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Forests, Volume 10, Issue 8 (August 2019)

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Cover Story (view full-size image) We identified models of white pine blister rust infection which indicated that an August and [...] Read more.
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Open AccessArticle
Spatiotemporal Simulation of Net Ecosystem Productivity and Its Response to Climate Change in Subtropical Forests
Forests 2019, 10(8), 708; https://doi.org/10.3390/f10080708 - 20 Aug 2019
Viewed by 398
Abstract
Subtropical forests have great potential as carbon sinks; however, the relationship between net ecosystem productivity (NEP) and climate change is still unclear. This study took Zhejiang Province, a subtropical region, as an example. Based on remote sensing classification data of forest resources, the [...] Read more.
Subtropical forests have great potential as carbon sinks; however, the relationship between net ecosystem productivity (NEP) and climate change is still unclear. This study took Zhejiang Province, a subtropical region, as an example. Based on remote sensing classification data of forest resources, the integrated terrestrial ecosystem carbon cycle (InTEC) model was used to simulate the spatiotemporal dynamics of the forest NEP in Zhejiang Province during 1985–2015 and analyze its response to meteorological factors such as temperature, precipitation, relative humidity, and radiation. Three patterns emerged: (1) The optimized InTEC model can better simulate the forest NEP in Zhejiang Province, and the correlation coefficient between the simulated NEP and observed NEP was up to 0.75. (2) From 1985 to 2015, the increase in the total NEP was rapid, with an average annual growth rate of 1.52 Tg·C·yr−1. During 1985–1988, the forests in Zhejiang Province were carbon sources. After 1988, the forests turned into carbon sinks and this continued to increase. During 2000–2015, more than 97% of the forests in Zhejiang Province were carbon sinks. The total NEP reached 32.02 Tg·C·yr−1, and the annual mean NEP increased to 441.91 gC·m−2·yr−1. The carbon sequestration capacity of forests in the east and southwest of Zhejiang Province is higher than that in the northeast of Zhejiang Province. (3) From 2000 to 2015, there was an extremely significant correlation between forest NEP and precipitation, with a correlation coefficient of 0.85. Simultaneously, the forest NEP showed a negative correlation with temperature and radiation, with a correlation coefficient of −0.56 for both, and the forest NEP was slightly negatively correlated with relative humidity. The relative contribution rates of temperature, precipitation, relative humidity, and radiation data to NEP showed that the contribution of precipitation to NEP is the largest, reaching 61%, followed by temperature and radiation at 18% and 17%, respectively. The relative contribution rate of relative humidity is the smallest at only 4%. During the period of 1985–1999, due to significant man-made disturbances, the NEP had a weak correlation with temperature, precipitation, relative humidity, and radiation. The results of this study are important for addressing climate change and illustrating the response mechanism between subtropical forest NEP and climate change. Full article
(This article belongs to the collection Forests Carbon Fluxes and Sequestration)
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Open AccessArticle
Growth of Abies sachalinensis Along an Urban Gradient Affected by Environmental Pollution in Sapporo, Japan
Forests 2019, 10(8), 707; https://doi.org/10.3390/f10080707 - 20 Aug 2019
Viewed by 344
Abstract
Urban tree growth is often affected by reduced water availability, higher temperatures, small and compacted planting pits, as well as high nutrient and pollution inputs. Despite these hindering growth conditions, recent studies found a surprisingly better growth of urban trees compared to trees [...] Read more.
Urban tree growth is often affected by reduced water availability, higher temperatures, small and compacted planting pits, as well as high nutrient and pollution inputs. Despite these hindering growth conditions, recent studies found a surprisingly better growth of urban trees compared to trees at rural sites, and an enhanced growth of trees in recent times. We compared urban versus rural growing Sakhalin fir (Abies sachalinensis (F. Schmidt) Mast.) trees in Sapporo, northern Japan and analyzed the growth differences between growing sites and the effects of environmental pollution (NO2, NOX, SO2 and OX) on tree growth. Tree growth was assessed by a dendrochronological study across a gradient from urban to rural sites and related to high detailed environmental pollution data with mixed model approaches and regression analyses. A higher growth of urban trees compared to rural trees was found, along with an overall accelerated growth rate of A. sachalinensis trees over time. Moreover, environmental pollution seems to positively affect tree growth, though with the exception of oxides OX which had strong negative correlations with growth. In conclusion, higher temperatures, changed soil nutrient status, higher risks of water-logging, increased oxide concentrations, as well as higher age negatively affected the growth of rural trees. The future growth of urban A. sachalinensis will provide more insights as to whether the results were induced by environmental pollution and climate or biased on a higher age of rural trees. Nevertheless, the results clearly indicate that environmental pollution, especially in terms of NO2 and NOX poses no threat to urban tree growth in Sapporo. Full article
(This article belongs to the Special Issue Growth and Ecosystem Services of Urban Trees)
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Open AccessArticle
Density Dependence of Egg Recruitment and Moth Dispersal in Spruce Budworms
Forests 2019, 10(8), 706; https://doi.org/10.3390/f10080706 - 20 Aug 2019
Cited by 2 | Viewed by 348
Abstract
Egg recruitment quantifies the relative importance of realized fecundity and migration rates in the population dynamics of highly mobile insects. We develop here a formal context upon which to base the measurement and interpretation of egg recruitment in population dynamics of eastern and [...] Read more.
Egg recruitment quantifies the relative importance of realized fecundity and migration rates in the population dynamics of highly mobile insects. We develop here a formal context upon which to base the measurement and interpretation of egg recruitment in population dynamics of eastern and western spruce budworms, two geographically separated species that share a very similar ecology. Under most circumstances, per capita egg recruitment rates in these budworms are higher in low-density populations and lower in high-density populations, relative to the regional mean: Low-density populations are nearly always migration sinks for gravid moths, and dense populations nearly always sources. The slope of this relationship, measured on a log scale, is negatively correlated with migration rate, and ranges between 0 and −1. The steeper the slope, the more marked net migration. Using our western spruce budworm observations, we found strong evidence of density-dependent emigration in budworms, so migration is not simply a random perturbation in the lagged, density-dependent stochastic process leading to budworm outbreaks. It is itself statistically and biologically density-dependent. Therefore, moth migration is a synchronizing factor and a spread mechanism that is essential to understanding the development and expansion of spruce budworm outbreaks at regional scales in the boreal forests of North America. Full article
(This article belongs to the Special Issue Protection Strategy against Spruce Budworm)
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Open AccessArticle
Predicting the Bioclimatic Habitat Suitability of Ginkgo biloba L. in China with Field-Test Validations
Forests 2019, 10(8), 705; https://doi.org/10.3390/f10080705 - 20 Aug 2019
Viewed by 366
Abstract
Ginkgo (Ginkgo biloba L.) is not only considered a ‘living fossil’, but also has important ecological, economic, and medicinal values. However, the impact of climate change on the performance and distribution of this plant is an increasing concern. In this study, we [...] Read more.
