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Forests, Volume 8, Issue 8 (August 2017)

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Cover Story (view full-size image) Using the 2016 gypsy moth (Lymantria dispar) outbreak in Southern New England as a case study, the [...] Read more.
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Open AccessArticle Land-Use Redistribution Compensated for Ecosystem Service Losses Derived from Agriculture Expansion, with Mixed Effects on Biodiversity in a NW Argentina Watershed
Forests 2017, 8(8), 303; https://doi.org/10.3390/f8080303
Received: 21 June 2017 / Revised: 12 August 2017 / Accepted: 14 August 2017 / Published: 18 August 2017
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Abstract
Areas of land abandonment and agriculture expansion usually differ in location and associated environmental characteristics; thus, land-use redistribution affects the provision of ecosystem services and biodiversity conservation. In a subtropical region undergoing land redistribution patterns characteristic of Latin America, we estimated 20-year changes
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Areas of land abandonment and agriculture expansion usually differ in location and associated environmental characteristics; thus, land-use redistribution affects the provision of ecosystem services and biodiversity conservation. In a subtropical region undergoing land redistribution patterns characteristic of Latin America, we estimated 20-year changes in food production, above-ground carbon stocks and soil erosion due to land cover change, and the potential effects of such redistribution of forests on the diversity of birds and mammals. Between 1986 and 2006, despite only 0.3% of net forest cover change, 7% of the total area (ca. 280,000 has) switched between forest and non-forest covers. Food production increased by 46%, while the estimated ecosystem services changed by less than 10%. Forest carbon remained stable, with gains in montane humid forests compensating for losses in lowlands. Modeled soil erosion increased, but sediment accumulation at the watershed bottom remained stable. The responses of birds and mammals to forest redistribution differed and were stronger in birds. Due to the strong responses of birds to forest loss, lowland bird communities might be especially threatened by current land-use trends. Results suggest that land redistribution associated with the adjustment of agriculture towards soils suitable for mechanized agriculture can help mitigate associated losses in ecosystem services and biodiversity, but species and supporting services depending on easily-converted ecosystems require appropriate landscape management practices. Full article
(This article belongs to the Special Issue How Topography Impacts Forests under Global Change?)
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Open AccessArticle Use of Multi-Temporal UAV-Derived Imagery for Estimating Individual Tree Growth in Pinus pinea Stands
Forests 2017, 8(8), 300; https://doi.org/10.3390/f8080300
Received: 7 July 2017 / Revised: 1 August 2017 / Accepted: 10 August 2017 / Published: 18 August 2017
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Abstract
High spatial resolution imagery provided by unmanned aerial vehicles (UAVs) can yield accurate and efficient estimation of tree dimensions and canopy structural variables at the local scale. We flew a low-cost, lightweight UAV over an experimental Pinus pinea L. plantation (290 trees distributed
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High spatial resolution imagery provided by unmanned aerial vehicles (UAVs) can yield accurate and efficient estimation of tree dimensions and canopy structural variables at the local scale. We flew a low-cost, lightweight UAV over an experimental Pinus pinea L. plantation (290 trees distributed over 16 ha with different fertirrigation treatments) to determine the tree positions and to estimate individual tree height (h), diameter (d), biomass (wa), as well as changes in these variables between 2015 and 2017. We used Structure from Motion (SfM) and 3D point cloud filtering techniques to generate the canopy height model and object-based image analysis to delineate individual tree crowns (ITC). ITC results were validated using accurate field measurements over a subsample of 50 trees. Comparison between SfM-derived and field-measured h yielded an R2 value of 0.96. Regressions using SfM-derived variables as explanatory variables described 79% and 86–87% of the variability in d and wa, respectively. The height and biomass growth estimates across the entire study area for the period 2015–2017 were 0.45 m ± 0.12 m and 198.7 ± 93.9 kg, respectively. Significant differences (t-test) in height and biomass were observed at the end of the study period. The findings indicate that the proposed method could be used to derive individual-tree variables and to detect spatio-temporal changes, highlighting the potential role of UAV-derived imagery as a forest management tool. Full article
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Open AccessArticle Climate-Induced Northerly Expansion of Siberian Silkmoth Range
Forests 2017, 8(8), 301; https://doi.org/10.3390/f8080301
