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Selective logging can impact tree composition and the long-term sustainability of forests. Studying the ecological consequences of logging practices is crucial for guiding forest management strategies aiming at maintaining ecological integrity and supporting landscape-level conservation goals. We investigated the consequences of very low-intensity selective logging in multiple tree life stages across a logged forest chronosequence in Gabon. We found that species composition differed between logged and unlogged forests at all life stages (seedlings, saplings, and adults), which were most pronounced in the understory of older forests (logged 10 years prior) compared to unlogged areas. However, logging explained a small portion of the variation in species composition (

Evaluation and monitoring of forest biomass are important to help combat global warming and conserve biodiversity. Above ground biomass (AGB) mapping has been effectively used to assess forest loss, degradation, and recovery in the tropics. In this study, temporal (2007, 2010, and 2015) AGB maps were developed for the Mayan Zone of the Yucatan Peninsula, México integrating vegetation data from the National Forest Inventory (NFI) with synthetic aperture radar (SAR) image data (ALOS PALSAR). We assess if degradation could be attributed to the land use categories present in the study area: selectively logged forest, shifting agriculture, permanent commercial cultivation, and conservation forest. Spatial autoregressive models are applied to determine differences in AGB dynamics between land use categories, compared to baselines of mature conserved forest. We find that forest biomass remains stable in the study area. AGB does not differ in selectively logged areas compared to conserved mature forests. Biomass losses are observed due to deforestation for commercial cropping and pasture. AGB in shifting agriculture areas, however, fluctuates and shows a slight gain from 2007 to 2015. AGB mapping using NFI data and SAR imagery has the potential for monitoring forest loss and degradation on the Yucatan Peninsula. [ABSTRACT FROM AUTHOR]

Selective logging is one of the largest drivers of tropical forest degradation. While logged forests often retain high alpha‐diversity of tropical trees at local spatial scales, understanding how selective logging impacts tree beta‐diversity and community composition across far larger spatial scales remains a key unresolved question.We leverage large datasets of more than 155,000 adult trees over 35 cm DBH covering 3100 ha of Amazonian rainforest to inform simulations of selective logging harvests across a gradient of logging intensity (0–40 m3 ha−1). These simulations incorporate real world price data, account for all forest damage throughout the harvest process and assume preferential harvest of the most valuable stems. We use the simulations to assess how selective logging affects canopy tree beta‐diversity and composition across large spatial scales, whether nestedness or turnover of species best explains variation in communities across space, and how the spatial scale of sampling influences observed beta‐diversity effects.Selective logging had minimal impacts on beta‐diversity across the canopy tree community, but caused substantial subtractive heterogenization in community composition for larger trees, in particular very large trees over 110 cm DBH. Turnover is the dominant component of tree beta‐diversity in unlogged and logged forests. Increasing the spatial grain of sampling reduced the observed importance of logging in explaining patterns of beta‐diversity in very large tree communities.Synthesis and applications. Minimal impacts on tree beta‐diversity across large spatial scales points towards the retention of substantial conservation value in logged tropical forests. Strong subtractive heterogenization in very large trees indicates the breakdown of broad scale patterns of composition with potential negative consequences for recruitment processes, fauna reliant upon emergent trees, and other ecosystem functions and services. Avoiding large‐scale erosion of very large tree community composition in the Amazon requires stronger conservation policies, including enforced retention or maximum cutting diameters. [ABSTRACT FROM AUTHOR]

Selective logging is a major cause of forest degradation in the tropics, but its precise scale, location and timing are not known as wide-area, automated remote sensing methods are not yet available at this scale. This limits the abilities of governments to police illegal logging, or monitor (and thus receive payments for) reductions in degradation. Sentinel-1, a C-band Synthetic Aperture Radar satellite mission with a 12-day repeat time across the tropics, is a promising tool for this due to the known appearance of shadows in images where canopy trees are removed. However, previous work has relied on optical satellite data for calibration and validation, which has inherent uncertainties, leaving unanswered questions about the minimum magnitude and area of canopy loss this method can detect. Here, we use a novel bi-temporal LiDAR dataset in a forest degradation experiment in Gabon to show that canopy gaps as small as 0.02 ha (two 10 m × 10 m pixels) can be detected by Sentinel-1. The accuracy of our algorithm was highest when using a timeseries of 50 images over 20 months and no multilooking. With these parameters, canopy gaps in our study site were detected with a false alarm rate of 6.2%, a missed detection rate of 12.2%, and were assigned disturbance dates that were a good qualitative match to logging records. The presence of geolocation errors and false alarms makes this method unsuitable for confirming individual disturbances. However, we found a linear relationship ( r 2 = 0.74 ) between the area of detected Sentinel-1 shadow and LiDAR-based canopy loss at a scale of 1 hectare. By applying our method to three years' worth of imagery over Gabon, we produce the first national scale map of small-magnitude canopy cover loss. We estimate a total gross canopy cover loss of 0.31 Mha, or 1.3% of Gabon's forested area, which is a far larger area of change than shown in currently available forest loss alert systems using Landsat (0.022 Mha) and Sentinel-1 (0.019 Mha). Our results, which are made accessible through Google Earth Engine, suggest that this approach could be used to quantify the magnitude and timing of degradation more widely across tropical forests. [ABSTRACT FROM AUTHOR]

The soil carbon pool holds an enormous amount of carbon, making it the largest reservoir in the terrestrial ecosystem. However, there is growing concern that unsustainable logging methods damage the soil ecosystem, thus triggering the release of soil carbon into the atmosphere hence contributing to ongoing climate change. This study uses a replicated (n = 4) logging experiment to examine the impact of supervised logging with climber cutting (SLCC) and conventional logging (CL) on basic soil characteristics, litter input to soils, soil carbon pools, and soil respiration in a mixed dipterocarp forest 26 years after logging. This study found that there was no significant difference observed in the soil physicochemical properties and total carbon pools between the logging treatments and the virgin forest. Soil carbon pools dominated the total carbon pools, and the highest mean value was recorded in SLCC (87.95 ± 13.67 Mg C ha−1). Conventional logging had a lower mean value (71.17 ± 12.09 Mg C ha−1) than virgin forest (83.20 ± 11.97 Mg C ha−1). SLCC also shows a higher value of soil respiration rate (161.75 ± 21.67 mg C m−2 h−1) than CL (140.54 ± 12.54 mg C m−2 h−1). These findings highlight the importance of accurate quantification of the effect of different logging methods on the forest’s carbon pools.