Ginkgo (Ginkgo biloba L.) is not only considered a ‘living fossil’, but also has important ecological, economic, and medicinal values. However, the impact of climate change on the performance and distribution of this plant is an increasing concern. In this study, we developed a bioclimatic model based on data about the occurrence of ginkgo from 277 locations, and validated model predictions using a wide-ranging field test (12 test sites, located at the areas from 22.49° N to 39.32° N, and 81.11° E to 123.53° E). We found that the degree-days below zero were the most important climate variable determining ginkgo distribution. Based on the model predictions, we classified the habitat suitability for ginkgo into four categories (high, medium, low, and unsuitable), accounting for 9.29%, 6.09%, 8.46%, and 76.16% of China’s land area, respectively. The ANOVA results of the validation test showed significant differences in observed leaf-traits among the four habitat types (p < 0.05), and importantly the rankings of the leaf traits were consistent with our classification of the habitat suitability, suggesting the effectiveness of our classification in terms of biological and economic significance. In addition, we projected that suitable (high and medium) habitats for ginkgo would shrink and shift northward under both the RCP4.5 and RCP8.5 climate change scenarios for three future periods (the 2020s, 2050s, and 2080s). However, the area of low-suitable habitat would increase, resulting in a slight decrease in unsuitable habitats. Our findings contribute to a better understanding of climate change impact on this plant and provide a scientific basis for developing adaptive strategies for future climate. Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessReview
Kinetics of Water Vapor Sorption in Wood Cell Walls: State of the Art and Research Needs
Forests 2019, 10(8), 704; https://doi.org/10.3390/f10080704 - 20 Aug 2019
Viewed by 403
Abstract
Water vapor sorption is the most fundamental aspect of wood-moisture relations. It is directly or indirectly related to the physical properties of wood and the onset of wood-damage mechanisms. While sorption properties of cellulosic materials have been utilized since antiquity, the time-dependent transition [...] Read more.
Water vapor sorption is the most fundamental aspect of wood-moisture relations. It is directly or indirectly related to the physical properties of wood and the onset of wood-damage mechanisms. While sorption properties of cellulosic materials have been utilized since antiquity, the time-dependent transition from one moisture content to another (i.e., sorption kinetics) has received much less attention. In this critical review, we present the state-of-the-art of water vapor sorption kinetics in wood. We first examine different experimental methods that have been used to measure sorption kinetics, from the quartz helix vacuum balance beginning in earnest in the 1930s, to automated sorption balances used recently. We then give an overview of experimental observations and describe the physical phenomena that occur during the sorption process, which potentially govern the following kinetics: boundary layer mass transfer resistance, heat of sorption, cell wall diffusion, swelling, and polymer mobility. Finally, we evaluate theoretical models that have been proposed for describing sorption kinetics, considering both experimental data and the physical processes described in the previous section. It is clear that no previously developed model can phenomenologically describe the sorption process. Instead, new models are needed. We conclude that the development of new models will require more than simple gravimetric measurements. In addition to mass changes, complementary techniques are needed to probe other important physical quantities on multiple length scales. Full article
(This article belongs to the Special Issue Wood-Moisture Relations)
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Open AccessArticle
Socioeconomic Impacts of the Billion Trees Afforestation Program in Khyber Pakhtunkhwa Province (KPK), Pakistan
Forests 2019, 10(8), 703; https://doi.org/10.3390/f10080703 - 19 Aug 2019
Viewed by 392
Abstract
In recent decades, the terrestrial ecosystem in Khyber Pakhtunkhwa Province (KPK), Pakistan, has undergone tremendous destruction. To restore environmental conditions, the government implemented the Billion Tree Afforestation Program (BTAP), with a high target to impact multidimensional aspects of the terrestrial ecosystem. The government [...] Read more.
In recent decades, the terrestrial ecosystem in Khyber Pakhtunkhwa Province (KPK), Pakistan, has undergone tremendous destruction. To restore environmental conditions, the government implemented the Billion Tree Afforestation Program (BTAP), with a high target to impact multidimensional aspects of the terrestrial ecosystem. The government claims that it is local residents who have benefited the most from the BTAP. Hence, the objective of this research was to examine the socioeconomic impact and local rural perception of the BTAP in three districts of KPK. Primary data were collected from 406 households. Fundamental orientation theory was used to assess the social impacts of the BTAP, while cost–benefit analysis was applied to examine its economic impact. The results show that the overall social impacts of the BTAP are satisfactory and beneficial, increasing social sustainability by 69% between 2014 and 2018. Additionally, based on the cost–benefit analysis and perception-based analysis, it was found that the BTAP positively affects the economic conditions of rural households. The community livelihood increased during the program, with a total net income of 6.9 million USD in the three districts of KPK. It is concluded that the majority of respondents have benefited from participation in the BTAP. The sustainability of rural livelihood is one of the main concerns related to the establishment of the BTAP. Effort is needed by the government and other parties to both increase rural household income and to protect the environment. Full article
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Open AccessArticle
Dynamics of Abies nephrolepis Seedlings in Relation to Environmental Factors in Seorak Mountain, South Korea
Forests 2019, 10(8), 702; https://doi.org/10.3390/f10080702 - 19 Aug 2019
Viewed by 396
Abstract
We present novel evidence of environmental drivers of seedling density in Abies nephrolepis, an alpine and subalpine tree species. Continuous monitoring of natural conditions is required to understand forest ecosystem dynamics. We investigated Abies nephrolepis seedling dynamics in relation to biotic and [...] Read more.
We present novel evidence of environmental drivers of seedling density in Abies nephrolepis, an alpine and subalpine tree species. Continuous monitoring of natural conditions is required to understand forest ecosystem dynamics. We investigated Abies nephrolepis seedling dynamics in relation to biotic and abiotic factors. The survey, which included the measurement of trees and seedlings, was carried out from March to October in 2016 and 2018. Monitoring sites in the coniferous forests of Seorak Mountain were divided into 27 quadrats. We analyzed relationships using simple and multiple linear regression. The majority of Abies nephrolepis individuals had a diameter at breast height less than l0 cm, and the number of seedlings increased over the study period. This reflects survival and growth due to successive annual mast seeding events. Aspect direction (R2 = 0.201, p < 0.05), rock exposure (R2 = 0.364, p < 0.001), canopy openness (R2 = 0.322, p < 0.05), herbaceous cover (R2 = 0.268, p < 0.01), and basal area (R2 = 0.199, p < 0.05) show significant linear relationships with seedling density. Seedling density was positively related to rock exposure, canopy openness, and species richness, and there was a negative relationship between herbaceous cover and basal area (p < 0.0001). The relative importance of predictor variables was as follows: Rock exposure (40.3%), canopy openness (30.2%), basal area (13.9%), herbaceous cover (11.5%), and species richness (4.1%). Seedling density was most strongly influenced by the presence of large rocks, which provide shelter from harsh winds and a substrate for moss. We conclude that appropriate canopy openness creates a synergistic relationship. We found a positive association between the Abies nephrolepis seedling density in subalpine forests and certain physical environmental factors. Therefore, environmental gradients about the roles of rocks and canopies apply, even in this habitat. Full article
(This article belongs to the Special Issue Forest Stand Dynamics and Its Applications)
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Open AccessArticle
Mobile Terrestrial Photogrammetry for Street Tree Mapping and Measurements
Forests 2019, 10(8), 701; https://doi.org/10.3390/f10080701 - 19 Aug 2019
Viewed by 302
Abstract
Urban forests are often heavily populated by street trees along right-of-ways (ROW), and monitoring efforts can enhance municipal tree management. Terrestrial photogrammetric techniques have been used to measure tree biometry, but have typically used images from various angles around individual trees or forest [...] Read more.
