Forests

23 pages, 341 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Forests in 2019

by Forests Editorial Office

Forests 2020, 11(1), 122; https://doi.org/10.3390/f11010122 - 20 Jan 2020

Viewed by 4005

The editorial team greatly appreciates the reviewers who have dedicated their considerable time and expertise to the journal’s rigorous editorial process over the past 12 months, regardless of whether the papers are finally published or not [...] Full article

15 pages, 3418 KiB

Open AccessArticle

Image Data Acquisition for Estimating Individual Trees Metrics: Closer Is Better

by Hospice A. Akpo, Gilbert Atindogbé, Maxwell C. Obiakara, Arios B. Adjinanoukon, Madaï Gbedolo, Philippe Lejeune and Noël H. Fonton

Forests 2020, 11(1), 121; https://doi.org/10.3390/f11010121 - 19 Jan 2020

Cited by 8 | Viewed by 3620

Abstract

Background and Objectives: The recent use of Structure-from-Motion with Multi-View Stereo photogrammetry (SfM-MVS) in forestry has underscored its robustness in tree mensuration. This study evaluated the differences in tree metrics resulting from various related SfM-MVS photogrammetric image acquisition scenarios. Materials and Methods: Scaled [...] Read more.

Background and Objectives: The recent use of Structure-from-Motion with Multi-View Stereo photogrammetry (SfM-MVS) in forestry has underscored its robustness in tree mensuration. This study evaluated the differences in tree metrics resulting from various related SfM-MVS photogrammetric image acquisition scenarios. Materials and Methods: Scaled tri-dimensional models of 30 savanna trees belonging to five species were built from photographs acquired in a factorial design with shooting distance (d = 1, 2, 3, 4 and 5 m away from tree) and angular shift (α = 15°, 30°, 45° and 60°; nested in d). Tree stem circumference at 1.3 m and bole volume were estimated using models resulting from each of the 20 scenarios/tree. Mean absolute percent error (MAPE) was computed for both metrics in order to compare the performance of each scenario in relation to reference data collected using a measuring tape. Results: An assessment of the effect of species identity (s), shooting distance and angular shift showed that photographic point cloud density was dependent on α and s, and optimal for 15° and 30°. MAPEs calculated on stem circumferences and volumes significantly differed with d and α, respectively. There was a significant interaction between α and s for both circumference and volume MAPEs, which varied widely (1.6 ± 0.4%–20.8 ± 23.7% and 2.0 ± 0.6%–36.5 ± 48.7% respectively), and were consistently lower for smaller values of d and α. Conclusion: The accuracy of photogrammetric estimation of individual tree attributes depended on image-capture approach. Acquiring images 2 m away and with 30° intervals around trees produced reliable estimates of stem circumference and bole volume. Research Highlights: This study indicates that the accuracy of photogrammetric estimations of individual tree attributes is species-dependent. Camera positions in relation to the subject substantially influence the level of uncertainty in measurements. Full article

(This article belongs to the Special Issue Forest Resources Assessments: Mensuration, Inventory and Planning)

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15 pages, 2325 KiB

Open AccessEditor’s ChoiceArticle

Strategies for Modeling Regeneration Density in Relation to Distance from Adult Trees

by Daniel Moreno-Fernández, Alicia Ledo, Isabel Cañellas and Fernando Montes

Forests 2020, 11(1), 120; https://doi.org/10.3390/f11010120 - 19 Jan 2020

Cited by 7 | Viewed by 3830

Abstract

Research Highlights: We proposed new methodologies for the spatial analysis of regeneration processes and compared with existing approaches. Background and Objectives: Identifying the spatial relationship between adult trees and new cohorts is fundamental to understanding the dynamics of regeneration and therefore helps us [...] Read more.

Research Highlights: We proposed new methodologies for the spatial analysis of regeneration processes and compared with existing approaches. Background and Objectives: Identifying the spatial relationship between adult trees and new cohorts is fundamental to understanding the dynamics of regeneration and therefore helps us to optimize the stand density and natural regeneration when undertaking regeneration fellings. Most of the statistical approaches analyzing the spatial dependence between adult trees and new individuals (seedlings or saplings) require a complete census and mapping of all individuals. However, approaches considering individuals grouped into sampling points or subplots (i.e., density data) are limited. In this study, we reviewed and compared approaches (intertype point pattern analyses and a generalized additive model) to describe the spatial relationship between adult trees and density regeneration in a Pinus sylvestris L. monospecific stand in Spain. We also proposed a new approach (intertype mark variance function) to disentangle the effect of the tree-size on sapling density and the effect of the spatial pattern. Materials and Methods: To this end, we used a half-hectare plot in which all the individuals of P. sylvestris have been mapped and measured. Results: Our results indicated that sapling distribution was related to distance from the adult trees, thus displaying distance-dependence patterns, but it was not related to the size of the adult trees. The intertype mark correlation function was an useful tool to distinguish the effect of the marks (sapling density and tree size) from the effect of the spatial pattern of the classes (trees cohorts in our case). Conclusions: The largest number of saplings was found with increased distance between adult trees (>11 m), and the generalized additive model may be useful to explain spatial relationships between adult trees and regenerating cohorts when other measured biotic variables (e.g., soil stoniness, etc.) and repeated measurements are available. Full article

(This article belongs to the Special Issue Silviculture for Restoration and Regeneration)

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19 pages, 3776 KiB

Open AccessArticle

Biophysical Gradients and Performance of Whitebark Pine Plantings in the Greater Yellowstone Ecosystem

by David Laufenberg, David Thoma, Andrew Hansen and Jia Hu

Forests 2020, 11(1), 119; https://doi.org/10.3390/f11010119 - 19 Jan 2020

Cited by 4 | Viewed by 3975

Abstract

Research Highlights: The efficacy of planting for restoration is important for ecosystem managers. Planting efforts represent an opportunity for conserving and managing species during a population crisis. Background and Objectives: Federal agencies have been planting whitebark pine (WBP), an important subalpine species that [...] Read more.

Research Highlights: The efficacy of planting for restoration is important for ecosystem managers. Planting efforts represent an opportunity for conserving and managing species during a population crisis. Background and Objectives: Federal agencies have been planting whitebark pine (WBP), an important subalpine species that is late to mature and long-lived, for three decades in the Greater Yellowstone Ecosystem (GYE). These efforts have been met with varying success, and they have not been evaluated beyond the first five years post-planting. Ecosystem managers will continue to plant WBP in the GYE for years to come, and this research helps to inform and identify higher quality habitat during a period of changing climate and high GYE WBP mortality rates. Materials and Methods: We use a combination of field sampling and a water balance model to investigate local biophysical gradients as explanatory variables for WBP performance at twenty-nine GYE planting sites. Results: We found that the WBP growth rate was positively correlated with actual evapotranspiration (AET) and was greatest when cumulative growing season AET was above 350 mm. Growth rate was not strongly affected by competition at the levels found in this study. However, site density change over time was negatively affected by mean growing season temperature and when more than five competitors were present within 3.59 m radius. Conclusions: If they make it to maturity, trees that are planted this season will not begin to produce cones until the latter half of this century. We recommend planting efforts that optimize AET for growth rate objectives, minimize water deficit (WD) that cause stress and mortality, and removing competitors if they exceed five within a short distance of seedlings. Full article

(This article belongs to the Special Issue Ecology and Restoration of Whitebark Pine)

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20 pages, 9929 KiB

Open AccessArticle

A Novel GIS-Based Random Forest Machine Algorithm for the Spatial Prediction of Shallow Landslide Susceptibility

by Viet-Hung Dang, Nhat-Duc Hoang, Le-Mai-Duyen Nguyen, Dieu Tien Bui and Pijush Samui

Forests 2020, 11(1), 118; https://doi.org/10.3390/f11010118 - 19 Jan 2020

Cited by 74 | Viewed by 7971

Abstract

This study developed and verified a new hybrid machine learning model, named random forest machine (RFM), for the spatial prediction of shallow landslides. RFM is a hybridization of two state-of-the-art machine learning algorithms, random forest classifier (RFC) and support vector machine (SVM), in [...] Read more.

