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Forests, Volume 10, Issue 7 (July 2019)

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Cover Story (view full-size image) The aim of this paper is to construct a framework by which the hydrological dynamics of boreal [...] Read more.
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Open AccessArticle
Optimizing Quality of Wood Pellets Made of Hardwood Processing Residues
Forests 2019, 10(7), 607; https://doi.org/10.3390/f10070607
Received: 19 June 2019 / Revised: 16 July 2019 / Accepted: 19 July 2019 / Published: 23 July 2019
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Abstract
Small-scale wood pellet producers often use a trial-and-error approach for determining adequate blending of available wood processing residues and pelletizing parameters. Developing general guidelines for optimizing wood pellet quality and meeting market standards would facilitate their market entry and profitability. Four types of [...] Read more.
Small-scale wood pellet producers often use a trial-and-error approach for determining adequate blending of available wood processing residues and pelletizing parameters. Developing general guidelines for optimizing wood pellet quality and meeting market standards would facilitate their market entry and profitability. Four types of hardwood residues, including green wood chips, dry shavings, and solid and engineered wood sawdust, were investigated to determine the optimum blends of feedstocks and pelletizing conditions to produce pellets with low friction force, high density and high mechanical strength. The feedstock properties reported in this study included particle size distribution, wood moisture content, bulk density, ash content, calorific values, hemicelluloses, lignin, cellulose, extractives, ash major and minor elements, and carbon, nitrogen, and sulfur. All residues tested could potentially be used for wood pellet production. However, high concentrations of metals, such as aluminum, could restrict their use for accessing markets for high-quality pellets. Feedstock moisture content and composition (controlled by the proportions of the various residue sources within blends) were the most important parameters that determined pellet quality, with pelletizing process parameters having less overall influence. Residue blends with a moisture content of 9%–13.5% (dry basis), composed of 25%–50% of sawdust generated by sawing of wood pieces and a portion of green chips generated by trimming of green wood, when combined with a compressive force of 2000 N or more during pelletizing, provided optimum results in terms of minimizing friction and increasing pellet density and mechanical strength. Developing formal relationships between the type of process that generates residues, the properties of residues hence generated, and the quality of wood pellets can contribute to optimize pellet production methods. Full article
(This article belongs to the Special Issue Supply Chain Optimization for Biomass and Biofuels)
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Open AccessArticle
Land Use Changes, Disturbances, and Their Interactions on Future Forest Aboveground Biomass Dynamics in the Northern US
Forests 2019, 10(7), 606; https://doi.org/10.3390/f10070606
Received: 24 June 2019 / Accepted: 21 July 2019 / Published: 23 July 2019
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Abstract
Land use change (LUC), disturbances, and their interactions play an important role in regional forest carbon (C) dynamics. Here we quantified how these activities and events may influence future aboveground biomass (AGB) dynamics in forests using national forest inventory (NFI) and Landsat time [...] Read more.
Land use change (LUC), disturbances, and their interactions play an important role in regional forest carbon (C) dynamics. Here we quantified how these activities and events may influence future aboveground biomass (AGB) dynamics in forests using national forest inventory (NFI) and Landsat time series data in the Northern United States (US). Total forest AGB predictions were based on simulations of diameter growth, mortality, and recruitment using matrix growth models under varying levels of LUC and disturbance severity (low (L), medium (M), and high (H)) every five years from 2018 to 2098. Land use change included the integrated effects of deforestation and reforestation/afforestation (forest [F]→agriculture [A], settlements [S, urbanization/other], and A&S→F), specifically, conversion from F→A, F→S, F→A&S, A→F, S→F, and A&S→F. Disturbances included natural and anthropogenic disturbances such as wildfire, weather, insects and disease, and forest harvesting. Results revealed that, when simultaneously considering both medium LUC and disturbances, total forest AGB predictions of LUC + fire, LUC + weather, LUC + insect & disease, and LUC + harvest indicated substantial increases in regional C stocks (± standard deviation) from 1.88 (±0.13) to 3.29 (±0.28), 3.10 (±0.24), 2.91 (±0.19), and 2.68 (±0.17) Pg C, respectively, from 2018 to 2098. An uncertainty analysis with fuzzy sets suggested that medium LUC under disturbances would lead to greater forest AGB C uptake than undisturbed forest C uptake with high certainty, except for LUC + harvest. The matrix models in this study were parameterized using NFI and Landsat data from the past few decades. Thus, our results imply that if recent trends persist, LUC will remain an important driver of forest C uptake, while disturbances may result in C emissions rather than undisturbed forest C uptake by 2098. The combined effects of LUC and disturbances may serve as an important driver of C uptake and emissions in the Northern US well into the 21st century. Full article
(This article belongs to the Section Forest Inventory, Quantitative Methods and Remote Sensing)
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Open AccessArticle
Acoustic-Based Prediction of End-Product-Based Fibre Determinates within Standing Jack Pine Trees
Forests 2019, 10(7), 605; https://doi.org/10.3390/f10070605
Received: 6 June 2019 / Revised: 16 July 2019 / Accepted: 18 July 2019 / Published: 23 July 2019
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Abstract
The objective of this study was to specify, parameterize, and evaluate an acoustic-based inferential framework for estimating commercially-relevant wood attributes within standing jack pine (Pinus banksiana Lamb) trees. The analytical framework consisted of a suite of models for predicting the dynamic modulus [...] Read more.
The objective of this study was to specify, parameterize, and evaluate an acoustic-based inferential framework for estimating commercially-relevant wood attributes within standing jack pine (Pinus banksiana Lamb) trees. The analytical framework consisted of a suite of models for predicting the dynamic modulus of elasticity (me), microfibril angle (ma), oven-dried wood density (wd), tracheid wall thickness (wt), radial and tangential tracheid diameters (dr and dt, respectively), fibre coarseness (co), and specific surface area (sa), from dilatational stress wave velocity (vd). Data acquisition consisted of (1) in-forest collection of acoustic velocity measurements on 61 sample trees situated within 10 variable-sized plots that were established in four mature jack pine stands situated in boreal Canada followed by the removal of breast-height cross-sectional disk samples, and (2) given (1), in-laboratory extraction of radial-based transverse xylem samples from the 61 disks and subsequent attribute determination via Silviscan-3. Statistically, attribute-specific acoustic prediction models were specified, parameterized, and, subsequently, evaluated on their goodness-of-fit, lack-of-fit, and predictive ability. The results indicated that significant (p ≤ 0.05) and unbiased relationships could be established for all attributes but dt. The models explained 71%, 66%, 61%, 42%, 30%, 19%, and 13% of the variation in me, wt, sa, co, wd, ma, and dr, respectively. Simulated model performance when deploying an acoustic-based wood density estimate indicated that the expected magnitude of the error arising from predicting dt, co, sa, wt, me, and ma prediction would be in the order of ±8%, ±12%, ±12%, ±13%, ±20%, and ±39% of their true values, respectively. Assessment of the utility of predicting the prerequisite wd estimate using micro-drill resistance measures revealed that the amplitude-based wd estimate was inconsequentially more precise than that obtained from vd (≈ <2%). A discourse regarding the potential utility and limitations of the acoustic-based computational suite for forecasting jack pine end-product potential was also articulated. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Open AccessArticle
Potential Solar Radiation as a Driver for Bark Beetle Infestation on a Landscape Scale
Forests 2019, 10(7), 604; https://doi.org/10.3390/f10070604
Received: 28 May 2019 / Revised: 6 July 2019 / Accepted: 18 July 2019 / Published: 23 July 2019
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Abstract
In recent decades, Norway spruce (Picea abies L. Karst.) forests of the High Tatra Mountains have suffered unprecedented tree mortality caused by European spruce bark beetle (Ips typographus L.). Analysis of the spatiotemporal pattern of bark beetle outbreaks across the landscape [...] Read more.