Urban forests are often heavily populated by street trees along right-of-ways (ROW), and monitoring efforts can enhance municipal tree management. Terrestrial photogrammetric techniques have been used to measure tree biometry, but have typically used images from various angles around individual trees or forest plots to capture the entire stem while also utilizing local coordinate systems (i.e., non-georeferenced data). We proposed the mobile collection of georeferenced imagery along 100 m sections of urban roadway to create photogrammetric point cloud datasets suitable for measuring stem diameters and attaining positional x and y coordinates of street trees. In a comparison between stationary and mobile photogrammetry, diameter measurements of urban street trees (N = 88) showed a slightly lower error (RMSE = 8.02%) relative to non-mobile stem measurements (RMSE = 10.37%). Tree Y-coordinates throughout urban sites for mobile photogrammetric data showed a lower standard deviation of 1.70 m relative to 2.38 m for a handheld GPS, which was similar for X-coordinates where photogrammetry and handheld GPS coordinates showed standard deviations of 1.59 m and the handheld GPS 2.36 m, respectively—suggesting higher precision for the mobile photogrammetric models. The mobile photogrammetric system used in this study to create georeferenced models for measuring stem diameters and mapping tree positions can also be potentially expanded for more wide-scale applications related to tree inventory and monitoring of roadside infrastructure. Full article
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Open AccessArticle
3-D Reconstruction of an Urban Landscape to Assess the Influence of Vegetation in the Radiative Budget
Forests 2019, 10(8), 700; https://doi.org/10.3390/f10080700 - 19 Aug 2019
Viewed by 454
Abstract
Increased urbanization and climate change have resulted in the intensification of the urban heat island (UHI) effect, particularly in tropical cities. One of the main causes of UHI is the man-made urban surfaces influencing the radiation budget by absorbing, reflecting, and emitting radiation [...] Read more.
Increased urbanization and climate change have resulted in the intensification of the urban heat island (UHI) effect, particularly in tropical cities. One of the main causes of UHI is the man-made urban surfaces influencing the radiation budget by absorbing, reflecting, and emitting radiation at various wavelengths. The radiative budget of a city is directly influenced by the urban geometry, surface materials, direct solar radiation and incident angle, and atmospheric diffuse radiation. Vegetation cover, in contrast, can decrease UHI by intercepting radiation and through the process of photosynthesis. Better understanding the effect of urban vegetation on the radiative budget can thus contribute towards the mitigation of the UHI effect and ultimately the development of climate resilient urban spaces. To analyze the contribution of vegetation to the radiative budget of a city, a detailed simulation of the complex interaction between the built environment and the vegetation is required. This study proposes an approach for analyzing the 3-D structure of both vegetation and built environment to quantify the contribution of vegetation to the radiative budget of an urban landscape. In a first step, a detailed 3-D model of Singapore including buildings and vegetation was reconstructed using a combination of free and commercial Earth Observation data. Then, the 3-D Discrete Anisotropic Radiative Transfer (DART) model was repurposed to estimate the radiation absorbed by the urban surfaces accounting for the presence of vegetation cover with changing Leaf Area Density (LAD) conditions. The presence of trees in the scene accounted for a significant reduction of the absorbed radiation by buildings and ground. For example, in the case of a residential low-building neighborhood, although having low tree cover, the reduction of the absorbed radiation by buildings and ground was up to 15.5% for a LAD =1. The field validation shows good agreement (R2 = 0.9633, RMSE = 10.8830 and Bias = −1.3826) between the DART-simulated shortwave exitance and upwelling shortwave measurements obtained from a net radiometer mounted on a local flux tower in the urban area of Singapore, over the studied period. Our approach can be used for neighborhood-scale analysis, at any desired location of a city, to allow test scenarios with varying surface materials and vegetation properties. Full article
(This article belongs to the Special Issue Forestry Applications of DART Model)
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Open AccessArticle
Assessing the Efficacy of Seedling Planting as a Forest Restoration Technique in Temperate Hardwood Forests Impacted by Invasive Species
Forests 2019, 10(8), 699; https://doi.org/10.3390/f10080699 - 18 Aug 2019
Viewed by 605
Abstract
The emerald ash borer (Agrilus planipennis Fairmaire; EAB) is an invasive insect that causes mortality of trees in the genus Fraxinus, creating canopy gaps that may facilitate invasion by exotic plants. Planting native tree seedlings under EAB-infested Fraxinus may accelerate succession [...] Read more.
The emerald ash borer (Agrilus planipennis Fairmaire; EAB) is an invasive insect that causes mortality of trees in the genus Fraxinus, creating canopy gaps that may facilitate invasion by exotic plants. Planting native tree seedlings under EAB-infested Fraxinus may accelerate succession and preclude invasive plant expansion; however, the effectiveness of this approach has not been experimentally tested. We assessed understory seedling planting of Quercus rubra, Carya laciniosa, and Juglans cinerea in EAB-infested forests, where the invasive shrub Lonicera maackii (Amur honeysuckle) was removed. We tested whether the use of plastic tree shelters (“tree tubes”) or planting season (fall versus spring) contributed to the success of the reforestation plan by measuring growth rates (cm/yr) and survivorship two and seven years after planting. After seven years, seedling survivorship was <25% for all species and planting techniques. Quercus rubra exhibited poor survivorship with one seedling surviving to the conclusion of the experiment. Juglans cinerea and C. laciniosa had higher survivability and growth rates than did Q. rubra after two and seven years. Effects of tree tubes were weak and temporary. After 2 years, Q. rubra seedling survivorship was higher in tree tubes; however, by the end of the experiment 29 of the 30 Q. rubra seedlings in tree tubes had died. Juglans cinerea seedlings grew faster when planted in the fall compared to the spring, but overall survivorship of these seedlings was unaffected by planting season. Neither the use of tree shelters nor the planting season contributed to the growth or survival of C. laciniosa seedlings. In summary, our results indicate that seedling planting of Carya and Juglans may be a useful way to increase biodiversity in regenerating forests; however, the resource-expensive processes of over-wintering seedlings and using tree shelters may not increase the success of reforestation efforts. Full article
(This article belongs to the Special Issue Natural Regeneration in Mixed Hardwood Forests)
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Open AccessArticle
Identification of RING-H2 Gene Candidates Related to Wood Formation in Poplar
Forests 2019, 10(8), 698; https://doi.org/10.3390/f10080698 - 17 Aug 2019
Viewed by 328
Abstract
RING-H2 genes, the most abundant RING-type genes encoding putative ubiquitin ligase E3, are involved in diverse biological processes. Whether RING-H2 genes are related to wood formation remains to be identified in trees. In this study, we identified 288 RING-H2 genes in Populus trichocarpa [...] Read more.
RING-H2 genes, the most abundant RING-type genes encoding putative ubiquitin ligase E3, are involved in diverse biological processes. Whether RING-H2 genes are related to wood formation remains to be identified in trees. In this study, we identified 288 RING-H2 genes in Populus trichocarpa, and found that the segmental and tandem duplication events contributed to RING-H2 gene expansion. Microarray dataset (from Affymetrix poplar genome arrays) showed that 64 of the 249 RING-H2 genes were highly or preferentially expressed in stem xylem. According to the AspWood RNAseq dataset, the transcription levels of genes PtrRHH21, 33, 48, 69, 88, 93, 94, 121, 141, 166, 175, 192, 208, 214, 250 and 257 were significantly increased in the xylem ranging from the expanding xylem to the lignifying xylem, suggesting their association with wood formation. Promoter analyses revealed that most of the preferentially xylem-expressed RING-H2 genes possessed SNBE, TERE, M46RE, AC and SMRE cis-elements, which are involved in secondary cell wall biosynthesis and programmed cell death. Based on the promoter GUS-based analysis result, PtrRHH94 was indicated to be associated with wood formation in transgenic P. trichocarpa. Taken together, dozens of Populus RING-H2 gene candidates associated with wood formation have been identified based on multiple gene expression analyses. Full article
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Open AccessArticle
Drought-Induced Mortality Is Related to Hydraulic Vulnerability Segmentation of Tree Species in a Savanna Ecosystem
Forests 2019, 10(8), 697; https://doi.org/10.3390/f10080697 - 17 Aug 2019
Viewed by 332
Abstract
Vulnerability segmentation (VS) has been widely suggested to protect stems and trunks from hydraulic failure during drought events. In many ecosystems, some species have been shown to be non-segmented (NS species). However, it is unclear whether drought-induced mortality is related to VS. To [...] Read more.
