belongs to the Special Issue Tropical Forest Ecology and Management for the Anthropocene)
Open AccessArticle Effect of Auxins and Associated Metabolic Changes on Cuttings of Hybrid Aspen
Forests 2017, 8(4), 117; doi:10.3390/f8040117
Received: 26 January 2017 / Revised: 27 March 2017 / Accepted: 4 April 2017 / Published: 10 April 2017
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Abstract
In the present study, an attempt was made to induce rooting from single-node cuttings of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) with different concentrations of Indole-3-acetic acid (IAA), Indole-3-Butytric acid (IBA) and 1-Naphthylacetic acid (NAA). Among the three auxins
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In the present study, an attempt was made to induce rooting from single-node cuttings of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) with different concentrations of Indole-3-acetic acid (IAA), Indole-3-Butytric acid (IBA) and 1-Naphthylacetic acid (NAA). Among the three auxins used, 0.54 mM NAA showed more effective induction on rooting as compared to IAA and IBA at the whole level. Thereafter, 0.54 mM NAA was used further for the anatomical and biochemical investigation. The results showed that it took 12 days from the differentiation of primordium to the appearance of young adventitious roots under NAA application. It was found that endogenous IAA, Zeatin riboside (ZR) and Gibberellic Acid (GA3) levels increased, but Abscisic acid (ABA) decreased in cuttings with NAA treatment. In contrast to the endogenous IAA level, NAA resulted in a decrease in IAA-oxidase (IAAO) activity. Similarly, the decreased peroxidase (POD) activity, consistent with down-regulation of expressed levels of POD1 and POD2, was observed in NAA-treated cuttings. Moreover, NAA resulted in a higher activity in polyphenol oxidase (PPO) compared with control cuttings. Collectively, the study highlighted that 0.54 mM NAA is efficient on rooting in hybrid aspen, and its effect on metabolic changes during rooting was discussed, which can provide valuable information for propagating hybrid aspen. Full article
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Open AccessArticle Can Carbon Fluxes Explain Differences in Soil Organic Carbon Storage under Aspen and Conifer Forest Overstories?
Forests 2017, 8(4), 118; doi:10.3390/f8040118
Received: 25 January 2017 / Revised: 31 March 2017 / Accepted: 6 April 2017 / Published: 11 April 2017
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Abstract
Climate- and management-induced changes in tree species distributions are raising questions regarding tree species-specific effects on soil organic carbon (SOC) storage and stability. Quaking aspen (Populus tremuloides Michx.) is the most widespread tree species in North America, but fire exclusion often promotes
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Climate- and management-induced changes in tree species distributions are raising questions regarding tree species-specific effects on soil organic carbon (SOC) storage and stability. Quaking aspen (Populus tremuloides Michx.) is the most widespread tree species in North America, but fire exclusion often promotes the succession to conifer dominated forests. Aspen in the Western US have been found to store more SOC in the mineral soil than nearby conifers, but we do not yet fully understand the source of this differential SOC accumulation. We measured total SOC storage (0–50 cm), characterized stable and labile SOC pools, and quantified above- and belowground litter inputs and dissolved organic carbon (DOC) fluxes during snowmelt in plots located in N and S Utah, to elucidate the role of foliage vs. root detritus in SOC storage and stabilization in both ecosystems. While leaf litterfall was twice as high under aspen as under conifers, input of litter-derived DOC with snowmelt water was consistently higher under conifers. Fine root (<2 mm) biomass, estimated root detritus input, and root-derived DOC fluxes were also higher under conifers. A strong positive relationship between root and light fraction C content suggests that root detritus mostly fueled the labile fraction of SOC. Overall, neither differences in above- and belowground detritus C inputs nor in detritus-derived DOC fluxes could explain the higher and more stable SOC pools under aspen. We hypothesize that root–microbe–soil interactions in the rhizosphere are more likely to drive these SOC pool differences. Full article
(This article belongs to the Special Issue Tree Species, as Major Drivers of Forest Ecosystems Functioning)
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Open AccessArticle A Basal Area Increment-Based Approach of Site Productivity Evaluation for Multi-Aged and Mixed Forests
Forests 2017, 8(4), 119; doi:10.3390/f8040119
Received: 17 February 2017 / Revised: 29 March 2017 / Accepted: 1 April 2017 / Published: 12 April 2017
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Abstract
Accurate estimates of forest site productivity are essential for environmental planning and forest management. In this study, we developed a new productivity index, hereafter termed basal area potential productivity index (BAPP), to estimate site productivity for irregular and complex forests characterized by multi-aged,
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Accurate estimates of forest site productivity are essential for environmental planning and forest management. In this study, we developed a new productivity index, hereafter termed basal area potential productivity index (BAPP), to estimate site productivity for irregular and complex forests characterized by multi-aged, multi-species, and multi-layer stands. We presented the biological relevance of BAPP with its computational details. We also compared BAPP against basal area realized productivity (BARP) in order to verify the practicability and reliability of BAPP. Time-series data of the national forest inventory on 1912 permanent sample plots that were located in two main forest types and consisted of oak-dominated mixed forests and other broadleaf forests in northeast China were used to demonstrate the application of BAPP. The results showed that the value of BAPP for each sample plot was larger than or equal to the corresponding BARP value for each forest type. For appropriately managed stands with relatively better site conditions, the values of both BARP and BAPP were almost identical. The values of the difference between BAPP and BARP could therefore be used to effectively assess forest site productivity. Meanwhile, BAPP also provides much reliable and valuable information that can aid decision-making in forest management. Full article
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Open AccessArticle Fire History of Appalachian Forests of the Lower St-Lawrence Region (Southern Quebec)