This study developed and verified a new hybrid machine learning model, named random forest machine (RFM), for the spatial prediction of shallow landslides. RFM is a hybridization of two state-of-the-art machine learning algorithms, random forest classifier (RFC) and support vector machine (SVM), in which RFC is used to generate subsets from training data and SVM is used to build decision functions for these subsets. To construct and verify the hybrid RFM model, a shallow landslide database of the Lang Son area (northern Vietnam) was prepared. The database consisted of 101 shallow landslide polygons and 14 conditioning factors. The relevance of these factors for shallow landslide susceptibility modeling was assessed using the ReliefF method. Experimental results pointed out that the proposed RFM can help to achieve the desired prediction with an F1 score of roughly 0.96. The performance of the RFM was better than those of benchmark approaches, including the SVM, RFC, and logistic regression. Thus, the newly developed RFM is a promising tool to help local authorities in shallow landslide hazard mitigations. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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13 pages, 3585 KiB

Open AccessArticle

Circumferential and Longitudinal δ¹³C Variability in a Larix decidua Trunk from the Swiss Alps

by Jan Esper, Dana F.C. Riechelmann and Steffen Holzkämper

Forests 2020, 11(1), 117; https://doi.org/10.3390/f11010117 - 17 Jan 2020

Cited by 8 | Viewed by 3354

Abstract

Tree-ring stable isotopes are insightful proxies providing information on pre-instrumental climate fluctuations, yet the variability of these data within a tree trunk has not been fully explored. Here, we analyze longitudinal and circumferential changes in tree-ring δ¹³C values from 1991–2010, considering [...] Read more.

Tree-ring stable isotopes are insightful proxies providing information on pre-instrumental climate fluctuations, yet the variability of these data within a tree trunk has not been fully explored. Here, we analyze longitudinal and circumferential changes in tree-ring δ¹³C values from 1991–2010, considering seven height levels from 1 to 13 m above ground and six sampling directions (radii) separated by 60° around the stem. The disk samples were taken from a 360-year old European larch (Larix decidua Mill.) that grew at 1675 m above sea level in the Simplon Valley, Switzerland. Results show that the circumferential δ¹³C variability, defined as the difference between the minimum and maximum isotope values within a single ring at a certain height, ranges from 0.5 to 2.8‰. These differences appear substantial as they match the range of year-to-year variations retained in long tree-ring δ¹³C time series used for climate reconstruction. The assessment of longitudinal variability demonstrated a systematic change of ~0.1‰ m⁻¹ towards isotopically heavier (less negative) δ¹³C values with increasing tree height, likely reflecting a vertical gradient towards isotopically heavier needle tissue due to changing microclimatic conditions and CO₂ stratification within the canopy. Calibration against regional climate data indicates no substantial signal changes in δ¹³C values within the trunk. We conclude that the longitudinal isotope gradient adds uncertainty to long δ¹³C chronologies derived from subfossil material of unknown (and changing) sampling heights. The large circumferential variability recorded in the sub-alpine larch suggests that more than two cores are needed to analyze absolute δ¹³C values representative for each tree. Full article

(This article belongs to the Section Forest Ecology and Management)

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13 pages, 5651 KiB

Open AccessArticle

Influence of Leaf Physical Properties on Single-Leaf Vibrational Response to Sound

by Mengmeng Li and Jian Kang

Forests 2020, 11(1), 115; https://doi.org/10.3390/f11010115 - 17 Jan 2020

Cited by 10 | Viewed by 5171

Abstract

Plant leaves respond to environmental sounds by vibration. This study aimed to examine such responses by evaluating the influences of physical properties on vibrational amplitude, velocity and frequency before and during sound stimulation. Nine plant species with a wide range of leaf sizes, [...] Read more.

Plant leaves respond to environmental sounds by vibration. This study aimed to examine such responses by evaluating the influences of physical properties on vibrational amplitude, velocity and frequency before and during sound stimulation. Nine plant species with a wide range of leaf sizes, qualities and thicknesses and petiole lengths, widths and thicknesses were selected. In the absence of external sound, the leaf amplitude was ~1 μm, the vibrational velocity was ~0.05 mm s^-1 and the vibrational frequency was ~0–15 Hz. After sound stimulation, however, the amplitude increased by 1–5.4×, the velocity was 1.75–14.1× higher and produced another spectral peak at ~80–95 Hz. Nevertheless, the amplitude and velocity varied by up to 1–10× among species mainly because of differences in leaf texture. However, these factors did not markedly change in succulent leaves because their thick epidermal cuticles and high water content buffered vibrations. In contrast, leathery leaves and papery and membranous leaves were highly responsive to sound stimuli. Leaf size, mass and thickness and petiole length, width and thickness also influenced leaf vibration. There is a positive correlation between noise reduction and leaf velocity. Noise reduction effect increases with the increase in leaf velocity until about 0.6 mm s⁻¹ and then decreases. The relationship between leaf physical properties and leaf vibration may be used to study sound response and noise reduction in different plant species. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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18 pages, 790 KiB

Open AccessArticle

Determinants of Non-Timber Forest Product Planting, Development, and Trading: Case Study in Central Vietnam

by Thanh Van Nguyen, Jie Hua Lv, Thi Thanh Huyen Vu and Bin Zhang

Forests 2020, 11(1), 116; https://doi.org/10.3390/f11010116 - 16 Jan 2020

Cited by 28 | Viewed by 6192

Abstract

Non-timber forest products (NTFPs) play an active role in economic development, improving household livelihoods, raising the value of forestry production, and supporting sustainable forest management. This study involved a comprehensive assessment of the growth, development, and trade of NTFPs in Vietnam by combining [...] Read more.

Non-timber forest products (NTFPs) play an active role in economic development, improving household livelihoods, raising the value of forestry production, and supporting sustainable forest management. This study involved a comprehensive assessment of the growth, development, and trade of NTFPs in Vietnam by combining logistic and tobit methods. Surveys were used to interview 400 households in three regions of Central Vietnam. Results showed that the planting, development, and trading of NTFPs are shaped by forestry production experience, the number of laborers, the percentage of wage earners, agricultural income, timber income, per capita income, the presence of bank deposits, the distance between forest and house, an understanding of forestry economic policies, and participation in technical training. Each factor had a different level of influence. Among the six NTFP groups, the groups generating yarn and medicines produced the highest income and had a strong impact on household reliance on NTFPs. This was followed by NTFPs used to generate food, oil, and plastic. The proportion of people with wages, and the income variable system, negatively impacted NTFP planting and income generation, which reduced household reliance on NTFPs. This means that there is a trade-off between NTFPs and other income generating activities. In the future, the government should develop specific plans, policies, and strategies for developing each type of NTFP suitable to each region’s natural conditions. The policies should include supporting people with low-interest bank loans; expanding the number of training courses to increase their understanding of forestry economic policies; and implementing cultivation techniques and forest care to improve the productivity, quality, and efficiency of NTFP products. Full article

(This article belongs to the Section Forest Ecology and Management)

17 pages, 1942 KiB

Open AccessEditor’s ChoiceArticle

Interregional Crown Width Models for Individual Trees Growing in Pure and Mixed Stands in Austria

by Rafael Buchacher and Thomas Ledermann

Forests 2020, 11(1), 114; https://doi.org/10.3390/f11010114 - 16 Jan 2020

Cited by 27 | Viewed by 4244

Abstract

Crown width is a functional trait that is commonly used to improve the estimation of above-ground biomass of forests and is often included as a predictor variable in forest growth models. Most of the existing crown width models reflect the relationship between crown [...] Read more.