Vulnerability segmentation (VS) has been widely suggested to protect stems and trunks from hydraulic failure during drought events. In many ecosystems, some species have been shown to be non-segmented (NS species). However, it is unclear whether drought-induced mortality is related to VS. To understand this, we surveyed the mortality and recruitment rate and measured the hydraulic traits of leaves and stems as well as the photosynthesis of six tree species over five years (2012–2017) in a savanna ecosystem in Southwest China. Our results showed that the NS species exhibited a higher mortality rate than the co-occurring VS species. Across species, the mortality rate was not correlated with xylem tension at 50% loss of stem hydraulic conductivity (P50stem), but was rather significantly correlated with leaf water potential at 50% loss of leaf hydraulic conductance (P50leaf) and the difference in water potential at 50% loss of hydraulic conductance between the leaves and terminal stems (P50leaf-stem). The NS species had higher Huber values and maximum net photosynthetic rates based on leaf area, which compensated for a higher mortality rate and promoted rapid regeneration under the conditions of dry–wet cycles. To our knowledge, this study is the first to identify the difference in drought-induced mortality between NS species and VS species. Our results emphasize the importance of VS in maintaining hydraulic safety in VS species. Furthermore, the high mortality rate and fast regeneration in NS species may be another hydraulic strategy in regions where severe seasonal droughts are frequent. Full article
(This article belongs to the Special Issue Tree Hydraulic Functioning)
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Open AccessArticle
Bark Beetle Epidemics, Life Satisfaction, and Economic Well-Being
Forests 2019, 10(8), 696; https://doi.org/10.3390/f10080696 - 16 Aug 2019
Viewed by 367
Abstract
Evidence of increased biotic disturbances in forests due to climate change is accumulating, necessitating the development of new approaches for understanding the impacts of natural disturbances on human well-being. The recent Mountain Pine Beetle (MPB) outbreak in the western United States, which was [...] Read more.
Evidence of increased biotic disturbances in forests due to climate change is accumulating, necessitating the development of new approaches for understanding the impacts of natural disturbances on human well-being. The recent Mountain Pine Beetle (MPB) outbreak in the western United States, which was historically unprecedented in scale, provides an opportunity for testing the adequacy of the life satisfaction approach (LSA) to estimate the impact of large-scale forest mortality on subjective well-being. Prior research in this region used the hedonic method (HM) to estimate the economic impacts of the MPB outbreak, and results are used here to evaluate the reasonableness of economic estimates based upon the LSA. While economic estimates based upon the LSA model do not appear to be unreasonable, several limitations in using the LSA for nonmarket valuations are discussed. New avenues for research that link the LSA with stated preference methods are discussed that appear likely to address major concerns with standard LSA models as used in nonmarket valuation. Full article
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Open AccessArticle
Unmanned Aerial Vehicles and Biosecurity: Enabling Participatory-Design to Help Address Social Licence to Operate Issues
Forests 2019, 10(8), 695; https://doi.org/10.3390/f10080695 - 16 Aug 2019
Viewed by 506
Abstract
Forest health can be adversely affected by invasive organisms. Biosecurity measures to prevent the establishment of harmful invasive organisms at national points of entry (e.g., airports or shipping ports) are vital to protect forest health. Innovations in pest eradication technologies are being developed [...] Read more.
Forest health can be adversely affected by invasive organisms. Biosecurity measures to prevent the establishment of harmful invasive organisms at national points of entry (e.g., airports or shipping ports) are vital to protect forest health. Innovations in pest eradication technologies are being developed based on their efficiencies and effectiveness. However, the question of whether people find them acceptable is rarely considered. In New Zealand, research is underway into the use of highly targeted pesticide spraying using unmanned aerial vehicles (UAVs) as a novel technology to eradicate pest species that impact forest, food, and fibre sectors. Public approval for such technologies, however, can be a critical aspect for their success. A tool can be technically effective (achieve eradication), but uptake may be impossible if communities do not trust the technology. We developed a method for enabling discussions about the use of UAVs and their acceptability in general before being operationalized for biosecurity. This paper presents an investigation of how “participatory-design”, an often tactile, visual, and inclusive process of community engagement can improve the acceptance of technology use in the public sphere. We asked people, both scientists and citizens, to evaluate the acceptability of a range of UAV uses (including biosecurity) along a continuum and then explored the reasons for their placement. Key criteria for acceptable and unacceptable uses were subsequently developed to help technology designers and operators consider aspects of social acceptability during design processes. Our tool and approach facilitated discussions around technology acceptability that were subsequently adopted by our technical design team for the development and the use of acceptable UAVs for biosecurity. This research shows how systematic approaches to design can help uncover and mitigate social acceptability issues through inclusive design under increasing threats of biosecurity, whether related to challenges of trade or climate change. Full article
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Open AccessArticle
Measuring Tree Height with Remote Sensing—A Comparison of Photogrammetric and LiDAR Data with Different Field Measurements
Forests 2019, 10(8), 694; https://doi.org/10.3390/f10080694 - 16 Aug 2019
Viewed by 442
Abstract
We contribute to a better understanding of different remote sensing techniques for tree height estimation by comparing several techniques to both direct and indirect field measurements. From these comparisons, factors influencing the accuracy of reliable tree height measurements were identified. Different remote sensing [...] Read more.
We contribute to a better understanding of different remote sensing techniques for tree height estimation by comparing several techniques to both direct and indirect field measurements. From these comparisons, factors influencing the accuracy of reliable tree height measurements were identified. Different remote sensing methods were applied on the same test site, varying the factors sensor type, platform, and flight parameters. We implemented light detection and ranging (LiDAR) and photogrammetric aerial images received from unmanned aerial vehicles (UAV), gyrocopter, and aircraft. Field measurements were carried out indirectly using a Vertex clinometer and directly after felling using a tape measure on tree trunks. Indirect measurements resulted in an RMSE of 1.02 m and tend to underestimate tree height with a systematic error of −0.66 m. For the derivation of tree height, the results varied from an RMSE of 0.36 m for UAV-LiDAR data to 2.89 m for photogrammetric data acquired by an aircraft. Measurements derived from LiDAR data resulted in higher tree heights, while measurements from photogrammetric data tended to be lower than field measurements. When absolute orientation was appropriate, measurements from UAV-Camera were as reliable as those from UAV-LiDAR. With low flight altitudes, small camera lens angles, and an accurate orientation, higher accuracies for the estimation of individual tree heights could be achieved. The study showed that remote sensing measurements of tree height can be more accurate than traditional triangulation techniques if the aforementioned conditions are fulfilled. Full article
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Open AccessArticle
Implications of Selective Harvesting of Natural Forests for Forest Product Recovery and Forest Carbon Emissions: Cases from Tarai Nepal and Queensland Australia
Forests 2019, 10(8), 693; https://doi.org/10.3390/f10080693 - 15 Aug 2019
Cited by 1 | Viewed by 381
Abstract
Selective logging is one of the main natural forest harvesting approaches worldwide and contributes nearly 15% of global timber needs. However, there are increasing concerns that ongoing selective logging practices have led to decreased forest product supply, increased forest degradation, and contributed to [...] Read more.
