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David Edwards - One of the best experts on this subject based on the ideXlab platform.
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detecting tropical Selective Logging with c band sar data may require a time series approach
Remote Sensing of Environment, 2021Co-Authors: Matthew G. Hethcoat, David Edwards, João M. B. Carreiras, Robert G. Bryant, S QueganAbstract:Abstract Selective Logging is the primary driver of forest degradation in the tropics and reduces the capacity of forests to harbour biodiversity, maintain key ecosystem processes, sequester carbon, and support human livelihoods. While the preceding decade has seen a tremendous improvement in the ability to monitor forest disturbances from space, large-scale (spatial and temporal) forest monitoring systems have almost universally relied on optical satellite data from the Landsat program, whose effectiveness is limited in tropical regions with frequent cloud cover. Synthetic aperture radar (SAR) data can penetrate clouds and have been utilized in forest mapping applications since the early 1990s, but only recently has SAR data been widely available on a scale sufficient to facilitate pan-tropical Selective Logging detection systems. Here, a detailed Selective Logging dataset from three lowland tropical forest regions in the Brazilian Amazon was used to assess the effectiveness of SAR data from Sentinel-1, RADARSAT-2, and Advanced Land Observing Satellite-2 Phased Arrayed L-band Synthetic Aperture Radar-2 (ALOS-2 PALSAR-2) for monitoring tropical Selective Logging. We built Random Forests models aimed at classifying pixel-based differences between logged and unlogged areas. In addition, we used the Breaks For Additive Season and Trend (BFAST) algorithm to assess if a dense time series of Sentinel-1 imagery displayed recognizable shifts in pixel values after Selective Logging. In general, Random Forests classification with SAR data (Sentinel-1, RADARSAT-2, and ALOS-2 PALSAR-2) performed poorly, having high commission and omission errors for logged observations. This suggests little to no difference in pixel-based metrics between logged and unlogged areas for these sensors, particularly at lower Logging intensities. In contrast, the Sentinel-1 time series analyses indicated that areas under higher intensity Selective Logging (> 20 m3 ha−1) show a distinct spike in the number of pixels that included a breakpoint during the Logging season. BFAST detected breakpoints in 50% of logged pixels and exhibited a false alarm rate of approximately 20 m3 ha−1) within the Amazon.
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Selective Logging reduces body size in omnivorous and frugivorous tropical forest birds
Biological Conservation, 2021Co-Authors: Simone Messina, Suzan Benedick, Cindy C. P. Cosset, David Costantini, Suzanne Tomassi, Marcel Eens, David EdwardsAbstract:Abstract Selective Logging is the main anthropogenic disturbance in tropical forests, driving shifts in species abundances. Body size and body condition are important metrics of fitness that may be affected by habitat degradation. We conducted a four-year study to investigate how Selective Logging impacted the body size and body condition index (BCI) of 55 Bornean bird species and whether changes in body metrics were associated with shifts in relative population abundance. Frugivorous and omnivorous birds had reduced body size in Selectively logged versus unlogged forest, but we found no evidence for Selective removal of individuals driven by sex differences or post-fledging body size, indicating different developmental conditions for frugivores and omnivores in logged forest. Change in body size between forest types showed no clear patterns for insectivorous birds, and did not differ between IUCN categories. BCI of birds was affected by study year, suggesting an effect of climatic conditions on food availability, but not by Logging. At the community level, post-Logging change in population abundance was not associated with reduced body size, although between species variation suggests that adverse environmental conditions and different coping strategies underlie body size reductions in logged forest. Our study suggests that body size is a valuable metric to assess how Logging impacts forest birds, pointing towards potential functional consequences related to seed dispersal within logged forests and need for improved silvicultural practices.
