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Forests, Volume 8, Issue 11 (November 2017)

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Editorial

Jump to: Research

Open AccessEditorial Variability and Disturbances as Key Factors in Forest Pathology and Plant Health Studies
Forests 2017, 8(11), 441; doi:10.3390/f8110441
Received: 13 November 2017 / Accepted: 14 November 2017 / Published: 15 November 2017
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Abstract
The plant disease triangle (PDT) is as old as the field of modern plant pathology, and it postulates that any plant disease is the outcome of the interaction between a pathogen, a host, and the environment. Recently, the need has emerged to study
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The plant disease triangle (PDT) is as old as the field of modern plant pathology, and it postulates that any plant disease is the outcome of the interaction between a pathogen, a host, and the environment. Recently, the need has emerged to study not only how the three elements of the PDT directly influence disease, but to focus on how they indirectly affect one another, consequently modifying the final outcome. It is also essential to structure such analyses within three major external frameworks provided by landscape level disturbances, climate change, and anthropogenic effects. The studies included in this issue cover a wide range of topics using an equally varied list of approaches, and they showcase the important role these indirect and often non-linear processes have on the development of forest diseases. Full article
(This article belongs to the Special Issue Forest Pathology and Plant Health)
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Research

Jump to: Editorial

Open AccessArticle Germination of Seeds of Melanoxylon brauna Schott. under Heat Stress: Production of Reactive Oxygen Species and Antioxidant Activity
Forests 2017, 8(11), 405; doi:10.3390/f8110405
Received: 9 August 2017 / Revised: 6 October 2017 / Accepted: 9 October 2017 / Published: 25 October 2017
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Abstract
In this article, the authors aimed to analyze the physiological and biochemical alterations in Melanoxylon brauna seeds subjected to heat stress. For this, seed germination, electric conductivity (EC), the production of reactive oxygen species (ROS), and the activity of antioxidant enzymes were assessed.
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In this article, the authors aimed to analyze the physiological and biochemical alterations in Melanoxylon brauna seeds subjected to heat stress. For this, seed germination, electric conductivity (EC), the production of reactive oxygen species (ROS), and the activity of antioxidant enzymes were assessed. Seeds were incubated at constant temperatures of 25, 35, and 45 °C. Independent samples were first incubated at 35 and 45 °C and then transferred to 25 °C after the intervals of 24, 48, 72, and 96 h. To evaluate EC, seeds were soaked for 0, 24, 48, and 72 h, at 25, 35, and 45 °C and then transferred to Erlenmeyer flasks containing 75 mL of deionized water at 25 °C, for 24 h. ROS production and enzyme activity were assessed every 24 h in seeds soaked at the aforementioned temperatures. Germination did not occur at 45 °C. Seeds soaked at 35 °C for 72 h and then transferred to 25 °C showed higher percentages of germination and a higher germination speed. Seed soaking at 45 °C increased peroxide production, which compromised the antioxidant enzyme system due to a reduction in the activity of enzymes APX, POX, and CAT, thus ultimately also compromising the cell membrane system. Full article
(This article belongs to the Special Issue Seedling Production and Field Performance of Seedlings)
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Open AccessArticle Wild Apple Growth and Climate Change in Southeast Kazakhstan
Forests 2017, 8(11), 406; doi:10.3390/f8110406
Received: 31 August 2017 / Revised: 20 October 2017 / Accepted: 22 October 2017 / Published: 26 October 2017
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Abstract
Wild populations of Malus sieversii [Ldb.] M. Roem are valued genetic and watershed resources in Inner Eurasia. These populations are located in a region that has experienced rapid and on-going climatic change over the past several decades. We assess relationships between climate variables
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Wild populations of Malus sieversii [Ldb.] M. Roem are valued genetic and watershed resources in Inner Eurasia. These populations are located in a region that has experienced rapid and on-going climatic change over the past several decades. We assess relationships between climate variables and wild apple radial growth with dendroclimatological techniques to understand the potential of a changing climate to influence apple radial growth. Ring-width chronologies spanning 48 to 129 years were developed from 12 plots in the Trans-Ili Alatau and Jungar Alatau ranges of Tian Shan Mountains, southeastern Kazakhstan. Cluster analysis of the plot-level chronologies suggests different temporal patterns of growth variability over the last century in the two mountain ranges studied. Changes in the periodicity of annual ring-width variability occurred ca. 1970 at both mountain ranges, with decadal-scale variability supplanted by quasi-biennial variation. Seascorr correlation analysis of primary and secondary weather variables identified negative growth associations with spring precipitation and positive associations with cooler fall-winter temperatures, but the relative importance of these relationships varied spatially and temporally, with a shift in the relative importance of spring precipitation ca. 1970 at Trans-Ili Alatau. Altered apple tree radial growth patterns correspond to altered climatology in the Lake Balkhash Basin driven by unprecedented intensified Arctic Oscillations after the late 1970s. Full article
(This article belongs to the Special Issue Tree-Ring Records of Climatic Impacts on Forests)
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Open AccessArticle Taxon-Independent and Taxon-Dependent Responses to Drought in Seedlings from Quercus robur L., Q. petraea (Matt.) Liebl. and Their Morphological Intermediates
Forests 2017, 8(11), 407; doi:10.3390/f8110407
Received: 31 August 2017 / Revised: 21 October 2017 / Accepted: 24 October 2017 / Published: 27 October 2017
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Abstract
The increasing severity and frequency of summer droughts at mid-latitudes in Europe may impact forest regeneration. We investigated whether the sympatric species Quercus robur L., Q. petraea (Matt.) Liebl., and their morphological intermediates respond differentially to water deficit. Acorns were sourced from a
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The increasing severity and frequency of summer droughts at mid-latitudes in Europe may impact forest regeneration. We investigated whether the sympatric species Quercus robur L., Q. petraea (Matt.) Liebl., and their morphological intermediates respond differentially to water deficit. Acorns were sourced from a naturally mixed population. Half of the potted seedlings were subjected to two successive drought periods during the first growing season, each followed by a plentiful re-watering. The surviving drought-exposed seedlings subsisted independent of the taxon of the mother tree. The phenological responses were also taxon-independent. However, drought-exposed plants showed a retarded height growth in the year following the treatment which was taxon-dependent. Offspring from Q. robur and from trees with leaves resembling Q. robur leaves and infructescences resembling Q. petraea infructescences showed a stronger decrease in height growth compared to the offspring from Q. petraea and from trees with leaves resembling Q. petraea leaves and infructescences resembling Q. robur infructescences. Diameter growth in the year following the drought treatment showed a weak taxon-dependent response. Together, our results may suggest that the composition of oak species and their hybrids in natural oak forests could be altered upon prolonged periods of precipitation deficit. Full article
(This article belongs to the Special Issue Seedling Production and Field Performance of Seedlings)
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Open AccessCommunication Visual Assessment of Surface Fuel Loads Does Not Align with Destructively Sampled Surface Fuels
Forests 2017, 8(11), 408; doi:10.3390/f8110408
Received: 16 September 2017 / Revised: 14 October 2017 / Accepted: 26 October 2017 / Published: 27 October 2017
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Abstract
Fuel load and structure are fundamental drivers of fire behaviour. Accurate data is required for managers and researchers to better understand our ability to alter fire risk. While there are many ways to quantify fuel, visual assessment methods are generally considered the most
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Fuel load and structure are fundamental drivers of fire behaviour. Accurate data is required for managers and researchers to better understand our ability to alter fire risk. While there are many ways to quantify fuel, visual assessment methods are generally considered the most efficient. Visual hazard assessments are commonly used by managers, government agencies and consultants to provide a fuel hazard score or rating but not a quantity of fuel. Many systems attempt to convert the hazard score or rating to a fuel load for use in fire behaviour models. Here we investigate whether the conversion table in the widely used Overall Fuel Hazard Guide (OFHG) matches destructively sampled fuel loads from 116 sites across five forest types. We specifically examine whether there are quantifiable differences that can be attributed to forest type. We found there is overlap between the two methods for low, moderate and high hazard categories, however for the very high and extreme hazard categories, visual assessment overestimated fuel load in four of the five forest types. Using a commonly applied fire behaviour model, we found that the overestimation of fuel load in very high and extreme hazard categories leads to an overestimation of fire behavior in these hazard categories. Full article
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Open AccessArticle Genetic Variation, Heritability and Genotype × Environment Interactions of Resin Yield, Growth Traits and Morphologic Traits for Pinus elliottii at Three Progeny Trials
Forests 2017, 8(11), 409; doi:10.3390/f8110409
Received: 26 July 2017 / Revised: 25 October 2017 / Accepted: 25 October 2017 / Published: 30 October 2017
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Abstract
To better understand the genetic control of resin yield, growth traits and morphologic traits for Pinus elliottii families, genetic relationships among these traits were examined in three 27-year-old progeny trials located in Jingdezhen, Jian and Ganzhou, Jiangxi Province, China. In total, 3695 trees
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To better understand the genetic control of resin yield, growth traits and morphologic traits for Pinus elliottii families, genetic relationships among these traits were examined in three 27-year-old progeny trials located in Jingdezhen, Jian and Ganzhou, Jiangxi Province, China. In total, 3695 trees from 112 families were assessed at the three sites. Significant site, family and family × site effects were found for resin yield, growth traits and morphologic traits. Resin yield and growth traits were found to be under moderate genetic control for the three sites combined, with family heritability and individual narrow-sense heritability ranging from 0.41 to 0.55 and 0.11 to 0.27, respectively. The coefficient of genotypic variation (CVG) of stem volume (SV) and crown surface area (CSA) were higher than those of other traits at each site. Genetic correlation estimates indicated that selection for growth traits might lead to a large increment in resin yield (RY), and most morphologic traits had moderate to strong correlations with growth traits at each individual site. One possible strategy in tree breeding would be to maximize resin production through selection for growth traits. Full article
(This article belongs to the Special Issue Genetics and Genomics of Forest Trees)
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Open AccessArticle Deterministic Models of Growth and Mortality for Jack Pine in Boreal Forests of Western Canada
Forests 2017, 8(11), 410; doi:10.3390/f8110410
Received: 23 October 2017 / Revised: 30 October 2017 / Accepted: 30 October 2017 / Published: 30 October 2017
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Abstract
We developed individual tree deterministic growth and mortality models for jack pine (Pinus banksiana Lamb.) using data from permanent sample plots in Alberta, Saskatchewan and Manitoba, Canada. Height and diameter increment equations were fitted using nonlinear mixed effects models. Logistic mixed models
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We developed individual tree deterministic growth and mortality models for jack pine (Pinus banksiana Lamb.) using data from permanent sample plots in Alberta, Saskatchewan and Manitoba, Canada. Height and diameter increment equations were fitted using nonlinear mixed effects models. Logistic mixed models were used to estimate jack pine survival probability based on tree and stand characteristics. The resulting models showed that (1) jack pine growth is significantly influenced by competition; (2) competitive effects differ between species groups; and (3) survival probability is affected by tree size and growth, stand composition, and stand density. The estimated coefficients of selected growth and mortality functions were implemented into the Mixedwood Growth Model (MGM) and the simulated predictions were evaluated against independently measured data. The validation showed that the MGM can effectively model jack pine trees and stands, providing support for its use in management planning. Full article