Forests 2017, 8(4), 120; doi:10.3390/f8040120
Received: 3 March 2017 / Revised: 31 March 2017 / Accepted: 5 April 2017 / Published: 11 April 2017
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Abstract
Sugar maple (Acer saccharum) forests are among the main forest types of eastern North America. Sugar maple stands growing on Appalachian soils of the Lower St-Lawrence region are located at the northeastern limit of the northern hardwood forest zone. Given the
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Sugar maple (Acer saccharum) forests are among the main forest types of eastern North America. Sugar maple stands growing on Appalachian soils of the Lower St-Lawrence region are located at the northeastern limit of the northern hardwood forest zone. Given the biogeographical position of these forests at the edge of the boreal biome, we aimed to reconstruct the fire history and document the occurrence of temperate and boreal trees in sugar maple sites during the Holocene based on soil macrocharcoal analysis. Despite having experienced a different number of fire events, the fire history of the maple sites was broadly similar, with two main periods of fire activity, i.e., early- to mid-Holocene and late-Holocene. A long fire-free interval of at least 3500 years separated the two periods from the mid-Holocene to 2000 years ago. The maple sites differ with respect to fire frequency and synchronicity of the last millennia. According to the botanical composition of charcoal, forest vegetation remained relatively homogenous during the Holocene, except recently. Conifer and broadleaf species coexisted in mixed forests during the Holocene, in phase with fire events promoting the regeneration of boreal and temperate tree assemblages including balsam fir (Abies balsamea) and sugar maple. Full article
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Open AccessArticle Volume and Carbon Estimates for the Forest Area of the Amhara Region in Northwestern Ethiopia
Forests 2017, 8(4), 122; doi:10.3390/f8040122
Received: 20 February 2017 / Revised: 3 April 2017 / Accepted: 11 April 2017 / Published: 15 April 2017
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Abstract
Sustainable forest management requires a continuous assessment of the forest conditions covering the species distribution, standing tree volume as well as volume increment rates. Forest inventories are designed to record this information. They, in combination with ecosystem models, are the conceptual framework for
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Sustainable forest management requires a continuous assessment of the forest conditions covering the species distribution, standing tree volume as well as volume increment rates. Forest inventories are designed to record this information. They, in combination with ecosystem models, are the conceptual framework for sustainable forest management. While such management systems are common in many countries, no forest inventory system and/or modeling tools for deriving forest growth information are available in Ethiopia. This study assesses, for the first time, timber volume, carbon, and Net Primary Production (NPP) of forested areas in the Amhara region of northwestern Ethiopia by combining (i) terrestrial inventory data, and (ii) land cover classification information. The inventory data were collected from five sites across the Amhara region (Ambober, Gelawdiwos, Katassi, Mahiberesilasse and Taragedam) covering three forest types: (i) forests, (ii) shrublands (exclosures) and (ii) woodlands. The data were recorded on 198 sample plots and cover diameter at breast height, tree height, and increment information. In order to extrapolate the local terrestrial inventory data to the whole Amhara region, a digital land cover map from the Amhara’s Bureau of Agriculture was simplified into (i) forest, (ii) shrubland, and (iii) woodland. In addition, the forest area is further stratified in five elevation classes. Our results suggest that the forest area in the Amhara region covers 2% of the total land area with an average volume stock of 65.7 m3·ha−1; the shrubland covers 27% and a volume stock of 3.7 m3·ha−1; and the woodland covers 6% and an average volume stock of 27.6 m3·ha−1. The corresponding annual volume increment rates are 3.0 m3·ha−1, for the forest area; 1.0 m3·ha−1, for the shrubland; and 1.2 m3·ha−1, for the woodland. The estimated current total volume stock in the Amhara region is 59 million m3. Full article
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Open AccessArticle Distribution of Soil Organic Carbon in Riparian Forest Soils Affected by Frequent Floods (Southern Québec, Canada)
Forests 2017, 8(4), 124; doi:10.3390/f8040124
Received: 10 February 2017 / Revised: 1 April 2017 / Accepted: 14 April 2017 / Published: 19 April 2017
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Abstract
Measuring soil organic carbon (SOC) in riparian forest soils affected by floods is crucial for evaluating their concentration and distribution along hydrological gradients (longitudinal and transversal). Hydromorphological factors (e.g., sedimentation vs. erosion, size of floodplain, flood recurrence) may be the cause of major
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Measuring soil organic carbon (SOC) in riparian forest soils affected by floods is crucial for evaluating their concentration and distribution along hydrological gradients (longitudinal and transversal). Hydromorphological factors (e.g., sedimentation vs. erosion, size of floodplain, flood recurrence) may be the cause of major variations in the concentration of organic matter and SOC in soils and could have a direct impact on C levels in soil profiles. For this study, SOC concentrations were assessed in riparian soils collected along transects perpendicular to the riverbanks which cross through inundated and non-inundated zones. Other soil properties (e.g., acidity, nitrogen, texture, bulk density) that may affect the concentration of SOC were also considered. The main purpose of this study was to assess SOC concentrations in soils subjected to flooding with those outside the flood zones, and also measure various soil properties (in surface soils and at various depths ranging from 0 to 100 cm) for each selected area. Across the various areas, SOC shows marked differences in concentration and spatial distribution, with the lowest values found in mineral soils affected by successive floods (recurrence of 0–20 years). SOC at 0–20 cm in depth was significantly lower in active floodplains (Tukey HSD test), with average values of 2.29 ± 1.64% compared to non-inundated soils (3.83 ± 2.22%). The proportion of C stocks calculated in soils (inundated vs. non-inundated zones) was significantly different, with average values of 38.22 ± 10.40 and 79.75 ± 29.47 t·ha−1, respectively. Flood frequency appears to be a key factor in understanding the low SOC concentrations in floodplain soils subjected to high flood recurrence (0–20 years). Full article