Crown width is a functional trait that is commonly used to improve the estimation of above-ground biomass of forests and is often included as a predictor variable in forest growth models. Most of the existing crown width models reflect the relationship between crown width, tree size and competition variables, but do not consider the effect of species mixture. In this study, we developed crown width models for individual-tree of the major tree species growing in Austria. Because these models should be applicable for mixed and pure stands and should also take into account the characteristics of different sites, the relationship between crown width, site variables and species composition was investigated. For that purpose, we used data from a sub-sample of the Austrian National Forest Inventory, which comprises crown width measurements of about 8900 trees from 1508 sample plots. Because of the hierarchical structure of the data set (i.e., trees nested within the plot) which destroys the independencies between observations, linear mixed-effects models were used. The species composition of the stand was included via the species-specific relative proportions of basal area. To describe the interregional variability of crown width, dummy variables were introduced, which account for region-specific differences. Site characteristics were incorporated through the altitude, slope and aspect of the site. For Norway spruce, silver fir, Scots pine, European larch, European beech, oak species and ash/maple species it was possible to develop crown width models, which reflect the effects of site characteristics and species composition of the stand. The crown widths of shade-tolerant species reacted mainly positively to admixture, whereas light-demanding species reacted with decreasing crown widths. Coniferous species were not as strongly affected by mixture as broadleaf species. Full article

(This article belongs to the Special Issue Modelling Mixing Effects in Forest Stands)

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17 pages, 3951 KiB

Open AccessArticle

Shifts in Leaf and Branch Elemental Compositions of Pinus massoniana (Lamb.) Following Three-Year Rainfall Exclusion

by Tian Lin, Xuan Fang, Yongru Lai, Huaizhou Zheng and Jinmao Zhu

Forests 2020, 11(1), 113; https://doi.org/10.3390/f11010113 - 16 Jan 2020

Cited by 8 | Viewed by 3056

Abstract

We investigated changes in leaf and branch stoichiometry of Pinus massoniana caused by seasonal variation and experimental drought in response to a three-year manipulation of the rainfall exclusion. The results showed that (1) in response to rainfall exclusion manipulation, plant capacity to regulate [...] Read more.

We investigated changes in leaf and branch stoichiometry of Pinus massoniana caused by seasonal variation and experimental drought in response to a three-year manipulation of the rainfall exclusion. The results showed that (1) in response to rainfall exclusion manipulation, plant capacity to regulate leaf potassium (K) concentrations were notably lower than for leaf nitrogen (N) and phosphorus (P) concentrations. Thus, the plants modulated leaf N and P concentrations to improve water use efficiency, which take part in drought resistance mechanisms. Leaf K concentrations decreased continuously, having additional indirect negative effects on plant fitness. (2) The effects of seasonal variation on both the leaf K and P concentrations were significantly stronger than on leaf N concentrations. High leaf N and P concentrations and a low N:P ratio in the growing season improved the growth rate. (3) Principal component analyses (PCA) revealed that to adapt to drought, the plants regulated nutrient elements and then maintained certain stoichiometries as a capital to resist stress. Our results suggest that, on nutrient-poor soils, a lack of N or P (or both) would probably impede P. massoniana’s response to drought. Full article

(This article belongs to the Special Issue Tree Responses to Drought)

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20 pages, 6164 KiB

Open AccessArticle

Relative Contribution of Growing Season Length and Amplitude to Long-Term Trend and Interannual Variability of Vegetation Productivity over Northeast China

by Yuke Zhou

Forests 2020, 11(1), 112; https://doi.org/10.3390/f11010112 - 16 Jan 2020

Cited by 10 | Viewed by 3828

Abstract

In the context of global warming, the terrestrial ecosystem productivity over the Northern Hemisphere presents a substantially enhanced trend. The magnitude of summer vegetation maximum growth, known as peak growth, remains only partially understood for its role in regulating changes in vegetation productivity. [...] Read more.

In the context of global warming, the terrestrial ecosystem productivity over the Northern Hemisphere presents a substantially enhanced trend. The magnitude of summer vegetation maximum growth, known as peak growth, remains only partially understood for its role in regulating changes in vegetation productivity. This study aimed to estimate the spatiotemporal dynamics of the length of growing season (LOS) and maximum growth magnitude (MAG) over Northeast China (NEC) using a long-term satellite record of normalized difference vegetation index (NDVI) for the period 1982–2015, and quantifying their relative contribution to the long-term trend and inter-annual variability (IAV) of vegetation productivity. Firstly, the key phenological metrics, including MAG and start and end of growing season (SOS, EOS), were derived. Secondly, growing season vegetation productivity, measured as the Summary of Vegetation Index (VIsum), was obtained by cumulating NDVI values. Thirdly, the relative impacts of LOS and MAG on the trend and IAV in VIsum were explored using the relative importance (RI) method at pixel and vegetation cover type level. For the entire NEC, LOS, and MAG exhibited a slightly decreasing trend and a weak increasing trend, respectively, thus resulting in an insignificant change in VIsum. The temporal phases of VIsum presented a consistent pace with LOS, but changed asynchronously with MAG. There was an underlying cycle of about 10 years in the changes of LOS, MAG, and VIsum. At a regional scale, VIsum tended to maintain a rising trend in the northern coniferous forest and grassland in western and southern NEC. The spatial distribution of the temporal trends of LOS and MAG generally show a contrasting pattern, in which LOS duration is expected to shorten (negative trend) in the central cropland and in some southwestern grasslands (81.5% of the vegetated area), while MAG would increase (positive trend) in croplands, southern grasslands, and northern coniferous forests (16.5%). The correlation index for the entire NEC suggested that LOS was negatively associated with MAG, indicating that the extended vegetation growth duration would result in a lower growth peak and vice versa. Across the various vegetation types, LOS was a substantial factor in controlling both the trend and IAV of VIsum (RI = 75%). There was an opposite spatial pattern in the relative contribution of LOS and MAG to VIsum, where LOS dominated in the northern coniferous forests and in the eastern broadleaf forests, with MAG mainly impacting croplands and the western grasslands (RI = 27%). Although LOS was still the key factor controlling the trend and IAV of VIsum during the study period, this situation may change in the case peak growth amplitude gradually increases in the future. Full article

(This article belongs to the Special Issue Remotely-Sensed Phenology of Forests under Changing Climate Conditions)

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9 pages, 1508 KiB

Open AccessReview

On the Management of Large-Diameter Trees in China’s Forests

by Chuping Wu, Bo Jiang, Weigao Yuan, Aihua Shen, Shuzhen Yang, Shenhao Yao and Jiajia Liu

Forests 2020, 11(1), 111; https://doi.org/10.3390/f11010111 - 16 Jan 2020

Cited by 26 | Viewed by 5629

Abstract

Large-diameter trees have mainly been used for timber production in forestry practices. Recently, their critical roles played in biodiversity conservation and maintenance of ecosystem functions have been recognized. However, current forestry policy on the management of large-diameter trees is weak. As China is [...] Read more.

Large-diameter trees have mainly been used for timber production in forestry practices. Recently, their critical roles played in biodiversity conservation and maintenance of ecosystem functions have been recognized. However, current forestry policy on the management of large-diameter trees is weak. As China is the biggest consumer of large-diameter timbers, how to maintain sustainable large-diameter timber resources as well as maximize ecological functions of the forests is a critical question to address. Here we summarize historical uses, distribution patterns, and management strategies of large-diameter trees in China. We found that large-diameter trees are mainly distributed in old-growth forests. Although China’s forest cover has increased rapidly in the past decades, large-diameter trees are rarely found in plantation forests and secondary forests. We suggest that knowledge of large-diameter trees should be widely disseminated in local forestry departments, especially their irreplaceable value in terms of biodiversity conservation and ecosystem functions. Protection of large-diameter trees, especially those in old-growth forests, is critical for sustainable forestry. To meet the increasing demand of large-diameter timbers, plantation forests and secondary forests should apply forest density management with thinning to cultivate more large-diameter trees. Full article

(This article belongs to the Special Issue Forest Structure and Sustainable Resource Management)

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15 pages, 2192 KiB

Open AccessArticle

Genetic Structure of Norway Spruce Ecotypes Studied by SSR Markers

by Zuzana Bínová, Jiří Korecký, Jakub Dvořák, Jan Bílý, Dagmar Zádrapová, Václav Jansa and Milan Lstibůrek

Forests 2020, 11(1), 110; https://doi.org/10.3390/f11010110 - 16 Jan 2020

Cited by 15 | Viewed by 4198

Abstract

Norway spruce is a widespread and economically highly important tree species in Central Europe which occurs there in different morphotypic forms (also known as ecotypes). Previously established common garden experiments indicated that the morphological differentiation is most likely genetically determined. The genetic structure [...] Read more.