Selective logging is among the main causes of tropical forest degradation, but little is known about its effects on greenhouse gas (GHG) fluxes from highly weathered Ferralsol soils in Africa. We measured soil CO2, N2O, and CH4 fluxes, and their soil controlling factors at two forests that had undergone conventional selective logging and reduced-impact logging in Cameroon. Each logging system had four replicate plots, each included the disturbed strata (road, logging deck, skidding trail, and felling gap) and an undisturbed reference area. Measurements were conducted monthly from September 2016 to October 2017. Annual GHG fluxes ranged from 4.9 to 18.6 Mg CO2–C, from 1.5 to 79 kg N2O–N, and from − 4.3 to 71.1 kg CH4–C ha−1 year−1. Compared to undisturbed areas, soil CO2 emissions were reduced and soil CH4 emissions increased in skidding trails, logging decks and roads (P < 0.01) whereas soil N2O emissions increased in skidding trails (P = 0.03–0.05). The combined disturbed strata had 28% decrease in soil CO2 emissions, 83% increase in soil N2O emissions, and seven times higher soil CH4 emissions compared to undisturbed area (P ≤ 0.01). However, the disturbed strata represented only 4–5% of the area impacted in both logging systems, which reduced considerably the changes in soil GHG fluxes at the landscape level. Across all strata, soil GHG fluxes were regulated by soil bulk density and water-filled pore space, indicating the influence of soil aeration and gas diffusion, and by soil organic carbon and nitrogen, suggesting the control of substrate availability on microbial processes of these GHG. [ABSTRACT FROM AUTHOR]

Birds are crucial in maintaining the balance of many ecosystems and provide various ecological services. Understanding their sensitivity to human disturbances should be prioritized in understudy areas for effective conservation practices. Using mist nets, this study characterized mostly understory bird communities (insectivorous, frugivorous, granivorous, and nectarivorous birds) in three habitat types (pristine forest, selectively logged forest, and young oil palm plantation) in the Talangaye rainforest, Southwest Cameroon. A total of 845 birds belonging to 27 families and 85 species were recorded in the three habitats after 294 h of mist netting. Overall, the mist-netted community was largely dominated by insectivores, followed by frugivores, nectarivores, granivores, and carnivores. Although mean species richness, abundance, and Simpson diversity index did not vary significantly among habitat types, mean species abundance and diversity index decreased in selectively logged forest and young oil palm plantation and species richness increased in both habitats. The species richness, abundance, and diversity index for insectivorous and frugivorous birds were lowest in the young oil palm plantations. For granivores, species richness and abundance increased following selective logging and the establishment of oil palm plantation. The highest mean species richness and diversity index in nectarivores were recorded in the young oil palm plantations. The study showed that selective logging and establishment of oil palm plantation had variable effects on the bird communities in the Talangaye rainforest. Also, the frugivorous birds appeared to be more sensitive to both types of disturbances, while the insectivores were more sensitive to habitat loss/conversion. [ABSTRACT FROM AUTHOR]

We combined measurements of tree growth and carbon dioxide exchange to investigate the effects of selective logging on the Aboveground Live Biomass (AGLB) of a tropical rain forest in the Amazon. Most of the measurements began at least 10 months before logging and continued at least 36 months after logging. The logging removed ∼15% of the trees with Diameter at Breast Height (DBH) greater than 35 cm, which resulted in an instantaneous 10% reduction in AGLB. Both wood production and mortality increased following logging, while Gross Primary Production (GPP) was unchanged. The ratio of wood production to GPP (the wood Carbon Use Efficiency or wood CUE) more than doubled following logging. Small trees (10 cm < DBH < 35 cm) accounted for most of the enhanced wood production. Medium trees (35 cm < DBH < 55 cm) that were within 30 m of canopy gaps created by the logging also showed increased growth. The patterns of enhanced growth are most consistent with logging-induced increases in light availability. The AGLB continued to decline over the study, as mortality outpaced wood production. Wood CUE and mortality remained elevated throughout the 3 years of postlogging measurements. The future trajectory of AGLB and the forest's carbon balance are uncertain, and will depend on how long it takes for heterotrophic respiration, mortality, and CUE to return to prelogging levels.

Highlights • Reduced Impact Logging lowers carbon emissions from selective logging. • Forest certification was not related to reduced carbon emissions. • Modified agricultural tractors for skidding significantly reduces emissions. Abstract On the Yucatan Peninsula in Mexico, communities (ejidos) that selectively log their forests help reduce deforestation and are an important source of timber for national and international markets. If carried out without proper planning and reduced-impact logging (RIL) practices, forest disturbances and carbon emissions from these harvests can be substantial. To assess variation in logging-induced emissions and to estimate potential reductions in those emissions, we estimated carbon impacts from damage to trees > 5 cm DBH in the annual cutting areas of ten forest-managing ejidos. Baselines were developed for emissions from felling, skidding and transport of timber and then ejidos were compared with respect to whether they were Forest Stewardship Council (FSC) certified, size of annual cutting area, logging intensity, and implementation of RIL practices, particularly directional felling, skid trail planning, and the use of small modified agricultural tractors instead of large forestry skidders. The carbon impacts of enrichment planting in multiple-tree felling gaps (400–1800 m2) were also evaluated. Carbon emissions from selective logging averaged 1.52 Mg m−3 but ranged 1.19–2.55 Mg m−3 among the 10 ejidos. Most emissions were from the remnants of trees felled for their timber (73%), followed by skidding (11%), transport infrastructure (i.e. logging roads and landings; 8%), and collateral damage from felling (7%). Our analyses indicate that FSC certification was not associated with any difference in carbon emissions from selective logging but that employment of RIL practices resulted in fewer damaged trees and lower carbon emissions even in ejidos with high logging intensities. Use of modified agricultural tractors for log yarding (i.e., skidding) reduced C emissions by 0.15 Mg m−3 or 5 Mg km−1 of skid trail. Greater collateral damage was found in multiple felling gaps but the increased emissions were offset by reductions in the remnants of harvest trees. Adoption of RIL-C practices by all community forestry ejidos in the region would contribute substantially to the Mexican forest sector's efforts to mitigate climate change. [ABSTRACT FROM AUTHOR]