In recent decades, Norway spruce (Picea abies L. Karst.) forests of the High Tatra Mountains have suffered unprecedented tree mortality caused by European spruce bark beetle (Ips typographus L.). Analysis of the spatiotemporal pattern of bark beetle outbreaks across the landscape in consecutive years can provide new insights into the population dynamics of tree-killing insects. A bark beetle outbreak occurred in the High Tatra Mountains after a storm damaged more than 10,000 ha of forests in 2004. We combined yearly Landsat-derived bark beetle infestation spots from 2006 to 2014 and meteorological data to identify the susceptibility of forest stands to beetle infestation. We found that digital elevation model (DEM)-derived potential radiation loads predicted beetle infestation, especially in the peak phase of beetle epidemic. Moreover, spots attacked at the beginning of our study period had higher values of received solar radiation than spots at the end of the study period, indicating that bark beetles prefer sites with higher insolation during outbreak. We conclude that solar radiation, easily determined from the DEM, better identified beetle infestations than commonly used meteorological variables. We recommend including potential solar radiation in beetle infestation prediction models. Full article
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Open AccessArticle
Contrasting Response to Drought and Climate of Planted and Natural Pinus pinaster Aiton Forests in Southern Spain
Forests 2019, 10(7), 603; https://doi.org/10.3390/f10070603
Received: 3 July 2019 / Revised: 11 July 2019 / Accepted: 19 July 2019 / Published: 22 July 2019
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Abstract
Extreme drought events and increasing aridity are leading to forest decline and tree mortality, particularly in populations near the limits of the species distribution. Therefore, a better understanding of the growth response to drought and climate change could show the vulnerability of forests [...] Read more.
Extreme drought events and increasing aridity are leading to forest decline and tree mortality, particularly in populations near the limits of the species distribution. Therefore, a better understanding of the growth response to drought and climate change could show the vulnerability of forests and enable predictions of future dieback. In this study, we used a dendrochronological approach to assess the response to drought in natural and planted forests of the maritime pine (Pinus pinaster Aiton) located in its southernmost distribution (south of Spain). In addition, we investigated how environmental variables (climatic and site conditions) and structural factors drive radial growth along the biogeographic and ecological gradients. Our results showed contrasting growth responses to drought of natural and planted stands, but these differences were not significant after repeated drought periods. Additionally, we found differences in the climate–growth relationships when comparing more inland sites (wet previous winter and late spring precipitation) and sites located closer to the coast (early spring precipitation). Response functions emphasized the negative effect of defoliation and drought, expressed as the June standard precipitation-evapotranspiration index calculated for the 12-month temporal scale and the mean temperature in the current February, on growth. The strong relationship between climatic variables and growth enabled acceptable results to be obtained in a modeling approach. The study and characterization of this tree species’ response to drought will help to improve the adaptive management of forests under climate change. Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessArticle
Removing the Scaling Error Caused by Allometric Modelling in Forest Biomass Estimation at Large Scales
Forests 2019, 10(7), 602; https://doi.org/10.3390/f10070602
Received: 14 June 2019 / Accepted: 20 July 2019 / Published: 22 July 2019
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Abstract
To estimate the responses of forest ecosystems, most relationships in biological systems are described by allometric relationships, the parameters of which are determined based on field measurements. The use of existing observed data errors may occur during the scaling of fine-scale relationships to [...] Read more.
To estimate the responses of forest ecosystems, most relationships in biological systems are described by allometric relationships, the parameters of which are determined based on field measurements. The use of existing observed data errors may occur during the scaling of fine-scale relationships to describe ecosystem properties at a larger ecosystem scale. Here, we analyzed the scaling error in the estimation of forest ecosystem biomass based on the measurement of plots (biomass or volume per hectare) using an improved allometric equation with a scaling error compensator. The efficiency of the compensator on reducing the scaling error was tested by simulating the forest stand populations using pseudo-observation. Our experiments indicate that, on average, approximately 94.8% of the scaling error can be reduced, and for a case study, an overestimation of 3.6% can be removed in practice from a large-scale estimation for the biomass of Pinus yunnanensis Franch. Full article
(This article belongs to the Section Forest Inventory, Quantitative Methods and Remote Sensing)
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Open AccessArticle
The Characteristics of Soil C, N, and P Stoichiometric Ratios as Affected by Geological Background in a Karst Graben Area, Southwest China
Forests 2019, 10(7), 601; https://doi.org/10.3390/f10070601
Received: 31 May 2019 / Revised: 11 July 2019 / Accepted: 17 July 2019 / Published: 19 July 2019
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Abstract
Understanding ecological stoichiometric characteristics of soil nutrient elements is crucial to guide ecological restoration and agricultural cultivation in karst rocky desertification region, but the information about the effect of the geological background on ecological stoichiometric ratios remains unknown. Soils from different landforms, including [...] Read more.
Understanding ecological stoichiometric characteristics of soil nutrient elements is crucial to guide ecological restoration and agricultural cultivation in karst rocky desertification region, but the information about the effect of the geological background on ecological stoichiometric ratios remains unknown. Soils from different landforms, including a basin, slope, and plateau, were sampled to investigate the spatial variance of the ecological stoichiometric characteristics of soil carbon (C), nitrogen (N), and phosphorus (P) under different rocky desertification grades (LRD: light rocky desertification; MRD: moderate rocky desertification; and SRD: severe rocky desertification) in a karst graben basin of Southwest China. Soil C:N ratio was not significantly influenced by rocky desertification grade, which was at a relatively stable level in the same landform, but soil C:P and N:P ratios increased with increasing rocky desertification grade. This change was consistent with increased soil organic carbon (SOC) and total nitrogen (TN) concentrations in the same geomorphic location along with the intensification of rocky desertification, but soil P concentration remained at a relatively stable level, indicating that P may be the limiting macronutrient for plant growth during vegetation restoration in a karst graben area. The soil C:N ratio of slope land was larger than that of the basin and plateau, while the soil C:P ratio and N:P ratio of the slope and plateau were significantly larger than that of the basin. The correlations between pH and C, N, and P stoichiometry decreased significantly when Ca was used as a control variable. In sharp contrast, the correlations between Ca and C, N, and P stoichiometry were highly significant no matter whether pH was used as a control variable, suggesting the important role of Ca in soil C, N, and P stoichiometry in karst graben basins. Full article
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Open AccessArticle
Complete Chloroplast Genome of Pinus densiflora Siebold & Zucc. and Comparative Analysis with Five Pine Trees
Forests 2019, 10(7), 600; https://doi.org/10.3390/f10070600
Received: 15 May 2019 / Revised: 11 July 2019 / Accepted: 16 July 2019 / Published: 19 July 2019
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Abstract
Pinus densiflora (Korean red pine) is widely distributed in East Asia and considered one of the most important species in Korea. In this study, the complete chloroplast genome of P. densiflora was sequenced by combining the advantages of Oxford Nanopore MinION and Illumina [...] Read more.