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Open AccessArticle REDD+ Contribution to Well-Being and Income Is Marginal: The Perspective of Local Stakeholders
Forests 2017, 8(4), 125; doi:10.3390/f8040125
Received: 2 February 2017 / Revised: 15 March 2017 / Accepted: 23 March 2017 / Published: 19 April 2017
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Abstract
In addition to being a global strategy for reducing greenhouse gas emissions from tropical deforestation, Reducing Emission from Deforestation and Degradation (REDD+) intends to protect and improve the well-being and income of local stakeholders. The intention is to provide livelihood support in exchange
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In addition to being a global strategy for reducing greenhouse gas emissions from tropical deforestation, Reducing Emission from Deforestation and Degradation (REDD+) intends to protect and improve the well-being and income of local stakeholders. The intention is to provide livelihood support in exchange for local stakeholder involvement in protecting forests. Eleven years after the launch of REDD+ at COP 11 in Montreal, the degree of success in meeting well-being and income goals is examined in six countries (Brazil, Peru, Cameroon, Tanzania, Indonesia, Vietnam) at 22 initiatives, 149 villages, and approximately 4000 households through a counter-factual approach. Half the villages and households are inside and half are outside the sphere of REDD+. Measurements are made at two points in time (2010–2012, and 2013–2014). This paper focuses on measurement of the subjective perception of local stakeholders. The study finds that REDD+ has not contributed significantly to perceived well-being and income sufficiency, in spite of the fact that most households have not only engaged with REDD+ interventions, but view them favorably. REDD+’s limited achievement to date is due to unavailability of funding, among other obstacles. Recommendations are made for enhanced attention to well-being and income sufficiency in the event that REDD+ eventually takes off. Full article
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Open AccessArticle Unsustainability Risk Causality in a Private Industrial Forest: An Institutional Analysis of Factors Affecting Stand Ecosystem Services in Kochi Prefecture, Japan
Forests 2017, 8(4), 126; doi:10.3390/f8040126
Received: 7 March 2017 / Revised: 3 April 2017 / Accepted: 17 April 2017 / Published: 19 April 2017
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Abstract
Much research in recent years has analyzed the ecosystem service aspect of forests, while highlighting the need for sustainable forests. Forest management mechanisms at an inter-institutional level in Japan have been identified to hinder the implementation of forest management that is focused on
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Much research in recent years has analyzed the ecosystem service aspect of forests, while highlighting the need for sustainable forests. Forest management mechanisms at an inter-institutional level in Japan have been identified to hinder the implementation of forest management that is focused on the equal production of ecosystem services. This study presents an institutional analysis of unsustainability risk causality in a private industrial forest in Kochi Prefecture, Japan, from an ecosystem perspective incorporating common ecosystem service hazards that affect the sustainability functions of forests. This was performed with the aim to offer a basis for a less complicated analysis of ecosystem service hazards in industrial forests and to provide causal clarity at different institution levels. It was found that due to Japan’s systematic top-down forest management approach with the law at the top, vertical relationships cause direct and indirect negative horizontal relationships at each institutional level. To mitigate vertical and horizontal effects, institutional adaptions must be performed to address a combination of satisfier and hygiene factors. Under current conditions of non-enforceable forest policy, objectives and decisions regarding policy and management instruments at the national level must be integrated. This requires effective and adaptive multi-level institutional governance. Full article
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Open AccessArticle Sydowia polyspora Dominates Fungal Communities Carried by Two Tomicus Species in Pine Plantations Threatened by Fusarium circinatum
Forests 2017, 8(4), 127; doi:10.3390/f8040127
Received: 6 March 2017 / Revised: 12 April 2017 / Accepted: 17 April 2017 / Published: 20 April 2017
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Abstract
Bark beetles (Coleoptera, Scolytinae) carry a diverse filamentous fungal community sometimes acting as vectors or carriers of phytopathogens. In this study, mycobiota carried by two Tomicus species (Tomicus piniperda and Tomicus destruens) were investigated through (i) morphological and molecular identification of
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Bark beetles (Coleoptera, Scolytinae) carry a diverse filamentous fungal community sometimes acting as vectors or carriers of phytopathogens. In this study, mycobiota carried by two Tomicus species (Tomicus piniperda and Tomicus destruens) were investigated through (i) morphological and molecular identification of taxa; (ii) taxonomic richness, diversity, evenness, dominance and phoresy indices; (iii) ecological network analysis and (iv) statistical co-occurrence analysis. The studied mycobiota were formed by eleven taxa and showed a moderate fungal diversity with low evenness. The fungus Sydowia polyspora was significantly abundant and dominated the community. All the fungal taxa were randomly associated. Both insect species (T. piniperda and T. destruens) were collected from plantations of Pinus radiata infected by Fusarium circinatum. The ecological factors that could drive community ecology and phoretic links between fungi and bark beetles are discussed. Full article
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Open AccessArticle Long-Term Susceptibility of Even- and Uneven-Aged Northern Hardwood Stands to Partial Windthrow
Forests 2017, 8(4), 128; doi:10.3390/f8040128
Received: 23 February 2017 / Revised: 3 April 2017 / Accepted: 18 April 2017 / Published: 20 April 2017
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Abstract