Selective logging is one of the main natural forest harvesting approaches worldwide and contributes nearly 15% of global timber needs. However, there are increasing concerns that ongoing selective logging practices have led to decreased forest product supply, increased forest degradation, and contributed to forest based carbon emissions. Taking cases of natural forest harvesting practices from the Tarai region of Nepal and Queensland Australia, this study assesses forest product recovery and associated carbon emissions along the timber production chain. Field measurements and product flow analysis of 127 commercially harvested trees up to the exit gate of sawmills and interaction with sawmill owners and forest managers reveal that: (1) Queensland selective logging has less volume recovery (52.8%) compared to Nepal (94.5%) leaving significant utilizable volume in the forest, (2) Stump volume represents 5.5% of total timber volume in Nepal and 3.9% in Queensland with an average stump height of 43.3 cm and 40.1 cm in Nepal and Queensland respectively, (3) Average sawn timber output from the harvested logs is 36.3% in Queensland against 61% in Nepal, (4) Nepal and Queensland leave 0.186 Mg C m−3 and 0.718 Mg C m−3 on the forest floor respectively, (5) Each harvested tree damages an average of five plant species in Nepal and four in Queensland predominantly seedlings in both sites, and (6) Overall logging related total emissions in Queensland are more than double (1.099 Mg C m−3) those in Nepal (0.488 Mg C m−3). We compared these results with past studies and speculated on possible reasons for and potential implications of these results for sustainable forest management and reducing emissions from deforestation and forest degradation. Full article
(This article belongs to the Special Issue Forest Carbon Inventories and Management)
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Open AccessReview
Changes in Major Insect Pests of Pine Forests in Korea Over the Last 50 Years
Forests 2019, 10(8), 692; https://doi.org/10.3390/f10080692 - 15 Aug 2019
Viewed by 362
Abstract
Understanding the occurrence patterns of forest pests is fundamental for effective forest management from both economic and ecological perspectives. Here, we review the history of the occurrence patterns and causes of outbreaks and declines of pests in Korean pine forests over the last [...] Read more.
Understanding the occurrence patterns of forest pests is fundamental for effective forest management from both economic and ecological perspectives. Here, we review the history of the occurrence patterns and causes of outbreaks and declines of pests in Korean pine forests over the last 50 years. During this period, the major pests of pine forests in Korea have shifted from pine caterpillar (Dendrolimus spectabilis Butler) to the pine needle gall midge (PNGM, Thecodiplosis japonensis (Uchida and Inouye)) and finally to pine wilt disease (PWD) caused by the pine wood nematode (Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle). Outbreaks of pine caterpillar, a native species in Korea, have been recorded as far back as 900 years, and it was the most relevant forest pest in Korea until the 1970s. The decline of its importance has been attributed to reforestation and higher levels of subsequent natural enemy activity. The PNGM is an invasive species, first discovered in Korea in 1929, that became widely distributed by 1992 and the major forest pest in the 1980s and 1990s. A suite of parasitic wasps attacking the PNGM contributed at least partially to the decline of PNGM densities. Following the decline of the PNGM, damage from PWD has increased since 2003. These shifts in major forest pests might be related to changes in forest composition and interactions among forest pests. Therefore, a new management strategy for controlling forest pests is required to mitigate the decline of pine forests in Korea. Full article
(This article belongs to the Special Issue Impacts, Monitoring and Management of Forest Pests and Diseases)
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Open AccessArticle
Farmers’ Willingness to Accept Compensation to Maintain the Benefits of Urban Forests
Forests 2019, 10(8), 691; https://doi.org/10.3390/f10080691 - 15 Aug 2019
Viewed by 355
Abstract
The Returning Farmland to Forest Program (RFFP) was implemented in China in 1999 with the goal of supporting environmental restoration by returning significant areas of cultivated land to forest. While afforestation supports long-term ecosystem services like carbon sequestration and the reduction of soil [...] Read more.
The Returning Farmland to Forest Program (RFFP) was implemented in China in 1999 with the goal of supporting environmental restoration by returning significant areas of cultivated land to forest. While afforestation supports long-term ecosystem services like carbon sequestration and the reduction of soil and water loss, it also reduces the amount of available arable land, putting financial pressure on those who depend on it for their livelihoods. In an effort to balance both ecological and economic benefits, regional governments offer financial compensation to farmers to offset these pressures in the form of a dollar amount per hectare of reforested land. The current study explores participants’ willingness to accept pay (WTA), along with the difference between the offered per hectare compensation and the amount deemed acceptable by RFFP participants in the region. To this end, 92 households from the representative afforestation area were surveyed in Huining County, Gansu Province, China - an area of strategic ecological importance in the Loess Plateau. The results showed 12.0% of the surveyed respondents to be satisfied with the current compensation policy, while 88.0% of respondents were not. The respondents’ lower and upper WTA limits were $221/ha/year and $1331/ha/year, respectively, with an average WTA of $777/ha/year. The compensation that respondents would be most willing to accept was distributed in the $444–888/ha/year and the $889–1331/ha/year ranges, accounting for 37.0% and 31.5% of the total responses, respectively. Gender, age, and education were found to be the main factors influencing a respondents’ WTA. Results of the survey suggest that the actual compensation amount ($355/ha/year) is much lower than respondents’ WTA, and that compensation measures and policies should be improved to guarantee a basic income. Full article
(This article belongs to the Special Issue Benefits of the Urban Forest under Global Change)
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Open AccessArticle
A Geospatial Decision Support System Tool for Supporting Integrated Forest Knowledge at the Landscape Scale
Forests 2019, 10(8), 690; https://doi.org/10.3390/f10080690 - 14 Aug 2019
Viewed by 601
Abstract
Forests are part of a complex landscape mosaic and play a crucial role for people living both in rural and urbanized spaces. Recent progresses in modelling and Decision Support System (DSS) applied to the forestry sector promise to improve public participative forest management [...] Read more.