Pinus densiflora (Korean red pine) is widely distributed in East Asia and considered one of the most important species in Korea. In this study, the complete chloroplast genome of P. densiflora was sequenced by combining the advantages of Oxford Nanopore MinION and Illumina MiSeq. The sequenced genome was then compared with that of a previously published conifer plastome. The chloroplast genome was found to be circular and comprised of a quadripartite structure, including 113 genes encoding 73 proteins, 36 tRNAs and 4 rRNAs. It had short inverted repeat regions and lacked ndh gene family genes, which is consistent with other Pinaceae species. The gene content of P. densiflora was found to be most similar to that of P. sylvestris. The newly attempted sequencing method could be considered an alternative method for obtaining accurate genetic information, and the chloroplast genome sequence of P. densiflora revealed in this study can be used in the phylogenetic analysis of Pinus species. Full article
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Open AccessArticle
Comparison of Three Algorithms to Estimate Tree Stem Diameter from Terrestrial Laser Scanner Data
Forests 2019, 10(7), 599; https://doi.org/10.3390/f10070599
Received: 1 April 2019 / Revised: 11 July 2019 / Accepted: 15 July 2019 / Published: 18 July 2019
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Abstract
Terrestrial laser scanners provide accurate and detailed point clouds of forest plots, which can be used as an alternative to destructive measurements during forest inventories. Various specialized algorithms have been developed to provide automatic and objective estimates of forest attributes from point clouds. [...] Read more.
Terrestrial laser scanners provide accurate and detailed point clouds of forest plots, which can be used as an alternative to destructive measurements during forest inventories. Various specialized algorithms have been developed to provide automatic and objective estimates of forest attributes from point clouds. The STEP (Snakes for Tuboid Extraction from Point cloud) algorithm was developed to estimate both stem diameter at breast height and stem diameters along the bole length. Here, we evaluate the accuracy of this algorithm and compare its performance with two other state-of-the-art algorithms that were designed for the same purpose (i.e., the CompuTree and SimpleTree algorithms). We tested each algorithm against point clouds that incorporated various degrees of noise and occlusion. We applied these algorithms to three contrasting test sites: (1) simulated scenes of coniferous stands in Newfoundland (Canada), (2) test sites of deciduous stands in Phalsbourg (France), and (3) coniferous plantations in Quebec, Canada. In most cases, the STEP algorithm predicted diameter at breast height with higher R2 and lower RMSE than the other two algorithms. The STEP algorithm also achieved greater accuracy when estimating stem diameter in occluded and noisy point clouds, with mean errors in the range of 1.1 cm to 2.28 cm. The CompuTree and SimpleTree algorithms respectively produced errors in the range of 2.62 cm to 6.1 cm and 1.03 cm to 3.34 cm, respectively. Unlike CompuTree or SimpleTree, the STEP algorithm was not able to estimate trunk diameter in the uppermost portions of the trees. Our results show that the STEP algorithm is more adapted to extract DBH and stem diameter automatically from occluded and noisy point clouds. Our study also highlights that SimpleTree and CompuTree require data filtering and results corrections. Conversely, none of these procedures were applied for the implementation of the STEP algorithm. Full article
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Open AccessArticle
Response of Ecosystem Water Use Efficiency to Drought over China during 1982–2015: Spatiotemporal Variability and Resilience
Forests 2019, 10(7), 598; https://doi.org/10.3390/f10070598
Received: 16 May 2019 / Revised: 13 July 2019 / Accepted: 17 July 2019 / Published: 18 July 2019
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Abstract
Ecosystem water use efficiency (WUE describes carbon-water flux coupling in terrestrial ecosystems. Understanding response and resilience of WUE to drought are essential for sustainable water resource and ecosystem management under increasing drought risks over China due to climate warming. Here we analyzed the [...] Read more.
Ecosystem water use efficiency (WUE describes carbon-water flux coupling in terrestrial ecosystems. Understanding response and resilience of WUE to drought are essential for sustainable water resource and ecosystem management under increasing drought risks over China due to climate warming. Here we analyzed the response of ecosystem WUE to drought (spatiotemporal variability and resilience) over China during 1982–2015 based on an evapotranspiration (ET) dataset based on the model tree ensemble (MTE) algorithm using flux-tower ET measurements and satellite-retrieved GPP data. The results showed that the multiyear average WUE was 1.55 g C kg−1 H2O over China. WUE increased in 77.1% of Chinese territory during the past 34 years. During drought periods, the ecosystem WUE increased mainly in the northeast of Inner Mongolia, Northeast China and some regions in southern China with abundant forests but decreased in northwestern and central China. An apparent lagging effect of drought on ecosystem WUE was observed in the east of Inner Mongolia and Northeast China, the west and east regions of North China and the central part of Tibetan Plateau. Some ecosystems (e.g., deciduous needle-leaf forests, deciduous broadleaf forests, evergreen broadleaf forests and evergreen needle-leaf forests) in Central China, Northeast and Southwest China exhibited relatively greater resilience to drought than others by improving their WUE. Our findings would provide useful information for Chinese government to adopt a reasonable approach for maintaining the structure and functions of ecosystems under drought disturbance in future. Full article
(This article belongs to the Special Issue Water Cycling and Drought Responses of Forest Ecosystems)
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Open AccessArticle
Influence of Microtopography and Soil Treatments on Tree Establishment on a Reclaimed Quarry
Forests 2019, 10(7), 597; https://doi.org/10.3390/f10070597
Received: 10 June 2019 / Revised: 6 July 2019 / Accepted: 11 July 2019 / Published: 18 July 2019
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Abstract
Research Highlights: Reclaimed minesites provide an opportunity to establish plantings of tree species of special concern, such as the American chestnut (Castanea dentata (Marshall) Borkh.), white oak (Quercus alba L.) and shortleaf pine (Pinus echinata Mill.). Background and Objectives: Reforestation [...] Read more.
Research Highlights: Reclaimed minesites provide an opportunity to establish plantings of tree species of special concern, such as the American chestnut (Castanea dentata (Marshall) Borkh.), white oak (Quercus alba L.) and shortleaf pine (Pinus echinata Mill.). Background and Objectives: Reforestation success may be influenced by the physical and chemical characteristics of the substrate, which can be manipulated as part of the reclamation process. The objective of this study was to test the effects of three common reclamation treatments on the establishment of the above species on quarry overburden. Materials and Methods: This study tested the influence of lime and fertilizer (100 or 400 kg/ha N) application, loose dumped substrate vs. single pass grading and the resulting microtopography, on the survival and growth of planted 1:0 seedlings over seven years on reclaimed quarry overburden. Results: Grading had a negative impact on the survival of all species. Lime and fertilizer also influenced survival, but effects differed between species. A single application of fertilizer at the time of planting had a lasting and significant influence on the growth of all species. At year seven, across all species, microtopography influenced root collar diameter. The greatest growth was seen on the east upper, and west mid-slope positions. Conclusions: Fertilization and microtopography created by different site preparation techniques at the time of stand establishment can have a significant influence on tree growth over the first seven years. Full article
(This article belongs to the Special Issue Monitoring and Management of Forest Recovery)
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Open AccessArticle
Characterizing Diameter Distributions for Uneven-Aged Pine-Oak Mixed Forests in the Qinling Mountains of China
Forests 2019, 10(7), 596; https://doi.org/10.3390/f10070596
Received: 13 June 2019 / Revised: 30 June 2019 / Accepted: 15 July 2019 / Published: 17 July 2019
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Abstract
Pine-oak mixed forests in the Qinling Mountains are an essential part of the ecosystem in Northwestern China. Diameter distribution models for four species groups of pine-oak mixed forests were developed using the Weibull function. Both moment and hybrid estimation approaches were used to [...] Read more.