While uneven-aged silviculture may appear preferable to even-aged silviculture in terms of stand susceptibility to windthrow (major wind damage), the scientific evidence is equivocal on this issue, because the two systems do not operate over the same time frame. The goal of this
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While uneven-aged silviculture may appear preferable to even-aged silviculture in terms of stand susceptibility to windthrow (major wind damage), the scientific evidence is equivocal on this issue, because the two systems do not operate over the same time frame. The goal of this study was to evaluate the windthrow susceptibility of even- and uneven-aged stands over a 100-year period. Susceptibility to windthrow of North American hardwood stands was evaluated by coupling a stand growth model (Forest Vegetation Simulator, or FVS) to stem windthrow probability equations from the literature. This coupling was straightforward given that FVS provides the diameter at breast height (DBH) of each tree within a stand over the simulation period. Windthrow susceptibility equations also use DBH to calculate stem windthrow probability. Our results show that average loss due to windthrow under uneven-aged management can be twice that observed under even-aged management at moderate wind severity for sugar maple-dominated stands. This result should be interpreted with caution because of the impossibility in our simulations of considering differences in tree form development between the two approaches. Nevertheless, this study clearly shows that even-/uneven-aged silviculture comparisons should be made on a long-term basis since uneven-aged stands are continuously susceptible to windthrow, while even-aged stands tend to be little affected by windthrow in their early developmental stages. Full article
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Open AccessArticle Critical Habitat Elements, with an Emphasis on Coarse Woody Debris, Associated with Ant Presence or Absence in the Moist Cold Sub-Boreal Forests of the Interior of British Columbia
Forests 2017, 8(4), 129; doi:10.3390/f8040129
Received: 28 March 2017 / Revised: 14 April 2017 / Accepted: 17 April 2017 / Published: 20 April 2017
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Abstract
Given both the ubiquity and ecological roles described for ants in British Columbia, an understanding of the habitat elements critical to predicting their presence is desirable. We used logistic regression to model the presence and absence of ants in sub-boreal lodgepole pine (
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Given both the ubiquity and ecological roles described for ants in British Columbia, an understanding of the habitat elements critical to predicting their presence is desirable. We used logistic regression to model the presence and absence of ants in sub-boreal lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) forests of west-central British Columbia (BC). Methodological emphasis was placed on the association between ants and coarse woody debris (CWD) because of a high degree of utilization of this resource for nesting. Five species of ants, Camponotus herculeanus (L.), Formica aserva Forel, F. neorufibarbis Emery, Leptothorax muscorum (Nylander), and Myrmica alaskensis Wheeler, comprised approximately 90% of all captures in samples of CWD within five seral ages (2–3, 8–10, 13–15, 23–25 years post-harvest, and non-harvested stands). Seral age, presence of other ant colonies of the same species, decay class of CWD, its surface area, and whether the wood was downed woody debris (DWD) or a stump, were significant variables affecting ant presence or absence. These results are explained in the context of ant species autecology as it relates to living in cool climates. Full article
(This article belongs to the Special Issue Coarse Woody Debris of Forests in a Changing World)
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Open AccessArticle Urbanization Drives SOC Accumulation, Its Temperature Stability and Turnover in Forests, Northeastern China
Forests 2017, 8(4), 130; doi:10.3390/f8040130
Received: 11 December 2016 / Revised: 14 April 2017 / Accepted: 15 April 2017 / Published: 20 April 2017
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Abstract
Global urbanization is a vital process shaping terrestrial ecosystems but its effects on forest soil carbon (C) dynamics are still not well defined. To clarify the effects of urbanization on soil organic carbon (SOC) variation, 306 soil samples were collected and analyzed under
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Global urbanization is a vital process shaping terrestrial ecosystems but its effects on forest soil carbon (C) dynamics are still not well defined. To clarify the effects of urbanization on soil organic carbon (SOC) variation, 306 soil samples were collected and analyzed under two urban–rural gradients, defined according to human disturbance time and ring road development in Changchun, northeast China. Forest SOC showed a linear increase with increasing human disturbance time from year 1900 to 2014 (13.4 g C m−2 year−1), and a similar trend was found for the ring road gradient. Old-city regions had the longest SOC turnover time and it increased significantly with increasing urbanization (p = 0.011). Along both urban–rural gradients SOC stability toward temperature variation increased with increasing urbanization, meaning SOC stability in old-city regions was higher than in new regions. However, none of the urban–rural gradients showed marked changes in soil basal respiration rate. Both Pearson correlation and stepwise regression proved that these urbanization-induced SOC patterns were closely associated with landscape forest (LF) proportion and soil electrical conductivity (EC) changes in urban–rural gradients, but marginally related with tree size and compositional changes. Overall, Changchun urbanization-induced SOC accumulation was 60.6–98.08 thousand tons, accounting for 12.8–20.7% of the total forest C biomass sequestration. Thus, China’s rapid urbanization-induced SOC sequestration, stability and turnover time, should be fully estimated when evaluating terrestrial C balance. Full article
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Open AccessArticle Red Alder-Conifer Stands in Alaska: An Example of Mixed Species Management to Enhance Structural and Biological Complexity
Forests 2017, 8(4), 131; doi:10.3390/f8040131
Received: 30 January 2017 / Revised: 10 April 2017 / Accepted: 14 April 2017 / Published: 21 April 2017
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Abstract
There is worldwide interest in managing forests to improve biodiversity, enhance ecosystem services and assure long-term sustainability of forest resources. An increasingly important goal of forest management is to increase stand diversity and improve wildlife and aquatic habitat. Well-planned silvicultural systems containing a