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Detecting tropical Selective Logging with SAR data requires a time series approach
2020Co-Authors: Matthew G. Hethcoat, David Edwards, Robert G. Bryant, Jmb Carreiras, Shaun QueganAbstract:Selective Logging is the primary driver of forest degradation in the tropics and reduces the capacity of forests to harbour biodiversity, maintain key ecosystem processes, sequester carbon, and support human livelihoods. While the preceding decade has seen a tremendous improvement in the ability to monitor forest disturbances from space, advances in forest monitoring have almost universally relied on optical satellite data from the Landsat program, whose effectiveness is limited in tropical regions with frequent cloud cover. Synthetic aperture radar (SAR) data can penetrate clouds and have been utilized in forest mapping applications since the early 1990s, but no study has exclusively used SAR data to map tropical Selective Logging. A detailed Selective Logging dataset from three lowland tropical forest regions in the Brazilian Amazon was used to assess the effectiveness of SAR data from Sentinel-1, RADARSAT-2 and PALSAR-2 for monitoring tropical Selective Logging. We built Random Forest models in an effort to classify pixel-based differences in logged and unlogged areas. In addition, we used the BFAST algorithm to assess if a dense time series of Sentinel-1 imagery displayed recognizable shifts in pixel values after Selective Logging. Random Forest classification with SAR data (Sentinel-1, RADARSAT-2, and ALOS-2 PALSAR-2) performed poorly, having high commission and omission errors for logged observations. This suggests little to no difference in pixel-based metrics between logged and unlogged areas for these sensors. In contrast, the Sentinel-1 time series analyses indicated that areas under higher intensity Selective Logging (> 20 m3 ha-1) show a distinct spike in the number of pixels that included a breakpoint during the Logging season. BFAST detected breakpoints in 50% of logged pixels and exhibited a false alarm rate of approximately 10% in unlogged forest. Overall our results suggest that SAR data can be used in time series analyses to detect tropical Selective Logging at high intensity Logging locations within the Amazon (> 20 m3 ha-1). These results have important implications for current and future abilities to detect Selective Logging with freely available SAR data from SAOCOM 1A, the planned continuation missions of Sentinel-1 (C and D), ALOS PALSAR-1 archives (expected to be opened for free access in 2020), and the upcoming launch of NISAR.
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Mass-abundance scaling in avian communities is maintained after tropical Selective Logging.
Ecology and evolution, 2020Co-Authors: Cindy C. P. Cosset, Matthew G. Hethcoat, James J. Gilroy, Umesh Srinivasan, David EdwardsAbstract:Selective Logging dominates forested landscapes across the tropics. Despite the structural damage incurred, Selectively logged forests typically retain more biodiversity than other forest disturbances. Most Logging impact studies consider conventional metrics, like species richness, but these can conceal subtle biodiversity impacts. The mass-abundance relationship is an integral feature of ecological communities, describing the negative relationship between body mass and population abundance, where, in a system without anthropogenic influence, larger species are less abundant due to higher energy requirements. Changes in this relationship can indicate community structure and function changes.We investigated the impacts of Selective Logging on the mass-abundance scaling of avian communities by conducting a meta-analysis to examine its pantropical trend. We divide our analysis between studies using mist netting, sampling the understory avian community, and point counts, sampling the entire community.Across 19 mist-netting studies, we found no consistent effects of Selective Logging on mass-abundance scaling relative to primary forests, except for the omnivore guild where there were fewer larger-bodied species after Logging. In eleven point-count studies, we found a more negative relationship in the whole community after Logging, likely driven by the frugivore guild, showing a similar pattern.Limited effects of Logging on mass-abundance scaling may suggest high species turnover in logged communities, with like-for-like replacement of lost species with similar-sized species. The increased negative mass-abundance relationship found in some logged communities could result from resource depletion, density compensation, or increased hunting; potentially indicating downstream impacts on ecosystem functions. Synthesis and applications. Our results suggest that size distributions of avian communities in logged forests are relatively robust to disturbance, potentially maintaining ecosystem processes in these forests, thus underscoring the high conservation value of logged tropical forests, indicating an urgent need to focus on their protection from further degradation and deforestation.