Pine-oak mixed forests in the Qinling Mountains are an essential part of the ecosystem in Northwestern China. Diameter distribution models for four species groups of pine-oak mixed forests were developed using the Weibull function. Both moment and hybrid estimation approaches were used to predict the Weibull parameters. For each approach, three fitting methods (maximum likelihood estimator regression (MLER), cumulative distribution function regression (CDFR) and modified CDFR) were employed to obtain estimates for coefficients of regression equations to predict Weibull parameters. Overall results indicated that the Moment Estimation approach was better than the Hybrid approach, and that the CDFR method was superior to the MLER and modified CDFR methods. The combination of Moment Estimation and CDFR is recommended. The models constructed in this study enable the prediction of the diameter distribution of uneven-aged pine-oak mixed forests in the Qinling Mountains based on common stand-level information. Full article
(This article belongs to the Section Forest Inventory, Quantitative Methods and Remote Sensing)
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Open AccessArticle
The Role of Streamside Native Forests on Dissolved Organic Matter in Forested and Agricultural Watersheds in Northwestern Patagonia
Forests 2019, 10(7), 595; https://doi.org/10.3390/f10070595
Received: 10 May 2019 / Revised: 3 July 2019 / Accepted: 9 July 2019 / Published: 17 July 2019
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Abstract
Streamside native forests are known for their key role in water provision, commonly referred to as buffers that control the input or output of nutrients from terrestrial to aquatic ecosystems (i.e., nitrogen or carbon cycle). In order to assess the functional role of [...] Read more.
Streamside native forests are known for their key role in water provision, commonly referred to as buffers that control the input or output of nutrients from terrestrial to aquatic ecosystems (i.e., nitrogen or carbon cycle). In order to assess the functional role of indigenous forests along streamside channels, we measured 10 parameters associated with DOM (Dissolved Organic Matter) at 42 points in 12 small catchments (15–200 ha) dominated by native forests (reference, WNF), forest plantations (WFP) and agricultural lands (WAL) in which the land cover portion was calculated in the entire watershed and along 30 and 60-m wide buffer strips. We found that watersheds WFP and WAL were statistically different than WNF, according to DIC concentrations (Dissolved Inorganic Carbon) and the intensity of the maximum fluorescence of DOM components. Using linear models, we related streamside native forest coverage in buffer strips with DOM parameters. The increase of streamside native forest coverage in 60 m wide buffer strips (0–100%) was related to lower DIC concentrations (0.89 to 0.28 mg C L−1). In watersheds WFP and WAL, the humic and fulvic-like components (0.42 to 1.42 R.U./mg C L−1) that predominated were related to an increase in streamside native forest coverage in the form of a 60 m wide buffer strip (0–75%). This is evidence that streamside native forests influence outputs of detritus and lowered in-stream processing with concomitant downstream transport, and functional integrity and water quality. We propose that DOM quantity and quality may be a potential tool for the identification of priority areas near streams for conservation and ecological restoration in terms of recovery of water quality as an important ecosystem service. The results of this study are useful to inform policy and regulations about the width of streamside native forests as well as their characteristics and restrictions. Full article
(This article belongs to the Special Issue Managing Forests and Water for People under a Changing Environment)
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Open AccessArticle
Effect of Woodchips Biochar on Sensitivity to Temperature of Soil Greenhouse Gases Emissions
Forests 2019, 10(7), 594; https://doi.org/10.3390/f10070594
Received: 17 June 2019 / Revised: 11 July 2019 / Accepted: 14 July 2019 / Published: 17 July 2019
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Abstract
Research Highlights: Biochar is the carbonaceous product of pyrolysis or the gasification of biomass that is used as soil amendment to improve soil fertility and increase soil carbon stock. Biochar has been shown to increase, decrease, or have no effect on the emissions [...] Read more.
Research Highlights: Biochar is the carbonaceous product of pyrolysis or the gasification of biomass that is used as soil amendment to improve soil fertility and increase soil carbon stock. Biochar has been shown to increase, decrease, or have no effect on the emissions of greenhouse gases (GHG) from soil, depending on the specific soil and biochar characteristics. However, the temperature sensitivity of these gas emissions in biochar-amended soils is still poorly investigated. Background and Objectives: A pot experiment was set up to investigate the impact of woodchips biochar on the temperature sensitivity of the main GHG (CO2, CH4, and N2O) emissions from soil. Materials and Methods: Nine pots (14 L volume) were filled with soil mixed with biochar at two application rates (0.021 kg of biochar/kg of soil and 0.042 kg of biochar/kg of soil) or with soil alone as the control (three pots per treatment). Pots were incubated in a growth chamber and the emissions of CO2, CH4, and N2O were monitored for two weeks with a cavity ring-down gas analyzer connected to three closed dynamic chambers. The temperature in the chamber increased from 10 °C to 30 °C during the first week and decreased back to 10 °C during the second week, with a daily change of 5 °C. Soil water content was kept at 20% (w/w). Results: Biochar application did not significantly affect the temperature sensitivity of CO2 and N2O emissions. However, the sensitivity of CH4 uptake from soil significantly decreased by the application of biochar, reducing the CH4 soil consumption compared to the un-amended soil, especially at high soil temperatures. Basal CO2 respiration at 10 °C was significantly higher in the highest biochar application rate compared to the control soil. Conclusions: These results confirmed that the magnitude and direction of the influence of biochar on temperature sensitivity of GHG emissions depend on the specific GHG considered. The biochar tested in this study did not affect soil N2O emission and only marginally affected CO2 emission in a wide range of soil temperatures. However, it showed a negative impact on soil CH4 uptake, particularly at a high temperature, having important implications in a future warmer climate scenario and at higher application rates. Full article
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Open AccessArticle
Production and Regression Models for Biomass and Carbon Captured in Gmelina arborea Roxb. Trees in Short Rotation Coppice Plantations in Costa Rica
Forests 2019, 10(7), 593; https://doi.org/10.3390/f10070593
Received: 9 May 2019 / Revised: 11 July 2019 / Accepted: 15 July 2019 / Published: 17 July 2019
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Abstract
Mortality, diameter at 30 cm over ground level, height, biomass production, and carbon capture (CC) for different tree components (trunk, bark, branches, and leaves) in two locations in Costa Rica, during their first three years and with three plantation spacings (1.0 × 0.5 [...] Read more.
Mortality, diameter at 30 cm over ground level, height, biomass production, and carbon capture (CC) for different tree components (trunk, bark, branches, and leaves) in two locations in Costa Rica, during their first three years and with three plantation spacings (1.0 × 0.5 m, 1.0 × 1.0 m, and 1.0 × 2.0 m) were obtained for Gmelina arborea Roxb. trees growing in short rotation coppice systems (SRC). In addition, regression models were developed to predict biomass production and CC using location, age, spacing, and their interactions. Biomass production was measured by weight of trees without considering dendrometric variables. Results showed that mortality was lower than 15% for one location, with probable high fertility, and almost 85% for the other location. Diameter and height of trees increased with plantation age in both locations. The highest biomass production and CC were observed in the spacings of 1.0 × 0.5 m2 and 1.0 × 1.0 m2, with 20 Mg/ha/year and 8 Mg/ha/year, respectively. The models to predict biomass production in trunk with bark, branches, leaves, total biomass without leaves, and CC in trunk, branch, and total biomass were developed using this equation: Y = β1 + β2 (location × age) + β3 (age) + β4 (spacing). The R2 values varied from 0.66 to 0.84, with error from 0.88 to 10.75 and indicators of goodness of fit from 60 to 83%. Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessArticle
Deepening Rooting Depths Improve Plant Water and Carbon Status of a Xeric Tree during Summer Drought
Forests 2019, 10(7), 592; https://doi.org/10.3390/f10070592
Received: 9 June 2019 / Revised: 11 July 2019 / Accepted: 15 July 2019 / Published: 16 July 2019
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Abstract
Exploring the effects of drought on trees of different sizes is an important research topic because the size-dependent mortality pattern of the major dominant species significantly affects the structure and function of plant communities. Here we studied the physiological performance and non-structural carbohydrates [...] Read more.