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There is worldwide interest in managing forests to improve biodiversity, enhance ecosystem services and assure long-term sustainability of forest resources. An increasingly important goal of forest management is to increase stand diversity and improve wildlife and aquatic habitat. Well-planned silvicultural systems containing a mixture of broadleaf-conifer species have potential to enhance stand diversity and provide other ecosystem services earlier than typical even-aged conifer plantations. Here, we use the example of mixed Sitka spruce/western hemlock and red alder in young, managed stands in southeast Alaska to achieve these goals. We briefly describe the silvics of Sitka spruce, western hemlock and red alder plantations as pure conifer stands or pure broadleaf stands. Then, we synthesize studies of mixed red alder-Sitka spruce/western hemlock stands in southeast Alaska and present their potential for improving stand structural complexity, biodiversity and other ecosystem services over pure conifer forests. Finally, we discuss some of the opportunities and potential tradeoffs for managing mixed broadleaf-conifer stands for providing a number of natural resources and the influence of these broadleaf-conifer forests on ecosystem linkages and processes. Full article
(This article belongs to the Special Issue Dynamics and Management of Boreal Forests)
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Open AccessArticle Tree Height-Diameter Relationships in the Alpine Treeline Ecotone Compared with Those in Closed Forests on Changbai Mountain, Northeastern China
Forests 2017, 8(4), 132; doi:10.3390/f8040132
Received: 24 February 2017 / Revised: 7 April 2017 / Accepted: 11 April 2017 / Published: 21 April 2017
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Abstract
Height-diameter relationship is one of the most important stature characteristics of trees. It will change with climatic conditions because height and diameter growth displays different sensitivities to climatic factors such as temperature. Detecting and understanding changes in the stature of trees growing along
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Height-diameter relationship is one of the most important stature characteristics of trees. It will change with climatic conditions because height and diameter growth displays different sensitivities to climatic factors such as temperature. Detecting and understanding changes in the stature of trees growing along altitudinal gradients up to their upper limits can help us to better understand the adaptation strategy of trees under global warming conditions. On Changbai Mountain in northeastern China, height-diameter datasets were collected for 2723 Erman’s birch (Betula ermanii Cham.) in the alpine treeline ecotone in 2006 and 2013, and for 888 Erman’s birch, spruce (Picea jezoensis Siebold & Zucc. Carr.), larch (Larix olgensis A. Henry), and fir (Abies nephrolepis Trautv. ex Maxim.) along an altitudinal gradient below the alpine treeline in 2006. These datasets were utilized to explore both changes in the stature of birch at the alpine treeline over time and variations in tree stature of different tree species across altitudes at a given time point (2006). Results showed that birch saplings (<140 cm in height) became stunted while birches with a height of >140 cm became more tapered in the alpine treeline ecotone. The stature of birch along the altitudinal gradient became more tapered from 1700 to 1900 m above see level (a.s.l.) and then became more stunted from 1900 to 2050 m a.s.l., with 1900 m a.s.l. being the altitudinal inflection point in this pattern. The treeline birch, due to its great temperature magnitude of distribution, displayed higher stature-plasticity in terms of its height-diameter ratio than the lower elevation species studied. The stature of birch is strongly modulated by altitude-related temperature but also co-influenced by other environmental factors such as soil depth and available water, wind speed, and duration and depth of winter snow cover. The high stature-plasticity of birch makes it fare better than other species to resist and adapt to, as well as to survive and develop in the harsh alpine environment. Full article
(This article belongs to the Special Issue Treeline Ecotone Dynamics)
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Open AccessArticle Assessing Impacts of Wood Utilisation Scenarios for a Lithuanian Bioeconomy: Impacts on Carbon in Forests and Harvested Wood Products and on the Socio-Economic Performance of the Forest-Based Sector
Forests 2017, 8(4), 133; doi:10.3390/f8040133
Received: 17 January 2017 / Revised: 4 April 2017 / Accepted: 18 April 2017 / Published: 22 April 2017
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Abstract
Climate change and transition towards a bioeconomy are seen as both challenges and opportunities for the forest-based sector in Europe. Transition towards a bioeconomy will in most cases rely on intensified use of renewable resources and/or advancement in technology. However, how can the
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Climate change and transition towards a bioeconomy are seen as both challenges and opportunities for the forest-based sector in Europe. Transition towards a bioeconomy will in most cases rely on intensified use of renewable resources and/or advancement in technology. However, how can the intensified use of renewable resources be combined with climate change mitigation measures to increase carbon sinks in the forest-based sector? Additionally, what are the possible socio-economic and environmental impacts of intensified wood use? In this study, we examined the impacts of increased wood utilisation in Lithuania. The objective of this study was to assess the effects of increased domestic wood utilisation on: (i) employment; (ii) the economic performance of the sector; (iii) carbon in forest biomass and soil; and (iv) carbon in harvested wood products (HWP). The system boundaries were set in accordance with international greenhouse gas reporting to include only domestic wood flows. We assessed alternative wood utilisation scenarios using a forest resource model and a tool to assess sustainability impacts of (wood) value chains, using country specific data on wood (carbon) flows. Our results indicate that increased wood use could lead to trade-offs between six selected indicators. Opportunities for employment and the economic performance of the forest-based sector improved in all scenarios due to increased wood utilisation. However, when forest fellings increased, the carbon stored in forests decreased, the carbon stored in HWP increased, but overall the total carbon stored in forests and HWP decreased. When considering also additional substitution effects until the year 2100, the scenario with reduced wood exports generated larger total climate change mitigation effects than the baseline. Our results suggest that increased wood utilisation might support Lithuania’s bioeconomy through increased socio-economic benefits. National positive climate change mitigation effects could be gained only if additional actions to utilise more domestic wood for long-life HWP will be taken. Full article