Forests are part of a complex landscape mosaic and play a crucial role for people living both in rural and urbanized spaces. Recent progresses in modelling and Decision Support System (DSS) applied to the forestry sector promise to improve public participative forest management and decision-making in planning and conservation issues. However, most DSS are not open-source systems, being in many cases software designed for site-specific applications in forest ecosystems. Furthermore, some of these systems often miss challenging the integration of other land uses within the landscape matrix, which is a key issue in modern forestry planning aiming at linking recent developments in open-source Spatial-DSS systems to sectorial forest knowledge. This paper aims at demonstrating that a new type of S-DSS, developed within the Life+ project SOILCONSWEB over an open-source Geospatial Cyber-Infrastructure (GCI) platform, can provide a strategic web-based operational tool for forest resources management and multi-purpose planning. In order to perform simulation modelling, all accessible via the Web, the GCI platform supports acquisition and processing of both static and dynamic data (e.g., spatial distribution of soil and forest types, growing stock and yield), data visualization and computer on-the-fly applications. The DSS forestry tool has been applied to a forest area of 5,574 ha in the southern Apennines of Peninsular Italy, and it has been designed to address forest knowledge and management providing operational support to private forest owners and decision-makers involved in management of forest landscape at different levels. Such a geospatial S-DSS tool for supporting integrated forest knowledge at landscape represents a promising tool to implement sustainable forest management and planning. Results and output of the platform will be shown through a short selection of practical case studies. Full article
(This article belongs to the Section Forest Economics and Human Dimensions)
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Open AccessArticle
Economic and Environmental Optimization of the Forest Supply Chain for Timber and Bioenergy Production from Beetle-Killed Forests in Northern Colorado
Forests 2019, 10(8), 689; https://doi.org/10.3390/f10080689 - 14 Aug 2019
Viewed by 422
Abstract
Harvesting mountain pine beetle-infested forest stands in the northern Colorado Rocky Mountains provides an opportunity to utilize otherwise wasted resources, generate net revenues, and minimize greenhouse gas (GHG) emissions. Timber and bioenergy production are commonly managed separately, and their integration is seldom considered. [...] Read more.
Harvesting mountain pine beetle-infested forest stands in the northern Colorado Rocky Mountains provides an opportunity to utilize otherwise wasted resources, generate net revenues, and minimize greenhouse gas (GHG) emissions. Timber and bioenergy production are commonly managed separately, and their integration is seldom considered. Yet, degraded wood and logging residues can provide a feedstock for bioenergy, while the sound wood from beetle-killed stands can still be used for traditional timber products. In addition, beneficial greenhouse gas emission (GHG) savings are often realized only by compromising net revenues during salvage harvest where beetle-killed wood has a relatively low market value and high harvesting cost. In this study we compared Sequential and Integrated decision-making scenarios for managing the supply chain from beetle-killed forest salvage operations. In the Sequential scenario, timber and bioenergy production was managed sequentially in two separate processes, where salvage harvest was conducted without considering influences on or from bioenergy production. Biomass availability was assessed next as an outcome from timber production managed to produce bioenergy products. In the Integrated scenario, timber and bioenergy production were managed jointly, where collective decisions were made regarding tree salvage harvest, residue treatment, and bioenergy product selection and production. We applied a multi-objective optimization approach to integrate the economic and environmental objectives of producing timber and bioenergy, and measured results by total net revenues and total net GHG emission savings, respectively. The optimization model results show that distinctively different decisions are made in selecting the harvesting system and residue treatment under the two scenarios. When the optimization is fully economic-oriented, 49.6% more forest areas are harvested under the Integrated scenario than the Sequential scenario, generating 12.3% more net revenues and 50.5% more net GHG emission savings. Comparison of modelled Pareto fronts also indicate the Integrated decision scenario provides more efficient trade-offs between the two objectives and performs better than the Sequential scenario in both objectives. Full article
(This article belongs to the Special Issue Supply Chain Optimization for Biomass and Biofuels)
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Open AccessArticle
Expression Analysis of the NAC Transcription Factor Family of Populus in Response to Salt Stress
Forests 2019, 10(8), 688; https://doi.org/10.3390/f10080688 - 14 Aug 2019
Viewed by 379
Abstract
Research Highlights: Sequence phylogeny, genome organisation, gene structure, conserved motifs, promoter cis-element and expression profiling of poplar NACs related to salt stress were detected. In addition, expression of two salt-induced NACs was analysed. Background and Objectives: NAC transcription factor (TF) proteins are involved [...] Read more.
Research Highlights: Sequence phylogeny, genome organisation, gene structure, conserved motifs, promoter cis-element and expression profiling of poplar NACs related to salt stress were detected. In addition, expression of two salt-induced NACs was analysed. Background and Objectives: NAC transcription factor (TF) proteins are involved in a wide range of functions during plant development and stress-related endurance processes. To understand the function of Populus NAC TFs in salt stress tolerance, we characterised the structure and expression profile of a total of 289 NAC members. Materials and Methods: Sequence phylogeny, genome organisation, gene structure, motif composition and promoter cis-element were detected using bioinformatics. The expression pattern of Populus NAC TFs under salt stress was also detected using RNA-Seq and RT-qPCR. Results: Synteny analysis showed that 46 and 37 Populus NAC genes were involved in whole-genome duplication and tandem duplication events, respectively. The expression pattern of Populus NAC TFs under salt stress showed the expression of the 289 PtNACs of 84K poplar was induced. Similar expression trends of NACs were found in Populus simonii × P. nigra T. S. Hwang et Liang and Arabidopsis thaliana (L.) Heynh. Conclusions: The correlation analysis showed that the expression of two differentially expressed NAC genes PtNAC024 and PtNAC182 was significantly associated with most of the 63 differentially expressed genes tested. The expression of PtNAC024 and PtNAC182 in different tissues was also analysed in silico and different expression patterns were found. Together, this study provides a solid basis to explore stress-related NAC TF functions in Populus salt tolerance and development. Full article
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Open AccessArticle
Automated Cable Road Layout and Harvesting Planning for Multiple Objectives in Steep Terrain
Forests 2019, 10(8), 687; https://doi.org/10.3390/f10080687 - 14 Aug 2019
Viewed by 396
Abstract
Cable yarding is the most commonly used technique for harvesting timber from steep terrain in central Europe. During the planning process, one important task is to define the cable road layout. This means that the harvesting technology and cable road location must be [...] Read more.
Cable yarding is the most commonly used technique for harvesting timber from steep terrain in central Europe. During the planning process, one important task is to define the cable road layout. This means that the harvesting technology and cable road location must be specified for a given timber parcel. Although managers must minimize harvesting costs, it is even more important that such work on forests reduces the potential for damage to the residual stand and ensures that environmental conditions remain suitable for regeneration. However, current methods are geared only toward minimizing harvesting costs and are computationally demanding and difficult to handle for the end user. These limitations hinder broad application of such methods. Further, the underlying productivity models used for cost estimation do not cover all conditions of an area and they cannot be applied over a whole harvesting area. To overcome these shortcomings, we present: (1) a multiobjective optimization approach that leads to realistic, practicable results that consider multiple conflicting design objectives, and (2) a concept for an easy-to-use application. We compare the practical applicability and performance of the results achieved with multiobjective optimization with those achieved with single-objective (cost-minimal) optimization. Based on these points, we then present and discuss a concept for a user-friendly implementation. The model was tested on two sites in Switzerland. The study produced the following major findings: (1) Single-objective alternatives have no practical relevance, whereas multiobjective alternatives are preferable in real-world applications and lead to realistic solutions; (2) the solution process for a planning unit should include analysis of the Pareto frontier; and (3) results can only be made available within a useful period of time by parallelizing computing operations. Full article
(This article belongs to the Special Issue Forest Operations in Environmentally Sensitive Areas)
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Open AccessArticle
Estimating Crown Structure Parameters of Moso Bamboo: Leaf Area and Leaf Angle Distribution
Forests 2019, 10(8), 686; https://doi.org/10.3390/f10080686 - 14 Aug 2019
Viewed by 335
Abstract
Both leaf area (LA) and leaf angle distribution are the most important eco-physiological measures of tree crowns. However, there are limited published investigations on the two parameters of Moso bamboo (Phyllostachys edulis (Carrière) J. Houz., abbreviated as MB). The aim [...] Read more.