Exploring the effects of drought on trees of different sizes is an important research topic because the size-dependent mortality pattern of the major dominant species significantly affects the structure and function of plant communities. Here we studied the physiological performance and non-structural carbohydrates (NSCs) dynamics of a small xeric tree species, Haloxylon ammodendron (C.A.Mey.) of different tree size with varying rooting depth, during summer drought. We measured predawn (Ψpd) and midday (Ψm) leaf water potential, osmotic potential at saturated turgor (π100), and turgor lost point (Ψtlp), stomatal conductance (gs) at noon, maximum photochemical efficiency of photosystem II (Fv/Fm) in the morning, and NSCs concentration, from June–September. Our results demonstrated that the summer drought reduces the overall performance of physiological traits of the small young trees more than the larger adult trees. Ψpd, gs and Fv/Fm dropped larger in the small-diameter groups than the larger diameter groups. Substantial osmotic adjustments were observed in small size individuals (with lower π100 and Ψtlp) to cope with summer drought. Furthermore, mean concentration of NSCs for the leaf and shoot were higher in September than in July in every basal stem diameter classes suggested the leaf and shoot acted as reserve for NSC. However the root NSCs concentrations within each basal stem diameter class exhibited less increase in September than in the July. At the same time, the small young tress had lower root NSCs concentrations than the larger adult tree in both July and September. The contrasting root NSC concentrations across the basal stem diameter classes indicated that the roots of smaller trees may be more vulnerable to carbon starvation under non-lethal summer drought. The significant positive relationship between rooting depth and physiological traits & root NSCs concentration emphasize the importance of rooting depth in determining the seasonal variation of water status, gas exchange and NSCs. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Open AccessArticle
Super Absorbent Polymers Buried within Dry Soil Attract Formosan Subterranean Termites (Blattodea: Rhinotermitidae)
Forests 2019, 10(7), 591; https://doi.org/10.3390/f10070591
Received: 26 June 2019 / Revised: 9 July 2019 / Accepted: 15 July 2019 / Published: 16 July 2019
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Abstract
Baiting is one of the main methods to control subterranean termites. Many previous studies showed that subterranean termites avoid making tunnels within dry soil and feeding on dry wood, which may decrease bait infestation and consumption in drought areas. Super absorbent polymers are [...] Read more.
Baiting is one of the main methods to control subterranean termites. Many previous studies showed that subterranean termites avoid making tunnels within dry soil and feeding on dry wood, which may decrease bait infestation and consumption in drought areas. Super absorbent polymers are a group of materials that can retain large amounts of water and improve the moisture content of soil and bait matrices, and therefore may attract termites. In the present study, choice tests were conducted in the laboratory to investigate the aggregation and feeding behaviors of Formosan subterranean termites, Coptotermes formosanus Shiraki, in response to the three super absorbent polymers—sodium polyacrylate (Na-PAM), potassium polyacrylate (K-PAM), and poly(acrylamide-co-acrylic acid) potassium salt (P(AM/AA))—that were either placed within soil or filled in the void volume of baiting containers. Under dry-soil (30%-moisture) conditions, termites consumed significantly more wood in the chambers where super absorbent polymers were buried than in the control chambers (super absorbent polymer was not placed within soil). In addition, Na-PAM placed within dry soil significantly increased termite aggregation compared with the control chambers. However, no aggregation or feeding preference was detected when super absorbent polymers were placed within wet soil (60%-moisture). Also, filling super absorbent polymers into the void volume of baiting containers did not attract termites, whether the soil was dry or wet. Our study showed that placing super absorbent polymers within soil around bait stations may increase bait consumption by subterranean termites in drought locations. Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessArticle
Changes in Carbon Balance of Harvested Wood Products Resulting from Different Wood Utilization Scenarios
Forests 2019, 10(7), 590; https://doi.org/10.3390/f10070590
Received: 5 June 2019 / Revised: 8 July 2019 / Accepted: 15 July 2019 / Published: 16 July 2019
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Abstract
The bioeconomy focuses on the production of renewable biological resources and the utilisation of these resources and waste streams into value added products. One of the most important aims of the forest industry is the sustainable production of wood. Improved utilization of available [...] Read more.
The bioeconomy focuses on the production of renewable biological resources and the utilisation of these resources and waste streams into value added products. One of the most important aims of the forest industry is the sustainable production of wood. Improved utilization of available industrial wood assortments generates profit for all in the supply chain. At the same time, it may ensure the production of long-life harvested wood products (HWP), and consequently, increase the volume of carbon stored. The objective of this study is to compare different scenarios of industrial wood utilization in Slovakia and the resulting impacts on the national carbon balance. In the proposed scenarios, we aimed to evaluate changes in the current utilization of domestic wood resources through optimizing harvested wood assortments. Two inventory stock methods were applied to determine the potential quality of domestic wood and its utilization through appropriate distribution of outputs. The model scenario assumes that the higher share of industrial roundwood utilised to produce long-life HWP (sawnwood, wood-based panels) will increase carbon sequestration in HWP. Other scenarios quantify the differences between the carbon volumes stored in HWP using the modelled wood assortment supplemented with alternatives with and without export. The results confirmed that increasing the level of carbon stored in HWP can be achieved by changing the wood assortment structure, while maintaining the same level of volume felled. The highest level of carbon stock was observed in the scenario assuming the optimal structure of wood assortments and no wood export. The scenario that optimized wood assortments and excluded wood exports resulted in the highest level of predicted carbon stock, estimated at 4.87 million tons (mil. tons). Full article
(This article belongs to the Section Forest Ecology and Management)
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Open AccessArticle
Phenotypic Correlations among Growth and Selected Wood Properties in White Spruce (Picea glauca (Moench) Voss)
Forests 2019, 10(7), 589; https://doi.org/10.3390/f10070589
Received: 1 June 2019 / Revised: 10 July 2019 / Accepted: 15 July 2019 / Published: 16 July 2019
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Abstract
We examined phenotypic relationships among radial growth-related, physical (i.e., related to wood density), and anatomical (i.e., related to tracheid dimensions) wood properties in white spruce (Picea glauca (Moench) Voss), in order to determine the strength and significance of their correlations. Additionally, principal [...] Read more.
We examined phenotypic relationships among radial growth-related, physical (i.e., related to wood density), and anatomical (i.e., related to tracheid dimensions) wood properties in white spruce (Picea glauca (Moench) Voss), in order to determine the strength and significance of their correlations. Additionally, principal component analysis (PCA) was used to establish if all of the properties must be measured and to determine the key properties that can be used as proxies for the other variables. Radial growth-related and physical properties were measured with an X-ray densitometer, while anatomical properties were measured with a Fiber Quality Analyzer. Fifteen wood properties (tracheid length (TL) and diameter (TD), earlywood tracheid length (ETL) and diameter (ETD), latewood tracheid length (LTL) and diameter (LTD), ring width (RW), ring area (RA), earlywood width (EWW), latewood width (LWW), latewood proportion (LWP), ring density (RD), intra-ring density variation, earlywood density (EWD), and latewood density (LWD)) were assessed. Relationships were evaluated at intra-ring and inter-ring levels in the juvenile wood (JW) and mature wood (MW) zones. Except for a few cases when mature tracheid diameter (TD) was involved, all intra-ring anatomical properties were highly and significantly correlated. Radial growth properties were correlated, with stronger relationships in MW compared to JW. Physical properties were often positively and significantly correlated in both JW and MW. A higher earlywood density coupled with a lower latewood density favored wood uniformity, i.e., the homogeneity of ring density within a growth ring. Managing plantations to suppress trees growth during JW formation, and enhancing radial growth when MW formation starts will favor overall wood quality. In order, RW-EWW-RA, TL-ETL-LTL, and RD-EWD-LWP are the three clusters that appeared in the three wood zones, the whole pith-to-bark radial section, the juvenile wood zone, and the mature wood zone. Full article
(This article belongs to the Special Issue Tree Crown Dynamics and Morphology)
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Open AccessArticle
Forest Structure, Wood Standing Stock, and Tree Biomass in Different Restoration Systems in the Brazilian Atlantic Forest
Forests 2019, 10(7), 588; https://doi.org/10.3390/f10070588
Received: 15 June 2019 / Revised: 4 July 2019 / Accepted: 8 July 2019 / Published: 15 July 2019
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Abstract
Reliable estimates of tree growth and wood yield are fundamental to support the management of restored forests and better reconcile the objectives of recovering biodiversity with the provision of ecosystem services. In this study, wood standing volumes and tree biomass stocks were estimated [...] Read more.