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Open AccessArticle Dispersal Patterns of Pine Wilt Disease in the Early Stage of Its Invasion in South Korea
Forests 2017, 8(11), 411; doi:10.3390/f8110411
Received: 26 September 2017 / Revised: 25 October 2017 / Accepted: 25 October 2017 / Published: 30 October 2017
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Abstract
We characterized the dispersal patterns of pine wilt disease (PWD) in the early stage of its invasion in the South Korea, and estimated the influence of environmental factors on the dispersal of PWD. Data were obtained in 10 regions with at least five
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We characterized the dispersal patterns of pine wilt disease (PWD) in the early stage of its invasion in the South Korea, and estimated the influence of environmental factors on the dispersal of PWD. Data were obtained in 10 regions with at least five consecutive years of data for 10 years from 1994 to 2005. The dispersal patterns of PWD were categorized into four types: type 1 is a jumping type of dispersal, forming new patches; type 2 infestations are ones without any expansion of patch size; and types 3 and 4, respectively, show uni-directional or multi-directional dispersal outward from an existing patch. Dispersal patterns changed during different phases of the pathogen’s invasion history: type 1 was the most frequent in the early invasion stage. Annual dispersal distance showed regional variations. Human population density had a positive correlation with the dispersal distance of PWD, indicating that anthropogenic factors can contribute to the dispersal of PWD. Our results suggested that dispersal through jumping from areas occupied by PWD was the main dispersal route in the early stage of invasion and that after this phase, the existing colonies expanded and merged. These results supported the existence of stratified dispersal patterns of PWD. Full article
(This article belongs to the Special Issue Ecological Management of Pine Forests)
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Open AccessArticle Decomposition of Leaves and Fine Roots in Three Subtropical Plantations in China Affected by Litter Substrate Quality and Soil Microbial Community
Forests 2017, 8(11), 412; doi:10.3390/f8110412
Received: 9 August 2017 / Revised: 19 October 2017 / Accepted: 23 October 2017 / Published: 30 October 2017
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Abstract
Leaf and root litter decomposition has been a major research focus. However, the possible effects of belowground microbial community structure and diversity on this process are poorly understood. Understanding the biochemical mechanisms controlling aboveground decomposition processes is important to predict the changes of
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Leaf and root litter decomposition has been a major research focus. However, the possible effects of belowground microbial community structure and diversity on this process are poorly understood. Understanding the biochemical mechanisms controlling aboveground decomposition processes is important to predict the changes of soil carbon and nutrient cycling in response to changes of forest management regimes. Here, we explore the biochemical controls of leaf and fine root decomposition in three subtropical plantations (Ford Erythrophleum (Erythrophleum fordii Oliver), Masson Pine (Pinus massoniana Lamb.)), and a mixed plantation containing both species) using the litterbag method, and soil microbial communities were determined using phospholipid fatty acid profiles. Overall, leaves decomposed more rapidly than fine roots, potentially due to the faster degradation of their cellulose component, but not lignin. In addition, leaf and fine root decomposition rates varied among plantations, being higher in E. fordii and lower in P. massoniana. Substrate quality such as N, Ca, lignin concentration, and C/N ratio were responsible for the decomposition rate changes among plantation types. Moreover, we used redundancy analysis to examine the relationships between litter decomposition and soil microbial community composition and diversity. Results revealed that actinobacteria and arbuscular mycorrhizal fungi community were the key determinants affecting leaf and fine root litter decomposition, respectively. Our work demonstrates that litter decomposition was linked to substrate quality and to the structure of soil microbial communities, and evidences the probable role of E. fordii in increasing soil nutrient availability, especially N, P and Ca. Additional data on phospholipid fatty acid (PLFA) or DNA marker groups within the litterbags over time may provide insights into litter decomposition dynamics, which represents potential objectives for future long-term decomposition studies. Full article
(This article belongs to the Special Issue Forest Fine Roots in Changing Climate)
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Open AccessArticle Low Light Availability Associated with American Beech Is the Main Factor for Reduced Sugar Maple Seedling Survival and Growth Rates in a Hardwood Forest of Southern Quebec
Forests 2017, 8(11), 413; doi:10.3390/f8110413
Received: 22 September 2017 / Revised: 27 October 2017 / Accepted: 29 October 2017 / Published: 31 October 2017
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Abstract
Several recent studies have reported a marked increase in American beech dominance (Fagus grandifolia Ehrh.) relative to sugar maple (Acer saccharum Marsh.) in late successional forests of North America. However, many factors have been proposed to explain this sudden shift in
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Several recent studies have reported a marked increase in American beech dominance (Fagus grandifolia Ehrh.) relative to sugar maple (Acer saccharum Marsh.) in late successional forests of North America. However, many factors have been proposed to explain this sudden shift in tree species composition. We investigated the microsite factors responsible for maple regeneration failure under maple-beech stands, focusing on both light availability and soil conditions. The survival and growth of maple seedlings planted in the natural soil and in pots with enriched soil were monitored for two years, as well as foliar nutrition and herbivory damages of natural seedlings. The results indicate that low light availability associated with the presence of beech is the primary factor leading to maple regeneration failures. Soil nutrient availability and foliar nutrition of natural seedlings did not differ between forest types. Yet, the results indicate that factors such as allelopathy and preferential herbivory on maple seedlings under beech could be superimposed effects that hinder maple regeneration. Under similar forests, a control of beech sapling abundance in the understory followed by selection cutting could be one way to promote and maintain maple populations in the longer term. Full article
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Open AccessArticle Climate Impacts on Tree Growth in the Sierra Nevada
Forests 2017, 8(11), 414; doi:10.3390/f8110414
Received: 16 July 2017 / Revised: 14 October 2017 / Accepted: 26 October 2017 / Published: 1 November 2017
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Abstract
Rising temperatures and aridity may negatively impact tree growth, and therefore ecosystem services like carbon sequestration. In the Sierra Nevada in California, annual variation in precipitation is high, and forests have already been impacted by several recent severe droughts. In this study, we
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Rising temperatures and aridity may negatively impact tree growth, and therefore ecosystem services like carbon sequestration. In the Sierra Nevada in California, annual variation in precipitation is high, and forests have already been impacted by several recent severe droughts. In this study, we used growth census data from long-term plots in the Sierra Nevada to calibrate an annual climate-dependent growth model. Our results highlight a high diversity of responses to climate, although the effects of climate are small compared to those of tree size and competition. Some species grow less during dry years (Pinus contorta and Calocedrus decurrens) but, surprisingly, other species exhibit higher growth during dry years (Pinus monticola, Abies magnifica, Pinus jeffreyi, Quercus kelloggii). These results emphasize the need for growth models to take into account species variability, as well as spatial heterogeneity, when studying mixed conifer forests. So far, temperatures have increased in California, and tree growth of some species may drastically decrease in the Sierra Nevada if warming continues, leading to changes in forest structure and composition as well as potential changes in wood production and carbon sequestration. Full article
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Open AccessArticle Impacts of Early Thinning of a Eucalyptus globulus Labill. Pulplog Plantation in Western Australia on Economic Profitability and Harvester Productivity
Forests 2017, 8(11), 415; doi:10.3390/f8110415
Received: 13 September 2017 / Revised: 30 October 2017 / Accepted: 30 October 2017 / Published: 1 November 2017
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Abstract
The impact of the manipulation of plantation stocking density on individual tree size can affect final harvest costs and machine productivity. This paper investigated the impact of four early-age thinning treatments applied to a Eucalyptus globulus Labill. pulplog plantation in south-west Western Australia
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The impact of the manipulation of plantation stocking density on individual tree size can affect final harvest costs and machine productivity. This paper investigated the impact of four early-age thinning treatments applied to a Eucalyptus globulus Labill. pulplog plantation in south-west Western Australia on economic profitability and harvester productivity. Eighteen sample plots were randomly laid out in the study area. The nominal 700, 500, and 400 stems per hectare (sph) plots were thinned to waste 3.2 years after establishment while the nominal 1000 sph (UTH) plots were left unthinned. The economic analysis showed that all thinning treatments resulted in a lower Land Expectation Value (LEV) and net financial loss over the full rotation at their theoretical optimal rotation age when compared with the unthinned control treatment. Tree growth and form were positively impacted by thinning. However, associated reductions in harvesting costs were less than the value losses resulting from reduced per hectare yield. Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
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Open AccessArticle Soil Nitrogen Storage, Distribution, and Associated Controlling Factors in the Northeast Tibetan Plateau Shrublands
Forests 2017, 8(11), 416; doi:10.3390/f8110416
Received: 28 August 2017 / Revised: 27 October 2017 / Accepted: 29 October 2017 / Published: 1 November 2017
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Abstract
Although the soils in the Tibetan Plateau shrublands store large amounts of total nitrogen (N), the estimated values remain uncertain because of spatial heterogeneity and a lack of field observations. In this study, we quantified the regional soil N storage, spatial and vertical
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Although the soils in the Tibetan Plateau shrublands store large amounts of total nitrogen (N), the estimated values remain uncertain because of spatial heterogeneity and a lack of field observations. In this study, we quantified the regional soil N storage, spatial and vertical density distributions, and related climatic controls using 183 soil profiles sampled from 61 sites across the Northeast Tibetan Plateau shrublands during the period of 2011–2013. Our analysis revealed a soil N storage value of 132.40 Tg at a depth of 100 cm, with an average density of 1.21 kg m−2. Soil N density was distributed at greater levels in alpine shrublands, compared with desert shrublands. Spatially, soil N densities decreased from south to north and from east to west, and, vertically, the soil N in the upper 30 and 50 cm accounted for 42% and 64% of the total soil N stocks in the Tibetan Plateau. However, compared with desert shrublands, the surface layers in alpine shrublands exhibited a larger distribution of soil N stocks. Overall, the soil N density in the top 30 cm increased significantly with the mean annual precipitation (MAP) and tended to decrease with the mean annual temperature (MAT), although the dominant climatic controls differed among shrubland types. Specifically, MAP in alpine shrublands, and MAT in desert shrubland, had a weak effect on N density. Soil pH can significant affect soil N density in the Tibetan Plateau shrublands. In conclusion, changes in soil N density should be monitored over the long term to provide accurate information about the effects of climatic factors. Full article
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Open AccessArticle Compatible System for Predicting Total and Merchantable Stem Volume over and under Bark, Branch Volume and Whole-Tree Volume of Pine Species
Forests 2017, 8(11), 417; doi:10.3390/f8110417
Received: 22 September 2017 / Revised: 26 October 2017 / Accepted: 26 October 2017 / Published: 1 November 2017
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Abstract
Accurate quantification of branch volume in trees is important for sustainable forest management, especially as these fractions are increasingly used for bioenergy, and for precise forest CO2 quantification. Whereas a large focus has been placed on the compatible estimation of tree taper