Norway spruce is a widespread and economically highly important tree species in Central Europe which occurs there in different morphotypic forms (also known as ecotypes). Previously established common garden experiments indicated that the morphological differentiation is most likely genetically determined. The genetic structure of Norway spruce morphological variants might be an indicator (marker) of specific sustainability in forest ecosystems. In this study, we investigated 436 individuals from autochthonous populations belonging to three different ecotypes. The main aim was to evaluate a level of genetic intra and interpopulation diversity among the low, medium and high-elevation ecotypes using both expressed sequence tag simple sequence repeats (EST – SSR) and genomic SSR markers. Sixteen highly polymorphic microsatellite loci folded in two newly designed multiplexes were used to depicture the genetic structure of targeted trees. Important allele frequency parameters, such as the mean expected (0.722, SE = 0.061) and observed (0.585, SE = 0.062) heterozygosity and mean effective number of alleles (N_e = 5.943, SE = 1.279), were estimated. The low genetic differentiation detected among different ecotypes (F_st = 0.008) was further discussed and clarified. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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17 pages, 1728 KiB

Open AccessArticle

Impact of Land Use/Cover Change on Ecosystem Service Values in the Kilombero Valley Floodplain, Southeastern Tanzania

by Nangware Kajia Msofe, Lianxi Sheng, Zhenxin Li and James Lyimo

Forests 2020, 11(1), 109; https://doi.org/10.3390/f11010109 - 15 Jan 2020

Cited by 57 | Viewed by 5416

Abstract

Land use/cover change (LUCC) attributed to natural factors and human activities has led to the loss of ecosystem services, making the quantitative valuation of ecosystem services the scientific focal pointfor sustainable development. This study assessed changes in the ecosystem services values (ESVs) due [...] Read more.

Land use/cover change (LUCC) attributed to natural factors and human activities has led to the loss of ecosystem services, making the quantitative valuation of ecosystem services the scientific focal pointfor sustainable development. This study assessed changes in the ecosystem services values (ESVs) due to LUCC during the period 1990–2016 in the Kilombero Valley floodplain, located in southeastern Tanzania. Moderate resolution Landsat images from 1990, 2010 and 2016 were obtained and analyzed using a random forest (RF) algorithm for classification, and ArcGIS Desktop software (version 10.2, Esri, Redlands, CA, USA) for mapping to assess the LUCC. The ESVs were estimated based on the benefit transfer approach using adopted global value coefficients and modified local value coefficients. The results revealed that the aggregated ESVs of the forests, bushlands, wetlands, and water had decreased, consequently leading to a total loss of US$ 811.5 million (26.6%) in ESVs over the past 26 years when calculated with the modified local value coefficients to US$ 3000.7 million (42.3%) when calculated with global value coefficients. Moreover, the loss in the ESV was attributed to the decreased values of water regulation, climate regulation, erosion control, nutrient cyclying, habitat/refugia, and water supply, with the exception of the values of food production and biological control, which gradually increased during the study period. This study provided minimum estimates of the ecosystem service values, which willcontribute to the formulation of policy actions and strategies for sustainable management of the Kilombero Valley floodplain and inform various stakeholders on the tradeoffs involved in the use of land resources. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

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14 pages, 2999 KiB

Open AccessArticle

Development of Fine Root Biomass of Two Contrasting Urban Tree Cultivars in Response to Drought Stress

by Chi Zhang, Laura Myrtiá Faní Stratópoulos, Chao Xu, Hans Pretzsch and Thomas Rötzer

Forests 2020, 11(1), 108; https://doi.org/10.3390/f11010108 - 15 Jan 2020

Cited by 17 | Viewed by 4274

Abstract

Global climate change associated with rapid urbanization is projected to cause a worsening of environmental problems such as extreme heat and drought in cities. Urban trees play an essential role in improving air quality, fixing carbon, mitigating environmental degradation, and providing other ecosystem [...] Read more.

Global climate change associated with rapid urbanization is projected to cause a worsening of environmental problems such as extreme heat and drought in cities. Urban trees play an essential role in improving air quality, fixing carbon, mitigating environmental degradation, and providing other ecosystem services. However, limited research has been conducted on belowground processes, which hampers a comprehensive understanding of the effect of climate change and urbanization on urban tree growth. Fine roots (<2-mm diameter) are the primary pathway for water and nutrient uptake by plants, and they considerably contribute to the survival of urban trees under drought stress. In this study, we conducted a controlled experiment on the development of fine roots of Tilia cordata Mill ‘Greenspire’ and Tilia tomentosa Moench ‘Brabant’ in response to drought stress via soil coring. Our results indicate that the two cultivars have different strategies for coping with drought. Tilia tomentosa ‘Brabant’, originating from drier regions, gave allocation to deeper soil parts priority probably to obtain more water. On the other hand, Tilia cordata ‘Greenspire’, which is native in Central Europe, showed a negative response to water shortage and preferred a more horizontal development of fine roots rather than a vertical development. Long-term studies are needed to gain a better understanding of the belowground processes of urban trees to select tree species and cultivars which are appropriate for planting in major cities, particularly with regard to future climate change. Full article

(This article belongs to the Special Issue Tree Responses to Drought)

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13 pages, 1894 KiB

Open AccessEditor’s ChoiceArticle

Chemical Fingerprinting of Wood Sampled along a Pith-to-Bark Gradient for Individual Comparison and Provenance Identification

by Victor Deklerck, Cady A. Lancaster, Joris Van Acker, Edgard O. Espinoza, Jan Van den Bulcke and Hans Beeckman

Forests 2020, 11(1), 107; https://doi.org/10.3390/f11010107 - 15 Jan 2020

Cited by 21 | Viewed by 4603

Abstract

Background and Objectives: The origin of traded timber is one of the main questions in the enforcement of regulations to combat the illegal timber trade. Substantial efforts are still needed to develop techniques that can determine the exact geographical provenance of timber and [...] Read more.