Reliable estimates of tree growth and wood yield are fundamental to support the management of restored forests and better reconcile the objectives of recovering biodiversity with the provision of ecosystem services. In this study, wood standing volumes and tree biomass stocks were estimated in different ecological restoration systems and at two sites with contrasting soil fertility, in order to evaluate the potential trade-offs between biodiversity and forest production. At each site, a complete randomized block design, with three replications of six treatments, was established in 1997–1998: direct seeding (DIRS), high-diversity tree plantation (HDIV), modified “Taungya” agroforestry system (AFS), mixed plantation with timber and firewood species (MIX), managed agroforestry system (AFSm) and managed mixed plantation (MIXm). We inventoried all trees with diameter at breast height (DBH) ≥ 5 cm in 450 m2 per treatment per plot, 19–20 years after establishment, using site-specific allometric models. Significant site effects were found for tree height, tree density and wood volume. Restoration systems (treatments) affected forest structure and forest productivity. Higher wood stock and biomass tree were observed in the less complex system (DIRS), while AFSm and HDIV reconciled higher species richness and diversity with good wood volume yields and tree biomass. Full article
(This article belongs to the Special Issue Forest Structure and Sustainable Resource Management)
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Open AccessArticle
Complete Chloroplast Genome Sequence and Phylogenetic Analysis of Quercus bawanglingensis Huang, Li et Xing, a Vulnerable Oak Tree in China
Forests 2019, 10(7), 587; https://doi.org/10.3390/f10070587
Received: 5 June 2019 / Revised: 7 July 2019 / Accepted: 12 July 2019 / Published: 15 July 2019
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Abstract
Quercus bawanglingensis Huang, Li et Xing, an endemic evergreen oak of the genus Quercus (Fagaceae) in China, is currently listed in the Red List of Chinese Plants as a vulnerable (VU) plant. No chloroplast (cp) genome information is currently available for Q. bawanglingensis [...] Read more.
Quercus bawanglingensis Huang, Li et Xing, an endemic evergreen oak of the genus Quercus (Fagaceae) in China, is currently listed in the Red List of Chinese Plants as a vulnerable (VU) plant. No chloroplast (cp) genome information is currently available for Q. bawanglingensis, which would be essential for the establishment of guidelines for its conservation and breeding. In the present study, the cp genome of Q. bawanglingensis was sequenced and assembled into double-stranded circular DNA with a length of 161,394 bp. Two inverted repeats (IRs) with a total of 51,730 bp were identified, and the rest of the sequence was separated into two single-copy regions, namely, a large single-copy (LSC) region (90,628 bp) and a small single-copy (SSC) region (19,036 bp). The genome of Q. bawanglingensis contains 134 genes (86 protein-coding genes, 40 tRNAs and eight rRNAs). More forward (29) than inverted long repeats (21) are distributed in the cp genome. A simple sequence repeat (SSR) analysis showed that the genome contains 82 SSR loci, involving 84.15% A/T mononucleotides. Sequence comparisons among the nine complete cp genomes, including the genomes of Q. bawanglingensis, Q. tarokoensis Hayata (NC036370), Q. aliena var. acutiserrata Maxim. ex Wenz. (KU240009), Q. baronii Skan (KT963087), Q. aquifolioides Rehd. et Wils. (KX911971), Q. variabilis Bl. (KU240009), Fagus engleriana Seem. (KX852398), Lithocarpus balansae (Drake) A. Camus (KP299291) and Castanea mollissima Bl. (HQ336406), demonstrated that the diversity of SC regions was higher than that of IR regions, which might facilitate identification of the relationships within this extremely complex family. A phylogenetic analysis showed that Fagus engleriana and Trigonobalanus doichangensis form the basis of the produced evolutionary tree. Q. bawanglingensis and Q. tarokoensis, which belong to the group Ilex, share the closest relationship. The analysis of the cp genome of Q. bawanglingensis provides crucial genetic information for further studies of this vulnerable species and the taxonomy, phylogenetics and evolution of Quercus. Full article
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Open AccessArticle
On the Effect of Heat Treatments on the Adhesion, Finishing and Decay Resistance of Japanese cedar (Cryptomeria japonica D. Don) and Formosa acacia (Acacia confuse Merr.(Leguminosae))
Forests 2019, 10(7), 586; https://doi.org/10.3390/f10070586
Received: 14 June 2019 / Revised: 8 July 2019 / Accepted: 11 July 2019 / Published: 13 July 2019
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Abstract
In Taiwan, it is important to maintain sustainable development of the forestry industry in order to raise the self-sufficiency of domestic timber. Japanese cedar (Cryptomeria D. Don and Formosa acacia (Acacia confusa Merr.(Leguminosae)) have abundant storage options and are the potential [...] Read more.
In Taiwan, it is important to maintain sustainable development of the forestry industry in order to raise the self-sufficiency of domestic timber. Japanese cedar (Cryptomeria D. Don and Formosa acacia (Acacia confusa Merr.(Leguminosae)) have abundant storage options and are the potential candidates for this purpose. Heat treatment is a new environment-friendly method used to enhance the dimensional stability and durability of wood. On treatment, a surface with new characteristics is produced because of wood component changes. Consequently, an inactivated surface and a weak boundary layer are generated, and the wettability for adhesives and coatings is reduced. Furthermore, it decreases the pH value of the wood surface, and results in delay or acceleration during the curing of adhesives. This phenomenon must be paid attention to for practical applications of heat-treated wood. Ideal heat-treated conditions of C. japonica and A. confusa woods with productive parameters such as temperature, holding time, heating rate, and thicknesses of wood were identified in our previous study. In this research work, we focus on the normal shear strength of heat-treated wood with adhesives such as urea-formaldehyde resin (UF) and polyvinyl acetate (PVAc), and the finishing performances of heat-treated wood with polyurethane (PU) and nitrocellulose lacquer (NC) coatings as well as assessing the decay-resistance of heat-treated wood. The results show that heat-treated wood had a better decay resistance than untreated wood. The mass decrease of heat-treated wood was only 1/3 or even less than the untreated wood. The normal shear strength of heat-treated wood with UF and PVAc decreased from 99% to 72% compared to the untreated wood, but the wood failure of heat-treated wood was higher than that of the untreated one. Furthermore, the adhesion and impact resistance of wood finished by PU and NC coatings showed no difference between the heat-treated wood and untreated wood. The finished heat-treated wood had a superior durability and better gloss retention and lightfastness than that of the untreated wood. Full article
(This article belongs to the Special Issue Wood Protection and Preservation)
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Open AccessArticle
Performance Analysis of Log Extraction by a Small Shovel Operation in Steep Forests of South Korea
Forests 2019, 10(7), 585; https://doi.org/10.3390/f10070585
Received: 7 May 2019 / Revised: 6 July 2019 / Accepted: 11 July 2019 / Published: 13 July 2019
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Abstract
In South Korea, logs for low-value products, such as pulpwood and fuelwood, are primarily extracted from harvest sites and transported to roadside or landing areas using small shovels. Previous studies on log extraction, however, have focused on cable yarding operations with the goal [...] Read more.