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Accurate quantification of branch volume in trees is important for sustainable forest management, especially as these fractions are increasingly used for bioenergy, and for precise forest CO2 quantification. Whereas a large focus has been placed on the compatible estimation of tree taper and bole volume with and without bark, little effort has been made to develop models that allow a simultaneous prediction of these variables together with tree branch volume. In this study, 595 Pinus cooperi trees and 700 Pinus durangensis trees were sampled in pine-oak forests in the Sierra Madre Occidental, Mexico. A compatible system for predicting two segmented taper functions, over and under bark; the corresponding merchantable volumes; coarse branch volume and whole-tree volume was fitted using a modified continuous autoregressive structure to account for autocorrelation. The proposed compatible equations explained more than 97% of the observed variability in diameter over and under bark, volume over and under bark, and total tree volume and more than 64% of the observed variability in branch volume in both species. The method described can theoretically be replicated for any tree species, thus providing a better understanding of the patterns of volume distribution by components, potentially improving carbon accounting system and forest bioenergy planning. Full article
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Open AccessArticle Growth and Its Relationship to Individual Genetic Diversity of Mountain Hemlock (Tsuga mertensiana) at Alpine Treeline in Alaska: Combining Dendrochronology and Genomics
Forests 2017, 8(11), 418; doi:10.3390/f8110418
Received: 13 September 2017 / Revised: 27 October 2017 / Accepted: 29 October 2017 / Published: 2 November 2017
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Abstract
Globally, alpine treelines are characterized as temperature-limited environments with strong controls on tree growth. However, at local scales spatially heterogeneous environments generally have more variable impacts on individual patterns of tree growth. In addition to the landscape spatial heterogeneity there is local variability
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Globally, alpine treelines are characterized as temperature-limited environments with strong controls on tree growth. However, at local scales spatially heterogeneous environments generally have more variable impacts on individual patterns of tree growth. In addition to the landscape spatial heterogeneity there is local variability in individual tree genetic diversity (level of individual heterozygosity). It has been hypothesized that higher individual heterozygosity will result in more consistent patterns of growth. In this article, we combine genomics and dendrochronology to explore the relationship between individual genetic diversity and tree growth at a mountain hemlock (Tsuga mertensiana Bong. Carr) alpine treeline on the Kenai Peninsula, Alaska, USA. We correlated average observed individual heterozygosity with average tree-ring width and variance in tree-ring width within individuals to test the hypothesis that trees with higher individual heterozygosity will also have more consistent growth patterns, suggesting that they may be more resilient to climate and environmental fluctuations at the alpine treeline. Our results showed that there was no significant relationship between tree growth and individual heterozygosity. However, there was a significant positive relationship between average tree-ring width and variance in tree-ring width implying that overall, fast growing trees in stressful environments, such as the alpine treeline, grow unstably regardless of the level of individual heterozygosity. Full article
(This article belongs to the Special Issue Treeline Ecotone Dynamics)
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Open AccessArticle Dynamics of Understory Shrub Biomass in Six Young Plantations of Southern Subtropical China
Forests 2017, 8(11), 419; doi:10.3390/f8110419
Received: 3 August 2017 / Revised: 18 October 2017 / Accepted: 30 October 2017 / Published: 2 November 2017
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Abstract
Understory shrubs are an important component of forest ecosystems and drive ecosystem processes, such as ecosystem carbon cycling. However, shrub biomass carbon stocks have rarely been reported, which limits our understanding of ecosystem C stock and cycling. In this study, we evaluated carbon
[...] Read more.
Understory shrubs are an important component of forest ecosystems and drive ecosystem processes, such as ecosystem carbon cycling. However, shrub biomass carbon stocks have rarely been reported, which limits our understanding of ecosystem C stock and cycling. In this study, we evaluated carbon accumulation of shrub species using allometric equations based on height and basal diameter in six subtropical plantations at the age of 1, 3, 4 and 6 years. The results showed that plantation type did not significantly affect the total biomass of shrubs, but it significantly affected the biomass of Rhodomyrtus tomentosa, Ilex asprella, Clerodendrum fortunatum and Baeckea frutescens. The biomass of dominant shrub species R. tomentosa, I. asprella, Gardenia jasminoides and Melastoma candidum increased with stand age, while the biomass of C. fortunatum and B. frutescens decreased. The inconsistent biomass-time patterns of different shrub species may be the primary reason for the altered total shrub biomass in each plantation. Consequently, we proposed that R. tomentosa, I. asprella, G. jasminoides and M. candidum could be preferable for understory carbon accumulation and should be maintained or planted because of their important functions in carbon accumulation and high economic values in the young plantations of southern subtropical China. Full article
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Open AccessArticle Transcriptome Characterization of the Chinese Fir (Cunninghamia lanceolata (Lamb.) Hook.) and Expression Analysis of Candidate Phosphate Transporter Genes
Forests 2017, 8(11), 420; doi:10.3390/f8110420
Received: 31 August 2017 / Revised: 21 October 2017 / Accepted: 31 October 2017 / Published: 3 November 2017
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Abstract
Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) is the most important afforestation tree species in China because of its excellent timber quality and high yield. However, the limited availability of phosphorus in forest soils is widespread and has become an important factor in
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Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) is the most important afforestation tree species in China because of its excellent timber quality and high yield. However, the limited availability of phosphorus in forest soils is widespread and has become an important factor in the declining productivity of Chinese fir plantations. Here we used the Illumina HiSeq™ 2000 DNA sequencing platform to sequence root, stem, and leaf transcriptomes of one-year old Chinese fir clones with phosphorus treatment. Approximately 236,529,278 clean reads were obtained and generated 35.47 G of sequencing data. These reads were assembled into 413,806 unigenes with a mean length of 520 bp. In total, 109,596 unigenes were annotated in the NR (NCBI non-redundant) database, 727,287 genes were assigned for GO (Gene Ontology) terms, information for 92,001 classified unigenes was assigned to 26 KOG (Karyotic Orthologous Groups) categories, and 57,042 unigenes were significantly matched with 132 KEGG (Kyoto Encyclopedia of Genes and Genomes) predicted pathways. In total, 49 unigenes were identified as exhibiting inorganic phosphate transporter activity, and 14 positive genes’ expression patterns in different phosphorus deficiency treatments were analyzed by qRT-PCR to explore their putative functions. This study provides a basic foundation for functional genomic studies of the phosphate transporter in Chinese fir, and also presents an extensive annotated sequence resource for molecular research. Full article
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Open AccessArticle Effects of Reforestation and Site Preparation Methods on Early Growth and Survival of Scots Pine (Pinus sylvestris L.) in South-Eastern Poland
Forests 2017, 8(11), 421; doi:10.3390/f8110421
Received: 5 October 2017 / Revised: 26 October 2017 / Accepted: 31 October 2017 / Published: 4 November 2017
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Abstract
Successful tree regeneration is a key process in ensuring forest sustainability and one of the most crucial investments made in silviculture. This study compared the effects of three reforestation methods (planting, direct seeding, and natural regeneration) and three mechanical site preparation methods (double
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Successful tree regeneration is a key process in ensuring forest sustainability and one of the most crucial investments made in silviculture. This study compared the effects of three reforestation methods (planting, direct seeding, and natural regeneration) and three mechanical site preparation methods (double mould-board forest plough (FP); active plough (AP); and forest mill (FM)) on biometric parameters, survival, and density of Scots pine (Pinus sylvestris L.) seedlings in the first 4 years of growth in a clear-cut area in south-eastern Poland. Planted seedlings were higher, thicker in root collar, and had higher survival rates after the fourth growing season than trees from natural regeneration and direct seeding. Site preparation methods did not affect the density of planted seedlings. After natural regeneration and direct seeding, seedling density was lower and less homogeneous (plots with no seedlings) in FM soil preparation in comparison to other methods. The survival of pines in all reforestation methods was not affected significantly by site preparation methods. Our results indicate that the best mechanical site preparation method for planting is FM, as this is the one that least disturbs the soil environment. For direct seeding the best results were achieved after AP preparation. Natural regeneration of Scots pine was most effective after FP use, and in relatively wet years also after AP use. Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessArticle Differences in Human versus Lightning Fires between Urban and Rural Areas of the Boreal Forest in Interior Alaska
Forests 2017, 8(11), 422; doi:10.3390/f8110422
Received: 4 September 2017 / Revised: 17 October 2017 / Accepted: 31 October 2017 / Published: 4 November 2017
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Abstract
In western North America, the carbon-rich boreal forest is experiencing warmer temperatures, drier conditions and larger and more frequent wildfires. However, the fire regime is also affected by direct human activities through suppression, ignition, and land use changes. Models are important predictive tools
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In western North America, the carbon-rich boreal forest is experiencing warmer temperatures, drier conditions and larger and more frequent wildfires. However, the fire regime is also affected by direct human activities through suppression, ignition, and land use changes. Models are important predictive tools for understanding future conditions but they are based on regional generalizations of wildfire behavior and weather that do not adequately account for the complexity of human–fire interactions. To achieve a better understanding of the intensity of human influence on fires in this sparsely populated area and to quantify differences between human and lightning fires, we analyzed fires by both ignition types in regard to human proximity in urban (the Fairbanks subregion) and rural areas of interior Alaska using spatial (Geographic Information Systems) and quantitative analysis methods. We found substantial differences in drivers of wildfire: while increases in fire ignitions and area burned were caused by lightning in rural interior Alaska, in the Fairbanks subregion these increases were due to human fires, especially in the wildland urban interface. Lightning fires are starting earlier and fires are burning longer, which is much more pronounced in the Fairbanks subregion than in rural areas. Human fires differed from lightning fires in several ways: they started closer to settlements and highways, burned for a shorter duration, were concentrated in the Fairbanks subregion, and often occurred outside the brief seasonal window for lightning fires. This study provides important insights that improve our understanding of the direct human influence on recently observed changes in wildfire regime with implications for both fire modeling and fire management. Full article
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Open AccessArticle Soil Preferences in Germination and Survival of Limber Pine in the Great Basin White Mountains
Forests 2017, 8(11), 423; doi:10.3390/f8110423
Received: 26 September 2017 / Revised: 2 November 2017 / Accepted: 2 November 2017 / Published: 5 November 2017
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Abstract
In the Great Basin, limber pine is a sub-alpine tree species that is colonizing newly available habitat above treeline in greater numbers than treeline-dominating Great Basin bristlecone pine, especially on dolomite soil, where few plants are able to grow and where limber pine
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In the Great Basin, limber pine is a sub-alpine tree species that is colonizing newly available habitat above treeline in greater numbers than treeline-dominating Great Basin bristlecone pine, especially on dolomite soil, where few plants are able to grow and where limber pine adults are rare. To examine the role of soil type on germination and establishment of limber pine, I sowed limber pine seeds in containers of the three main White Mountains soil types in one location while measuring soil moisture and temperature. I found that dolomite soil retains water longer, and has higher soil water content, than quartzite and granite soils and has the coolest maximum growing season temperatures. Limber pine germination and survival were highest in dolomite soil relative to quartzite and granite where limber pine adults are more common. While adult limber pines are rare on dolomite soils, young limber pines appear to prefer them. This indicates that limber pine either has only recently been able to survive in treeline climate on dolomite or that bristlecone pine has some long-term competitive advantage on dolomite making limber pine, a species with 1500 year old individuals, an early succession species in Great Basin sub-alpine forests. Full article