Background and Objectives: The origin of traded timber is one of the main questions in the enforcement of regulations to combat the illegal timber trade. Substantial efforts are still needed to develop techniques that can determine the exact geographical provenance of timber and this is vital to counteract the destructive effects of illegal logging, ranging from economical loss to habitat destruction. The potential of chemical fingerprints from pith-to-bark growth rings for individual comparison and geographical provenance determination is explored. Materials and Methods: A wood sliver was sampled per growth ring from four stem disks from four individuals of Pericopsis elata (Democratic Republic of the Congo) and from 14 stem disks from 14 individuals of Terminalia superba (Côte d’Ivoire and Democratic Republic of the Congo). Chemical fingerprints were obtained by analyzing these wood slivers with Direct Analysis in Real Time Time-Of-Flight Mass Spectrometry (DART TOFMS). Results: Individual distinction for both species was achieved but the accuracy was dependent on the dataset size and number of individuals included. As this is still experimental, we can only speak of individual comparison and not individual distinction at this point. The prediction accuracy for the country of origin increases with increasing sample number and a random sample can be placed in the correct country. When a complete disk is removed from the training dataset, its rings (samples) are correctly attributed to the country with an accuracy ranging from 43% to 100%. Relative abundances of ions appear to contribute more to differentiation compared to frequency differences. Conclusions: DART TOFMS shows potential for geographical provenancing but is still experimental for individual distinction; more research is needed to make this an established method. Sampling campaigns should focus on sampling tree cores from pith-to-bark, paving the way towards a chemical fingerprint database for species provenance. Full article

(This article belongs to the Special Issue Wood Science and Tropical Forest Ecology)

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21 pages, 3602 KiB

Open AccessArticle

Contribution Towards a Comprehensive Methodology for Wood-Based Biomass Material Flow Analysis in a Circular Economy Setting

by Alexandra Marques, Jorge Cunha, Annelies De Meyer and Kranti Navare

Forests 2020, 11(1), 106; https://doi.org/10.3390/f11010106 - 15 Jan 2020

Cited by 18 | Viewed by 6315

Abstract

It is challenging to quantify the production of wood-based biomass, to define the type and where it comes from, how it is used, and the amount that remains available. This information is crucial for the implementation of national and transnational regulations and is [...] Read more.

It is challenging to quantify the production of wood-based biomass, to define the type and where it comes from, how it is used, and the amount that remains available. This information is crucial for the implementation of national and transnational regulations and is a pillar for the development of the future bio-based circular economy. A variety of studies estimate the production of biomass, performs material flow analyses, or addresses supply chain modelling. These studies are often built upon distinct assumptions, tailored to a specific purpose, and often poorly described. This makes comparison amongst studies, generalization of results, or replication hard to even impossible. This paper presents a comprehensive methodology for wood-based biomass material flow analysis, anchored in Material Flow Analysis, built upon literature review and deducted through systematization of previous studies. This is a five-step approach, consisting of (1) adopt proper terminology; (2) obtain accurate estimates for the biomass flows; (3) Sankey diagram for resource balance representation; (4) scenario analysis; (5) stakeholders validation. The focus is to provide instructions for producing a generalized Sankey diagram, from the categorization of biomass resources, uses/applications in a circular economy setting, towards the development of scenario analysis. Its practical implementation is presented by defining the yearly wood-based biomass resource balance of Portugal and the waste wood resource balance of Flanders. The main data sources for the quantification of the biomass sources and uses/applications are identified. Based on the insights from these case studies, our methodological approach already shows to be replicable and with comparable results. This enables the comparison of resource flows between different regions and countries and also monitoring the progress over time. This leads to improved data which can be instruments for supporting companies’ decision-making processes (e.g., infrastructure investments or other strategic decisions), as well as designing policy strategies and incentives. Full article

(This article belongs to the Special Issue Supply Chain Optimization for Biomass and Biofuels)

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14 pages, 2176 KiB

Open AccessArticle

The Role of Climate Niche, Geofloristic History, Habitat Preference, and Allometry on Wood Density within a California Plant Community

by Rebecca A. Nelson, Emily J. Francis, Joseph A. Berry, William K. Cornwell and Leander D. L. Anderegg

Forests 2020, 11(1), 105; https://doi.org/10.3390/f11010105 - 14 Jan 2020

Cited by 8 | Viewed by 4069

Abstract

Research Highlights: To better understand within-community variation in wood density, our study demonstrated that a more nuanced approach is required beyond the climate–wood density correlations used in global analyses. Background and Objectives: Global meta-analyses have shown higher wood density is associated with higher [...] Read more.

Research Highlights: To better understand within-community variation in wood density, our study demonstrated that a more nuanced approach is required beyond the climate–wood density correlations used in global analyses. Background and Objectives: Global meta-analyses have shown higher wood density is associated with higher temperatures and lower rainfall, while site-specific studies have explained variation in wood density with structural constraints and allometry. On a regional scale, uncertainty exists as to what extent climate and structural demands explain patterns in wood density. We explored the role of species climate niche, geofloristic history, habitat specialization, and allometry on wood density variation within a California forest/chaparral community. Materials and Methods: We collected data on species wood density, climate niche, geofloristic history, and riparian habitat specialization for 20 species of trees and shrubs in a California forest. Results: We found a negative relationship between wood density and basal diameter to height ratio for riparian species and no relationship for non-riparian species. In contrast to previous studies, we found that climate signals had weak relationships with wood density, except for a positive relationship between wood density and the dryness of a species’ wet range edge (species with drier wet range margins have higher wood density). Wood density, however, did not correlate with the aridity of species’ dry range margins. Geofloristic history had no direct effect on wood density or climate niche for modern California plant communities. Conclusions: Within a California plant community, allometry influences wood density for riparian specialists, but non-riparian plants are ‘overbuilt’ such that wood density is not related to canopy structure. Meanwhile, the relationship of wood density to species’ aridity niches challenges our classic assumptions about the adaptive significance of high wood density as a drought tolerance trait. Full article

(This article belongs to the Special Issue Relationship between Forest Ecophysiology and Environment)

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14 pages, 4639 KiB

Open AccessArticle

Cloning, Characterization and Expression Analysis of the Phosphate Starvation Response Gene, ClPHR1, from Chinese Fir

by Wanting Chen, Ranhong Chen, Ying Zhang, Jiaoyang Li, Mulualem Tigabu, Xiangqing Ma and Ming Li

Forests 2020, 11(1), 104; https://doi.org/10.3390/f11010104 - 14 Jan 2020

Cited by 5 | Viewed by 3152

Abstract

The study on the function and sequence of PHR1 (Phosphate Starvation Response gene 1) gene, which plays a central role in plant phosphorus (Pi) signal regulatory network, is of great significance to further study response mechanisms to Pi deficiency. In this work, the [...] Read more.

The study on the function and sequence of PHR1 (Phosphate Starvation Response gene 1) gene, which plays a central role in plant phosphorus (Pi) signal regulatory network, is of great significance to further study response mechanisms to Pi deficiency. In this work, the previously selected Pi-efficient Chinese fir clone M32 was used as research material to obtain the full-length sequence of ClPHR1 transcription factors in Chinese fir by RACE (Rapid Amplification of cDNA Ends) full-length cloning technique, and the structure, function and subcellular localization of ClPHR1 gene encoding protein were analyzed. The temporal and spatial expression characteristics of ClPHR1 transcription factors in Chinese fir under low Pi stress were also analyzed, and the overexpression of ClPHR1 gene in transgenic Arabidopsis thaliana was obtained to verify the function of ClPHR1 gene under low Pi stress. The results showed that the length of the ClPHR1 gene obtained by rapid amplification of cDNA ends technique was 1954 bp, of which 1512 bp was an open reading frame. ClPHR1 was predicted to be an unstable hydrophilic protein with only one possible transmembrane domain. The ClPHR1 gene had a highly conserved MYB-CC domain, which is similar to the PHR1 gene of other plants. Phylogenetic tree analysis showed that the sequence had high homology with PHR1 genes in the Prunus species. The ClPHR1 was expressed in all organs of Chinese fir, with the highest expression in the roots, followed by the leaves with the lowest expression in stems. ClPHR1 expression in roots was reduced dramatically at the beginning of Pi stress treatment and followed by an increase at 7days; in leaves, it increased dramatically at the beginning of Pi starvation treatment and showed a decreasing trend after 3 days; in stems, the expression level of ClPHR1 increased after 7 days of Pi stress treatment. The transient expression vector was introduced into plant cells, and it was found that ClPHR1 was located in the nucleus and was a MYB-CC transcription factor expressed in the cell nucleus. The ClPHR1 overexpression vector was constructed, and then introduced into Arabidopsis thaliana by agrobacterium infection inflorescence method. The expressions of Pi transporter genes, AtPHT1;1, AtPHT1;2, AtPHT1;8 and AtPHT1;9, was significantly higher in the overexpressing strain than that in the wild type strain. The results suggest that the ClPHR1 transcription factor could regulate the regulation of downstream Pi transporter gene and increase Pi utilization efficiency of the Chinese fir under Pi stress. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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10 pages, 1199 KiB

Open AccessArticle

Disentangling the Roles of Topography, Patch, and Land Use on Conservation Trait Status of Specialist Birds in Marginal Forest Land Use Types

by Petr Zasadil, Dušan Romportl and Jakub Horák

Forests 2020, 11(1), 103; https://doi.org/10.3390/f11010103 - 14 Jan 2020

Cited by 8 | Viewed by 3021

Abstract

One of the main questions in ecology and conservation is how organisms are governed and affected by their traits within the context of abiotic gradients. The main question of our study addresses how patch, topography, and land use influence conservation trait status (rarity [...] Read more.