Received: 15 June 2017 / Revised: 20 July 2017 / Accepted: 10 August 2017 / Published: 16 August 2017
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Abstract
Siberian silkmoth (Dendrolimus sibiricus Tschetv.) is a dangerous pest that has affected nearly 2.5 × 106 ha of “dark taiga” stands (composed of Abies sibirica, Pinus sibirica and Picea obovata) within the latitude range of 52°–59° N. Here we
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Siberian silkmoth (Dendrolimus sibiricus Tschetv.) is a dangerous pest that has affected nearly 2.5 × 106 ha of “dark taiga” stands (composed of Abies sibirica, Pinus sibirica and Picea obovata) within the latitude range of 52°–59° N. Here we describe a current silkmoth outbreak that is occurring about half degree northward of its formerly documented outbreak range. This outbreak has covered an area of about 800 thousand ha with mortality of conifer stands within an area of about 300 thousand ha. The primary outbreak originated in the year 2014 within stands located on gentle relatively dry southwest slopes at elevations up to 200 m above sea level (a.s.l.) Then the outbreak spread to the mesic areas including northern slopes and the low-elevation forest belts along the Yenisei ridge. Within the outbreak area, the northern Siberian silkmoth population has reduced generation length from two to one year. Our study showed that the outbreak was promoted by droughts in prior years, an increase of the sum of daily temperatures (t > +10 °C), and a decrease in ground cover moisture. Within the outbreak area, secondary pests were also active, including the aggressive Polygraphus proximus bark borer beetle. The outbreak considered here is part of the wide-spread (panzonal) Siberian silkmoth outbreak that originated during 2014–2015 with a range of up to 1000 km in southern Siberia. Our work concludes that observed climate warming opens opportunities for Siberian silkmoth migration into historically outbreak free northern “dark taiga” stands. Full article
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Open AccessFeature PaperArticle The Impact of Water Content on Sources of Heterotrophic Soil Respiration
Forests 2017, 8(8), 299; https://doi.org/10.3390/f8080299
Received: 13 June 2017 / Revised: 7 August 2017 / Accepted: 11 August 2017 / Published: 16 August 2017
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Abstract
Heterotrophic respiration (RH) is a major flux of CO2 from forest ecosystems and represents a large source of uncertainty in estimating net ecosystem productivity (NEP) using regional soil respiration (RS) models. RH from leaf litter (RHL
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Heterotrophic respiration (RH) is a major flux of CO2 from forest ecosystems and represents a large source of uncertainty in estimating net ecosystem productivity (NEP) using regional soil respiration (RS) models. RH from leaf litter (RHL) may contribute greatly to annual RH estimates, but its contribution may be misrepresented due to the logistical and technical challenges associated with chamber-based field measurements of RHL. The purpose of this study was to evaluate the sensitivity of sources of RH (mineral soil-derived heterotrophic respiration [RHM] and leaf litter-derived heterotrophic respiration [RHL]) of a loblolly pine plantation (Pinus taeda L.) to varying soil and litter water content over the course of a dry down event. Additionally, we investigated whether fertilization influenced RHL and RHM to understand how forest nutrient management may impact forest soil carbon (C) dynamics. RHL was measured under dry conditions and at field capacity to evaluate water content controls on RHL, determine the duration of increased CO2 release following wetting, and evaluate the potential contribution to total RH. We also measured RHM inside collars that excluded plant roots and litter inputs, from field capacity until near-zero RHM rates were attained. We found that RHL was more sensitive to water content than RHM, and increased linearly with increasing litter water content (R2 = 0.89). The contribution of RHL to RH was greatest immediately following the wetting event, and decreased rapidly to near-zero rates between 3 and 10 days. RHM also had a strong relationship with soil water content (R2 = 0.62), but took between 200 and 233 days to attain near-zero RHM rates. Fertilization had no effect on RHM (p = 0.657), but significantly suppressed RHL rates after the wetting event (p < 0.009). These results demonstrate that there is great temporal variability in both CO2 released and the water content of differing sources of RH, and forest fertilization may largely impact forest floor C stocks. This variability may not be captured reliably using conventional weekly to monthly chamber-based field sampling efforts and could lead to over- or underestimation of RH. In the context of climate change, changes in the frequency and intensity of wetting and drying events will likely alter RHL and its contribution to RS. Separate consideration of RH sources and controls, along with increased field sampling frequency using chamber-based methodology under a broader range of specific environmental conditions, are likely needed to reduce variability in RH estimates and improve the accuracy of forest NEP predictions. Full article