(This article belongs to the Special Issue Treeline Ecotone Dynamics)
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Open AccessArticle Genetic Differentiation and Population Genetic Structure of the Chinese Endemic Dipteronia Oliv. Revealed by cpDNA and AFLP Data
Forests 2017, 8(11), 424; doi:10.3390/f8110424
Received: 2 July 2017 / Revised: 21 September 2017 / Accepted: 31 October 2017 / Published: 6 November 2017
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Abstract
Dipteronia Oliv. is an endangered genus found in China with two species, D. sinensis and D. dyeriana. Previous morphological, cytogenetic, and molecular studies have suggested that D. dyeriana is a species related to D. sinensis. However, it is unclear how the
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Dipteronia Oliv. is an endangered genus found in China with two species, D. sinensis and D. dyeriana. Previous morphological, cytogenetic, and molecular studies have suggested that D. dyeriana is a species related to D. sinensis. However, it is unclear how the two species diverged and whether gene flow exists between these two species. Here, we performed a molecular study at the population level to characterize genetic differentiation and decipher the phylogeographic history for Dipteronia species based on newly sequenced chloroplast DNA (cpDNA) and amplified fragment length polymorphisms (AFLP) date retrieved from our previous studies. No haplotype was shared between the two species in the cpDNA network. However, the phylogenetic analysis suggested that a haplotype found in D. sinensis (H4) showed a closer relationship with haplotypes of D. dyeriana. Based on our estimated time of divergence, these two cpDNA haplotype lineages of Dipteronia diverged at about 31.19 Ma. Furthermore, two genetic clusters with asymmetric gene flow were supported based on the structure analysis, which corresponded with the two Dipteronia species, and we also detected a low level of asymmetric gene flow between these two species according to the MIGRATE analysis using AFLP data. During the Last Glacial Maximum (LGM, c.21 kya BP), the genus’ predicted distribution was more or less similar to that at present, which was also supported by the mismatch analyses that showed no population expansion of the two Dipteronia populations after the LGM. The combined cpDNA and AFLP data revealed significant genetic differentiation between the two Dipteronia species with asymmetric gene flow, which can be explained by the varying phylogeographical histories of these two species. Full article
(This article belongs to the Special Issue Plant Diversity and Phytogeography in Forests)
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Open AccessArticle The Effect of Logging and Strip Cutting on Forest Floor Light Condition and Following Change
Forests 2017, 8(11), 425; doi:10.3390/f8110425
Received: 3 September 2017 / Revised: 21 October 2017 / Accepted: 31 October 2017 / Published: 7 November 2017
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Abstract
We monitored changes in light conditions at a primary forest and two managed forest sites (one with line planting) after reduced-impact logging in Central Kalimantan, Indonesia. We also assessed the effect of the light conditions on seedlings in the planting lines. Hemispherical photographs
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We monitored changes in light conditions at a primary forest and two managed forest sites (one with line planting) after reduced-impact logging in Central Kalimantan, Indonesia. We also assessed the effect of the light conditions on seedlings in the planting lines. Hemispherical photographs were taken over a period of 31 months in three 50 × 50-m quadrats at each site and in three 100-m transects along the planting lines. The location of each photo was categorized according to the corresponding type of disturbance, including skid trails, logging gaps, and planting lines. Following logging, the level of canopy openness (CO) increased at both managed forest sites and did not differ significantly between the two. However, CO was greater in skid trails and logging gaps than in planting lines. After 31 months, the mean level of CO at each managed site had decreased significantly due to the establishment of new seedlings. Correlations between changes in CO and the growth of planted seedlings suggested that growth was inhibited by the invasion of the new species. However, the level of CO along the planting lines was greater than that at other disturbed locations. A high level of CO promoted invasion by new species that colonized the space. Line planting may influence forest dynamics and maintain a high level of CO. Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
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Open AccessArticle Treefall Gap Mapping Using Sentinel-2 Images
Forests 2017, 8(11), 426; doi:10.3390/f8110426
Received: 27 September 2017 / Revised: 25 October 2017 / Accepted: 3 November 2017 / Published: 7 November 2017
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Abstract
Proper knowledge about resources in forest management is fundamental. One of the most important parameters of forests is their size or spatial extension. By determining the area of treefall gaps inside the compartments, a more accurate yield can be calculated and the scheduling
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Proper knowledge about resources in forest management is fundamental. One of the most important parameters of forests is their size or spatial extension. By determining the area of treefall gaps inside the compartments, a more accurate yield can be calculated and the scheduling of forestry operations could be planned better. Several field- and remote sensing-based approaches are in use for mapping but they provide only static measurements at high cost. The Earth Observation satellite mission Sentinel-2 was put in orbit as part of the Copernicus programme. With the 10-m resolution bands, it is possible to observe small-scale forestry operations like treefall gaps. The spatial extension of these gaps is often less than 200 m2, thus their detection can only be done on sub-pixel level. Due to the higher temporal resolution of Sentinel-2, multiple observations are available in a year; therefore, a time series evaluation is possible. The modelling of illumination can increase the accuracy of classification in mountainous areas. The method was tested on three deciduous forest sites in the Börzsöny Mountains in Hungary. The area evaluation produced less than 10% overestimation with the best possible solutions on the sites. The presented work shows a low-cost method for mapping treefall gaps which delivers annual information about the gap area in a deciduous forest. Full article
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Open AccessArticle Monetary Valuation of Natural Forest Habitats in Protected Areas
Forests 2017, 8(11), 427; doi:10.3390/f8110427
Received: 18 July 2017 / Revised: 29 September 2017 / Accepted: 7 November 2017 / Published: 10 November 2017
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Abstract
The progressive development of economic valuations of biodiversity in recent decade enables the application of the concept of payments for ecosystem services (PES) in order to conservation of forest biodiversity in protected areas. In this article, the PES concept principles are applied for
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The progressive development of economic valuations of biodiversity in recent decade enables the application of the concept of payments for ecosystem services (PES) in order to conservation of forest biodiversity in protected areas. In this article, the PES concept principles are applied for the monetary valuation of natural forest habitats, which were mapped in the Czech Republic in order to create the Natura 2000 European network. The method is based on expert evaluation of every type of mapped habitat by a point value (ranging from 1 to 6 points) for specific ecological evaluating criteria. The monetary value of every point of specific natural forest habitats was defined from the economic analysis of financial expenses of realised ecological restoration projects in the Czech Republic. This method is therefore based on a rather exceptional application of the PES concept, which is still rare in literature because it is based on actual invested financial means, not only on the potential willingness to spend these financial means. The presented results of the monetary valuation of the natural forest habitats in the Czech Republic indicate that the method used for the monetization of forest biodiversity in protected areas can represent a promising decision support tool in countries where habitat mapping results are available. Full article
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Open AccessArticle Short-Term Effects of Low Intensity Thinning on the Fine Root Dynamics of Pinus massoniana Plantations in the Three Gorges Reservoir Area, China
Forests 2017, 8(11), 428; doi:10.3390/f8110428
Received: 31 August 2017 / Revised: 2 November 2017 / Accepted: 3 November 2017 / Published: 12 November 2017
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Abstract
Fine roots play an important role in plant growth as well as carbon (C) and nutrient cycling in terrestrial ecosystems. Fine roots are important for understanding the contribution of forests to the global C cycle. Knowledge about this topic is still limited, especially
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Fine roots play an important role in plant growth as well as carbon (C) and nutrient cycling in terrestrial ecosystems. Fine roots are important for understanding the contribution of forests to the global C cycle. Knowledge about this topic is still limited, especially regarding the effects of different forest management practices. This study investigated the seasonal dynamics of fine roots (<2 mm) in masson pine (P. massoniana) plantations for one year after low intensity thinning by using a sequential soil coring method. The fine roots showed pronounced seasonal dynamics, with a peak of fine root biomass (FRB) occurring in September. Significant differences were noted in the seasonal dynamics of FRB for the different diameter size sub-classes (≤0.5 mm, 0.5–1 mm and 1–2 mm); also FRB was inversely related to soil depth. Moreover, the FRB (≤0.5 mm and 0.5–1 mm except 1–2 mm) in the thinning plots was greater than that in the control only in the upper soil layer (0–10 cm). Furthermore, the FRB varied significantly with soil temperature, moisture and nutrients depended on the diameter sub-class considered. Significant differences in the soil temperature and moisture levels were noted between low-intensity thinned and control plots. Soil nutrient levels slightly decreased after low-intensity thinning. In addition, there was a more sensitive relationship between the very fine roots (diameter < 0.5 mm) and soil nutrients. Our results showed an influence of low-intensity thinning on the fine root dynamics with a different magnitude according to fine root diameter sub-classes. These results provide a theoretical basis to promote the benefits of C cycling in the management of P. massoniana forests. Full article
(This article belongs to the Special Issue Forest Fine Roots in Changing Climate)
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Open AccessArticle Carbon Sequestration in Protected Areas: A Case Study of an Abies religiosa (H.B.K.) Schlecht. et Cham Forest
Forests 2017, 8(11), 429; doi:10.3390/f8110429
Received: 23 August 2017 / Revised: 17 October 2017 / Accepted: 28 October 2017 / Published: 12 November 2017
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Abstract
The effects of global climate change have highlighted forest ecosystems as a key element in reducing the amount of atmospheric carbon through photosynthesis. The objective of this study was to estimate the amount of carbon content and its percentage capture in a protected
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The effects of global climate change have highlighted forest ecosystems as a key element in reducing the amount of atmospheric carbon through photosynthesis. The objective of this study was to estimate the amount of carbon content and its percentage capture in a protected Abies religiosa forest in which the study area was zoned with satellite image analysis. Dendrometric and epidometric variables were used to determine the volume and increase of aerial biomass, and stored carbon and its capture rate using equations. The results indicate that this forest contains an average of 105.72 MgC ha−1, with an estimated sequestration rate of 1.03 MgC ha−1 yr−1. The results show that carbon capture increasing depends on the increase in volume. Therefore, in order to achieve the maximum yield in a forest, it is necessary to implement sustainable forest management that favors the sustained use of soil productivity. Full article
(This article belongs to the Special Issue Carbon and Nitrogen in Forest Ecosystems)
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Open AccessArticle Comparisons of Soil Properties, Enzyme Activities and Microbial Communities in Heavy Metal Contaminated Bulk and Rhizosphere Soils of Robinia pseudoacacia L. in the Northern Foot of Qinling Mountain
Forests 2017, 8(11), 430; doi:10.3390/f8110430
Received: 22 September 2017 / Revised: 4 November 2017 / Accepted: 7 November 2017 / Published: 12 November 2017
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Abstract
The toxic effects of heavy metal (HM) contamination on plant metabolism and soil microorganisms have been emphasized recently; however, little is known about the differences in soil physical, chemical, and biological properties between bulk and rhizosphere soils contaminated with HMs in forest ecosystem.