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A machine learning approach to map tropical Selective Logging
Remote Sensing of Environment, 2019Co-Authors: Matthew G. Hethcoat, David Edwards, João M. B. Carreiras, Robert G. Bryant, Filipe França, Shaun QueganAbstract:Abstract Hundreds of millions of hectares of tropical forest have been Selectively logged, either legally or illegally. Methods for detecting and monitoring tropical Selective Logging using satellite data are at an early stage, with current methods only able to detect more intensive timber harvest (>20 m3 ha−1). The spatial resolution of widely available datasets, like Landsat, have previously been considered too coarse to measure the subtle changes in forests associated with less intensive Selective Logging, yet most present-day Logging is at low intensity. We utilized a detailed Selective Logging dataset from over 11,000 ha of forest in Rondonia, southern Brazilian Amazon, to develop a Random Forest machine-learning algorithm for detecting low-intensity Selective Logging (
Plinio Sist - One of the best experts on this subject based on the ideXlab platform.
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Carbon recovery dynamics following disturbance by Selective Logging in Amazonian forests.
eLife, 2016Co-Authors: Camille Piponiot, Ervan Rutishauser, Plinio Sist, Marielos Peña-claros, Lucas Mazzei, Francis E. Putz, Alexander Shenkin, Nataly Ascarrunz, Celso Paulo De Azevedo, Christopher BaralotoAbstract:The Amazon rainforest in South America is the largest tropical forest in the world. Along with being home to a huge variety of plants and wildlife, rainforests also play an important role in storing an element called carbon, which is a core component of all life on Earth. Certain forms of carbon, such as the gas carbon dioxide, contribute to climate change so researchers want to understand what factors affect how much carbon is stored in rainforests. Trees and other plants absorb carbon dioxide from the atmosphere and then incorporate the carbon into carbohydrates and other biological molecules. The Amazon rainforest alone holds around 30% of the total carbon stored in land-based ecosystems. Humans Selectively harvest certain species of tree that produce wood with commercial value from the Amazon rainforest. This “Selective Logging” results in the loss of stored carbon from the rainforest, but the loss can be compensated for in the medium to long term if the forest is left to regrow. New trees and trees that survived the Logging grow to fill the gaps left by the felled trees. However, it is not clear how differences in the forest (for example, forest maturity), environmental factors (such as climate or soil) and the degree of the disturbance caused by the Logging affect the ability of the forest ecosystem to recover the lost carbon. Piponiot et al. used computer modeling to analyze data from over a hundred different forest plots across the Amazon rainforest. The models show that the forest’s ability to recover carbon after Selective Logging greatly differs between regions. For example, the overall amount of carbon recovered in the first ten years is predicted to be higher in a region in the north known as the Guiana Shield than in the south of the Amazonian basin where the climate is less favorable. The findings of Piponiot et al. highlight the key role the trees that survive Selective Logging play in carbon recovery. The next step would be to couple this model to historical maps of Logging to estimate how the areas of the rainforest that are managed by Selective Logging shape the overall carbon balance of the Amazon rainforest.
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Tree height reduction after Selective Logging in a tropical forest
Biotropica, 2016Co-Authors: Ervan Rutishauser, Bruno Hérault, Pascal Petronelli, Plinio SistAbstract:By harvesting scattered large trees, Selective Logging increases light availability and thereby stimulates growth and crown expansion at early-life stage among remnant trees. We assessed the effects of Logging on total and merchantable bole (i.e., lowest branch at crown base) heights on 952 tropical canopy trees in French Guiana. We observed reductions in both total (mean, _2.3 m) and bole (mean, _2.0 m) heights more than a decade after Selective Logging. Depending on local Logging intensity, height reductions resulted in 2–13 percent decreases in aboveground tree biomass and 3–17 percent decreases in bole volume. These results highlight the adverse effects of Logging at both tree and stand levels. This decrease in height is a further threat to future provision of key environmental services, such as timber production and carbon sequestration. (Resume d'auteur)
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Tree height reduction after Selective Logging in a tropical forest
Biotropica, 2016Co-Authors: Ervan Rutishauser, Bruno Hérault, Pascal Petronelli, Plinio SistAbstract:By harvesting scattered large trees, Selective Logging increases light availability and thereby stimulates growth and crown expansion at early-life stage among remnant trees. We assessed the effects of Logging on total and merchantable bole (i.e., lowest branch at crown base) heights on 952 tropical canopy trees in French Guiana. We observed reductions in both total (mean, -2.3 m) and bole (mean, -2.0 m) heights more than a decade after Selective Logging. Depending on local Logging intensity, height reductions resulted in 2-13 percent decreases in aboveground tree biomass and 3-17 percent decreases in bole volume. These results highlight the adverse effects of Logging at both tree and stand levels. This decrease in height is a further threat to future provision of key environmental services, such as timber production and carbon sequestration.