Selective logging remains a widespread practice in tropical forests, yet the long‐term effects of timber harvest on juvenile tree (i.e., sapling) recruitment across the hundreds of species occurring in most tropical forests remain difficult to predict. This uncertainty could potentially exacerbate threats to some of the thousands of timber‐valuable tree species in the Amazon. Our objective was to determine to what extent long‐term responses of tree species regeneration in logged forests can be explained by their functional traits. We integrate functional trait data for 13 leaf, stem, and seed traits from 25 canopy tree species with a range of life histories, such as the pioneer Goupia glabra and the shade‐tolerant Iryanthera hostmannii, together with over 30 yr of sapling monitoring in permanent plots spanning a gradient of harvest intensity at the Paracou Forest Disturbance Experiment (PFDE), French Guiana. We anticipated that more intensive logging would increase recruitment of pioneer species with higher specific leaf area, lower wood densities, and smaller seeds, due to the removal of canopy trees. We define a recruitment response metric to compare sapling regeneration to timber harvest intensity across species. Although not statistically significant, sapling recruitment decreased with logging intensity for eight of 23 species and these species tended to have large seeds and dense wood. A generalized linear mixed model fit using specific leaf area, seed mass, and twig density data explained about 45% of the variability in sapling dynamics. Effects of specific leaf area outweighed those of seed mass and wood density in explaining recruitment dynamics of the sapling community in response to increasing logging intensity. The most intense treatment at the PFDE, which includes stand thinning of non‐timber‐valuable adult trees and poison‐girdling for competitive release, showed evidence of shifting community composition in sapling regeneration at the 30‐yr mark, toward species with less dense wood, lighter seeds, and higher specific leaf area. Our results indicate that high‐intensity logging can have lasting effects on stand regeneration dynamics and that functional traits can help simplify general trends of sapling recruitment for highly diverse logged tropical forests. [ABSTRACT FROM AUTHOR]

Dense time series of stripmap RADARSAT-2 data acquired in the Multilook Fine mode were used for detecting and mapping the extent of selective logging operations in the tropical forest area in the northern part of the Republic of the Congo. Due to limited radiometric sensitivity to forest biomass variation at C-band, basic multitemporal change detection approach was supplemented by spatial texture analysis to separate disturbed forest from intact. The developed technique primarily uses multi-temporal aggregation of orthorectified synthetic aperture radar (SAR) imagery that are acquired before and after the logging operations. The actual change analysis is based on textural features of the log-ratio image calculated using two SAR temporal composites compiled of SAR scenes acquired before and after the logging operations. Multitemporal aggregation and filtering of SAR scenes decreased speckle and made the extracted textural features more prominent. The overall detection accuracy was around 80%, with some underestimation of the area of forest disturbance compared to reference based on optical data. The user’s accuracy for disturbed forest varied from 76.7% to 94.9% depending on the accuracy assessment approach. We conclude that change detection utilizing RADARSAT-2 time series represents a useful instrument to locate areas of selective logging in tropical forests.

Advancements in satellite-based forest monitoring increasingly enable the near real-time detection of small-scale tropical forest disturbances. However, there is an urgent need to enhance such monitoring methods with automated direct driver attributions to detected disturbances. This would provide important additional information to make forest disturbance alerts more actionable and useful for uptake by different stakeholders. In this study, we demonstrate spatially explicit and near real-time methods to monitor direct drivers of small-scale tropical forest disturbance across a range of tropical forest conditions in Suriname, the Republic of the Congo and the Democratic Republic of the Congo. We trained a convolutional neural network with Sentinel-1 and Sentinel-2 data to continuously classify newly detected RAdar for Detecting Deforestation (RADD) alerts as smallholder agriculture, road development, selective logging, mining or other. Different monitoring scenarios were evaluated based on varying sensor combinations, post-disturbance time periods and confidence levels. In general, the use of Sentinel-2 data was found to be most accurate for driver classifications, especially with data composited over a period of 4 to 6 months after the disturbance detection. Sentinel-1 data showed to be valuable for more rapid classifications of specific drivers, especially in areas with persistent cloud cover. Throughout all monitoring scenarios, s mallholder agriculture was classified most accurately, while road development, selective logging and mining were more challenging to distinguish. An accuracy assessment throughout the full extent of our study regions revealed a Macro-F1 score of 0.861 and an Overall Accuracy of 0.897 for the best performing model, based on the use of 6-month post-disturbance Sentinel-2 composites. Finally, we addressed three specific monitoring use cases that relate to rapid law enforcement against illegal activities, ecological impact assessments and timely carbon emission reporting, by optimizing the trade-off in classification timeliness and confidence to reach required accuracies. Our findings demonstrate the strong capacities of high spatiotemporal resolution satellite data for monitoring direct drivers of small-scale forest disturbance, considering different user interests. The produced forest disturbance driver maps can be accessed via: https://bartslagter94.users.earthengine.app/view/forest-disturbance-drivers. • Direct drivers of small-scale forest disturbance were classified with Sentinel data. • Multiple near real-time monitoring scenarios were tested across tropical regions. • Sentinel-2 is generally most accurate for driver classifications. • Sentinel-1 is valuable for rapid classifications, especially in cloud-covered areas. • Driver monitoring methods can be adapted for specific user needs. [ABSTRACT FROM AUTHOR]

One of the main environmental threats in the tropics is selective logging, which has degraded large areas of forest. In southeast Asia, enrichment planting with seedlings of the dominant group of dipterocarp tree species aims to accelerate restoration of forest structure and functioning. The role of tree diversity in forest restoration is still unclear, but the 'insurance hypothesis' predicts that in temporally and spatially varying environments planting mixtures may stabilize functioning owing to differences in species traits and ecologies. To test for potential insurance effects, we analyse the patterns of seedling mortality and growth in monoculture and mixture plots over the first decade of the Sabah biodiversity experiment. Our results reveal the species differences required for potential insurance effects including a trade-off in which species with denser wood have lower growth rates but higher survival. This trade-offwas consistent over time during the first decade, but growth and mortality varied spatially across our 500 ha experiment with species responding to changing conditions in different ways. Overall, average survival rates were extreme in monocultures than mixtures consistent with a potential insurance effect in which monocultures of poorly surviving species risk recruitment failure, whereas monocultures of species with high survival have rates of selfthinning that are potentially wasteful when seedling stocks are limited. Longer-term monitoring as species interactions strengthen will be needed to more comprehensively test to what degree mixtures of species spread risk and use limited seedling stocks more efficiently to increase diversity and restore ecosystem structure and functioning. [ABSTRACT FROM AUTHOR]

The extent to which tropical rain forests recover tree species richness, composition and community structure after clear-cutting or selective harvest is controversial. Thus, the conservation value of forests regenerated after harvest remains unclear, but critically important for biodiversity., We sampled trees from 164 25 × 25 m quadrats across a 160-km2 tropical rain forest landscape on Hainan Island, China, which had been clear-cut or selectively harvested and left to recover without management for up to 50 years. Species richness and species abundance distributions were compared among five successional categories to investigate changes in species richness and species abundance over time. Basal areas and three different species similarity indices were compared to reveal temporal changes in species composition and community structure., Species richness recovered faster than species composition and structure in both selectively logged and clear-cut forests. Both total number of species and number of rare species tended to increase from younger harvested forests through older harvested forests to old-growth intact forests. Within 20-40 years after harvest species composition of harvested forests tended towards that of old-growth forests, community similarity between harvested and old-growth forests decreased subsequently and basal area did not recover, given even a half-century of succession undisturbed by anthropogenic forces., Shortly after harvest, pioneer species increased rapidly, but shade-tolerant species required much more time to recover to former abundances. The shift from pioneer species to shade-tolerant species indicates significant recovery of logged forests., Selectively logged forests recovered more quickly and had higher conservation values than clear-cut forests., Synthesis and applications. Our findings indicate that logged tropical forests only partially recovered the characteristics of pre-harvest, primary forest after a half-century of succession. Recovery of the original tree biodiversity on such post-harvest landscapes will be slow at best, if measured by species composition or stand structure. Our study amplifies the importance of conserving tropical forest integrity and developing harvest and management approaches that facilitate full recovery of logged tropical forests. [ABSTRACT FROM AUTHOR]