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The toxic effects of heavy metal (HM) contamination on plant metabolism and soil microorganisms have been emphasized recently; however, little is known about the differences in soil physical, chemical, and biological properties between bulk and rhizosphere soils contaminated with HMs in forest ecosystem. The present study was conducted to evaluate the rhizosphere effect on soil properties, enzyme activities and bacterial communities associated with Robinia pseudoacacia L. along a HM contamination gradient. Soil organic matter (SOM), available nitrogen (AN) and phosphorus (AP) contents were significantly higher in rhizosphere soil than those in bulk soil at HM contaminated sites (p < 0.05). Compared to bulk soil, activities of four soil enzymes indicative of C cycle (β-glucosidase), N cycle (protease, urease) and P cycle (alkaline phosphatase) in rhizosphere soil across all study sites increased by 47.5%, 64.1%, 52.9% and 103.8%, respectively. Quantitative PCR (qPCR) and restriction fragment length polymorphism (RFLP) were used to determine the relative abundance, composition and diversity of bacteria in both bulk and rhizosphere soils, respectively. The copy number of bacterial 16S rRNA gene in bulk soil was significantly lower than that in rhizosphere soil (p < 0.05), and it had significantly negative correlations with total/DTPA-extractable Pb concentrations (p < 0.01). Alphaproteobacteria, Gammaproteobacteria and Firmicutes were the most dominant groups of bacteria at different study sites. The bacterial diversity index of Species richness (S) and Margalef (dMa) were significantly higher in rhizosphere soil compared with those in bulk soil, although no difference could be found in Simpson index (D) between bulk and rhizosphere soils (p > 0.05). Redundancy analysis (RDA) results showed that soil pH, EC, SOM and total/DTPA-extractable Pb concentrations were the most important variables affecting relative abundance, composition and diversity of bacteria (p < 0.05). Our study highlights the importance of rhizosphere effect on soil nutrient content, enzyme activity, bacterial abundance and community in HM contaminated forest soils. Further study is still required to understand the specific processes in the rhizosphere to achieve a suitable rhizosphere biotechnology for restoration of degraded forest ecosystem. Full article
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Open AccessArticle Forest Certification and Country of Origin: Choice Experiment Analysis of Outdoor Decking Material Selection in E-Commerce Market in Finland
Forests 2017, 8(11), 431; doi:10.3390/f8110431
Received: 31 August 2017 / Revised: 29 October 2017 / Accepted: 7 November 2017 / Published: 11 November 2017
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Abstract
Since the early 1990s, there has been hope that the uptake of certified forest products would ensure more sustainable forest management and also deliver business benefits along the value chain. Our study applies a Discrete Choice Experiment (DCE) to model an e-commerce purchase
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Since the early 1990s, there has been hope that the uptake of certified forest products would ensure more sustainable forest management and also deliver business benefits along the value chain. Our study applies a Discrete Choice Experiment (DCE) to model an e-commerce purchase in the case of multiple products with various attribute and certification combinations in the Finnish retail outdoor decking material market. We received 2772 responses from 231 participants in an online survey. Applying conditional logit and latent class models, we were able to assess the relative importance of attributes, identify various consumer segments, and simulate various scenarios for communicating the certification and origin of forest products and competing materials. Our results show that the most important attribute for consumer decision-making was the outdoor decking material followed by price, origin, and certification. Some consumer segments showed a habit of only choosing certain materials or domestic products, while paying less attention to other product attributes. Simulations for an e-commerce purchase situation also implied that communications concerning intangible product attributes, such as domestic origin and environmental certifications, could be used in the brand building of the forest sector to gain competitive advantage and increased market shares over other sectors. The results suggest that the conventional and constantly developing e-commerce marketing tools should be harnessed also in forest product and more general environmental marketing. Full article
(This article belongs to the Special Issue Sustainable Forest Management and Forest Certification)
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Open AccessArticle Spore Dispersal Patterns of Fusarium circinatum on an Infested Monterey Pine Forest in North-Western Spain
Forests 2017, 8(11), 432; doi:10.3390/f8110432
Received: 30 September 2017 / Revised: 26 October 2017 / Accepted: 7 November 2017 / Published: 15 November 2017
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Abstract
The airborne inoculum of Fusarium circinatum Nirenberg & O’Donnell, the fungal pathogen causing Pine Pitch Canker (PPC), is one of the main means of spread of the disease in forest stands and forest nurseries. Since this world-wide known pathogen was introduced in Europe,
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The airborne inoculum of Fusarium circinatum Nirenberg & O’Donnell, the fungal pathogen causing Pine Pitch Canker (PPC), is one of the main means of spread of the disease in forest stands and forest nurseries. Since this world-wide known pathogen was introduced in Europe, its biology in this newly infested area still remains scarcely known. To shed more light on this topic, we set up an experiment on a naturally PPC infested forest of Monterey pine in Galicia (NW Spain) with the following two goals: (i) to describe the seasonal spore dispersal pattern during one year of regular sampling and (ii) to assess the spatial spore dispersal pattern around the infested plot. Portable rotating arm spore traps were used and complemented with meteorological measurements. The abundance of F. circinatum spores in the samples was assessed by quantitative PCR (qPCR) with a hydrolysis probe. The results showed almost permanent occurrence of the air inoculum throughout the whole year, being detected in 27 of the 30 samplings. No clear temporal trends were observed, but a higher air inoculum was favoured by previous lower air temperatures and lower leaf wetness. Conversely, neither rainfall nor air humidity seemed to have any significant importance. The spatial spread of the inoculum was noted to be successful up to a distance of 1000 m in the wind direction, even with winds of just 5 m·s−1. Our study shows that rotating arm spore traps combined with qPCR may be an efficient tool for F. circinatum detection. Full article
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Open AccessArticle Lab and Field Warming Similarly Advance Germination Date and Limit Germination Rate for High and Low Elevation Provenances of Two Widespread Subalpine Conifers
Forests 2017, 8(11), 433; doi:10.3390/f8110433
Received: 30 September 2017 / Revised: 24 October 2017 / Accepted: 7 November 2017 / Published: 11 November 2017
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Abstract
Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to
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Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to climate and are also influenced by genetic variation among populations. We tested the climate sensitivity of germination and initial development for two widely distributed subalpine conifers, using controlled-environment growth chambers with one temperature regime from subalpine forest in the Colorado Rocky Mountains and one 5 °C warmer, and two soil moisture levels. We tracked germination rate and timing, rate of seedling development, and seedling morphology for two seed provenances separated by ~300 m elevation. Warming advanced germination timing and initial seedling development by a total of ~2 weeks, advances comparable to mean differences between provenances. Advances were similar for both provenances and species; however, warming reduced the overall germination rate, as did low soil moisture, only for Picea engelmannii. A three-year field warming and watering experiment planted with the same species and provenances yielded responses qualitatively consistent with the lab trials. Together these experiments indicate that in a warmer, drier climate, P. engelmannii germination, and thus regeneration, could decline, which could lead to declining subalpine forest populations, while Pinus flexilis forest populations could remain robust as a seed source for upslope range shifts. Full article
(This article belongs to the Special Issue Treeline Ecotone Dynamics)
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Open AccessArticle Policy Recommendation from Stakeholders to Improve Forest Products Transportation: A Qualitative Study
Forests 2017, 8(11), 434; doi:10.3390/f8110434
Received: 20 September 2017 / Revised: 5 November 2017 / Accepted: 9 November 2017 / Published: 12 November 2017
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Abstract
With recently announced federal funding and subsidies to redevelop vacant mills and the communities they were in, the forest products industry in Maine is poised to gain its momentum once again. One of the important components influencing the cost of delivered forest products
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With recently announced federal funding and subsidies to redevelop vacant mills and the communities they were in, the forest products industry in Maine is poised to gain its momentum once again. One of the important components influencing the cost of delivered forest products is transportation. A recent study in the region has shown that the location and availability of markets along with lack of skilled labor force are the major challenges faced by the forest products transportation sector in Maine. This study was focused on developing a management guideline which included various field level options for improving trucking enterprises in Maine. For this, a qualitative research approach utilizing a case study research tradition was employed, with in-depth semi-structured interviews with professionals directly related to the forest products transportation sector used for data generation. Thirteen semi-structured interviews were conducted, with each being audio recorded and later transcribed verbatim. Interview transcriptions were analyzed using NVivo 11. Suggestions, like increasing benefits to drivers and providing training, were proposed for challenges related to manpower shortage, while the marketing of new forest products and adjustment in some state-level policies were proposed for challenges related to the forest products market condition of the state. Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
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Open AccessArticle De Novo Transcriptome Sequencing in Passiflora edulis Sims to Identify Genes and Signaling Pathways Involved in Cold Tolerance
Forests 2017, 8(11), 435; doi:10.3390/f8110435
Received: 22 September 2017 / Revised: 31 October 2017 / Accepted: 6 November 2017 / Published: 12 November 2017
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Abstract
The passion fruit (Passiflora edulis Sims), also known as the purple granadilla, is widely cultivated as the new darling of the fruit market throughout southern China. This exotic and perennial climber is adapted to warm and humid climates, and thus is generally
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The passion fruit (Passiflora edulis Sims), also known as the purple granadilla, is widely cultivated as the new darling of the fruit market throughout southern China. This exotic and perennial climber is adapted to warm and humid climates, and thus is generally intolerant of cold. There is limited information about gene regulation and signaling pathways related to the cold stress response in this species. In this study, two transcriptome libraries (KEDU_AP vs. GX_AP) were constructed from the aerial parts of cold-tolerant and cold-susceptible varieties of P. edulis, respectively. Overall, 126,284,018 clean reads were obtained, and 86,880 unigenes with a mean size of 1449 bp were assembled. Of these, there were 64,067 (73.74%) unigenes with significant similarity to publicly available plant protein sequences. Expression profiles were generated, and 3045 genes were found to be significantly differentially expressed between the KEDU_AP and GX_AP libraries, including 1075 (35.3%) up-regulated and 1970 (64.7%) down-regulated. These included 36 genes in enriched pathways of plant hormone signal transduction, and 56 genes encoding putative transcription factors. Six genes involved in the ICE1–CBF–COR pathway were induced in the cold-tolerant variety, and their expression levels were further verified using quantitative real-time PCR. This report is the first to identify genes and signaling pathways involved in cold tolerance using high-throughput transcriptome sequencing in P. edulis. These findings may provide useful insights into the molecular mechanisms regulating cold tolerance and genetic breeding in Passiflora spp. Full article
(This article belongs to the Special Issue Genetics and Genomics of Forest Trees)
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Open AccessArticle Forest Type and Tree Characteristics Determine the Vertical Distribution of Epiphytic Lichen Biomass in Subtropical Forests
Forests 2017, 8(11), 436; doi:10.3390/f8110436
Received: 2 October 2017 / Revised: 3 November 2017 / Accepted: 10 November 2017 / Published: 12 November 2017
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Abstract
Epiphytic lichens are an important component in subtropical forests and contribute greatly to forest biodiversity and biomass. However, information on epiphytic lichens still remains scarce in forest conservation owing to the difficulty of accessing all canopy layers for direct observation. Here, epiphytic lichens