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limits of Selective Logging techniques including ril in tropical forests to sustain timber yields and to achieve sustainable forest management in general
International Forestry Review, 2010Co-Authors: Plinio Sist, Lucas Mazzei, Sylvie Gourletfleury, Lilian Blanc, Hari Priyadi, Ademir Roberto RuschelAbstract:Since the early 1950s, numerous silvicultural systems have been experimented in the tropics, particularly in Africa and Southeast Asia. However, most of the tropical countries adopted a polycyclic silvicultural system, also called Selective Logging. Over the past 2 decades, sets of timber harvesting practices known as reduced-impact Logging (RIL), designed to mitigate the deleterious environmental impacts of Logging operations, have been implemented mainly at the experimental scale in tropical forests. However, RIL techniques have also shown strong limitations in sustaining timber yield within a 30-40 year rotation as usually recommended in forest legislation in the tropics. Based on long-term forest dynamics monitoring of the impact of Selective Logging in permanent sample plots implemented in three continents (Central Africa, Indonesia, and Brazilian Amazon), this paper assesses the main impact of Selective Logging on forest dynamics and ecology of timber species. These results allow identification of the main limitations of Selective Logging, including RIL, to achieve both sustainable timber yield in particular and sustainable forest management in general in tropical forests. 5ilvicultural paradigms common to the three continents can be found, such as the need to Iimit Logging intensity and to define specific minimum and maximum diameter cutting. (Texte integral)
Gregory P Asner - One of the best experts on this subject based on the ideXlab platform.
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Selective Logging and its relation to deforestation
Geophysical monograph, 2013Co-Authors: Gregory P Asner, Michael Keller, Marco Lentini, Frank Merry, Carlos SouzaAbstract:Selective Logging is a major contributor to the social, economic, and ecological dynamics of Brazilian Amazonia. Logging activities have expanded from lowvolume floodplain harvests in past centuries to high-volume operations today that take about 25 million m3 of wood from the forest each year. The most common highimpact conventional and often illegal Logging practices result in major collateral forest damage, with cascading effects on ecosystem processes. Initial carbon losses and forest recovery rates following timber harvest are tightly linked to initial Logging intensity, which drives changes in forest gap fraction, fragmentation, and the light environment. Other ecological processes affected by Selective Logging include nutrient cycling, hydrological function, and postharvest disturbance such as fire. This chapter synthesizes the ecological impacts of Selective Logging, in the context of the recent socioeconomic conditions throughout Brazilian Amazonia, as determined from field-based and remote sensing studies carried out during the Large-Scale Biosphere-Atmosphere Experiment in Amazonia program.