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The tension between the large global demand for tropical timber, and ecological sustainability and local socioeconomic development in the fragile natural ecosystems of the Amazon region has challenged many generations. In this case study, carried out in an ecotone forest in the northern Brazilian Amazon, we seek to demonstrate how forest management can became more sustainable through silvicultural prescriptions that reduce forest degradation and soil erosion. We evaluated the effects of the sustainable forest management (SFM) on tree diversity, timber volumes, and carbon stocks. A continuous forest inventory was carried out in nine 1-ha permanent plots (900 subplots of 100 m²), distributed in three treatments with three repetitions: T1 = control without selective logging, T2 = SFM, and T3 = SFM + silvicultural treatment of thinning release by tree girdling and poisoning. SFM was carried out with an average of three commercial timber trees harvested per hectare with DBH (diameter at breast height) ≥ 50 cm, corresponding to a timber volume of 20 ± 6 m3 ha-1, equivalent to the removal of 7 ± 2 Mg C ha-1 (5% of the original C). The formation of clearings (gaps) arising from the falling of exploited trees (0.12 ± 0.09 ha) resulted in greater impacts on the forest structure than the construction of 4 m skidder trails (0.06 ± 0.04 ha), with an average of 7 ± 4 damaged trees ha-1 and 5 ± 3 dead trees ha-1. Although six trees species became locally extinct, tree diversity was little altered, and timber volumes and forest carbon volume stocks remained essentially constant at this average logging intensity. Based on our results, sustainable forest management can become an efficient model for land use in the Amazon when harvesting is carried out using this average logging intensity. However, long-term monitoring studies using permanent plots in ecotone forests in the Brazilian Amazon will still be necessary. Quantifying, evaluating, and reporting impacts related to forest management will enable the formation of an empirical basis to support sustanaible forestry practices and for updating environmental legislation, contributing to local socioeconomic development, and maintaining the environmental services provided globally by tropical forests. • We evaluated the effects of selective logging and silvicultural treatments. • The mean intensity of logging (20 ± 6 m3 ha-1) did not alter tree diversity. • The greatest impact came from clearings created by falling commercial timber trees. • Forest carbon stock may alter depending on the selective logging intensity. [ABSTRACT FROM AUTHOR]

Selective logging is pervasive across the tropics and unsustainable logging depletes forest biodiversity and carbon stocks. Improving the sustainability of logging will be crucial for meeting climate targets. Carbon-based payment for ecosystem service schemes, including REDD+, give economic value to standing forests and can protect them from degradation, but only if the revenue from carbon payments is greater than the opportunity cost of forgone or reduced logging. We currently lack understanding of whether carbon payments are feasible for protecting Amazonian forests from logging, despite the Amazon holding the largest unexploited timber reserves and an expanding logging sector. Using financial data and inventories of >660,000 trees covering 52,000 ha of Brazilian forest concessions, we estimate the carbon price required to protect forests from logging. We estimate that a carbon price of $7.90 per tCO 2 is sufficient to match the opportunity costs of all logging and fund protection of primary forest. Alternatively, improving the sustainability of logging operations by ensuring a greater proportion of trees are left uncut requires only slightly higher investments of $7.97–10.45 per tCO 2. These prices fall well below the current compliance market rate and demonstrate a cost-effective opportunity to safeguard large tracts of the Amazon rainforest from further degradation. • $7.90/tCO2 can cost-effectively prevent selective logging in the Brazilian Amazon. • Reducing harvests to spare some trees is marginally more costly at $7.97–10.45/tCO2. • Partial protection drives carbon losses but retains low-value timber species. • Increased protection of high-value species requires a small additional investment. • Payment roll-out requires long-term engagement from Government and local people. [ABSTRACT FROM AUTHOR]

• Low-intensity selective logging had negligible effects on basal area. • Recently logged (one year since logging) forests had more heterogeneous canopy openness. • Older logged (ten years since logging) forests had slightly higher sapling diversity. • Older logged forests had higher relative liana abundances. • Liana removal techniques may be the most effective option for management improvement. Tropical forests are under threat of increasing pressure from income-generating land uses. Selective logging is a compromise that allows use of the land while leaving much of the forest canopy intact across a landscape. However, the ecological impacts of selective logging are unclear, with evidence of positive, negative, and negligible effects on forest structure and diversity. We examined the impact of selective logging on the structure and diversity of evergreen tropical forest in the Monts de Cristal region, a chain of mid-elevation hills in northwestern Gabon. For three size classes (seedling, sapling, and adult) of woody plant species, we tested whether forest structure (canopy openness, stem density, basal area, and relative liana abundances) and diversity were altered in forests that had been logged one year and ten years prior, compared to unlogged forest. In general, we found no large impact of selective logging treatment on the structure and diversity of adult woody plant communities, but the seedling and sapling communities were affected. Compared to unlogged forest, one-year post-logging forest had greater variation in canopy openness and lower sapling stem density. Ten-year post-logging forest had higher seedling and sapling species evenness, higher sapling species diversity, and higher relative abundance of sapling-sized lianas compared to unlogged forest. Our results show that key differences between intact and selectively logged forests persist in the understory at least a decade after logging. Overall, these results contribute an additional data point in the literature on selective logging, specifically representing the impacts of very low impact selective logging in Central African forests. Our study highlights the value of exploring selective logging impacts at multiple time periods of recovery, and makes an important contribution to the knowledge Central African managed forests. [ABSTRACT FROM AUTHOR]

The growth of trees in forest canopy gaps left by the felling of adult commercial trees has been shown to differ for individual ecological guilds of tree species and initial site conditions prior to logging. The objective of this study was to identify patterns in individual tree diameter growth both for the tree population overall and as a function of ecological guild in specific for undisturbed and selectively logged forest and compare between the two. Data came from two areas of non-flooded forest of the Brazilian Amazon in the states of Amazonas and Para for trees with dbh >10 cm. For purposes of statistical analysis tree species were clustered in three ecological guilds based on bole wood specific gravity and successional status. Tree growth irrespective of ecological species guild in the vicinity of logging gaps for the three year period following the harvest event was significantly more elevated in relation to undisturbed forest and this positive difference was proportionately greater for Amazonas in relation to Para. Ecological guilds showed a pattern of increasing growth rate with decreasing bole wood specific gravity and successional status when area and site disturbance status where not taken under account. In response to logging all ecological guilds showed increased growth rates but all were proportional to levels found in the undisturbed forest. Tree species life history characteristics appear to be a more significant factor affecting tree growth than site disturbance status in response to logging at least for the first 3 years after the logging event. [ABSTRACT FROM AUTHOR]