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Epiphytic lichens are an important component in subtropical forests and contribute greatly to forest biodiversity and biomass. However, information on epiphytic lichens still remains scarce in forest conservation owing to the difficulty of accessing all canopy layers for direct observation. Here, epiphytic lichens were quantified on 73 whole trees in five forest types in Southwest China to clarify the vertical stratification of their biomass in subtropical forests. Lichen biomass was significantly influenced by forest type and host attributes, varying from 187.11 to 8.55 g∙tree−1 among forest types and from 289.81 to <0.01 g∙tree−1 among tree species. The vertical stratification of lichen biomass was also determined by forest type, which peaked at the top in primary Lithocarpus forest and middle-aged oak secondary forest and in the middle upper heights in other forests. Overall, the proportion of lichen biomass accounted for 73.17–100.00% of total lichen biomass on branches and 0.00–26.83% on trunks in five forests, and 64.53–100.00% and 0.00–35.47% on eight host species. Seven functional groups showed marked and various responses to tree height between and among forest types. This information improves our understanding of the distribution of epiphytic lichens in forest ecosystems and the promotion of forest management in subtropical China. Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessArticle Planting Waterscapes: Green Infrastructures, Landscape and Hydrological Modeling for the Future of Santa Cruz de la Sierra, Bolivia
Forests 2017, 8(11), 437; doi:10.3390/f8110437
Received: 20 October 2017 / Revised: 4 November 2017 / Accepted: 9 November 2017 / Published: 13 November 2017
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Abstract
The expansion of cities is an emerging and critical issue for the future of the planet. Water is one of the most important resources provided by urban and peri-urban landscapes, as it is directly or indirectly connected with the quality of the environment
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The expansion of cities is an emerging and critical issue for the future of the planet. Water is one of the most important resources provided by urban and peri-urban landscapes, as it is directly or indirectly connected with the quality of the environment and life. Santa Cruz de la Sierra is the leading city in Bolivia (and the second in Latin America) in regard to population growth and soil sealing. Water is available to the city mostly from the Piraí River basin, and is expected to be totally inadequate to support such powerful urban development. The project Aguacruz, which is financed by the Italian Agency for Cooperation and Development, aimed to (1) restructure and harmonize existing data on the landscape ecology, hydrological features, and functional aspects of the Piraí River; (2) build hydrological scenarios for the future of the basin by introducing a landscape ecology approach, and (3) involve stakeholders and local actors in decision-making processes oriented to increase the resilience of the urban–rural landscape of the Piraì River and the city of Santa Cruz. SWAT (Soil and Water Assessment Tools) tested five scenarios through simulating different landscape settings, from the current previsions for urban expansion to a sound implementation of green infrastructures, agroforestry, and regreening. The results indicate that integrated actions in rural–urban systems can lead to a substantial reversal of the trend toward a decline in water supply for the city. From a governance and planning perspective, the proposed actions have been configured as to induce (i) integrated waterscape ecological planning; and (ii) the preparation and approval of departmental regulations for the incorporation of green infrastructures in the municipalities. Full article
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Open AccessArticle Product and Residue Biomass Equations for Individual Trees in Rotation Age Pinus radiata Stands under Three Thinning Regimes in New South Wales, Australia
Forests 2017, 8(11), 439; doi:10.3390/f8110439
Received: 19 September 2017 / Revised: 9 November 2017 / Accepted: 10 November 2017 / Published: 14 November 2017
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Abstract
Using data from 239 trees that were destructively sampled and completely weighed in the field, four systems of nonlinear additive equations were developed for the estimation of product and residue fresh and dry weight of individual trees in rotation age (28 to 42
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Using data from 239 trees that were destructively sampled and completely weighed in the field, four systems of nonlinear additive equations were developed for the estimation of product and residue fresh and dry weight of individual trees in rotation age (28 to 42 years) Pinus radiata stands under three thinning regimes: unthinned (T0), one thinning (T1) and two thinnings (T2). To cater for all practical applications, the four systems of equations included diameter at breast height overbark (DBHOB) as the only independent variable or both DBHOB and total tree height as predictors either with or without the incorporation of dummy variables for stand types. For all systems, the property of additivity was guaranteed by placing constraints on the structural parameters of the system equations. The parameter estimates were obtained by the generalized methods of moments (GMM) following a comparison with weighted nonlinear seemingly unrelated regression (WNSUR). Based on the predicted values from the system that had DBHOB as the predictor and dummy variables for stand types, the percentage of total tree fresh weight accounted for by residues increased from 14.8% to 20.5%, from 15.6% to 22.2% and from 13.9% to 18.7% for trees in the T0, T1 and T2 stands, respectively, as DBHOB increased from 15 to 70 cm. The corresponding changes in the percentage of residue dry weight were from 15.1% to 16.1%, from 15.7% to 17.1% and from 14.9% to 15.8% for the three stand types. In addition, two systems of allocative equations were developed to allocate the predicted product and residue biomass to their respective subcomponents. The system of allocative equations for product biomass predicted that sawlogs with bark accounted for 83% to 85% of product fresh weight and 82% to 87% of product dry weight over the same range of DBHOB. The predicted allocation of total residue dry weight to stump changed little, between 12% and 13%, over the same diameter range, but it was slightly higher for trees with DBHOB between 30 and 45 cm. The predicted allocation of total residue biomass to branches increased from 18% to 65% in fresh weight and from 18% to 57% in dry weight and that to waste decreased from 71% to 27% in fresh weight and from 70% to 32% in dry weight as DBHOB increased from 15 to 70 cm. Among the five biomass components, prediction accuracy was the lowest for pulpwood and waste. The systems of additive and allocative biomass equations developed in this study provided the first example of how the two approaches could be used together for the estimation of total tree, major and sub-component biomass. They will provide forest management with an enhanced capacity to more accurately estimate product and residue biomass of rotation age trees and thus to include the production of biomass for renewable energy generation in their management systems for P. radiata plantations. Full article
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Open AccessArticle Occupational Safety and Health Concerns in Logging: A Cross-Sectional Assessment in Virginia
Forests 2017, 8(11), 440; doi:10.3390/f8110440
Received: 29 September 2017 / Revised: 9 November 2017 / Accepted: 13 November 2017 / Published: 15 November 2017
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Abstract
Increased logging mechanization has helped improve logging safety and health, yet related safety risks and concerns are not well understood. A cross-sectional study was completed among Virginia loggers. Participants (n = 122) completed a self-administered questionnaire focusing on aspects of safety and
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Increased logging mechanization has helped improve logging safety and health, yet related safety risks and concerns are not well understood. A cross-sectional study was completed among Virginia loggers. Participants (n = 122) completed a self-administered questionnaire focusing on aspects of safety and health related to logging equipment. Respondents were at a high risk of workplace injuries, with reported career and 12-month injury prevalences of 51% and 14%, respectively. Further, nearly all (98%) respondents reported experiencing musculoskeletal symptoms. Over half (57.4%) of respondents reported symptoms related to diesel exhaust exposure in their career. Few (15.6%), however, perceived their jobs to be dangerous. Based on the opinions and suggestions of respondents, three priority areas were identified for interventions: struck-by/against hazards, situational awareness (SA) during logging operations, and visibility hazards. To address these hazards, and to have a broader and more substantial positive impact on safety and health, we discuss the need for proactive approaches such as incorporating proximity technologies in a logging machine or personal equipment, and enhancing logging machine design to enhance safety, ergonomics, and SA. Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
Open AccessArticle The Optimum Slash Pile Size for Grinding Operations: Grapple Excavator and Horizontal Grinder Operations Model Based on a Sierra Nevada, California Survey
Forests 2017, 8(11), 442; doi:10.3390/f8110442
Received: 25 September 2017 / Revised: 10 November 2017 / Accepted: 13 November 2017 / Published: 15 November 2017
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Abstract
The processing of woody biomass waste piles for use as fuel instead of burning them was investigated. At each landing of slash pile location, a 132 kW grapple excavator was used to transfer the waste piles into a 522 kW horizontal grinder. Economies
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The processing of woody biomass waste piles for use as fuel instead of burning them was investigated. At each landing of slash pile location, a 132 kW grapple excavator was used to transfer the waste piles into a 522 kW horizontal grinder. Economies of scale could be expected when grinding a larger pile, although the efficiency of the loading operation might be diminished. Here, three piles were ground and the operations were time-studied: Small (20 m long × 15 m wide × 4 m high), Medium (30 × 24 × 4 m), and Large (35 × 30 × 4 m) piles. Grinding the Medium pile was found to be the most productive at 30.65 bone dry tons per productive machine hour without delay (BDT/PMH0), thereby suggesting that there might be an optimum size of slash pile for a grinding operation. Modeling of the excavator and grinder operations was also examined, and the constructed simulation model was observed to well-replicate the actual operations. Based on the modeling, the productivity of grinding at a landing area of 710 m2 of slash pile location was estimated to be 31.24 BDT/PMH0, which was the most productive rate. Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
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Open AccessArticle Assessment of Flammability of Moroccan Forest Fuels: New Approach to Estimate the Flammability Index
Forests 2017, 8(11), 443; doi:10.3390/f8110443
Received: 1 September 2017 / Revised: 8 November 2017 / Accepted: 14 November 2017 / Published: 15 November 2017
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Abstract
A new flammability index (FI) was developed, which integrated two parameters that are highly correlated to fuel moisture content (MC). These parameters are time-to-ignition and flame height. The newly obtained FI-values belong to the variation interval of {0; 20}. In addition to the
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A new flammability index (FI) was developed, which integrated two parameters that are highly correlated to fuel moisture content (MC). These parameters are time-to-ignition and flame height. The newly obtained FI-values belong to the variation interval of {0; 20}. In addition to the six flammability classes defined in the earlier work, a seventh class (FI > 16.5) was proposed to include fuel species with a high content of volatile flammable-compounds. Flammability testing and MC measurement were performed at a range of MC obtained through a drying process of samples. As a result, FI was statistically highly correlated with MC for all 13 Moroccan forest fuels tested in this study. Following this, linear regression equations were established to predict the FI-value as a function of MC. Therefore, the classification of flammability would depend on the species as well as the MC-value of the samples and the season in which they were collected. Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessArticle An Examination of Diameter Density Prediction with k-NN and Airborne Lidar
Forests 2017, 8(11), 444; doi:10.3390/f8110444
Received: 29 September 2017 / Revised: 30 October 2017 / Accepted: 10 November 2017 / Published: 16 November 2017
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Abstract
While lidar-based forest inventory methods have been widely demonstrated, performances of methods to predict tree diameters with airborne lidar (lidar) are not well understood. One cause for this is that the performance metrics typically used in studies for prediction of diameters can be