(This article belongs to the collection Forests Carbon Fluxes and Sequestration)
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Open AccessFeature PaperArticle How Climate Change Will Affect Forest Composition and Forest Operations in Baden-Württemberg—A GIS-Based Case Study Approach
Forests 2017, 8(8), 298; https://doi.org/10.3390/f8080298
Received: 6 June 2017 / Revised: 10 August 2017 / Accepted: 13 August 2017 / Published: 16 August 2017
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Abstract
In order to accommodate foreseen climate change in European forests, the following are recommended: (i) to increase the number of tree species and the structural diversity; (ii) to replace unsuitable species by native broadleaved tree species, and (iii) to apply close-to-nature silviculture. The
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In order to accommodate foreseen climate change in European forests, the following are recommended: (i) to increase the number of tree species and the structural diversity; (ii) to replace unsuitable species by native broadleaved tree species, and (iii) to apply close-to-nature silviculture. The state forest department of Baden-Württemberg (BW) currently follows the concept of Forest Development Types (FDTs). However, future climatic conditions will have an impact on these types of forest as well as timber harvesting operations. This Geographic Information System (GIS)-based analysis identified appropriate locations for main FDTs and timber harvesting and extraction methods through the use of species suitability maps, topography, and soil sensitivity data. Based on our findings, the most common FDT in the state forest of BW is expected to be coniferous-beech mixed forests with 29.0% of the total forest area, followed by beech-coniferous (20.5%) and beech-broadleaved (15.4%) mixed forests. Where access for fully mechanized systems is not possible, the main harvesting and extraction methods would be motor manual felling and cable yarding (29.1%). High proportions of large dimensioned trees will require timber extraction using forestry tractors, and these will need to be operated from tractor roads on sensitive soils (23.0%), and from skid trails on insensitive soils (18.4%). Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
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Open AccessArticle Comparison of Heat Transfer and Soil Impacts of Air Curtain Burner Burning and Slash Pile Burning
Forests 2017, 8(8), 297; https://doi.org/10.3390/f8080297
Received: 8 July 2017 / Revised: 6 August 2017 / Accepted: 10 August 2017 / Published: 16 August 2017
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Abstract
We measured soil heating and subsequent changes in soil properties between two forest residue disposal methods: slash pile burning (SPB) and air curtain burner (ACB). The ACB consumes fuels more efficiently and safely via blowing air into a burning container. Five burning trials
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We measured soil heating and subsequent changes in soil properties between two forest residue disposal methods: slash pile burning (SPB) and air curtain burner (ACB). The ACB consumes fuels more efficiently and safely via blowing air into a burning container. Five burning trials with different fuel sizes were implemented in northern California, USA. Soil temperature was measured at 1, 2, 3, 4, 6, and 8 cm depth. Immediately after burning, soil samples from two depths (0–10 and 10–20 cm) and ash samples were collected for analyzing organic matter; carbon and nitrogen content; and calcium, magnesium, and potassium concentrations. The highest temperature observed was 389 °C at 1 cm depth under the SPB. Mean peak temperatures were 133.2 °C and 162.2 °C for ACB and SPB, respectively. However, there were no significant differences in peak temperatures and duration of lethal soil temperatures (total minutes over 60 °C) between ACB and SPB. Heat transfer decreased rapidly as the soil depth increased. There is little evidence that any subsequent changes in soil chemical properties occurred, concluding that these small-scale burns had few negative impacts at our study site. Therefore, given the lack of extreme soil heating and more efficient and safer woody residue reduction, the ACB may be more effective than open SPB, especially where fire escape or long-term fire damage to soils are of concern. Full article
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Open AccessArticle Air Curtain Burners: A Tool for Disposal of Forest Residues
Forests 2017, 8(8), 296; https://doi.org/10.3390/f8080296
Received: 17 July 2017 / Revised: 9 August 2017 / Accepted: 10 August 2017 / Published: 14 August 2017
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Abstract
Open pile burning (OPB) forest residues have been limited due to several concerns, including atmospheric pollution, risk of fire spread, and weather conditions restrictions. Air Curtain Burner (ACB) systems could be an alternative to OPB and can avoid some of the negative effects