Animal-mediated seed dispersal is important for sustaining biological diversity in forest ecosystems, particularly in the tropics. Forest fragmentation, hunting, and selective logging modify forests in myriad ways and their effects on animal-mediated seed dispersal have been examined in many case studies. However, the overall effects of different types of human disturbance on animal-mediated seed dispersal are still unknown. We identified 35 articles that provided 83 comparisons of animal-mediated seed dispersal between disturbed and undisturbed forests; all comparisons except one were conducted in tropical or subtropical ecosystems. We assessed the effects of forest fragmentation, hunting, and selective logging on seed dispersal of fleshy-fruited tree species. We carried out a meta-analysis to test whether forest fragmentation, hunting, and selective logging affected 3 components of animal-mediated seed dispersal: frugivore visitation rate, number of seeds removed, and distance of seed dispersal. Forest fragmentation, hunting, and selective logging did not affect visitation rate and were marginally associated with a reduction in seed-dispersal distance. Hunting and selective logging, but not fragmentation, were associated with a large reduction in the number of seeds removed. Fewer seeds of large-seeded than of small-seeded tree species were removed in hunted or selectively logged forests. A plausible explanation for the consistently negative effects of hunting and selective logging on large-seeded plant species is that large frugivores, as the predominant seed dispersers for large-seeded plant species, are the first animals to be extirpated from hunted or logged forests. The reduction in forest area after fragmentation appeared to have weaker effects on frugivore communities and animal-mediated seed dispersal than hunting and selective logging. The differential effects of hunting and selective logging on large- and small-seeded tree species underpinned case studies that showed disrupted plant-frugivore interactions could trigger a homogenization of seed traits in tree communities in hunted or logged tropical forests. Meta Análisis de los Efectos de la Perturbación Humana sobre la Dispersión de Semillas por Animales [ABSTRACT FROM AUTHOR]

Abstract: There is growing consensus that sustainable use has a significant role to play in global conservation. Tropical forests are no different, and managing them for multiple products is envisioned as a preferable alternative to timber-dominant management models. Limited research, however, has tested coupling timber and non-timber harvests in multiple-use species for both economic gain and long-term species conservation. We employ matrix population models and the extinction time cumulative distribution function to examine one such species, Carapa guianensis. We investigated sustainable harvests of C. guianensis in two forest types in which it occurs naturally in western Amazonia, testing whether differences between forest types affect population responses to harvest under measured environmental stochasticity regimes. Our results indicated that some C. guianensis populations may be suitable for extraction of seeds, timber, or a combination of both. In upland or terra firme forest sites, model projections suggested that no tested levels of seed and timber extraction were sustainable. In contrast, we found the potential for compatibility between seed and timber harvest in occasionally inundated forests. In these sites, which are ecologically similar to wet areas where Carapa thrives throughout its range, our results suggested that 10% annual seed harvests were compatible with 100% timber harvests of trees ≥50cm twice a century, the equivalent of approximately two trees per hectare. Application of this research approach to other economically important tropical species could increase the diversity of Amazonian management and conservation options. [Copyright &y& Elsevier]

Abstract: Indonesia and Norway have entered into a landmark deal that will pay Indonesia up to US$1 billion for forest-conservation activities aimed at slowing rampant deforestation and resulting greenhouse gas emissions. A recent Presidential Instruction in Indonesia outlines a key deliverable of this “Partnership”—a two-year suspension on new concessions for clearing or logging of peat and old-growth forest. Here, we discuss the implications of this instruction for carbon and biodiversity protection. The protection of highly threatened deep peatlands represents a clear victory. However, by focusing solely on old-growth forests, the instruction excludes over 46million ha of selectively logged rainforests, which often have high carbon storage and biodiversity. This leaves the logged forests, most of which are in accessible lowland areas, highly vulnerable to re-logging and conversion for oil palm and pulpwood plantations. The instruction also could allow large areas of peatlands and old-growth forest to be converted to sugarcane—one of the world’s most rapidly expanding biofuel crops. While the Partnership could potentially help reform land-use planning and reduce illegal deforestation in Indonesia, we argue that Indonesia must also strive to protect vulnerable logged forests, which comprise a large part of the country’s high-carbon, high-biodiversity lands. [Copyright &y& Elsevier]

The article focuses on the strategies in dissociating the effects of logging and hunting on animal populations in central Africa. It compares the relative importance of selective logging and hunting to the effects of local-scale variation in forest structure and fruit abundance. It suggests that landscapes should be managed properly to balance conservation with the need for economic development and wild meat.

In tropical forests, selective logging removes large trees that are often the main contributors to pollination. We studied pollination patterns of the African mahogany, Entandrophragma cylindricum (Sapelli). We investigated two plots in Cameroon corresponding to three tree densities: unlogged forest (Ndama 2002), a mildly logged forest 1 year after logging (Ndama 2003) and a severely logged forest 30 years after logging (Dimako). We used four microsatellite markers to perform paternity analysis. Selfing remained below 2% in all treatments. Pollen flow was mainly long distance but with some proximity effects. Average observed within-plot pollination distances were 338, 266 and 385 m, and pollination by trees outside the plots was 70% (Ndama 2002), 74% (Ndama 2003) and 66% (Dimako). Despite sampling a limited number of seeds from a limited number of mother trees, we obtained seeds sired by 35.6–38.3% of the potential within-plot pollen donors. While trees 20 cm in diameter contributed to pollination, results in Dimako suggest that individual larger trees contribute more to pollination than small ones. This effect was not detected in the other treatments. The results suggest extensive pollen flow in Sapelli. Hence, in Sapelli, the main limiting factor for regeneration after logging may be a reduction in the number of trees capable of producing seeds rather genetic effects due to limits to pollen dispersal.Heredity (2007) 99, 151–160; doi:10.1038/sj.hdy.6800976; published online 2 May 2007 [ABSTRACT FROM AUTHOR]