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While lidar-based forest inventory methods have been widely demonstrated, performances of methods to predict tree diameters with airborne lidar (lidar) are not well understood. One cause for this is that the performance metrics typically used in studies for prediction of diameters can be difficult to interpret, and may not support comparative inferences between sampling designs and study areas. To help with this problem we propose two indices and use them to evaluate a variety of lidar and k nearest neighbor (k-NN) strategies for prediction of tree diameter distributions. The indices are based on the coefficient of determination (R2), and root mean square deviation (RMSD). Both of the indices are highly interpretable, and the RMSD-based index facilitates comparisons with alternative (non-lidar) inventory strategies, and with projects in other regions. K-NN diameter distribution prediction strategies were examined using auxiliary lidar for 190 training plots distribute across the 800 km2 Savannah River Site in South Carolina, USA. We evaluate the performance of k-NN with respect to distance metrics, number of neighbors, predictor sets, and response sets. K-NN and lidar explained 80% of variability in diameters, and Mahalanobis distance with k = 3 neighbors performed best according to a number of criteria. Full article
(This article belongs to the Section Forest Inventory, Quantitative Methods and Remote Sensing)
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Open AccessArticle Private Forest Governance, Public Policy Impacts: The Forest Stewardship Council in Russia and Brazil
Forests 2017, 8(11), 445; doi:10.3390/f8110445
Received: 29 August 2017 / Revised: 29 September 2017 / Accepted: 10 November 2017 / Published: 16 November 2017
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Abstract
Under what conditions do private forest governance standards influence state policy and behavior to become more oriented toward sustainability? We argue that governance schemes targeting firms may indirectly shape state behavior, even when designed to bypass state regulation. Through an examination of the
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Under what conditions do private forest governance standards influence state policy and behavior to become more oriented toward sustainability? We argue that governance schemes targeting firms may indirectly shape state behavior, even when designed to bypass state regulation. Through an examination of the Forest Stewardship Council (FSC) in Russia and Brazil, we find that the FSC has influenced domestic rhetoric, laws, and enforcement practices. FSC has had a more disruptive and consequential impact on Russia’s domestic forest governance; in Brazil, earlier transnational environmental campaigns had already begun to shift domestic institutions toward sustainability. Based on interview data and textual analysis of FSC and government documents, we identify the mechanisms of indirect FSC influence on states—professionalization, civil society mobilization, firm lobbying, and international market pressure, and argue that they are likely to be activated under conditions of poor and decentralized governance, overlapping and competing regulations and high foreign market demand for exports. Full article
(This article belongs to the Special Issue Sustainable Forest Management and Forest Certification)
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Open AccessArticle Using Linear Mixed-Effects Models with Quantile Regression to Simulate the Crown Profile of Planted Pinus sylvestris var. Mongolica Trees
Forests 2017, 8(11), 446; doi:10.3390/f8110446 (registering DOI)
Received: 17 October 2017 / Revised: 9 November 2017 / Accepted: 14 November 2017 / Published: 17 November 2017
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Abstract
Crown profile is mostly related to the competition of individual trees in the stands, light interception, growth, and yield of trees. A total of 76 sample trees with a total number of 889 whorls and 3658 live branches were used to develop the
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Crown profile is mostly related to the competition of individual trees in the stands, light interception, growth, and yield of trees. A total of 76 sample trees with a total number of 889 whorls and 3658 live branches were used to develop the outer crown profile model of the planted Pinus sylvestris var. mongolica trees in Heilongjiang Province, China. The power-exponential equation, modified Kozak equation, and simple polynomial equation were used and the model which showed the best performance was used as the basic model. The dummy variable approach was used to analyze the effect of stand age and stand density on the crown profile. Quantile regression for linear mixed-effects model, where the correlations between the series measurements on the same subject were considered, was used to model the outer crown profile. The results indicated that the power-exponential equation had the smallest error and was used as the basic model. Based on the dummy variable approach, stand age and stand density showed significant effects on the crown profile on the whole. Thus, they were directly included into the linear form of the power-exponential equation by a natural logarithm transformation to develop the quantile regression for the linear mixed-effects model. The 0.95th quantile regression model performed best in modeling the outer crown profile when compared to other quantiles. The prediction accuracy of the 0.95th quantile regression model by adding the random effects increased when compared to the quantile regression without random effect. The quantile regression for the linear mixed-effects model also showed an excellent performance in the largest crown radius prediction when compared to the quantile regression model. From suppressed trees to dominant trees, the crown radius increased, with tree size increasing for the same stand age and stand density increases. The crown radius of the suppressed trees from 21 to 40 year stands was the largest and the smallest was from older (>40 years) stands. The crown radius for both the intermediate and dominant trees from 21 to 40 year stands were similar and were larger than the younger (10–20 years) stands. The crown radius increased with tree size when the stand variables were constant. Furthermore, the crown radius increased with the increase of stand age, decreased with increasing stand density, and decreased with increased ratio of tree height to diameter at the breast height (HD) for trees with the same tree variables. Stand density had a weaker effect on the crown profile when compared to the HD. The growth rate of the crown radius of planted Pinus sylvestris var. mongolica trees increased with increasing stand age, and decreased with decreasing stand density. The growth rate of the crown radius decreased with increasing HD. Full article
(This article belongs to the Special Issue Successional Dynamics of Forest Structure and Function)
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Open AccessArticle Biomass Losses Caused by Teratosphaeria Leaf Disease in Eucalyptus globulus Short Rotation Forestry
Forests 2017, 8(11), 447; doi:10.3390/f8110447 (registering DOI)
Received: 19 September 2017 / Revised: 9 November 2017 / Accepted: 14 November 2017 / Published: 17 November 2017
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Abstract
This article presents the results of a study that examines the loss of biomass and energy, per hectare, caused by Teratosphaeria leaf disease (TLD) in Eucalyptus globulus short rotation forestry. The 95 Eucalyptus globulus taxa analyzed are from seeds of open pollinated families
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This article presents the results of a study that examines the loss of biomass and energy, per hectare, caused by Teratosphaeria leaf disease (TLD) in Eucalyptus globulus short rotation forestry. The 95 Eucalyptus globulus taxa analyzed are from seeds of open pollinated families of both Spanish and Australian origin. Tree height and diameter were measured and the crown damage index (CDI) assessed at 27 months of age. Taxa that have a certain tolerance to the disease have been identified. The taxon identified as code 283 is the one that shows lower CDI (42%) and with an average volume that exceeded 0.017 m3 at 27 months of age. Biomass losses were determined for each fraction of dry biomass of the tree (leaves, branches, twigs and bark) based on CDI. These losses were translated into terms of energy lost per hectare, depending on the CDI. A comparison was then carried out between the productivity of Eucalyptus globulus exhibiting various levels of TLD severity and poplar and willow clones used for bioenergy in Europe. In our region, the results show that despite the losses of biomass associated with TLD, Eucalyptus globulus remains competitive as long as CDI values are lower than 56%. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Open AccessArticle Soil Organic Matter Accumulation and Carbon Fractions along a Moisture Gradient of Forest Soils
Forests 2017, 8(11), 448; doi:10.3390/f8110448 (registering DOI)
Received: 23 October 2017 / Revised: 12 November 2017 / Accepted: 14 November 2017 / Published: 17 November 2017
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Abstract
The aim of the study was to present effects of soil properties, especially moisture, on the quantity and quality of soil organic matter. The investigation was performed in the Czarna Rózga Reserve in Central Poland. Forty circular test areas were located in a
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The aim of the study was to present effects of soil properties, especially moisture, on the quantity and quality of soil organic matter. The investigation was performed in the Czarna Rózga Reserve in Central Poland. Forty circular test areas were located in a regular grid of points (100 × 300 m). Each plot was represented by one soil profile located at the plot’s center. Sample plots were located in the area with Gleysols, Cambisols and Podzols with the water table from 0 to 100 cm. In each soil sample, particle size, total carbon and nitrogen content, acidity, base cations content and fractions of soil organic matter were determined. The organic carbon stock (SOCs) was calculated based on its total content at particular genetic soil horizons. A Carbon Distribution Index (CDI) was calculated from the ratio of the carbon accumulation in organic horizons and the amount of organic carbon accumulation in the mineral horizons, up to 60 cm. In the soils under study, in the temperate zone, moisture is an important factor in the accumulation of organic carbon in the soil. The highest accumulation of carbon was observed in soils of swampy variant, while the lowest was in the soils of moist variant. Large accumulation of C in the soils with water table 80–100 cm results from the thick organic horizons that are characterized by lower organic matter decomposition and higher acidity. The proportion of carbon accumulation in the organic horizons to the total accumulation in the mineral horizons expresses the distribution of carbon accumulated in the soil profile, and is a measure of quality of the organic matter accumulated. Studies have confirmed the importance of moisture content in the formation of the fractional organic matter. With greater soil moisture, the ratio of humic to fulvic acids (HA/FA) decreases, which may suggest an increase in carbon mobility in soils. Full article
(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)
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Open AccessArticle Exploring the Regional Potential of Lignocellulosic Biomass for an Emerging Bio-Based Economy: A Case Study from Southwest Germany
Forests 2017, 8(11), 449; doi:10.3390/f8110449 (registering DOI)
Received: 23 October 2017 / Revised: 13 November 2017 / Accepted: 14 November 2017 / Published: 17 November 2017
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Abstract
The globally emerging concepts and strategies for a “bioeconomy” rely on the vision of a sustainable bio-based substitution process. Fossil fuels are scarce and their use contributes to global warming. To replace them in the value chains, it is essential to gain knowledge
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The globally emerging concepts and strategies for a “bioeconomy” rely on the vision of a sustainable bio-based substitution process. Fossil fuels are scarce and their use contributes to global warming. To replace them in the value chains, it is essential to gain knowledge about quantities and spatial distributions of renewable resources. Decision makers specifically require knowledge-based models for rational development choices. In this paper, we demonstrate such an approach using remote sensing-derived maps that represent the potential available biomass of forests and trees outside forests (TOF). The maps were combined with infrastructure data, transport costs and wood pricing to calculate the potentially available biomass for a regional bioeconomy in the federal state of Baden-Württemberg in Southwest Germany. We estimated the spatially explicit regional supply of biomass using routable data in a GIS environment, and created an approach to find the most suitable positions for biomass conversion facilities by minimizing transport distances and biomass costs. The approach resulted in the theoretical, regional supply of woody biomass with transport distances between 10 and 50 km. For a more realistic assessment, we subsequently applied several restrictions and assumptions, compiled different scenarios, optimised transport distances and identified wood assortments. Our analysis demonstrated that a regional bioeconomy using only local primary lignocellulosic biomass is possible. There would be, however, strong competition with traditional wood-processing sectors, mainly thermal utilisation and pulp and paper production. Finally, suitable positions for conversion facilities in Baden-Württemberg were determined for each of the six most plausible scenarios. This case study demonstrates the value of remote sensing and GIS techniques for a flexible, expandable and upgradable spatially explicit decision model. Full article
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Open AccessArticle Responses of Contrasting Tree Functional Types to Air Warming and Drought
Forests 2017, 8(11), 450; doi:10.3390/f8110450 (registering DOI)
Received: 4 September 2017 / Revised: 8 November 2017 / Accepted: 14 November 2017 / Published: 17 November 2017
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Abstract