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Open AccessArticle Forest Company Dependencies and Impacts on Ecosystem Services: Expert Perceptions from China
Forests 2017, 8(4), 134; doi:10.3390/f8040134
Received: 13 February 2017 / Revised: 3 April 2017 / Accepted: 19 April 2017 / Published: 22 April 2017
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Abstract
Global awareness of sustainability issues is growing rapidly, and business organizations are called to address wider social and environmental concerns along with economic performance. However, limited systematic knowledge exists on the interactions between forest industries and natural ecosystems. We thus investigated the role
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Global awareness of sustainability issues is growing rapidly, and business organizations are called to address wider social and environmental concerns along with economic performance. However, limited systematic knowledge exists on the interactions between forest industries and natural ecosystems. We thus investigated the role of ecosystem services in the context of China’s forest sector. A qualitative research approach was used to elicit company external expert viewpoints on the topic. Our analysis focused on three themes: (1) forest company dependencies and impacts on ecosystem services; (2) business risks arising from dependencies and impacts; and (3) risk response strategies. The interviewed 20 experts identified a series of forest company dependencies and impacts (including negative and positive impacts) on several ecosystem services. The extent of dependencies and impacts is largely influenced by the business portfolio of the company. The perceived business risks include intense competition and the consequently increasing price for natural resources, which would affect forest company business plans, costs and outputs. The suggested strategies for turning risks into opportunities include outsourcing wood, changing production focus, promoting industrial upgrading and implementing regular assessments of corporate dependencies and impacts on ecosystem services. The findings of our study can guide companies’ decision-making in managing forest ecosystems sustainably. Full article
(This article belongs to the Special Issue Management Strategies for Forest Ecosystem Services)
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Open AccessArticle Chemical and Biochemical Properties of Soils Developed from Different Lithologies in Northwestern Spain (Galicia)
Forests 2017, 8(4), 135; doi:10.3390/f8040135
Received: 15 March 2017 / Revised: 11 April 2017 / Accepted: 19 April 2017 / Published: 22 April 2017
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Abstract
Physical and chemical soil properties are generally correlated with the parent material, as its composition may influence the pedogenetic processes, the content of nutrients, and the element biocycling. This research studied the chemical and biochemical properties of the A horizon from soils developed
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Physical and chemical soil properties are generally correlated with the parent material, as its composition may influence the pedogenetic processes, the content of nutrients, and the element biocycling. This research studied the chemical and biochemical properties of the A horizon from soils developed on different rocks like amphibolite, serpentinite, phyllite, and granite under a relatively similar climatic regime from Galicia (northwest Spain). In particular, the effect of the parent material on soil evolution, organic carbon sequestration, and the hormone-like activity of humic and fulvic acids were tested. Results indicated that all the soils were scarcely fertile because of low concentrations of available P, exchangeable Ca (except for the soils on serpentinite and phyllite), and exchangeable K, but sequestered relevant quantities of organic carbon. The scarce soil fertility was common to all soils independently of the parent material, and we attributed this similarity to the pedogenetic pressure induced by the climatic conditions. Also, the hormone-like activity of humic and fulvic acids, similar for all the soils, was probably due to pedogenesis. We hypothesized that the hormone-like activity of the humic substances helps growth and diffusion of vegetation in low fertile soils and, consequently, soil organic carbon sequestration too. Full article
(This article belongs to the Special Issue Soil Carbon Sequestration in Forests)
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Open AccessArticle Screening of Date Palm (Phoenix dactylifera L.) Cultivars for Salinity Tolerance
Forests 2017, 8(4), 136; doi:10.3390/f8040136
Received: 17 March 2017 / Revised: 14 April 2017 / Accepted: 20 April 2017 / Published: 22 April 2017
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Abstract
Date palm (Phoenix dactylifera L.) is a major fruit tree in the Middle East and it is a plant considered to be tolerant to a variety of abiotic stresses, including salinity. However, the physiological basis of its salinity tolerance is not fully
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Date palm (Phoenix dactylifera L.) is a major fruit tree in the Middle East and it is a plant considered to be tolerant to a variety of abiotic stresses, including salinity. However, the physiological basis of its salinity tolerance is not fully known. The objective of this study was to screen Omani date palm cultivars for tolerance or susceptibility to salt stress. Seedlings from 10 commercially important date palm cultivars were subjected to 240 mM NaCl, and several physiological parameters related to salinity tolerance traits were evaluated upon treatment. The cultivars were divided into two groups based on the dry weight (DW) of their leaf and root tissues, a parameter which was used as an indication of healthy growth. The results revealed that photosynthesis, electrolyte leakage (EL), and the shoot K+/Na+ ratio were all significantly reduced in the susceptible cultivars. In addition, the relative water content was higher in the tolerant cultivars in comparison with the susceptible ones. These results suggest that although date palm is tolerant to high salinity, there is variation in tolerance among different cultivars. Shoot Na+ exclusion, photosynthesis, and membrane stability are apparently the main determinants of tolerance and can be used in salinity tolerance screening of date palm. The results have shown new very tolerant cultivars (Manoma and Umsila) that could serve as genetic resources for improved date palm tolerance to salinity. Full article