The long-term viability of a forest industry in the Amazon region of Brazil depends on the maintenance of adequate timber volume and growth in healthy forests. Using extensive high-resolution satellite analyses, we studied the forest damage caused by recent logging operations and the likelihood that logged forests would be cleared within 4 years after timber harvest. Across 2,030,637 km2 of the Brazilian Amazon from 1999 to 2004, at least 76% of all harvest practices resulted in high levels of canopy damage sufficient to leave forests susceptible to drought and fire. We found that 16 ± 1% of selectively logged areas were deforested within 1 year of logging, with a subsequent annual deforestation rate of 5.4% for 4 years after timber harvests. Nearly all logging occurred within 25 km of main roads, and within that area, the probability of deforestation for a logged forest was up to four times greater than for unlogged forests. In combination, our results show that logging in the Brazilian Amazon is dominated by highly damaging operations, often followed rapidly by deforestation decades before forests can recover sufficiently to produce timber for a second harvest. Under the management regimes in effect at the time of our study in the Brazilian Amazon, selective logging would not be sustained. [ABSTRACT FROM AUTHOR]

The article present a study on forest structure recovery and spectral properties after selective logging in lowland Bolivia. The study is aimed at monitoring and enforcing forest management regulations. The researchers used high-technology remote sensing devices to effectively monitor selective logging in the Bolivian Amazon like the advanced spaceborne thermal emission and reflection radiometer (ASTER) satellite and the probabilistic spectral mixture model for deriving per-pixel fractional cover estimates of photosynthetic vegetation (PV), non-PV, and soil. The results were differentiated with the normalized difference in vegetation index. They found that individual felling-gap area was correlated with canopy openness, percentage liana coverage, and rates of vegetation regrowth.

1. The impact of habitat disturbance on biodiversity conservation and animal health is poorly understood. Selective logging results in a suite of alterations that may increase infection risk and susceptibility to infection in resident populations. 2. The aim of this study was to improve our understanding of this interplay by examining the effects of logging on infection risk and gastrointestinal parasite infections in three primate species whose populations have responded differently to selective logging in Kibale National Park, Uganda. Populations of redtail guenons Cercopithecus ascanius are declining in logged forest; red colobus Piliocolobus tephrosceles populations are in a state of slow recovery; and black-and-white colobus Colobus guereza populations are increasing in logged forest. 3. We collected faecal samples from these three primate species over a period of 5 years in logged and undisturbed forest, to compare parasite infection prevalence and the magnitude of multiple infections. We also analysed canopy and ground vegetation plots to compare environmental contamination with primate parasites in logged and undisturbed forest. 4. The prevalence and richness of gastrointestinal helminth and protozoan parasite infections, and the magnitude of multiple infections were greater for redtail guenons in logged than undisturbed forest, but these parameters did not differ between forest types for either colobine. Data from the canopy and ground vegetation plots revealed that infective stages of two representative generalist primate parasites occurred at higher densities in logged compared with undisturbed forest, signifying a greater infection risk for all primate species in logged forest. 5. Synthesis and applications. This study demonstrates that selective logging can be associated with changes in an important ecological association between hosts and parasites. Our results indicate that anthropogenic habitat change could influence patterns of parasite infection in primates with associated effects on population performance. Journal of Applied Ecology (2005) doi: 10.1111/j.1365-2664.2005.01049.x [ABSTRACT FROM AUTHOR]

Selective logging is an extensive land use in the Brazilian Amazon region. The soil-atmosphere fluxes of nitrous oxide (N2O), nitric oxide (NO), methane (CH4), and carbon dioxide (CO2) are studied on two soil types (clay Oxisol and sandy loam Ultisol) over two years (2000¿01) in both undisturbed forest and forest recently logged using reduced impact forest management in the Tapajos National Forest, near Santarem, Para, Brazil. In undisturbed forest, annual soil-atmosphere fluxes of N2O (mean ± standard error) were 7.9 ± 0.7 and 7.0 ± 0.6 ng N cm-2 h-1 for the Oxisol and 1.7 ± 0.1 and 1.6 ± 0.3 ng N cm-2 h-1 for the Ultisol for 2000 and 2001, respectively. The annual fluxes of NO from undisturbed forest soil in 2001 were 9.0 ± 2.8 ng N cm-2 h-1 for the Oxisol and 8.8 ± 5.0 ng N cm-2 h -1 for the Ultisol. Consumption of CH4 from the atmosphere dominated over production on undisturbed forest soils. Fluxes averaged -0.3 ± 0.2 and -0.1 ± 0.9 mg CH4 m-2 day-1 on the Oxisol and -1.0 ± 0.2 and -0.9 ± 0.3 mg CH4 m-2 day-1 on the Ultisol for years 2000 and 2001. For CO2 in 2001, the annual fluxes averaged 3.6 ± 0.4 μmol m-2 s-1 on the Oxisol and 4.9 ± 1.1 μmol m-2 s-1 on the Ultisol. We measured fluxes over one year each from two recently logged forests on the Oxisol in 2000 and on the Ultisol in 2001. Sampling in logged areas was stratified from greatest to least ground disturbance covering log decks, skid trails, tree-fall gaps, and forest matrix. Areas of strong soil compaction, especially the skid trails and logging decks, were prone to significantly greater emissions of N2O, NO, and especially CH4. In the case of CH4, estimated annual emissions from decks reached extremely high rates of 531 ± 419 and 98 ± 41 mg CH4 m-2 day-1, for Oxisol and Ultisol sites, respectively, comparable to wetland emissions in the region. We calculated excess fluxes from logged areas by subtraction of a background forest matrix or undisturbed forest flux and adjusted these fluxes for the proportional area of ground disturbance. Our calculations suggest that selective logging increases emissions of N2O and NO from 30% to 350% depending upon conditions. While undisturbed forest was a CH4 sink, logged forest tended to emit methane at moderate rates. Soil¿atmosphere CO2 fluxes were only slightly affected by logging. The regional effects of logging cannot be simply extrapolated based upon one site. We studied sites where reduced impact harvest management was used while in [ABSTRACT FROM AUTHOR]

The article presents a study which combines a field study of canopy gap fraction with spectral mixture analyses of satellite imagery and Landsat 7 ETM to evaluate landscape and dynamics of canopy damage after selective logging in an eastern Amazon forest. The use of Monte Carlo analysis and a spectral mixture model to estimate high spatial resolution cover of forest canopies is stated. The usefulness of the method for quantifying forest canopy cover fraction in intact forest areas is cited.