One of the main questions in ecology and conservation is how organisms are governed and affected by their traits within the context of abiotic gradients. The main question of our study addresses how patch, topography, and land use influence conservation trait status (rarity and red-list index) of birds generally, and of farmland and woodland specialists specifically, in marginal forest landscape types. We sampled birds from 68 traditional fruit orchards existing as remnants of agroforestry within the Pardubice Region of the Czech Republic during two consecutive years. We recorded 57 bird species, of which 31 species were forest dwellers and 16 farmland dwellers. Topographical predictors played the most significant role in influencing traits of the bird community as a whole. Farmland bird traits indicated the most balanced values, as they were significantly influenced by all studied predictor sets. Their responses nevertheless differed among the studied traits and also showed a more complex pattern because the values of interaction between some predictor categories were relatively high. Traits of woodland birds were most influenced by the patch configuration. We found that a structurally diversified marginal habitat type of traditional fruit orchards is able to promote a number of specialist species and also reveals important relationships between bird conservation traits and different predictor sets. Researchers should pay more attention to the conservation traits of birds and their interactions with environmental predictors. Furthermore, conservationists should be more attentive to the biodiversity value and sustainable management of traditional fruit orchards. Full article

(This article belongs to the Special Issue Forest Biodiversity under the Changing Land Use and Climate)

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20 pages, 1347 KiB

Open AccessArticle

A Framework for Characterizing and Regulating Ecosystem Services in a Management Planning Context

by Emin Zeki BASKENT

Forests 2020, 11(1), 102; https://doi.org/10.3390/f11010102 - 14 Jan 2020

Cited by 77 | Viewed by 8258

Abstract

Sustainable management promises to improve the conservation and utilization of ecosystem services and their contribution to human wellbeing through management plans. This paper explores the concept of characterization and integration of ecosystem services in a management planning concept. The integration process involves the [...] Read more.

Sustainable management promises to improve the conservation and utilization of ecosystem services and their contribution to human wellbeing through management plans. This paper explores the concept of characterization and integration of ecosystem services in a management planning concept. The integration process involves the identification, quantification, valuation, assessment, and monitoring of ecosystem services over time. The quantification of common ecosystem services, such as soil erosion, water conservation, recreation, biodiversity conservation, and carbon sequestration was explored. A framework was developed to integrate ecosystem services into management planning process. Ecosystem services are classified as provisioning, regulating, supporting, and cultural services with a defined typology. The conceptual framework acts as an organizing structure and it serves as a model for the management of ecosystems with their contribution to human wellbeing. Ecosystem management with multi-criteria decision techniques, information technologies and a structured participation is a proposed approach for the sustainable management of ecological, economic, and socio-cultural functions. Establishing the quantitative relationships between ecosystem services and societal benefits is essential. The provision of a universally accepted clear measurement of regulating, supporting, and cultural services is challenging. A commitment, vision, and strong willingness are required to adopt policies, regulations, and management objectives in planning. Integration can only be realized with prioritizing ecosystem services with the involvement of stakeholders. Substantial understanding of both the ecological and social systems is a prerequisite for sustainable management of ecosystem services. The ecosystem services with significant benefits to the wellbeing of society should primarily be characterized, their relative importance be weighted, and prioritized through a participatory approach. A holistic approach with a comprehensive decision support system is essential in forecasting the future provision of ecosystem services and assessing the trade-off analysis, resulting in better policy formulation before on-the-ground implementation. Full article

(This article belongs to the Special Issue Decision Support to Address Multiple Ecosystem Services in Forest Management Planning)

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14 pages, 4517 KiB

Open AccessArticle

Disturbance History and Dynamics of an Old-Growth Nothofagus Forest in Southern Patagonia

by Mariano Martín Amoroso and Ana Paula Blazina

Forests 2020, 11(1), 101; https://doi.org/10.3390/f11010101 - 14 Jan 2020

Cited by 6 | Viewed by 2992

Abstract

The identification of disturbance events using disturbance chronologies has become a valuable tool in reconstructing disturbance history in temperate forests worldwide; yet detailed reconstructions of disturbance history and their effect on the structure and dynamics of the old-growth Nothofagus forests in the southern [...] Read more.

The identification of disturbance events using disturbance chronologies has become a valuable tool in reconstructing disturbance history in temperate forests worldwide; yet detailed reconstructions of disturbance history and their effect on the structure and dynamics of the old-growth Nothofagus forests in the southern Patagonia are scarce. We reconstructed forest dynamics and disturbance history of an old-growth N. pumilio forest in the Toro River Valley, Santa Cruz, Argentina using dendroecological techniques. Since a variation in the disturbance regimes was expected with changing elevation, we sampled at different elevations. We found distinct differences in forest structure, dynamics, and disturbance history with changes in the elevation. The disturbance chronologies provided robust evidence that forests in the study area have been subjected to multiple disturbance events over the last 200 years. Yet, recognizing the agent of disturbance could be difficult in these montane forests and further studies are required. Moreover, disturbances might have varied from frequent, moderate- to high-severity events to less frequent and more severe events. This study represents the first of its kind for the temperate forests of Patagonia. Full article

(This article belongs to the Special Issue Forest Stand Dynamics and Its Applications)

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16 pages, 2758 KiB

Open AccessArticle

Effects of Soil Temperature, Water Content, Species, and Fertilization on Soil Respiration in Bamboo Forest in Subtropical China

by Houxi Zhang, Zhuangzhuang Qian and Shunyao Zhuang

Forests 2020, 11(1), 99; https://doi.org/10.3390/f11010099 - 13 Jan 2020

Cited by 18 | Viewed by 3784

Abstract

Understanding the change pattern of soil respiration (SR) and its drivers under different bamboo species and land management practices is critical for predicting soil CO₂ emission and evaluating the carbon budget of bamboo forest ecosystems. A 24-month field study was performed in [...] Read more.

Understanding the change pattern of soil respiration (SR) and its drivers under different bamboo species and land management practices is critical for predicting soil CO₂ emission and evaluating the carbon budget of bamboo forest ecosystems. A 24-month field study was performed in subtropical China to monitor SR in experimental plots of local bamboo (Phyllostachys glauca) without fertilization (PG) and commercial bamboo (Phyllostachys praecox) with and without fertilization (PPF and PP, respectively). The SR rate and soil properties were measured on a monthly timescale. Results showed that the SR rate ranged from 0.38 to 8.53 µmol CO₂ m⁻²s⁻¹, peaking in June. The PPF treatment had higher SR rates than the PP and PG treatments for most months; however, there were no significant differences among the treatments. The soil temperature (ST) in the surface layer (0–10 cm) was found to be the predominant factor controlling the temporal change pattern of the monthly SR rate in the PG and PP treatments (i.e., those without fertilization). A bivariate model is used to show that a natural factor—comprised of ST and soil water content (SWC)—explained 44.2% of the variation in the monthly SR rate, whereas biological (i.e., bamboo type) and management (i.e., fertilization) factors had a much smaller impact (less than 0.1% of the variation). The annual mean SR showed a significant positive correlation with soil organic matter (SOM; r = 0.51, P < 0.05), total nitrogen (TN; r = 0.47, P < 0.05), total phosphorus (TP; r = 0.60, P < 0.01), clay content (0.72, P < 0.05) and below-ground biomass (r = 0.60*), which altogether explain 69.0% of the variation in the annual SR. Our results indicate that the fertilization effect was not significant in SR rate for most months among the treatments, but was significant in the annual rate. These results may help to improve policy decisions concerning carbon sequestration and the management of bamboo forests in China. Full article