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Review

Jump to: Research

Open AccessReview Armillaria Pathogenesis under Climate Changes
Forests 2017, 8(4), 100; doi:10.3390/f8040100
Received: 21 January 2017 / Revised: 14 March 2017 / Accepted: 23 March 2017 / Published: 27 March 2017
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Abstract
Climate changes influencing forest ecosystems include increased air temperatures and CO2 concentrations as well as droughts and decreased water availability. These changes in turn effect changes in species composition of both host plants and pathogens. In the case of Armillaria, climate
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Climate changes influencing forest ecosystems include increased air temperatures and CO2 concentrations as well as droughts and decreased water availability. These changes in turn effect changes in species composition of both host plants and pathogens. In the case of Armillaria, climate changes cause an increase in the activity of individual species and modify the growth of rhizomorphs, increasing the susceptibility of trees. The relationship between climate changes and the biotic elements of Armillaria disease are discussed in overview. Full article
(This article belongs to the Special Issue Forest Pathology and Plant Health)
Open AccessReview Trailblazing the Carbon Cycle of Tropical Forests from Puerto Rico
Forests 2017, 8(4), 101; doi:10.3390/f8040101
Received: 14 February 2017 / Revised: 15 March 2017 / Accepted: 23 March 2017 / Published: 29 March 2017
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Abstract
We review the literature that led to clarifying the role of tropical forests in the global carbon cycle from a time when they were considered sources of atmospheric carbon to the time when they were found to be atmospheric carbon sinks. This literature
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We review the literature that led to clarifying the role of tropical forests in the global carbon cycle from a time when they were considered sources of atmospheric carbon to the time when they were found to be atmospheric carbon sinks. This literature originates from work conducted by US Forest Service scientists in Puerto Rico and their collaborators. It involves the classification of forests by life zones, estimation of carbon density by forest type, assessing carbon storage changes with ecological succession and land use/land cover type, describing the details of the carbon cycle of forests at stand and landscape levels, assessing global land cover by forest type and the complexity of land use change in tropical regions, and assessing the ecological fluxes and storages that contribute to net carbon accumulation in tropical forests. We also review recent work that couples field inventory data, remote sensing technology such as LIDAR, and GIS analysis in order to more accurately determine the role of tropical forests in the global carbon cycle and point out new avenues of carbon research that address the responses of tropical forests to environmental change. Full article
(This article belongs to the Special Issue Tropical Forest Ecology and Management for the Anthropocene)
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Open AccessReview Arthropod Diversity and Functional Importance in Old-Growth Forests of North America
Forests 2017, 8(4), 97; doi:10.3390/f8040097
Received: 26 January 2017 / Revised: 17 March 2017 / Accepted: 23 March 2017 / Published: 25 March 2017
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Abstract
Old-growth forests have become rare in North America but provide habitat for unique assemblages of species that often are rare in younger forests. Insects and related arthropods reach their highest diversity in old-growth forests because of their stable moderate temperature and relative humidity
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Old-growth forests have become rare in North America but provide habitat for unique assemblages of species that often are rare in younger forests. Insects and related arthropods reach their highest diversity in old-growth forests because of their stable moderate temperature and relative humidity and the rich variety of resources represented by high plant species richness and structural complexity. Old-growth arthropod assemblages typically are distinct from those in younger, managed forests. Major subcommunities include the arboreal community that is composed of a rich assemblage of herbivores, fungivores, and their associated predators and parasitoids that function to regulate primary production and nutrient fluxes, the stem zone community that includes bark- and wood-boring species and their associated predators and parasitoids that initiate the decomposition of coarse woody debris, and the forest floor community composed of a variety of detritivores, fungivores, burrowers, and their associated predators and parasitoids that are instrumental in litter decomposition. Insect outbreaks are relatively rare in old-growth forests, where the diversity of resources and predators limit population growth. In turn, insects contribute to plant diversity and limit primary production of host plant species, thereby promoting development of old-growth forest characteristics. Arthropods also provide important functions in decomposition and nutrient cycling that may be lost in younger, managed forests with limited provision of coarse woody debris and accumulated litter. Protection of remnant old-growth forests within the forest matrix may be particularly valuable for maintaining the diversity of plant and arthropod predators that can minimize outbreaks, thereby contributing to resilience to changing environmental conditions. Full article
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Open AccessReview Multicriteria Decision Analysis and Participatory Decision Support Systems in Forest Management
Forests 2017, 8(4), 116; doi:10.3390/f8040116
Received: 17 February 2017 / Revised: 5 April 2017 / Accepted: 5 April 2017 / Published: 10 April 2017
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Abstract
Growing concern about issues such as environmental quality or the sustainability of natural resources has led to the use of the Decision Support System (DSS), which originated in the business field, and is now part of environmental decision-making processes. The presence of environmental,