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Open pile burning (OPB) forest residues have been limited due to several concerns, including atmospheric pollution, risk of fire spread, and weather conditions restrictions. Air Curtain Burner (ACB) systems could be an alternative to OPB and can avoid some of the negative effects that may result from OPB. The main objective was to compare the burning consumption rates and costs of two types of ACB machines, the S-220 and BurnBoss. In addition, we tested a hand-pile burning (HPB) consumption rate for a comparison with BurnBoss unit. The S-220’s burning consumption rates ranged between 5.7 and 6.8 green metric ton (GmT)/scheduled machine hour (SMH) at a cost between US $12.8 and US $10.8/GmT, respectively. Costs were 70% higher when using the BurnBoss unit. Burning residue consumption rates and cost of disposal were considerably different: they were highly dependent on machine size, species, and fuel age of forest residues. Particularly, BurnBoss test burned over 40% more than HPB method and produced clean burn by airflow. The results from this study suggest that ACBs can be a useful tool to dispose of forest residues piled in many forests areas with less concerns of air quality and fire escape risks. Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
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Open AccessReview A Review of Carbon Forest Development in China
Forests 2017, 8(8), 295; https://doi.org/10.3390/f8080295
Received: 11 May 2017 / Revised: 7 August 2017 / Accepted: 10 August 2017 / Published: 13 August 2017
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Abstract
This paper provides an overview of China’s climate mitigation policy related to the forestry sector, with a special focus on the development of carbon forests which are established to mitigate climate change. A total of 3.5 million ha of carbon forest were planted
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This paper provides an overview of China’s climate mitigation policy related to the forestry sector, with a special focus on the development of carbon forests which are established to mitigate climate change. A total of 3.5 million ha of carbon forest were planted in the past decade. In recent years, the number of Voluntary Emission Reduction forest carbon projects has increased rapidly. The main challenges for future development of carbon forests under market mechanisms include increasing costs, uncertainty in the future supply and demand for China-certified emission reduction, and potential disputes between households and project developers. Full article
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Open AccessArticle Environmental Factors Driving the Recovery of Bay Laurels from Phytophthora ramorum Infections: An Application of Numerical Ecology to Citizen Science
Forests 2017, 8(8), 293; https://doi.org/10.3390/f8080293
Received: 24 July 2017 / Revised: 8 August 2017 / Accepted: 10 August 2017 / Published: 13 August 2017
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Abstract
Phytophthora ramorum is an alien and invasive plant pathogen threatening forest ecosystems in Western North America, where it can cause both lethal and non-lethal diseases. While the mechanisms underlying the establishment and spread of P. ramorum have been elucidated, this is the first
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Phytophthora ramorum is an alien and invasive plant pathogen threatening forest ecosystems in Western North America, where it can cause both lethal and non-lethal diseases. While the mechanisms underlying the establishment and spread of P. ramorum have been elucidated, this is the first attempt to investigate the environmental factors driving the recovery of bay laurel, the main transmissive host of the pathogen. Based on a large dataset gathered from a citizen science program, an algorithm was designed, tested, and run to detect and geolocate recovered trees. Approximately 32% of infected bay laurels recovered in the time period between 2005 and 2015. Monte Carlo simulations pointed out the robustness of such estimates, and the algorithm achieved an 85% average rate of correct classification. The association between recovery and climatic, topographic, and ecological factors was assessed through a numerical ecology approach mostly based on binary logistic regressions. Significant (p < 0.05) coefficients and the information criteria of the models showed that the probability of bay laurel recovery increases in association with high temperatures and low precipitation levels, mostly in flat areas. Results suggest that aridity might be a key driver boosting the recovery of bay laurels from P. ramorum infections. Full article
(This article belongs to the Special Issue Forest Pathology and Plant Health) Printed Edition available
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Open AccessFeature PaperCommunication Differential Effects of Coarse Woody Debris on Microbial and Soil Properties in Pinus densiflora Sieb. et Zucc. Forests
Forests 2017, 8(8), 292; https://doi.org/10.3390/f8080292
Received: 25 July 2017 / Revised: 8 August 2017 / Accepted: 10 August 2017 / Published: 11 August 2017
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Abstract
Although coarse woody debris (CWD) is important for soil functioning, the mechanism which affects soil properties beneath CWD are unclear. Here, initial changes in microbial and soil properties were studied using homogenous CWD samples in eight Korean red pine (Pinus densiflora Sieb.