(This article belongs to the Section Forest Ecology and Management)

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17 pages, 4860 KiB

Open AccessArticle

Tree-Ring Analysis Reveals Density-Dependent Vulnerability to Drought in Planted Mongolian Pines

by ShouJia Sun, Shuai Lei, HanSen Jia, Chunyou Li, JinSong Zhang and Ping Meng

Forests 2020, 11(1), 98; https://doi.org/10.3390/f11010098 - 13 Jan 2020

Cited by 18 | Viewed by 3465

Abstract

Population density influences tree responses to environmental stresses, such as drought and high temperature. Prolonged drought negatively affects the health of Mongolian pines in forests planted by the Three-North Shelter Forest Program in North China. To understand the relationship between stand density and [...] Read more.

Population density influences tree responses to environmental stresses, such as drought and high temperature. Prolonged drought negatively affects the health of Mongolian pines in forests planted by the Three-North Shelter Forest Program in North China. To understand the relationship between stand density and drought-induced forest decline, and to generate information regarding the development of future management strategies, we analyzed the vulnerability to drought of planted Mongolian pines at three stand densities. A tree-ring width index for trees from each density was established from tree-ring data covering the period 1988–2018 and was compared for differences in radial growth. Resistance (R_t), recovery (R_c), resilience (R_s), and relative resilience (RR_s) in response to drought events were calculated from the smoothed basal area increment (BAI) curves. The high-density (HDT) group showed a consistently lower tree-ring width than the border trees (BT) and low-density (LDT) groups. The BAI curve of the HDT group started to decrease five years earlier than the LDT and BT groups. Pearson correlation analysis revealed that the radial growth of all of the groups was related to precipitation, relative humidity (RH), potential evapotranspiration (ET₀), and standardized precipitation evapotranspiration index (SPEI) in the previous October and the most recent July, indicating that Mongolian pine trees of different densities had similar growth–climate relationships. Over the three decades, the trees experienced three severe drought events, each causing reduced tree-ring width and BAI. All of the groups showed similar R_c to each drought event, but the HDT group exhibited significantly lower R_t, R_s, and RR_s than the BT group, suggesting that the HDT trees were more vulnerable to repeated drought stress. The RR_s of the HDT group decreased progressively after each drought event and attained <0 after the third event. All of the groups showed similar trends regarding water consumption under varying weather conditions, but the HDT group showed significantly reduced whole-tree hydraulic capability compared with the other two groups. From these results, HDT trees exhibit ecophysiological memory effects from successive droughts, including sap flux dysfunction and higher competition index, which may prevent recovery of pre-drought growth rates. HDT trees may be at greater risk of mortality under future drought disturbance. Full article

(This article belongs to the Special Issue Forest Adaptation and Restoration in a Changing Environment)

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14 pages, 3157 KiB

Open AccessArticle

Effects of Canopy Microclimate on Chinese Chestnut (Castanea mollissima Blume) Nut Yield and Quality

by Yue Wen, Shuchai Su and Haicheng Zhang

Forests 2020, 11(1), 97; https://doi.org/10.3390/f11010097 - 13 Jan 2020

Cited by 8 | Viewed by 3373

Abstract

There are considerable differences in chestnut yield and quality across different chestnut-producing regions in China, indicating that environmental factors affect these properties of chestnuts. Furthermore, nut yield and quality differ depending on canopy position. Therefore, this study investigated the relationship between the canopy [...] Read more.

There are considerable differences in chestnut yield and quality across different chestnut-producing regions in China, indicating that environmental factors affect these properties of chestnuts. Furthermore, nut yield and quality differ depending on canopy position. Therefore, this study investigated the relationship between the canopy microclimate, nut yield, and quality. We determined microclimate factors from blossoming to ripening at different positions in the canopy. Nut yield and quality and the number of different branch types were measured at various canopy positions. The light intensity and temperature of the different canopy layers exhibited funnel-form distributions ranging from 0 to 3600 μmol·m²·s⁻¹ and from 32 to 37 °C, respectively. Canopy humidity showed an inverted funnel-shaped distribution ranging from 26% to 40%. Nut yield and quality in the top and outer canopies were higher than in the bottom and inner canopies. Branches in the top-middle and peripheral parts of the canopy also produced higher yields, especially strong branches that bore more nuts. Nut yield and quality had positive correlations with light intensity (r = 0.735) and temperature (r = 0.709), whereas they were inversely associated with humidity (r = −0.584). The nut yield was more than 200 gm⁻³ when the light intensity was above 1500 μmol·m²·s⁻¹, the temperature was above 34.4 °C, and the humidity was below 27.5%. Full article

(This article belongs to the Section Forest Ecology and Management)

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23 pages, 3739 KiB

Open AccessArticle

Characterization and Justification of Trees on an Inner-City Golf Course in Halifax, Canada: An Investigation into the Ecological Integrity of Institutional Greenspace

by Shauna Doll and Peter N. Duinker

Forests 2020, 11(1), 96; https://doi.org/10.3390/f11010096 - 13 Jan 2020

Cited by 3 | Viewed by 4348

Abstract

Institutional greenspaces such as golf courses, cemeteries, military bases, hospitals, and university campuses are not generally revered for their ecological integrity. The existence of golf courses in particular has been heavily debated due to widespread perceptions of these spaces as environmentally degrading. Though [...] Read more.

Institutional greenspaces such as golf courses, cemeteries, military bases, hospitals, and university campuses are not generally revered for their ecological integrity. The existence of golf courses in particular has been heavily debated due to widespread perceptions of these spaces as environmentally degrading. Though much of the total area of golf courses is occupied by heavily manicured lawns, Canadian golf courses tend to be well treed and thus show significant potential to enhance forest coverage and contribute to the conservation of native tree species when established on previously unforested land. To explore this potential, a tree inventory was carried out on an inner-city golf course in Halifax, Nova Scotia, and findings compared to an earlier inventory of more naturalized (i.e., ingrowth) forest areas in the same city. Based in the Acadian Forest Region, this case study used the characteristics of a healthy and mature Acadian Forest as a model for ecological integrity. It was found that both the golf course and the ingrowth populations were largely representative of a mixedwood Acadian forest. Likewise, both populations were in a similar stage of regeneration and exhibited similar stresses. These results suggest that if improved forest management approaches are employed, golf courses will effectively strengthen the ecological integrity of urban forests. This is an especially important finding in the climate change era when tree populations are likely to be subjected to new environmental stressors which may be alleviated via the human intervention that is available on managed lands such as institutional greenspaces. Full article

(This article belongs to the Section Forest Ecology and Management)

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19 pages, 2006 KiB

Open AccessEditor’s ChoiceArticle

Forecasting Forest Areas in Myanmar Based on Socioeconomic Factors

by Tetsuya Michinaka, Ei Ei Swe Hlaing, Thaung Naing Oo, Myat Su Mon and Tamotsu Sato

Forests 2020, 11(1), 100; https://doi.org/10.3390/f11010100 - 13 Jan 2020

Cited by 8 | Viewed by 5284

Abstract

National circumstances should be considered in establishing and adjusting forest reference emission levels (FRELs/FRLs) under the United Nations Programme on Reducing Emissions from Deforestation and Forest Degradation (UN-REDD+ Programme). Myanmar, one of the world’s least developed countries may face accelerating deforestation under an [...] Read more.