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Amazonia and Global Change - Selective Logging and its relation to deforestation
2013Co-Authors: Gregory P Asner, Michael Keller, Marco Lentini, Frank Merry, Carlos SouzaAbstract:Selective Logging is a major contributor to the social, economic, and ecological dynamics of Brazilian Amazonia. Logging activities have expanded from lowvolume floodplain harvests in past centuries to high-volume operations today that take about 25 million m3 of wood from the forest each year. The most common highimpact conventional and often illegal Logging practices result in major collateral forest damage, with cascading effects on ecosystem processes. Initial carbon losses and forest recovery rates following timber harvest are tightly linked to initial Logging intensity, which drives changes in forest gap fraction, fragmentation, and the light environment. Other ecological processes affected by Selective Logging include nutrient cycling, hydrological function, and postharvest disturbance such as fire. This chapter synthesizes the ecological impacts of Selective Logging, in the context of the recent socioeconomic conditions throughout Brazilian Amazonia, as determined from field-based and remote sensing studies carried out during the Large-Scale Biosphere-Atmosphere Experiment in Amazonia program.
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Long‐term carbon loss and recovery following Selective Logging in Amazon forests
Global Biogeochemical Cycles, 2010Co-Authors: Maoyi Huang, Gregory P AsnerAbstract:[1] Amazon deforestation contributes significantly to global carbon (C) emissions. In comparison, the contribution from Selective Logging to atmospheric CO2 emissions, and its impact on regional C dynamics, is highly uncertain. Using a new geographically based modeling approach in combination with high resolution remote sensing data from 1999 to 2002, we estimate that C emissions were 0.04–0.05 Pg C yr−1 due to Selective Logging from a ∼2,664,960 km2 region of the Brazilian Amazon. Selective Logging was responsible for 15–19% higher carbon emissions than reported from deforestation (clear-cutting) alone. Our simulations indicated that forest carbon lost via Selective Logging lasts two to three decades following harvest, and that the original live biomass takes up to a century to recover, if the forests are not subsequently cleared. The two- to three-decade loss of carbon results from the biomass damaged by Logging activities, including leaves, wood, and roots, estimated to be 89.1 Tg C yr−1 from 1999 to 2002 over the study region, leaving 70.0 Tg C yr−1 and 7.9 Tg C yr−1 to accumulate as coarse woody debris and soil C, respectively. While avoided deforestation is central to crediting rain forest nations for reduced carbon emissions, the extent and intensity of Selective Logging are also critical to determining carbon emissions in the context of Reduced Emissions from Deforestation and Forest Degradation (REDD). We show that a combination of automated high-resolution satellite monitoring and detailed forest C modeling can yield spatially explicit estimates of harvest-related C losses and subsequent recovery in support of REDD and other international carbon market mechanisms.
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long term carbon loss and recovery following Selective Logging in amazon forests
AGUFM, 2009Co-Authors: Maoyi Huang, Gregory P AsnerAbstract:[1] Amazon deforestation contributes significantly to global carbon (C) emissions. In comparison, the contribution from Selective Logging to atmospheric CO2 emissions, and its impact on regional C dynamics, is highly uncertain. Using a new geographically based modeling approach in combination with high resolution remote sensing data from 1999 to 2002, we estimate that C emissions were 0.04–0.05 Pg C yr−1 due to Selective Logging from a ∼2,664,960 km2 region of the Brazilian Amazon. Selective Logging was responsible for 15–19% higher carbon emissions than reported from deforestation (clear-cutting) alone. Our simulations indicated that forest carbon lost via Selective Logging lasts two to three decades following harvest, and that the original live biomass takes up to a century to recover, if the forests are not subsequently cleared. The two- to three-decade loss of carbon results from the biomass damaged by Logging activities, including leaves, wood, and roots, estimated to be 89.1 Tg C yr−1 from 1999 to 2002 over the study region, leaving 70.0 Tg C yr−1 and 7.9 Tg C yr−1 to accumulate as coarse woody debris and soil C, respectively. While avoided deforestation is central to crediting rain forest nations for reduced carbon emissions, the extent and intensity of Selective Logging are also critical to determining carbon emissions in the context of Reduced Emissions from Deforestation and Forest Degradation (REDD). We show that a combination of automated high-resolution satellite monitoring and detailed forest C modeling can yield spatially explicit estimates of harvest-related C losses and subsequent recovery in support of REDD and other international carbon market mechanisms.