Both leaf area (LA) and leaf angle distribution are the most important eco-physiological measures of tree crowns. However, there are limited published investigations on the two parameters of Moso bamboo (Phyllostachys edulis (Carrière) J. Houz., abbreviated as MB). The aim of this study was to develop allometric equations for predicting crown LA of MB by taking the diameter at breast height (DBH) and tree height (H) as predictors and to investigate the leaf angle distribution of a MB crown based on direct leaf angle measurements. Data were destructively sampled from 29 MB crowns including DBH, H, biomass and the area of sampled leaves, biomass of total crown leaves, and leaf angles. The results indicate that (1) the specific leaf area (SLA) of a MB crown decreases from the bottom to the top; (2) the vertical LA distribution of MB crowns follow a “Muffin top” shape; (3) the LA of MB crowns show large variations, from 7.42 to 74.38 m2; (4) both DBH and H are good predictors in allometry-based LA estimations for a MB crown; (5) linear, exponential, and logarithmic regressions show similar capabilities for the LA estimations; (6) leaf angle distributions from the top to the bottom of a MB crown can be considered as invariant; and (7) the leaf angle distribution of a MB crown is close to the planophile case. The results provide an important tool to estimate the LA of MB on the standing scale based on DBH or H measurements, provide useful prior knowledge for extracting leaf area indexes of MB canopies from remote sensing-based observations, and, therefore, will potentially serve as a crucial reference for calculating carbon balances and other ecological studies of MB forests. Full article
(This article belongs to the Special Issue Modeling of Forest Structure and Dynamics)
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Open AccessArticle
Decentralization Drivers beyond Legal Provisions: The Case of Collaborative Forest Management in Java Island
Forests 2019, 10(8), 685; https://doi.org/10.3390/f10080685 - 14 Aug 2019
Viewed by 437
Abstract
This study analyzes the impact of the Indonesian government’s decentralization policy and movement on the state forest community involvement program on the island of Java from 2000 to 2014. For more than 30 years, approximately 76 percent of the state-owned forests in Java, [...] Read more.
This study analyzes the impact of the Indonesian government’s decentralization policy and movement on the state forest community involvement program on the island of Java from 2000 to 2014. For more than 30 years, approximately 76 percent of the state-owned forests in Java, covering 2.4 mio. hectares (5.9 mio. acres or 9,266 square miles), or 42 percent of the forests in Java, were exclusively managed by the State Forest Company (SFC). The general perception was, and largely still is, that the decentralization era reforms had little or no effects in Java, simply because the national decentralization regulations essentially maintained this dominant role. Thus, possible effects were hardly examined. This study aims to fill this gap by analyzing whether the national decentralization movement and policy affected and changed the policies and practices of involving local actors and communities in Java’s state forest governance and management. Our analytical framework follows the Policy Arrangement Approach (PAA), comprising four main analytical dimensions for assessing change and stability: The actors involved; the distribution of power and resources; the existing and applied rules; and discourses concerning the topic of research. The analysis is based on an extensive review of scholarly literature and policy documents, as well as 73 in-depth interviews with actors, from the national to the local levels, of two districts in Central Java. Overall, our findings show that the nationwide decentralization movement significantly affects the modes of collaborative forest management in Java, much more than one would expect if only looking at changes in the respective legal texts. The movement fueled changes, inter alia, by promoting discourses on sustainable forest management for local development, and triggering the revival of grassroots movements further empowered by local non-governmental organizations (NGOs), as well as by triggering the formal institutionalization of the informal norms and practices of local communities. New actors entered the arena, and the distribution of power, resources and benefits drawn from state forest management has changed in favor of district authorities and local communities at the expense of the State Forest Company. Full article
(This article belongs to the Section Forest Economics and Human Dimensions)
Open AccessArticle
Assessing and Mapping Forest Landscape Quality in China
Forests 2019, 10(8), 684; https://doi.org/10.3390/f10080684 - 14 Aug 2019
Viewed by 340
Abstract
Forest landscape plays a critical role in the resource management and recreational planning of forest destinations. An assessment of forest landscape quality (FLQ) could reflect the distribution of landscape resources, hence identifying the hotpots and areas with high visual quality and protection values. [...] Read more.
Forest landscape plays a critical role in the resource management and recreational planning of forest destinations. An assessment of forest landscape quality (FLQ) could reflect the distribution of landscape resources, hence identifying the hotpots and areas with high visual quality and protection values. The objective of this study is to propose, for the first time, a methodology for assessing FLQ at the national level. Based on China’s forestry inventory database, the paper identified landform patterns and vegetative patterns as determinants (including 12 indicators) to establish an evaluation index system, and further implemented and mapped FLQ using the ArcGIS Engine platform. Results show high mountain ranges and tropical areas in China often have a high-quality forest landscape, while low FLQ scores are found in low mountains and foothills. The distribution of the four FLQ levels indicates most forest areas are featured with mediocre- or low- quality landscape values, and the differences of FLQ among different forest types are obvious. Furthermore, there is a relatively low correlation between the total forest area and the area of high-quality forest landscape. Overall, this study could contribute to enriching the existing assessment system for FLQ and to guiding the planning, policy development, and decision-making for China’s forestry administration. Full article
(This article belongs to the Section Forest Inventory, Quantitative Methods and Remote Sensing)
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Open AccessArticle
Bird Communities in Urban Riparian Areas: Response to the Local- and Landscape-Scale Environmental Variables
Forests 2019, 10(8), 683; https://doi.org/10.3390/f10080683 - 13 Aug 2019
Viewed by 403
Abstract
Understanding how environmental changes driven by urbanization impact the biodiversity in urban riparian areas has great importance for landscape planning and river ecosystem conservation. There have been many studies on the response of bird communities to different environmental variables in urban parks; however, [...] Read more.
Understanding how environmental changes driven by urbanization impact the biodiversity in urban riparian areas has great importance for landscape planning and river ecosystem conservation. There have been many studies on the response of bird communities to different environmental variables in urban parks; however, although supporting some of the highest bird diversities, case studies in urban riparian areas remain limited. In existing research, few studies have considered the impact of both local waterfront characteristics and surrounding environmental variables at a larger scale. In this study, we selected birds as the indicator to clarify their response to both local- and landscape-scale environmental variables in riparian areas of Tsing river, Beijing, in terms of (a) vegetation composition, (b) human disturbance, (c) land cover, and (d) landscape connectivity. We hypothesized that birds with different biological characteristics may respond differently to environmental variables. Birds were then further grouped according to the habitat type, residential type, and feeding type. It turned out that the coverage of grass and the disturbance of pedestrians are the most influential variables. Besides, compared with the land cover and landscape connectivity, the total contribution of vegetation characteristics and human disturbance accounts for the main proportion of explained variance. Information pertaining to these environmental variables can provide evidence to support bird conservation efforts in urban areas, and the identified distance threshold provides a basis for future landscape connectivity assessments. Full article
(This article belongs to the Special Issue Biodiversity and Management of Temperate Floodplain Forests)
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Open AccessArticle
Use of Time-of-Flight Ultrasound to Measure Wave Speed in Poplar Seedlings
Forests 2019, 10(8), 682; https://doi.org/10.3390/f10080682 - 13 Aug 2019
Viewed by 372
Abstract
In this study, 145 poplar (Populus × euramericana cv.’74/76’) seedlings, a common plantation tree species in China, were selected and their ultrasonic velocities were measured at four timepoints during the first growth year. After that, 60 poplar seedlings were randomly selected [...] Read more.