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Although coarse woody debris (CWD) is important for soil functioning, the mechanism which affects soil properties beneath CWD are unclear. Here, initial changes in microbial and soil properties were studied using homogenous CWD samples in eight Korean red pine (Pinus densiflora Sieb. et Zucc.) forests. For each forest, CWD samples (diameter: 11.1 ± 0.1 cm; length: 10.2 ± 0.0 cm) from similarly aged Korean red pine trees were laid on the mineral soil surface from May to June, 2016, and soils were sampled at points beneath CWD and at a distance of 1 m from the CWD after 1 year. Soils beneath the CWD had higher moisture but lower inorganic nitrogen (N) and a higher microbial biomass C (carbon)/N ratio than those sampled 1 m from the CWD. No differences in total C and N, labile C, pH, and C substrate utilization between the soils were significant. The difference in inorganic N between the soils decreased with increasing CWD decomposition, whereas that for microbial biomass fraction in total C and N increased correspondingly. Our results showed that soil microbial affinity for retaining N might become higher than that for retaining C under the presence of CWD, which possibly alters N availability and generates a spatial heterogeneity in forest soils. Full article
(This article belongs to the Special Issue Coarse Woody Debris of Forests in a Changing World)
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Open AccessArticle Carbon Emissions from Deforestation and Degradation in a Forest Reserve in Venezuela between 1990 and 2015
Forests 2017, 8(8), 291; https://doi.org/10.3390/f8080291
Received: 20 May 2017 / Revised: 4 August 2017 / Accepted: 10 August 2017 / Published: 11 August 2017
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Abstract
This study presents for the first time in Venezuela a joint analysis of deforestation and forest degradation processes, including its effects on carbon emissions. The Caparo Forest Reserve, located in the Western Plains ecoregion, in one of the national hot spots of deforestation,
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This study presents for the first time in Venezuela a joint analysis of deforestation and forest degradation processes, including its effects on carbon emissions. The Caparo Forest Reserve, located in the Western Plains ecoregion, in one of the national hot spots of deforestation, served as a case study using three different periods: 1990–2000, 2000–2010 and 2010–2015. In the context of the United Nations Framework Convention on Climate Change (UNFCCC) framework, the Practice Guidance for Land Use, Land-Use Change and Forestry from the Intergovernmental Panel on Climate Change (IPCC) was followed. These guidelines combine the activity data for the estimation of deforestation and degradation rates, in this case using open access Landsat imagery in conjunction with the TerraAmazon system with the emission factors, and these based on aboveground biomass (AGB) estimations using field data from permanent plots monitored during the study period. Deforestation was responsible of a net loss of −53,461 ha, while close to −3667 ha were classified as degraded forests during the 1990–2000 decade (−4.9% annual deforestation rate). An estimated area of −36,447 ha and −515 ha between 2000 and 2010 was affected by both processes (−4.3% annual forest loss), and −8111 ha and −737 ha between 2010 and 2015 (−3.2% per year). These processes were responsible for an estimated equivalent in carbon emissions of 2.21 ± 0.32 (SEM—Standard Error of the Mean) Mt CO2 year−1 (1990–2000), 1.56 ± 0.19 Mt CO2per year between 2000 and 2010, while 0.80 ± 0.11 Mt CO2 year−1 during the 2010–2015 period. Between 92.9% and 98.63% (mean 94.9%) of these emissions came from deforestation, and between 1.37% and 7.79% (mean 5.1%) from forest degradation. Using available data, at national scale, deforestation and forest degradation in Caparo represented, on average, 0.49% of the total CO2 emissions and about 1.79% of land use change related emissions for the same period in Venezuela. Finally, we briefly outline a set of elements so these results can serve as a baseline for the potential establishment of a Reducing Emissions from Deforestation and Forest Degradation (REDD+) strategy in the area. Full article
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Open AccessArticle An Analysis of Non-State and State Approaches for Forest Certification in Mexico
Forests 2017, 8(8), 290; https://doi.org/10.3390/f8080290
Received: 27 June 2017 / Revised: 29 July 2017 / Accepted: 4 August 2017 / Published: 10 August 2017
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Abstract
Mexico has had a non-state forest certification system under the Forest Stewardship Council (FSC) since it was initiated in 1993, and developed a new state-sponsored Mexican Forest Certification System (MFCS) that began in 2008. Several analyses have been made of FSC forest certification
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Mexico has had a non-state forest certification system under the Forest Stewardship Council (FSC) since it was initiated in 1993, and developed a new state-sponsored Mexican Forest Certification System (MFCS) that began in 2008. Several analyses have been made of FSC forest certification in Mexico, but none have summarized the new MFCS system or compared its standards with FSC. We compare the implementation of the non-state FSC market forest certification with the state-sponsored MFCS system in Mexico, and review literature on forest certification, focusing on all studies in Mexico. MFCS has had substantial enrollment of more than 902,802 ha by 2016, compared to 900,388 ha for the more-established FSC program. MFCS can be acceptable for stand-alone forest certification, and might be viewed as a stepwise path to FSC certification. The merits of both systems are analyzed in terms of standard content, likely sustainable forestry practices, access to markets, and community forestry enterprises. Full article
(This article belongs to the Special Issue Sustainable Forest Management and Forest Certification)
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Open AccessArticle Irregular Shelterwood Cuttings Promote Viability of European Yew Population Growing in a Managed Forest: A Case Study from the Starohorské Mountains, Slovakia
Forests 2017, 8(8), 289; https://doi.org/10.3390/f8080289
Received: 26 June 2017 / Revised: 3 August 2017 / Accepted: 3 August 2017 / Published: 9 August 2017
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Abstract
The increasing probability of Taxus baccata (L.) decline given climate change brings forth many uncertainties for conservation management decisions. In this article, the authors present the effects of applying regeneration cuttings since the year 2000 on the viability of the understory yew population.