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Selective Logging changes forest phenology in the Brazilian Amazon: Evidence from MODIS image time series analysis
Remote Sensing of Environment, 2009Co-Authors: Alexander Koltunov, Gregory P Asner, Susan L. Ustin, Inez FungAbstract:Abstract We present a large-scale study of the relationships between Selective Logging and forest phenology in the Brazilian Amazon. Time-series analysis of MODIS satellite data of Selectively logged forests in Mato Grosso, Brazil, shows that relatively low levels (5–10%) of canopy damage cause significant and long-lasting (more than 3 years) changes in forest phenology. Partial clearing slows forest green-up in the dry season, progressively dries the canopy, and induces overall seasonal deficits in canopy moisture and greenness. Given large and increasing geographic extent of Selective Logging throughout Amazonia, this phenological disturbance has a potential to impact carbon and water fluxes, nutrient dynamics, and other functional processes in these forests.
Anna Oldén - One of the best experts on this subject based on the ideXlab platform.
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Windthrow in streamside key habitats: Effects of buffer strip width and Selective Logging
Forest Ecology and Management, 2020Co-Authors: Hennariikka Mäenpää, Maiju Peura, Panu Halme, Juha Siitonen, Mikko Mönkkönen, Anna OldénAbstract:Abstract Streamside forests are preserved from clear-cut Logging in production forests and protected with uncut buffer strips in many countries. However, buffer strips often remain narrow due to economic reasons and, therefore, provide weak protection against adverse edge effects of clear-cuts and are vulnerable to windthrow. Selective Logging of buffer strips is sometimes allowed to reduce their costs, but the decreased tree density may expose the buffer to higher occurrence of windthrow. We used a replicated two-factor experiment to assess the effects of buffer width (15 m or 30 m) and Selective Logging (0% or 30% of the basal area removed) on the risk of windthrow in boreal streamside forests in Finland. We examined the windthrown trees 12 years after experimental Logging at 29 sites and at seven unlogged control sites. In addition, we studied the influence of topography and the extent of clear-cut Logging in the surrounding forests on windthrow risk. The proportion of windthrown spruces at sites with 15 m buffer strips was, on the average, six times higher than at control sites and 2.5 times higher than at sites with 30 m buffer strips. In contrast, the proportion of windthrown spruces did not differ between sites with 30 m buffer strips and control sites. Selective Logging did not increase the risk of windthrow strongly. However, sites with Selectively logged 30 m buffers were slightly more prone to windthrow than control sites. The proportion of windthrown trees tended to increase with the extent of the adjacent clear-cut areas on both sides of the stream. We conclude that a 15 m buffer strip is not wide enough to protect streamside forests from substantial windthrow, while a 30 m buffer strip is sufficient in most cases. Selective Logging of 30 m buffers may be undertaken at sites that are not under a high risk of windthrow. If Selective Logging enables a wider buffer strip, it may be a better option for protecting the streamside habitat from substantial windthrow than leaving a narrow buffer strip. Moreover, clear-cut harvesting on both sides of the stream should be avoided if the aim is to prevent excessive windthrow.
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the effect of buffer strip width and Selective Logging on riparian forest microclimate
Forest Ecology and Management, 2019Co-Authors: Anna Oldén, Maiju Peura, Sonja Saine, Janne S. Kotiaho, Panu HalmeAbstract:Abstract Riparian forests have cool and humid microclimates, and one aim of leaving forested buffer strips between clear-cut areas and streams is to conserve these microclimatic conditions. We used an experimental study set up of 35 streamside sites to study the impacts of buffer strip width (15 or 30 m) and Selective Logging within the buffer strips on summer-time air temperature, relative air humidity and canopy openness 12 years after Logging. The buffer strip treatments were compared to unlogged control sites. We found that 15-meter buffer strips with or without Selective Logging and 30-meter buffer strips with Selective Logging were insufficient in maintaining temperature, relative humidity and canopy openness at similar levels than they were in control sites. In contrast, 30-meter buffer strips differed only little from control sites, although they did have significantly lower mean air humidity. Microclimatic changes were increased by southern or southwestern aspect of the clear-cut, and by Logging on the opposite side of the stream. We also tested how the cover of three indicator mosses (Hylocomium splendens, Pseudobryum cinclidioides and Polytrichum commune) had changed (from pre-Logging to 12 years post-Logging) in relation to post-Logging air temperature, relative air humidity and canopy openness. We found that each of the species responded to at least one of these physical conditions. Air humidity was the most significant variable for explaining changes in the cover of the indicator moss species, suggesting that the changes in this microclimatic component has biological impacts. We conclude that to preserve riparian microclimatic conditions and species dependent on those, buffer strips should exceed 30 m in width, and not be Selectively logged. Wider buffer strips are required if the clear-cut is towards south or southwest, or if the two sides of the stream are logged at the same time or during subsequent years.