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Growing concern about issues such as environmental quality or the sustainability of natural resources has led to the use of the Decision Support System (DSS), which originated in the business field, and is now part of environmental decision-making processes. The presence of environmental, social, or economic dimensions has helped decision support systems to evolve to be able to tackle investigations that can contemplate all these variables, such as in the case of multicriteria decision analyses. In addition, new lifestyles, in which society recognizes more and more the contribution of forests to its welfare, have led to the need to involve stakeholders in decision-making processes. This article presents a review of different Multicriteria Decision Analysis (MCDA) and participatory decision support systems applied to forest environments. This last point is presented from the perspective of stakeholder participation in the processes and from the point of view of procedures or tools used. To do this, some of the research performed in forest environments within this current century is reviewed. Full article
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Open AccessReview Epidemiological History of Cypress Canker Disease in Source and Invasion Sites
Forests 2017, 8(4), 121; doi:10.3390/f8040121
Received: 27 February 2017 / Revised: 11 April 2017 / Accepted: 12 April 2017 / Published: 15 April 2017
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Abstract
Seiridium cardinale is a fungal pathogen responsible for pandemic cypress canker disease (CCD). The fungus has shown the ability to infect different hosts in many areas throughout the globe, but its spread and impact were favored by conducive environmental conditions. The most severe
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Seiridium cardinale is a fungal pathogen responsible for pandemic cypress canker disease (CCD). The fungus has shown the ability to infect different hosts in many areas throughout the globe, but its spread and impact were favored by conducive environmental conditions. The most severe epidemics were reported in California and the Mediterranean, the former considered the source area of the pathogen from which the Mediterranean infestation have originated. Here we reconstruct the epidemiological history of the disease in California and the Mediterranean. Evolution of the disease in the two contrasting areas was weighed in relation to differences between the two environments in terms of climate, landscape properties, and adopted management practices. In addition, differences emerged among the source and invasive populations in terms of genetic and phenotypic variability, structure, and mode of reproduction allow a few comments to be made about the environmental implications and related quarantine of new introductory events. Full article
(This article belongs to the Special Issue Forest Pathology and Plant Health)
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Open AccessReview Look Down to See What’s Up: A Systematic Overview of Treefall Dynamics in Forests
Forests 2017, 8(4), 123; doi:10.3390/f8040123
Received: 1 March 2017 / Revised: 12 April 2017 / Accepted: 14 April 2017 / Published: 17 April 2017
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Abstract
The study of treefall and its after-effects is a common theme in studies of forest structure and local dynamics, yet its value as descriptor of broader-scale ecological dynamics is rarely explored. Here we synthesize the most highly cited literature on treefalls, from 1985
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The study of treefall and its after-effects is a common theme in studies of forest structure and local dynamics, yet its value as descriptor of broader-scale ecological dynamics is rarely explored. Here we synthesize the most highly cited literature on treefalls, from 1985 to 2016 (in three-year blocks), highlighting the importance of the causes, characteristics and consequences of such events. We then ask how this knowledge might contribute to the broader conceptual model of forest dynamics, and develop two conceptual models, which we use to illustrate both the classic and alternative views of how forests ‘work’. Treefalls are one of the few ‘integrating’ attributes of forests, because of their ubiquity and longevity, and therefore can inform a variety of processes (e.g., tree mortality, turnover rates, structural impacts, recruitment, and fire frequency) due to their impacts occurring simultaneously over space (patterns), and time (legacy effects). The substantial knowledge that already exists on localized treefall dynamics should be combined with more integrative approaches to studying forest ecosystems, to investigate landscape-scale patterns of treefall and reconstruct past disturbance events. Full article
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Open AccessFeature PaperReview Traditional and Novel Indicators of Climate Change Impacts on European Forest Trees
Forests 2017, 8(4), 137; doi:10.3390/f8040137
Received: 3 February 2017 / Revised: 18 April 2017 / Accepted: 20 April 2017 / Published: 24 April 2017
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Abstract
The concern for the fate of forest ecosystems under climate change demands the development of a prompt and effective system for detecting the impacts of pressure factors, such as rising temperatures, drought conditions, and extreme climatic events. In ongoing European monitoring programs, the
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The concern for the fate of forest ecosystems under climate change demands the development of a prompt and effective system for detecting the impacts of pressure factors, such as rising temperatures, drought conditions, and extreme climatic events. In ongoing European monitoring programs, the health condition of trees is only assessed visually as a matter of course and there is limited evidence that enhanced crown defoliation implies physiological disturbance and reduced tree growth. The progress of the research makes it possible to apply methods developed in experimental conditions in forests for the fast and reliable assessment of impacts and of stress conditions. In this review, we analyze the most promising indicators of tree and forest health (at individual plant and ecosystem levels) for their potential application in forest ecosystems and their ability to support and integrate the traditional visual assessment, provide information on influential factors, and improve the prediction of stand dynamics and forest productivity. Full article
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