Climate change-induced rise of air temperatures and the increase of extreme climatic events, such as droughts, will largely affect plant growth and hydraulics, leading to mortality events all over the globe. In this study, we investigated the growth and hydraulic responses of seedlings
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Climate change-induced rise of air temperatures and the increase of extreme climatic events, such as droughts, will largely affect plant growth and hydraulics, leading to mortality events all over the globe. In this study, we investigated the growth and hydraulic responses of seedlings of contrasting functional types. Pinus sylvestris, Quercus spp. and Castanea sativa seedlings were grown in a common garden experiment under four treatments: control, air warming, drought and their combination during two consecutive growing periods. Height and diameter increments, stomatal conductance and stem water potentials were measured during both growing seasons. Additionally, hydraulic parameters such as xylem-specific native and maximum hydraulic conductivities, and native percentage of loss of conductivity were measured at the end of the entire experiment. Our results clearly pointed to different adaptive strategies of the studied species. Scots pine displayed a relatively isohydric behavior with a strict stomata control prohibiting native embolism whereas sweet chestnut and oak as relatively anisohydric species displayed an increased loss of native conductivity as a results of low water potentials. Seasonal timing of shoot and diameter growth also differed among functional types influencing drought impacts. Additionally, the possibility of embolism reversal seemed to be limited under the study conditions. Full article
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Open AccessArticle Genetic Variation in Quercus acutissima Carruth., in Traditional Japanese Rural Forests and Agricultural Landscapes, Revealed by Chloroplast Microsatellite Markers
Forests 2017, 8(11), 451; doi:10.3390/f8110451 (registering DOI)
Received: 23 August 2017 / Revised: 1 November 2017 / Accepted: 13 November 2017 / Published: 17 November 2017
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Abstract
Quercus acutissima Carruth. is an economically important species that has long been cultivated in Japan, so is a valuable subject for investigating the impact of human activities on genetic variation in trees. In total, 2152 samples from 18 naturally regenerated populations and 28
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Quercus acutissima Carruth. is an economically important species that has long been cultivated in Japan, so is a valuable subject for investigating the impact of human activities on genetic variation in trees. In total, 2152 samples from 18 naturally regenerated populations and 28 planted populations in Japan and 13 populations from the northeastern part of Eurasia, near Japan, were analyzed using six maternally inherited chloroplast (cpDNA) simple sequence repeat (SSR) markers. Although 23 haplotypes were detected in total, both the Japanese natural and artificial populations exhibited much lower genetic diversity than the continental populations. The level of genetic differentiation among natural populations in Japan was also much lower (GST = 0.261) than that on the continent (GST = 0.856). These results suggest that human activities, such as historical seed transfer, have reduced genetic diversity within and among populations and resulted in a homogeneous genetic structure in Japan. The genetic characteristics of natural and artificial populations of Quercus acutissima in Japan are almost the same and it is likely that most of the natural populations are thought to have originated from individuals that escaped from plantations. Full article
(This article belongs to the Special Issue Genetics and Genomics of Forest Trees)
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Open AccessArticle Effects of Nitrogen Deposition on Soil Dissolved Organic Carbon and Nitrogen in Moso Bamboo Plantations Strongly Depend on Management Practices
Forests 2017, 8(11), 452; doi:10.3390/f8110452 (registering DOI)
Received: 12 September 2017 / Revised: 11 November 2017 / Accepted: 13 November 2017 / Published: 17 November 2017
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Abstract
Soil dissolved organic carbon (DOC) and nitrogen (DON) play significant roles in forest carbon, nitrogen and nutrient cycling. The objective of the present study was to estimate the effect of management practices and nitrogen (N) deposition on soil DOC and DON in Moso
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Soil dissolved organic carbon (DOC) and nitrogen (DON) play significant roles in forest carbon, nitrogen and nutrient cycling. The objective of the present study was to estimate the effect of management practices and nitrogen (N) deposition on soil DOC and DON in Moso bamboo (Phyllostachys edulis (Carrière) J. Houz) plantations. This experiment, conducted for over 36 months, investigated the effects of four N addition levels (30, 60 and 90 kg N ha−1 year−1, and the N-free control) and two management practices (conventional management (CM) and intensive management (IM)) on DOC and DON. The results showed that DOC and DON concentrations were the highest in summer. Both intensive management and N deposition independently decreased DOC and DON in spring (p < 0.05) but not in winter. However, when combined with IM, N deposition increased DOC and DON in spring and winter (p < 0.05). Our results demonstrated that N deposition significantly increased the loss of soil DOC and DON in Moso plantations, and this reduction was strongly affected by IM practices and varied seasonally. Therefore, management practices and seasonal variation should be considered when using ecological models to estimate the effects of N deposition on soil DOC and DON in plantation ecosystems. Full article
(This article belongs to the Special Issue Carbon and Nitrogen in Forest Ecosystems)
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Open AccessArticle Decision Support System for Adaptive Regional-Scale Forest Management by Multiple Decision-Makers
Forests 2017, 8(11), 453; doi:10.3390/f8110453 (registering DOI)
Received: 27 October 2017 / Revised: 13 November 2017 / Accepted: 15 November 2017 / Published: 17 November 2017
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Abstract
Various kinds of decision support approaches (DSAs) are used in adaptive management of forests. Existing DSAs are aimed at coping with uncertainties in ecosystems but not controllability of outcomes, which is important for regional management. We designed a DSA for forest zoning to
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Various kinds of decision support approaches (DSAs) are used in adaptive management of forests. Existing DSAs are aimed at coping with uncertainties in ecosystems but not controllability of outcomes, which is important for regional management. We designed a DSA for forest zoning to simulate the changes in indicators of forest functions while reducing uncertainties in both controllability and ecosystems. The DSA uses a Bayesian network model based on iterative learning of observed behavior (decision-making) by foresters, which simulates when and where zoned forestry activities are implemented. The DSA was applied to a study area to evaluate wood production, protection against soil erosion, preservation of biodiversity, and carbon retention under three zoning alternatives: current zoning, zoning to enhance biodiversity, and zoning to enhance wood production. The DSA predicted that alternative zoning could enhance wood production by 3–11% and increase preservation of biodiversity by 0.4%, but decrease carbon stock by 1.2%. This DSA would enable to draw up regional forest plans while considering trade-offs and build consensus more efficiently. Full article
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Open AccessArticle Sustainable Forest Management and Social-Ecological Systems: An Institutional Analysis of Caatinga, Brazil
Forests 2017, 8(11), 454; doi:10.3390/f8110454 (registering DOI)
Received: 10 October 2017 / Revised: 14 November 2017 / Accepted: 16 November 2017 / Published: 18 November 2017
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Abstract
Sustainable Forest Management (SFM) has globally gained support as a strategy to use and manage forest resources while maintaining forest ecosystem services. However, type, relevance, and utilisation of forest ecosystem services vary across eco-regions, countries, and policy implementation pathways. As such, the concept
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Sustainable Forest Management (SFM) has globally gained support as a strategy to use and manage forest resources while maintaining forest ecosystem services. However, type, relevance, and utilisation of forest ecosystem services vary across eco-regions, countries, and policy implementation pathways. As such, the concept of SFM is subject to a series of translations within the social-ecological context in which it is implemented. This article discusses translations of SFM in Caatinga biome—a tropical dry forest in the north-eastern semi-arid region of Brazil. Our analysis is based on a qualitative analysis of 24 semi-structured interviews and 30 documents. We discuss SFM and the interplay of resources, governance, and actors. Results for Caatinga show that (1) a technical approach to SFM that focuses on firewood and charcoal production is dominant; that (2) SFM implementation practices hardly address the needs and interests of local populations; and that (3) local actors show little support for the implementation of SFM. We conclude that the social-ecological context of Caatinga shapes translations of SFM mostly in a techno-bureaucratic rather than a socially embedded way. As a result, local practices of forest use are excluded from the regional SFM approach, which negatively affects its implementation. Full article
(This article belongs to the Special Issue Forest Sustainable Management)
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Open AccessArticle Climate Change Mitigation Potential in Boreal Forests: Impacts of Management, Harvest Intensity and Use of Forest Biomass to Substitute Fossil Resources
Forests 2017, 8(11), 455; doi:10.3390/f8110455 (registering DOI)
Received: 29 September 2017 / Revised: 1 November 2017 / Accepted: 14 November 2017 / Published: 18 November 2017
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Abstract
The impacts of alternative forest management scenarios and harvest intensities on climate change mitigation potential of forest biomass production, utilization and economic profitability of biomass production were studied in three boreal sub-regions in Finland over a 40-year period. Ecosystem modelling and life cycle
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The impacts of alternative forest management scenarios and harvest intensities on climate change mitigation potential of forest biomass production, utilization and economic profitability of biomass production were studied in three boreal sub-regions in Finland over a 40-year period. Ecosystem modelling and life cycle assessment tools were used to calculate the mitigation potential in substituting fossil materials and energy, expressed as the net CO2 exchange. Currently recommended management targeting to timber production acted as a baseline management. Alternative management included maintaining 20% higher or lower stocking in forests and final felling made at lower breast height diameter than used in the baseline. In alternative management scenarios, logging residues and logging residues with coarse roots and stumps were harvested in final felling in addition to timber. The net CO2 exchange in the southern and eastern sub-regions was higher compared to the western one due to higher net ecosystem CO2 exchange (NEE) over the study period. Maintaining higher stocking with earlier final felling and intensified biomass harvest appeared to be the best option to increase both climate benefits and economic returns. Trade-offs between the highest net CO2 exchange and economic profitability of biomass production existed. The use of alternative displacement factors largely affected the mitigation potential of forest biomass. Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessArticle Incidence of Trailer Frame Structure on Driver’s Safety during Log Transportation
Forests 2017, 8(11), 456; doi:10.3390/f8110456 (registering DOI)
Received: 29 September 2017 / Revised: 9 November 2017 / Accepted: 11 November 2017 / Published: 18 November 2017
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Abstract
The frame structure of the trailer may influence both the traction and the tractor-trailer stability, especially along sloped paths. The aim of this research was to analyze a trailer overturning and the strains on the connected tractors (wheeled, or crawled) during log transportation
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The frame structure of the trailer may influence both the traction and the tractor-trailer stability, especially along sloped paths. The aim of this research was to analyze a trailer overturning and the strains on the connected tractors (wheeled, or crawled) during log transportation (loose or tied) along a hillside. Two two-axle trailers were used: tandem and turntable steering. Three types of measurements were carried out during the field tests: (i) the detachment from the ground of the rear upstream wheels (or crawler); (ii) the transversal and longitudinal strains occurring when the trailer overturned (and released the hooking system of the tractor); (iii) the lateral deviation of the rear wheels (or crawler) of the tractor. The study highlighted that the two-axle trailer with turntable steering combined with the crawl tractor gave better results in terms of safety during trailer overturning. In addition, independent of the type of trailer, a tied load was found to be more dangerous than a load restrained only by steel struts, because when overturning, the load forms a single unit with the trailer mass which increases the strains. Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
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