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The effect of buffer strip width and Selective Logging on streamside plant communities.
BMC Ecology, 2019Co-Authors: Anna Oldén, E. Lehkonen, Ville Selonen, Janne S. KotiahoAbstract:Background Riparian forests surrounding streams host high biodiversity values, but are threatened by clear-cut Logging. Narrow buffer strips of about 15 m are commonly left between the stream and the clear-cut, but studies suggest that the buffer width should be at least 30 m to protect riparian plant communities. Moreover, Selective Logging is often allowed on the buffer strips in order to increase economic gain. We used an experiment of 43 riparian sites where buffer strip width and Selective Logging within the strip were manipulated and supplemented with unlogged control sites. We report the short-term changes in the community composition of vascular plants and mosses near the stream (0–15 m distance).
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The effect of buffer strip width and Selective Logging on streamside plant communities
BMC, 2019Co-Authors: Anna Oldén, E. Lehkonen, Ville Selonen, Janne S. KotiahoAbstract:Abstract Background Riparian forests surrounding streams host high biodiversity values, but are threatened by clear-cut Logging. Narrow buffer strips of about 15 m are commonly left between the stream and the clear-cut, but studies suggest that the buffer width should be at least 30 m to protect riparian plant communities. Moreover, Selective Logging is often allowed on the buffer strips in order to increase economic gain. We used an experiment of 43 riparian sites where buffer strip width and Selective Logging within the strip were manipulated and supplemented with unlogged control sites. We report the short-term changes in the community composition of vascular plants and mosses near the stream (0–15 m distance). Results 15-meter buffers are not enough to protect the vascular plant communities from changes caused by a clear-cut irrespective of the Selective Logging on the buffer strip. For moss communities 15-m buffers were not enough if they were Selectively logged. Relative to the control sites, we observed no significant changes in community composition of vascular plants or mosses in the sites with 30-m buffer strips, whether Selectively logged or not. Conclusions We conclude that buffer strips of 15 m are not sufficient to protect streamside plant communities even in the short term, but that buffers of 30 m should be left on both sides of the stream. Selective Logging appears not to have effects on buffers that are at least 30 m wide. Thus, it may be more reasonable to increase buffer width and to allow Selective Logging on the wider buffer in order to compensate for the economic losses than to leave all trees on a narrow and ecologically insufficient buffer
Bruno Hérault - One of the best experts on this subject based on the ideXlab platform.