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The increasing probability of Taxus baccata (L.) decline given climate change brings forth many uncertainties for conservation management decisions. In this article, the authors present the effects of applying regeneration cuttings since the year 2000 on the viability of the understory yew population. By collecting data from a stand located at the centre of the largest population of European yew in Slovakia, containing approximately 160,000 individuals, and analysing tree-ring records from 38 sampled trees, the improved performance of yews, including stem growth, seed production, and number of regenerated individuals, was revealed. Thinning the canopy by removing 15% of the growing stock volume per decade, combined with the subsequent irregular shelterwood cuttings, was assessed as a useful strategy. Moreover, lower radial growth of females compared to males, but simultaneously their similar response to climate, suggests a possible trade-off between reproduction and growth. Release cuttings of up to 30% of the standing volume in the vicinity of the female trees, executed in the rainy summers following warmer winters, and consistent elimination of deer browsing, can further enhance the positive effects of applied cuts on yew viability. Overall, the suggested active measures could be considered as an effective option to preserve the unique biodiversity of calcareous beech-dominated forests in Central Europe. Full article
(This article belongs to the Special Issue Forest Sustainable Management)
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Open AccessArticle Mapping Tree Density in Forests of the Southwestern USA Using Landsat 8 Data
Forests 2017, 8(8), 287; https://doi.org/10.3390/f8080287
Received: 1 July 2017 / Revised: 1 August 2017 / Accepted: 4 August 2017 / Published: 9 August 2017
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Abstract
The increase of tree density in forests of the American Southwest promotes extreme fire events, understory biodiversity losses, and degraded habitat conditions for many wildlife species. To ameliorate these changes, managers and scientists have begun planning treatments aimed at reducing fuels and increasing
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The increase of tree density in forests of the American Southwest promotes extreme fire events, understory biodiversity losses, and degraded habitat conditions for many wildlife species. To ameliorate these changes, managers and scientists have begun planning treatments aimed at reducing fuels and increasing understory biodiversity. However, spatial variability in tree density across the landscape is not well-characterized, and if better known, could greatly influence planning efforts. We used reflectance values from individual Landsat 8 bands (bands 2, 3, 4, 5, 6, and 7) and calculated vegetation indices (difference vegetation index, simple ratios, and normalized vegetation indices) to estimate tree density in an area planned for treatment in the Jemez Mountains, New Mexico, characterized by multiple vegetation types and a complex topography. Because different vegetation types have different spectral signatures, we derived models with multiple predictor variables for each vegetation type, rather than using a single model for the entire project area, and compared the model-derived values to values collected from on-the-ground transects. Among conifer-dominated areas (73% of the project area), the best models (as determined by corrected Akaike Information Criteria (AICc)) included Landsat bands 2, 3, 4, and 7 along with simple ratios, normalized vegetation indices, and the difference vegetation index (R2 values for ponderosa: 0.47, piñon-juniper: 0.52, and spruce-fir: 0.66). On the other hand, in aspen-dominated areas (9% of the project area), the best model included individual bands 4 and 2, simple ratio, and normalized vegetation index (R2 value: 0.97). Most areas dominated by ponderosa, pinyon-juniper, or spruce-fir had more than 100 trees per hectare. About 54% of the study area has medium to high density of trees (100–1000 trees/hectare), and a small fraction (4.5%) of the area has very high density (>1000 trees/hectare). Our results provide a better understanding of tree density for identifying areas in need of treatment and planning for more effective treatment. Our analysis also provides an integrated method of estimating tree density across complex landscapes that could be useful for further restoration planning. Full article
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Open AccessFeature PaperArticle Estimation of Forest Biomass Patterns across Northeast China Based on Allometric Scale Relationship
Forests 2017, 8(8), 288; https://doi.org/10.3390/f8080288
Received: 30 June 2017 / Revised: 31 July 2017 / Accepted: 1 August 2017 / Published: 8 August 2017
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Abstract
This study develops a modeling framework for utilizing the large footprint LiDAR waveform data from the Geoscience Laser Altimeter System (GLAS) onboard NASA’s Ice, Cloud, and Land Elevation Satellite (ICESat), Moderate Resolution Imaging Spectro-Radiometer (MODIS) imagery, meteorological data, and forest measurements for monitoring
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This study develops a modeling framework for utilizing the large footprint LiDAR waveform data from the Geoscience Laser Altimeter System (GLAS) onboard NASA’s Ice, Cloud, and Land Elevation Satellite (ICESat), Moderate Resolution Imaging Spectro-Radiometer (MODIS) imagery, meteorological data, and forest measurements for monitoring stocks of total biomass (including aboveground biomass and root biomass). The forest tree height models were separately used according to the artificial neural network (ANN) and the allometric scaling and resource limitation (ASRL) tree height models which can both combine the climate data and satellite data to predict forest tree heights. Based on the allometric approach, the forest aboveground biomass model was developed from the field measured aboveground biomass data and the tree heights derived from two tree height models. Then, the root biomass should scale with the aboveground biomass. To investigate whether this approach is efficient for estimating forest total biomass, we used Northeast China as the object of study. Our results generally proved that the method proposed in this study could be meaningful for forest total biomass estimation (R2 = 0.699, RMSE = 55.86). Full article
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