In this study, 145 poplar (Populus × euramericana cv.’74/76’) seedlings, a common plantation tree species in China, were selected and their ultrasonic velocities were measured at four timepoints during the first growth year. After that, 60 poplar seedlings were randomly selected and cut down to determine their acoustic velocity, using the acoustic resonance method. The effects of influencing factors such as wood green density, microfibril angle, growth days, and root-collar diameter on acoustic speed in seedlings and the relationship between ultrasonic speed and acoustic resonance speed were investigated and analyzed in this work. The number of specimens used for investigating growth days and root-collar diameter was 145 in both cases, while 60 and two specimens were used for investigating wood density and the microfibril angle, respectively. The results of this study showed that the ultrasonic speed of poplar seedlings significantly and linearly increased with growth days, within 209 growing days. The ultrasonic velocity of poplar seedlings has a high and positive correlation with growth days, and the correlation was 0.99. However, no significant relationship was found between the ultrasonic velocity and root-collar diameter of poplar seedlings. Furthermore, a low and negative relationship was found between wood density and ultrasonic speed (R2 = 0.26). However, ultrasonic velocity significantly decreased with increasing microfibril angle (MFA) in two seedlings, and thus MFA may have an impact on ultrasonic speed in poplar seedlings. In addition, ultrasonic velocity was found to have a strong correlation with acoustic resonance velocity (R2 = 0.81) and a good correlation, R2 = 0.75, was also found between the dynamic moduli of elasticity from ultrasonic and acoustic resonance tests. The results of this study indicate that the ultrasonic technique can possibly be used to measure the ultrasound speed of young seedlings, and thus early screen seedlings for their stiffness properties in the future. Full article
(This article belongs to the Special Issue Wood Properties and Processing)
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Open AccessArticle
Chinese Fir Breeding in the High-Throughput Sequencing Era: Insights from SNPs
Forests 2019, 10(8), 681; https://doi.org/10.3390/f10080681 - 12 Aug 2019
Viewed by 403
Abstract
Knowledge on population diversity and structure is of fundamental importance for conifer breeding programs. In this study, we concentrated on the development and application of high-density single nucleotide polymorphism (SNP) markers through a high-throughput sequencing technique termed as specific-locus amplified fragment sequencing (SLAF-seq) [...] Read more.
Knowledge on population diversity and structure is of fundamental importance for conifer breeding programs. In this study, we concentrated on the development and application of high-density single nucleotide polymorphism (SNP) markers through a high-throughput sequencing technique termed as specific-locus amplified fragment sequencing (SLAF-seq) for the economically important conifer tree species, Chinese fir (Cunninghamia lanceolata). Based on the SLAF-seq, we successfully established a high-density SNP panel consisting of 108,753 genomic SNPs from Chinese fir. This SNP panel facilitated us in gaining insight into the genetic base of the Chinese fir advance breeding population with 221 genotypes for its genetic variation, relationship and diversity, and population structure status. Overall, the present population appears to have considerable genetic variability. Most (94.15%) of the variability was attributed to the genetic differentiation of genotypes, very limited (5.85%) variation occurred on the population (sub-origin set) level. Correspondingly, low FST (0.0285–0.0990) values were seen for the sub-origin sets. When viewing the genetic structure of the population regardless of its sub-origin set feature, the present SNP data opened a new population picture where the advanced Chinese fir breeding population could be divided into four genetic sets, as evidenced by phylogenetic tree and population structure analysis results, albeit some difference in membership of the corresponding set (cluster vs. group). It also suggested that all the genetic sets were admixed clades revealing a complex relationship of the genotypes of this population. With a step wise pruning procedure, we captured a core collection (core 0.650) harboring 143 genotypes that maintains all the allele, diversity, and specific genetic structure of the whole population. This generalist core is valuable for the Chinese fir advanced breeding program and further genetic/genomic studies. Full article
(This article belongs to the Special Issue Forest Genetic and Tree Improvement)
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Open AccessArticle
An End to End Process Development for UAV-SfM Based Forest Monitoring: Individual Tree Detection, Species Classification and Carbon Dynamics Simulation
Forests 2019, 10(8), 680; https://doi.org/10.3390/f10080680 - 11 Aug 2019
Viewed by 774
Abstract
To promote Bio-Energy with Carbon dioxide Capture and Storage (BECCS), which aims to replace fossil fuels with bio energy and store carbon underground, and Reducing Emissions from Deforestation and forest Degradation (REDD+), which aims to reduce the carbon emissions produced by forest degradation, [...] Read more.
To promote Bio-Energy with Carbon dioxide Capture and Storage (BECCS), which aims to replace fossil fuels with bio energy and store carbon underground, and Reducing Emissions from Deforestation and forest Degradation (REDD+), which aims to reduce the carbon emissions produced by forest degradation, it is important to build forest management plans based on the scientific prediction of forest dynamics. For Measurement, Reporting and Verification (MRV) at an individual tree level, it is expected that techniques will be developed to support forest management via the effective monitoring of changes to individual trees. In this study, an end-to-end process was developed: (1) detecting individual trees from Unmanned Aerial Vehicle (UAV) derived digital images; (2) estimating the stand structure from crown images; (3) visualizing future carbon dynamics using a forest ecosystem process model. This process could detect 93.4% of individual trees, successfully classified two species using Convolutional Neural Network (CNN) with 83.6% accuracy and evaluated future ecosystem carbon dynamics and the source-sink balance using individual based model FORMIND. Further ideas for improving the sub-process of the end to end process were discussed. This process is expected to contribute to activities concerned with carbon management such as designing smart utilization for biomass resources and projecting scenarios for the sustainable use of ecosystem services. Full article
(This article belongs to the Section Forest Inventory, Quantitative Methods and Remote Sensing)
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Open AccessArticle
Potential Effects of Climate Change on Fire Behavior, Economic Susceptibility and Suppression Costs in Mediterranean Ecosystems: Córdoba Province, Spain
Forests 2019, 10(8), 679; https://doi.org/10.3390/f10080679 - 11 Aug 2019
Viewed by 741
Abstract
The potentially large ecological, economic, and societal impacts of climate change makes it a significant problem of the 21st century. These consequences have led to tremendous development in climate change scenarios and new technologies to increase knowledge on the effect and efficiency of [...] Read more.
The potentially large ecological, economic, and societal impacts of climate change makes it a significant problem of the 21st century. These consequences have led to tremendous development in climate change scenarios and new technologies to increase knowledge on the effect and efficiency of mitigation and adaptation measures. Large fires will occur at a higher rate than currently because of lower fuel moisture content resulting in a lower resistance to burning. This is also evidenced by more extreme fire behavior that contributes to higher economic impacts, suppression difficulties and suppression costs. The economic susceptibility concept integrates a set of economic valuation approaches for valuing timber and non-timber resources, considering the fire behavior, and as a consequence, the net value changes for each resource. Flame length increased by 4.6% to 15.69%, according to the different future climate scenarios. Climate change is expected to cause widespread changes to economic susceptibility and suppression costs because of higher flame length and fire intensity. Therefore, our outcomes show an increase in the economic susceptibility of Córdoba Province in the medium and long term (2041–2070) between 6.05% and 25.99%, respectively. In addition, we have found an increase between 65.67% and 86.73% in suppression costs in the last decade. The digital version of the economic susceptibility model using Geographic Information Systems improves its operational capabilities enhancing also its dynamism and simplicity to accept modifications and predictions revisions. Full article
(This article belongs to the Special Issue Forest Fires under Climate, Social and Economic Changes)
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