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Tree height reduction after Selective Logging in a tropical forest
Biotropica, 2016Co-Authors: Ervan Rutishauser, Bruno Hérault, Pascal Petronelli, Plinio SistAbstract:By harvesting scattered large trees, Selective Logging increases light availability and thereby stimulates growth and crown expansion at early-life stage among remnant trees. We assessed the effects of Logging on total and merchantable bole (i.e., lowest branch at crown base) heights on 952 tropical canopy trees in French Guiana. We observed reductions in both total (mean, _2.3 m) and bole (mean, _2.0 m) heights more than a decade after Selective Logging. Depending on local Logging intensity, height reductions resulted in 2–13 percent decreases in aboveground tree biomass and 3–17 percent decreases in bole volume. These results highlight the adverse effects of Logging at both tree and stand levels. This decrease in height is a further threat to future provision of key environmental services, such as timber production and carbon sequestration. (Resume d'auteur)
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Tree height reduction after Selective Logging in a tropical forest
Biotropica, 2016Co-Authors: Ervan Rutishauser, Bruno Hérault, Pascal Petronelli, Plinio SistAbstract:By harvesting scattered large trees, Selective Logging increases light availability and thereby stimulates growth and crown expansion at early-life stage among remnant trees. We assessed the effects of Logging on total and merchantable bole (i.e., lowest branch at crown base) heights on 952 tropical canopy trees in French Guiana. We observed reductions in both total (mean, -2.3 m) and bole (mean, -2.0 m) heights more than a decade after Selective Logging. Depending on local Logging intensity, height reductions resulted in 2-13 percent decreases in aboveground tree biomass and 3-17 percent decreases in bole volume. These results highlight the adverse effects of Logging at both tree and stand levels. This decrease in height is a further threat to future provision of key environmental services, such as timber production and carbon sequestration.
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contrasting taxonomic and functional responses of a tropical tree community to Selective Logging
Journal of Applied Ecology, 2012Co-Authors: Bruno Hérault, Christopher Baraloto, Lilian Blanc, Helene Massot, Damien Bonal, Jean-françois Molino, C Timothy E Paine, Ericandre NicoliniAbstract:1. Considerable debate surrounds the extent to which tropical forests can be managed for resource extraction while conserving biodiversity and ecosystem properties, which depend on functional composition. Here we evaluate the compatibility of these aims by examining the effects of Logging on taxonomic and functional diversity and composition in a tropical forest. 2. Twenty years after Selective Logging, we inventoried 4140 stems regenerating in Logging gaps and adjacent undisturbed areas, and we integrated a database of 13 functional traits describing leaf and wood economics of tropical trees. 3. We found no differences in taxonomic and functional richness among habitats, but Logging gaps had significantly higher taxonomic and functional evenness. 4. Logging also effected striking, long-term changes in both species and functional composition. In particular, the xylem density of recruits in Logging gaps was 6% less than in unlogged forests, leaves were 11%less tough and had 6-13%greater mineral nutrient concentrations. 5. Synthesis and applications. Our results suggest that managers of tropical forests should limit overall surface area converted to Logging gaps by creating fewer, larger gaps during Selective Logging, to reduce impacts on the taxonomic and functional composition of the regenerating stand. (Resume d'auteur)
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Contrasting taxonomic and functional responses of a tropical tree community to Selective Logging
Journal of Applied Ecology, 2012Co-Authors: Christopher Baraloto, Bruno Hérault, Lilian Blanc, Timothy Charles Eliot Paine, Helene Massot, Damien Bonal, Jean-françois Molino, Daniel SabatierAbstract:1. Considerable debate surrounds the extent to which tropical forests can be managed for resource extraction while conserving biodiversity and ecosystem properties, which depend on functional composition. Here we evaluate the compatibility of these aims by examining the effects of Logging on taxonomic and functional diversity and composition in a tropical forest. 2. Twenty years after Selective Logging, we inventoried 4140 stems regenerating in Logging gaps and adjacent undisturbed areas, and we integrated a database of 13 functional traits describing leaf and wood economics of tropical trees. 3. We found no differences in taxonomic and functional richness among habitats, but Logging gaps had significantly higher taxonomic and functional evenness. 4. Logging also effected striking, long-term changes in both species and functional composition. In particular, the xylem density of recruits in Logging gaps was 6% less than in unlogged forests, leaves were 11% less tough and had 613% greater mineral nutrient concentrations. 5. Synthesis and applications. Our results suggest that managers of tropical forests should limit overall surface area converted to Logging gaps by creating fewer, larger gaps during Selective Logging, to reduce impacts on the taxonomic and functional composition of the regenerating stand.