In South Korea, logs for low-value products, such as pulpwood and fuelwood, are primarily extracted from harvest sites and transported to roadside or landing areas using small shovels. Previous studies on log extraction, however, have focused on cable yarding operations with the goal of improving productivity on steep slopes and inaccessible sites, leaving small-shovel operations relatively unexamined. Therefore, the main objectives were to determine small-shovel extraction productivity and costs and to evaluate the impact of related variables on productivity. In addition, we developed a model to estimate productivity under various site conditions. The study took place in 30 case study areas; each area has trees with stems at a diameter at breast height ranging from 18 to 32 cm and a steep slope (greater than 15%). The areas ranged from 241 to 1129 trees per hectare, with conifer, deciduous, and mixed stands. Small-shovel drives ranged from 36 to 72 m per extraction cycle from stump to landing. The results indicated that the mean extraction productivity of small-shovel operations ranged between 2.44 to 9.85 m3 per scheduled machine hour (including all delays). At the forest level, the estimated average stump-to-forest road log production costs were US $4.37 to 17.66/m3. Small-shovel productivity was significantly correlated with stem size (diameter at breast height and tree volume) and total travelled distance (TTD). However, a Pearson’s correlation analysis indicated that stand density and slope did not have a significant effect on productivity. Our findings provide insights into how stem size and TTD influence small shovel performance and the predictive ability of productivity. Further, this information may be a valuable asset to forest planners and managers. Full article
(This article belongs to the Special Issue Forest Operations: A Tool for Forest Restoration)
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Open AccessArticle
Exploring Nonlinear Intra-Annual Growth Dynamics in Fagus sylvatica L. Trees at the Italian ICP-Forests Level II Network
Forests 2019, 10(7), 584; https://doi.org/10.3390/f10070584
Received: 29 May 2019 / Revised: 11 July 2019 / Accepted: 12 July 2019 / Published: 13 July 2019
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Abstract
The European beech (Fagus sylvatica L.) is a widely distributed tree species across Europe, highly sensitive to climate change and global warming. This study illustrates results of a 5-year monitoring time period from eight sites of the ICP-Forests Level II (intensive monitoring [...] Read more.
The European beech (Fagus sylvatica L.) is a widely distributed tree species across Europe, highly sensitive to climate change and global warming. This study illustrates results of a 5-year monitoring time period from eight sites of the ICP-Forests Level II (intensive monitoring network) along the Italian latitudinal gradient. The tree-level relationship between tree growth dynamics and environmental factors, including seasonal climate fluctuations were investigated by means of tree-level Generalized Additive Mixed Models (GAMMs). Model results revealed that climate was responsible for just a portion of the variability in beech growth dynamics. Even if climatic predictors were highly significant in almost all sites, the model explained nearly 30% of the total variance (with just a maximum value of 71.6%), leaving the remaining variance unexplained and likely connected with forest management trajectories applied to each site (e.g., aged coppice and fully grown high forest). Climate change scenarios were then applied to predict site-specific future responses. By applying climate change scenarios, it was predicted that central and northern Italy would face similar climatic conditions to those currently detected at southern latitudes. A special case study was represented by VEN1 plot (Veneto, Northern Italy) whose current and future climate regimes were grouped in a unique and separated cluster. Full article
(This article belongs to the Special Issue Forest Stand Management and Biomass Growth)
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Open AccessArticle
Occurrence Prediction of the Citrus Flatid Planthopper (Metcalfa pruinosa (Say, 1830)) in South Korea Using a Random Forest Model
Forests 2019, 10(7), 583; https://doi.org/10.3390/f10070583
Received: 6 June 2019 / Revised: 28 June 2019 / Accepted: 9 July 2019 / Published: 12 July 2019
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Abstract
Invasive species cause a severe impact on existing ecosystems. The citrus flatid planthopper (CFP; Metcalfa pruinosa (Say, 1830)) is an invasive species in many countries. Predicting potential occurrence areas of the species related to environmental conditions is important for effective forest ecosystem management. [...] Read more.
Invasive species cause a severe impact on existing ecosystems. The citrus flatid planthopper (CFP; Metcalfa pruinosa (Say, 1830)) is an invasive species in many countries. Predicting potential occurrence areas of the species related to environmental conditions is important for effective forest ecosystem management. In this study, we evaluated the occurrence patterns of the CFP and predicted its potential occurrence areas in South Korea using a random forest model for a hazard rating of forests considering meteorological and landscape variables. We obtained the occurrence data of the CFP in South Korea from literature and government documents and extracted seven environmental variables (altitude, slope, distance to road (geographical), annual mean temperature, minimum temperature in January, maximum temperature in July, and annual precipitation (meteorological)) and the proportion of land cover types across seven categories (urban, agriculture, forest, grassland, wetland, barren, and water) at each occurrence site from digital maps using a Geographic Information System. The CFP occurrence areas were mostly located at low altitudes, near roads and urbanized areas. Our prediction model also supported these results. The CFP has a high potential to be distributed over the whole of South Korea, excluding high mountainous areas. Finally, factors related to human activities, such as roads and urbanization, strongly influence the occurrence and dispersal of the CFP. Therefore, we propose that these factors should be considered carefully in monitoring and surveillance programs for the CFP and other invasive species. Full article
(This article belongs to the Special Issue Impacts, Monitoring and Management of Forest Pests and Diseases)
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Open AccessArticle
Development of a Tree Growth Difference Equation and Its Application in Forecasting the Biomass Carbon Stocks of Chinese Forests in 2050
Forests 2019, 10(7), 582; https://doi.org/10.3390/f10070582
Received: 5 June 2019 / Revised: 8 July 2019 / Accepted: 11 July 2019 / Published: 12 July 2019
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Abstract
Global climate change has raised concerns about the relationship between ecosystems and forests, which is a core component of the carbon cycle and a critical factor in understanding and mitigating the effects of climate change. Forest models and sufficient information for predictions are [...] Read more.
Global climate change has raised concerns about the relationship between ecosystems and forests, which is a core component of the carbon cycle and a critical factor in understanding and mitigating the effects of climate change. Forest models and sufficient information for predictions are important for ensuring efficient afforestation activities and sustainable forest development. Based on the theory of difference equations and the general rules of tree growth, this study established a difference equation for the relationship between the ratio of tree diameter at breast height (DBH) to the tree height and age of age of China’s main arbor species. A comparison with equations that represent the traditional tree growth models, i.e., Logistic and Richards equations, showed that the difference equations exhibited higher precision for both fitting and verification data. Moreover, the biomass carbon stocks (BCS) of Chinese forests from 2013 to 2050 were predicted by combining the 8th Chinese Ministry of Forestry and partial continuous forest inventory (CFI) data sets. The results showed that the BCS of Chinese forests would increase from 7342 to 11,030 terra grams of carbon (Tg C) in 2013–2050, with an annual biomass C (carbon) sink of 99.68 Tg C year−1, and they indicated that the Chinese land-surface forest vegetation has an important carbon sequestration capability. Full article
(This article belongs to the Special Issue Influence of Climate Change on Tree Growth and Forest Ecosystems)
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Open AccessArticle
If They Come, Where will We Build It? Land-Use Implications of Two Forest Conservation Policies in the Deep Creek Watershed
Forests 2019, 10(7), 581; https://doi.org/10.3390/f10070581
Received: 1 June 2019 / Revised: 3 July 2019 / Accepted: 9 July 2019 / Published: 12 July 2019
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Abstract
Research Highlights: Forest conservation policies can drive land-use change to other land-use types. In multifunctional landscapes, forest conservation policies will therefore impact on other functions delivered by the landscape. Finding the best pattern of land use requires considering these interactions. Background and Objectives: [...] Read more.