Selective logging is a dominant form of land use in the Amazon basin and throughout the humid tropics, yet little is known about the spatial variability of forest canopy gap formation and closure following timber harvests. We established chronosequences of large-area (14–158 ha) selective logging sites spanning a 3.5-year period of forest regeneration and two distinct harvest methods: conventional logging (CL) and reduced-impact logging (RIL). Our goals were to: (1) determine the spatial characteristics of canopy gap fraction immediately following selective logging in the eastern Amazon; (2) determine the degree and rate of canopy closure in early years following harvest among the major landscape features associated with logging – tree falls, roads, skid trails and log decks; and (3) quantify spatial and temporal differences in canopy opening and closure in high- and low-damage harvests (CL vs. RIL). Across a wide range of harvest intensities (2.6–6.4 felled trees ha−1), the majority of ground damage occurred as skid trails (4–12%), whereas log decks and roads were only a small contributor to the total ground damage (<2%). Despite similar timber harvest intensities, CL resulted in more ground damage than RIL. Neither the number of log decks nor their individual or total area was correlated with the number of trees removed or intensity of tree harvesting (trees ha−1). The area of skids was well correlated with the ground area damaged (m2) per tree felled. In recently logged forest (0.5 years postharvest), gap fractions were highest in log decks (mean RIL=0.83, CL=0.99) and lowest in tree-fall areas (RIL: 0.26, CL: 0.41). However, the small surface area of log decks made their contribution to the total area-integrated forest gap fraction minor. In contrast, tree falls accounted for more than two-thirds of the area disturbed, but the canopy gaps associated with felled trees were much smaller than for log decks, roads and skids. Canopy openings decreased in size with distance from each felled tree crown. At 0.5 years postharvest, the area initially affected by the felling of each tree was approximately 100 m in radius for CL and 50 m for RIL. Initial decreases in gap fraction during the first 1.5 years of regrowth diminished in subsequent years. Throughout the 3.5-year period of forest recovery, tree-fall gap fractions remained higher in CL than in RIL treatments, but canopy gap closure rates were higher in CL than in RIL areas. During the observed recovery period, the canopy gap area affected by harvesting decreased in radius around each felled tree from 100 to 40 m in CL, and from 50 to 10 m in RIL. The results suggest that the full spatial and temporal dynamics of canopy gap fraction must be understood and monitored to predict the effects of selective logging on regional energy balance and climate regimes, biogeochemical processes including carbon cycling, and plant and faunal population dynamics. This paper also shows that remote sensing of log decks alone will not provide an accurate assessment of total forest area impacted by selective logging, nor will it be closely correlated to damage levels and canopy gap closure rates. [ABSTRACT FROM AUTHOR]

Coarse woody debris (CWD) is an important component of the carbon cycle in tropical forests. We measured the volume and density of fallen CWD at two sites, Cauaxi and Tapajós in the Eastern Amazon. At both sites we studied undisturbed forests (UFs) and logged forests 1 year after harvest. Conventional logging (CL) and reduced impact logging (RIL) were used for management on areas where the geometric volumes of logs harvested was about 25–30 m3 ha−1. Density for five classes of fallen CWD for large material (>10 cm diameter) ranged from 0.71 to 0.28 Mg m−3 depending upon the degree of decomposition. Density of wood within large fallen logs varied with position relative to the ground and with distance from the center of the log. Densities for materials with diameters from 2 to 5 and 5 to 10 cm were 0.36 and 0.45 Mg m−3, respectively. The average mass (±SE) of fallen CWD at Cauaxi was 55.2 (4.7), 74.7 (0.6), and 107.8 (10.5) Mg ha−1 for duplicate UF, RIL, and CL sites, respectively. At Tapajós, the average mass of fallen CWD was 50.7 (1.1) Mg ha−1 for UF and 76.2 (10.2) Mg ha−1 for RIL for duplicate sites compared with 282 Mg ha−1 for live aboveground biomass. Small- and medium-sized material (<10 cm dia.) accounted for 8–18% of the total fallen CWD mass. The large amount of fallen CWD at these UF sites relative to standing aboveground biomass suggests either that the forests have recently been subjected to a pulse of high mortality or that they normally suffer a high mortality rate in the range of 0.03 per year. Accounting for background CWD in UF, CL management produced 2.7 times as much CWD as RIL management. Excess CWD at logging sites would generate a substantial CO2 emission given the high rates of decay in moist tropical forests. [ABSTRACT FROM AUTHOR]

The study objective is to investigate the feasibility and the technical specifications required to develop an operational system in order to detect and monitor the selective logging activities in tropical forests. The research relies on a detailed understanding of the remotely sensed signal of natural and logged tropical forests. The experimental study is based on a 100,000 ha semi-deciduous forest located in the south-western part of the Central African Republic. This forest includes a protected area and an area allocated to timber production. Two Landsat Thematic Mapper (TM) images, six SPOT multi-spectral (XS) images and field information were used for the analysis. The 5-year interval between the two Landsat-TM images made it possible to study the forest regeneration dynamics. The SPOT XS time series was used to assess the respective influence of the season, the spatial resolution and the geometry of acquisition. While recent impact of tree fall can be detected, there is no way to identify the cause of a single tree fall, i.e. whether it was due to the natural forest dynamics, storm damage or logging. Nevertheless, logging activities were identified due to the local concentration of large gaps and the linear features of the skid trail. The logging trails are clearly detected but with different degrees of success depending on the image geometry. The seasonality and hazy atmospheric conditions did not significantly affect the detectability of the trails. The geometry of observation, i.e. the sensor viewing and sun illumination angles, appeared to be a key factor. More than 40% of the trail network can be missed when the geometry of acquisition is not suitable. Despite rapid canopy closure over the logging roads and skid trail surface, more than 50% of the network was still visible 5 years after the last timber extraction. However, the spatial resolution of the images became critical as soon as the contrast between trails and the forest vanished. On a 120 m regularised image recorded right after the logging, more than 95% of the logging trail network was still visible, but only 34% was detected on a 5-year post-harvest image. These results led to the definition of the main specifications for a remote sensing-based system for monitoring and controlling the logging activities in tropical forests. [Copyright &y& Elsevier]

The article presents a study to examine the impacts of selective logging on herbaceous plants of tropical forests. It analyzes the effects of logging intensity, time after logging, and skidder tracks, on the composition and diversity of the ground-level herb community of a terra-firme forest in central Amazonia.

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 <5% 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 (> 20 m3 ha−1) within the Amazon. • We assess two methods for monitoring selective logging with SAR data. • Logging records were used to train Random Forest models and monitor pixel time series. • Random Forest classification of SAR imagery had high commission and omission error. • Logged pixel showed breakpoints in their time series at highest logging intensities. • Sentinel-1 could be used to monitor the most intensively logged forests in the Amazon. [ABSTRACT FROM AUTHOR]