National circumstances should be considered in establishing and adjusting forest reference emission levels (FRELs/FRLs) under the United Nations Programme on Reducing Emissions from Deforestation and Forest Degradation (UN-REDD+ Programme). Myanmar, one of the world’s least developed countries may face accelerating deforestation under an open and democratic political system that desires rapid economic development. This research analyzes the impacts of population growth and economic development on forest areas in Myanmar by using panel data analysis, an econometrics approach based on panel data of forest areas, population, and gross domestic product (GDP) by states and regions in 2005, 2010, and 2015. This research revealed that per capita GDP and population density gave statistically significant negative impacts on forest areas. Using the regression model obtained above, medium population growth projections, and three GDP development scenarios, annual forest areas from 2016 to 2020 were forecast. The forecasting results showed possible higher deforestation under higher economic development. Finally, this research showed the necessity of adjusting the current average deforestation for RELs in the REDD+ scheme in Myanmar and the direction in which the adjustment should go. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

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15 pages, 4138 KiB

Open AccessArticle

Study on the Diurnal Dynamic Changes and Prediction Models of the Moisture Contents of Two Litters

by Yunlin Zhang and Ping Sun

Forests 2020, 11(1), 95; https://doi.org/10.3390/f11010095 - 12 Jan 2020

Cited by 21 | Viewed by 3379

Abstract

The occurrence and behavior of forest fires are mainly affected by litter moisture content, which is very important for fire risk forecasting. Errors in models of litter moisture content prediction mainly stem from the neglect of diurnal variation. Consequently, it is essential to [...] Read more.

The occurrence and behavior of forest fires are mainly affected by litter moisture content, which is very important for fire risk forecasting. Errors in models of litter moisture content prediction mainly stem from the neglect of diurnal variation. Consequently, it is essential to determine the diurnal variation of litter moisture content and establish a high-precision prediction model. In this study, the moisture contents of litters of Mongolian oak (Quercus mongolica) and Korean pine (Pinus koraiensis) were monitored at 1 h time steps to obtain the diurnal variations of moisture content, and two direct estimation (Nelson and Simard) methods as well as one meteorological factor regression method were selected to establish prediction models at 1 h time steps. The moisture contents of the two litter types showed obvious diurnal variation, and the changes were significantly correlated with the air temperature and relative humidity. The wind speed had no significant effect on the change within 1 h. The mean absolute error (MAE) values of the three prediction models of Mongolian oak were 1.02%, 1.03%, and 1.46%, and those of Korean pine were 0.50%, 0.50%, and 1.95%, respectively. Similarly, the mean relative error (MRE) values of the three prediction models of oak litter were 4.76%, 4.73%, and 6.65%, and those of pine were 3.53%, 3.59%, and 13.26%, respectively. These results indicated that the accuracy of the Nelson and Simard methods was similar, and both met the requirements for the forecasting of forest fire risk. Therefore, the direct estimation method was selected to predict the moisture contents of two litter types in this area. Full article

(This article belongs to the Special Issue Forest Fire Risk Prediction)

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16 pages, 5366 KiB

Open AccessArticle

The Effects of Ecological Factors on the Main Medicinal Components of Dendrobium officinale under Different Cultivation Modes

by Yingdan Yuan, Xinggang Tang, Zhaohui Jia, Chong Li, Jieyi Ma and Jinchi Zhang

Forests 2020, 11(1), 94; https://doi.org/10.3390/f11010094 - 12 Jan 2020

Cited by 72 | Viewed by 5614

Abstract

Dendrobium officinale is an important traditional Chinese medicinal plant and crop, which contains many kinds of medicinal components. The quality of medicinal plants is closely related to the ecological factors in a growing environment. The main components of D. officinale determined in this [...] Read more.

Dendrobium officinale is an important traditional Chinese medicinal plant and crop, which contains many kinds of medicinal components. The quality of medicinal plants is closely related to the ecological factors in a growing environment. The main components of D. officinale determined in this study were polysaccharides, total alkaloids and total flavonoids. In addition, this study dealt with the correlation of these components to 16 ecological factors under three different cultivation modes (Greenhouse, Bionic, Wild; Lu’an, Anhui Province, China). The relationship between ecological factors and quality factors was analyzed step by step using correlation analysis, principal component analysis and stepwise multiple linear regression. Eight ecological factors: maximum relative humidity, minimum relative humidity, maximum temperature, sunshine duration, soil pH, soil total nitrogen, soil total phosphorus and soil available phosphorus were considered as key factors that influenced the main medicinal qualities of cultivated D. officinale. This study provides an insight for exploring the complex relationship between ecological factors and D. officinale medicinal value in artificial cultivation. Full article

(This article belongs to the Section Forest Ecology and Management)

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30 pages, 12275 KiB

Open AccessEditor’s ChoiceArticle

A Survey in Natural Forest Ecosystems of Vietnam Reveals High Diversity of both New and Described Phytophthora Taxa including P. ramorum

by Thomas Jung, Bruno Scanu, Clive M. Brasier, Joan Webber, Ivan Milenković, Tamara Corcobado, Michal Tomšovský, Matěj Pánek, József Bakonyi, Cristiana Maia, Aneta Bačová, Milica Raco, Helen Rees, Ana Pérez-Sierra and Marília Horta Jung

Forests 2020, 11(1), 93; https://doi.org/10.3390/f11010093 - 12 Jan 2020

Cited by 72 | Viewed by 9330

Abstract

In 2016 and 2017, surveys of Phytophthora diversity were performed in 25 natural and semi-natural forest stands and 16 rivers in temperate and subtropical montane and tropical lowland regions of Vietnam. Using baiting assays from soil samples and rivers and direct isolations from [...] Read more.

In 2016 and 2017, surveys of Phytophthora diversity were performed in 25 natural and semi-natural forest stands and 16 rivers in temperate and subtropical montane and tropical lowland regions of Vietnam. Using baiting assays from soil samples and rivers and direct isolations from naturally fallen leaves, 13 described species, five informally designated taxa and 21 previously unknown taxa of Phytophthora were isolated from 58 of the 91 soil samples (63.7%) taken from the rhizosphere of 52 of the 64 woody plant species sampled (81.3%) in 20 forest stands (83.7%), and from all rivers: P. capensis, P. citricola VII, VIII, IX, X and XI, P. sp. botryosa-like 2, P. sp. meadii-like 1 and 2, P. sp. tropicalis-like 2 and P. sp. multivesiculata-like 1 from Phytophthora major phylogenetic Clade 2; P. castaneae and P. heveae from Clade 5; P. chlamydospora, P. gregata, P. sp. bitahaiensis-like and P. sp. sylvatica-like 1, 2 and 3 from Clade 6; P. cinnamomi (Pc), P. parvispora, P. attenuata, P. sp. attenuata-like 1, 2 and 3 and P. ×heterohybrida from Clade 7; P. drechsleri, P. pseudocryptogea, P. ramorum (Pr) and P. sp. kelmania from Clade 8, P. macrochlamydospora, P. sp. ×insolita-like, P. sp. ×kunnunara-like, P. sp. ×virginiana-like s.l. and three new taxa, P. sp. quininea-like, P. sp. ×Grenada 3-like and P. sp. ×Peru 4-like, from Clade 9; and P. sp. gallica-like 1 and 2 from Clade 10. The A1 and A2 mating types of both Pc and Pr co-occurred. The A2 mating type of Pc was associated with severe dieback of montane forests in northern Vietnam. Most other Phytophthora species, including Pr, were not associated with obvious disease symptoms. It is concluded that (1) Vietnam is within the center of origin of most Phytophthora taxa found including Pc and Pr, and (2) Phytophthora clades 2, 5, 6, 7, 8, 9, and 10 are native to Indochina. Full article

(This article belongs to the Special Issue Phytophthora Infestations in Forest Ecosystems)

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Forests, Volume 11, Issue 1 (January 2020) – 122 articles

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