Research Highlights: Forest conservation policies can drive land-use change to other land-use types. In multifunctional landscapes, forest conservation policies will therefore impact on other functions delivered by the landscape. Finding the best pattern of land use requires considering these interactions. Background and Objectives: Population growth continues to drive the development of land for urban purposes. Consequently, there is a loss of other land uses, such as agriculture and forested lands. Efforts to conserve one type of land use will drive more change onto other land uses. Absent effective collaboration among affected communities and relevant institutional agents, unexpected and undesirable land-use change may occur. Materials and Methods: A CLUE-S (Conversion of Land Use and its Effects at Small Scales) model was developed for the Deep Creek watershed, a small sub-basin in the Okanagan Valley of British Columbia, Canada. The valley is experiencing among the most rapid population growth of any region in Canada. Land uses were aggregated into one forested land-use type, one urban land-use type, and three agricultural types. Land-use change was simulated for combinations of two forest conservation policies. Changes are categorized by location, land type, and an existing agricultural land policy. Results: Forest conservation policies drive land conversion onto agricultural land and may increase the loss of low elevation forested land. Model results show where the greatest pressure for removing land from agriculture is likely to occur for each scenario. As an important corridor for species movement, the loss of low elevation forest land may have serious impacts on habitat connectivity. Conclusions: Forest conservation policies that do not account for feedbacks can have unintended consequences, such as increasing conversion pressures on other valued land uses. To avoid surprises, land-use planners and policy makers need to consider these interactions. Models such as CLUE-S can help identify these spatial impacts. Full article
(This article belongs to the Special Issue Watershed Scale Forest Restoration and Sustainable Development)
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Open AccessArticle
Local Participation in Forest Watershed Management: Design and Analysis of Experiences in Water Supply Micro-Basins with Forest Plantations in South Central Chile
Forests 2019, 10(7), 580; https://doi.org/10.3390/f10070580
Received: 1 May 2019 / Revised: 1 July 2019 / Accepted: 8 July 2019 / Published: 12 July 2019
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Abstract
The joint “International Forests and Water Conference 2018” highlighted among its main conclusions the need to involve the viewpoint and participation of local communities in the management and monitoring of forest watersheds. This topic constitutes a strategic and transverse challenge for the sciences [...] Read more.
The joint “International Forests and Water Conference 2018” highlighted among its main conclusions the need to involve the viewpoint and participation of local communities in the management and monitoring of forest watersheds. This topic constitutes a strategic and transverse challenge for the sciences and public policies in the current context of global climate change. As a contribution to this challenge, the aim of this research was to qualitatively describe and analyze a territorial intervention model based on two case studies. Both involve stakeholders from the public sector, forest companies, and rural communities within the framework of implementing a participatory process at a local scale. The first case study was based on the collective creation of a set of indicators for local water monitoring. The second case, through the incorporation of the social and local dimension, culminated in the collective creation of a forest watershed management guide. The research hypothesis was that the inclusion of stakeholders and local knowledge in forest watershed management is essential to create and/or strengthen local abilities that ensure the involvement of communities in water governance, surpassing the current informative and consultative approaches. The research methodology was qualitative, and the data collection strategies were focused on the compilation of the process, the participatory work, and gathering diverse local knowledge. The data analysis included content tabulation, including both local indicators and ones extracted from the guide. In both cases, the systematization process and the main empirical findings were included. Among the findings, it was observed that both the pilot of local indicators and the design of the forest watershed management guide confirmed that the main challenge of local participation is the effective inclusion of local knowledge in water governance. This ethical and methodological challenge must be approached more rigorously and with more commitment. Full article
(This article belongs to the Special Issue Managing Forests and Water for People under a Changing Environment)
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Open AccessArticle
Quantifying Impacts of National-Scale Afforestation on Carbon Budgets in South Korea from 1961 to 2014
Forests 2019, 10(7), 579; https://doi.org/10.3390/f10070579
Received: 31 May 2019 / Revised: 3 July 2019 / Accepted: 9 July 2019 / Published: 11 July 2019
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Abstract
Forests play an important role in regulating the carbon (C) cycle. The main objective of this study was to quantify the effects of South Korean national reforestation programs on carbon budgets. We estimated the changes in C stocks and annual C sequestration in [...] Read more.
Forests play an important role in regulating the carbon (C) cycle. The main objective of this study was to quantify the effects of South Korean national reforestation programs on carbon budgets. We estimated the changes in C stocks and annual C sequestration in the years 1961–2014 using Korea-specific models, a forest cover map (FCM), national forest inventory (NFI) data, and climate data. Furthermore, we examined the differences in C budgets between Cool forests (forests at elevations above 700 m) and forests in lower-altitude areas. Simulations including the effects of climate conditions on forest dynamics showed that the C stocks of the total forest area increased from 6.65 Tg C in 1961 to 476.21 Tg C in 2014. The model developed here showed a high degree of spatiotemporal reliability. The mean C stocks of the Cool forests and other forests increased from 4.03 and 0.43 Mg C ha−1, respectively, to 102.43 and 73.76 Mg C ha−1 at a rate of 1.82 and 1.36 Mg C ha−1 yr−1 during the same period. These results imply that, although the total Cool forest area of South Korea occupied only about 12.3% (772,788 ha) of the total forest area, the Cool forests play important roles in C balances and forest ecosystems in South Korea. Annual C sequestration totals are projected to decrease at a low rate in the near future because the overall growth rate of a mature forest decreases as the stand ages. Our results quantified forest C dynamics in South Korean forests before and after national reforestation programs. Furthermore, our results can help in development of regional and national forest management strategies to allow for sustainable development of society and to cope with climate change in South Korea. Full article
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Open AccessArticle
ASFORESEE: A Harmonized Model for Economic Evaluation of Forest Protection against Rockfall
Forests 2019, 10(7), 578; https://doi.org/10.3390/f10070578
Received: 17 May 2019 / Revised: 27 June 2019 / Accepted: 9 July 2019 / Published: 11 July 2019
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Abstract
Gravitational hazards, such as rockfall, constitute a major risk in mountainous areas, threatening dwellers, goods, and infrastructures, and ultimately posing a challenge to their development. Ecosystem-based solutions for Disaster Risk Reduction (Eco-DRR), such as protection forests, can play a significant role in mitigating [...] Read more.
Gravitational hazards, such as rockfall, constitute a major risk in mountainous areas, threatening dwellers, goods, and infrastructures, and ultimately posing a challenge to their development. Ecosystem-based solutions for Disaster Risk Reduction (Eco-DRR), such as protection forests, can play a significant role in mitigating these risks by integrating the protective structures currently adopted, which are often costly and could entail higher environmental impacts. This study develops an economic model called ASFORESEE (Alpine Space FORest Ecosystem Services Economic Evaluation) to assess the protective service forests provide against rockfall within a standardized framework adopting a precautionary approach. The Replacement Cost approach was adopted, measuring the protection effectiveness, the need for protection of the stakeholders and defining a harmonized method for the design of the defensive structures. Applying the model to a case study in the Italian Alps, the results show the forest has a relevant protective effect able to fulfil the stakeholders’ needs, with a value of 30,440 € ha−1, equal to 950 € ha−1 year−1, within the 25-year timespan considered. ASFORESEE could feasibly be adopted in other mountainous contexts, due to its harmonized structure reliant on minimal assumptions. Its adoption would foster the acknowledgment of the forest role and to further support the inclusion of Eco-DRR in local risk management plans. Full article
(This article belongs to the Special Issue Assessing, Valuing and Mapping Ecosystem Services)
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