• We censused unlogged, naturally regenerating and actively restored forest in Borneo. • Structure (stems >2 cm DBH) of logged and unlogged forest differed after 23–35 years. • Species richness & diversity were largely unaffected by logging or active restoration. • Tree community composition of logged forest remained distinct from unlogged forest. • Results indicate we should design and monitor restoration for community co-benefits. Selective logging has affected large areas of tropical forests and there is increasing interest in how to manage selectively logged forests to enhance recovery. However, the impacts of logging and active restoration, by liberation cutting and enrichment planting, on tree community composition are poorly understood compared to trajectories of biomass recovery. Here, we assess the long-term impacts of selective logging and active restoration for biomass recovery on tree species diversity, community composition, and forest structure. We censused all stems ≥2 cm diameter at breast height (DBH) on 46 permanent plots in unlogged, primary forest in the Danum Valley Conservation Area (DVCA; 12 plots, totalling 0.6 ha) and in sites logged 23–35 years prior to the census in the Ulu Segama Forest Reserve adjacent to DVCA (34 plots, totalling 1.7 ha) in Sabah, Malaysian Borneo. Active restoration treatments, including enrichment planting and climber cutting, were implemented on 17 of the logged forest plots 12–24 years prior to the census. Total plot-level basal area and pole (5–10 cm DBH) stem density were lower in logged than unlogged forests, however no difference was found in stem density amongst saplings (2–5 cm DBH) or established trees (≥10 cm DBH). Neither basal area, nor plot-level stem density varied with time since logging at any size class, although sapling and pole stem densities were lower in actively restored than naturally regenerating logged forest. Sapling species diversity was lower in logged than unlogged forest, however there were no other significant effects of logging on tree species richness or diversity indices. Tree species composition, however, differed between logged and unlogged forests across all stem size classes (PERMANOVA), reflected by 23 significant indicator species that were only present in unlogged forest. PERMANOVA tests revealed no evidence that overall species composition changed with time since logging or with active restoration treatments at any size class. However, when naturally regenerating and actively restored communities were compared, two indicator species were identified in naturally regenerating forest and three in actively restored forests. Together our results suggest that selective logging has a lasting effect on tree community composition regardless of active restoration treatments and, even when species richness and diversity are stable, species composition remains distinct from unlogged forest for more than two decades post-harvest. Active restoration efforts should be targeted, monitored, and refined to try to ensure positive outcomes for multiple metrics of forest recovery. [ABSTRACT FROM AUTHOR]

Dense time series of stripmap RADARSAT-2 data acquired in the Multilook Fine mode were used for detecting and mapping the extent of selective logging operations in the tropical forest area in the northern part of the Republic of the Congo. Due to limited radiometric sensitivity to forest biomass variation at C-band, basic multitemporal change detection approach was supplemented by spatial texture analysis to separate disturbed forest from intact. The developed technique primarily uses multi-temporal aggregation of orthorectified synthetic aperture radar (SAR) imagery that are acquired before and after the logging operations. The actual change analysis is based on textural features of the log-ratio image calculated using two SAR temporal composites compiled of SAR scenes acquired before and after the logging operations. Multitemporal aggregation and filtering of SAR scenes decreased speckle and made the extracted textural features more prominent. The overall detection accuracy was around 80%, with some underestimation of the area of forest disturbance compared to reference based on optical data. The user's accuracy for disturbed forest varied from 76.7% to 94.9% depending on the accuracy assessment approach. We conclude that change detection utilizing RADARSAT-2 time series represents a useful instrument to locate areas of selective logging in tropical forests. [ABSTRACT FROM AUTHOR]

• Once (L1) and twice-logged (L2) forests were compared to baseline (B). • Evergreen and deciduous forests were examined separately. • B and L1 were similar, while L2 had lower adult tree density and diversity. • L2 deciduous also had lower carbon stocks, overstory canopy and regeneration. • Reducing logging frequency and tailoring limits by forest type may improve recovery. The majority of Earth's tropical forests have been selectively logged; some on repeated occasions. Selective logging is known to affect forest structure, composition and function in various ways, but how such effects vary with logging frequency and across forest types remains unclear. In the Andaman Archipelago in India, we examined adult and pole-sized trees in baseline (unlogged since 1990s), once-logged (logged between 2007 and 2014) and twice-logged (logged in early 1990s and between 2007 and 2014) evergreen and deciduous forests, and tested whether higher logging frequency was associated with lower canopy cover, tree density, tree diversity, aboveground carbon stocks and divergence in species composition, including increased relative abundances of deciduous species in these forests. While once-logged evergreen and deciduous forests were similar to their respective baselines for most attributes assessed, and twice-logged evergreen forests had 22–24% lower adult tree density and diversity, twice-logged deciduous forests had 17–50% lower canopy cover, pole density, adult species diversity and above-ground carbon stocks, and 12% higher deciduous fractions compared to the baselines. Collectively our results reveal lasting impacts of repeated selective logging, even at relative low intensity, on tree communities and carbon storage. These impacts can potentially be mitigated by reducing logging frequency and retaining unlogged patches in logged landscapes, but management must also incorporate heterogeneity in responses and recovery across different forest types. In the Andaman Islands, all forests may require more than 15–25 years between logging events, with deciduous forests potentially requiring more stringent extraction limits compared to evergreen forests. [ABSTRACT FROM AUTHOR]

• Medium- and high-intensity thinning facilitated recruitment of Flindersia trees. • Medium intensity thinning promoted Flindersia individual tree growth rates most. • Flindersia tree growth rate was influenced by tree size, crown size and class most. • Only Flindersia tree growth rate in high intensity thinning changed over 46 years. Studies in low-diversity temperate forests clearly establish that thinning leads to increased growth of remaining trees. However, few studies have investigated the long-term impacts of thinning regimes on the growth responses of tropical timber species. In this study, we analysed data collected over a period of 46 years to assess the long-term growth responses and growth patterns of remnant trees of three key commercial species (Flindersia brayleyana F. Muell., Flindersia bourjotiana F. Muell. and Flindersia pimenteliana F. Muell.). We also examined how initial tree size, crown size and crown position within canopy, and neighbourhood competition affected growth rates of the three Flindersia species. Within these species, we assessed growth responses of trees above 10 cm diameter at breast height (DBH) in an Australian tropical rainforest, to different intensities of thinning i.e. logging only as a control and low-, medium- and high-intensity thinning (L, LT, MT and HT, respectively). Medium and high intensity treatments facilitated recruitment of all three Flindersia species into the >10 cm DBH class while medium intensity thinning resulted in the greatest average annual basal area increments (BAIs). The lower individual BAI of Flindersia species in HT was due to fewer large Flindersia trees remaining after thinning, combined with large numbers of recruits and slow growth of small remnant trees. BAI in HT increased initially, with a peak during 1981–1989 and then decreased. BAI was constant and varied little over time within the other treatments. High intensity thinning had prolonged impacts on the growth patterns of Flindersia trees over 46 years. Tree initial DBH, crown size and crown position within canopy explained most variation in individual BAIs of Flindersia trees. Both thinning intensity and measurement periods explained variation in individual BAIs of Flindersia trees. Larger remnant Flindersia trees with broad and dominant crowns tended to grow faster. BAIs of individual trees were negatively correlated with neighbourhood competition. If the goal of tropical native forest management is to improve productivity of target species, the results indicate that thinning should be sufficiently intense to reduce neighbourhood competition while maintaining large diameter commercially desirable trees with large and dominant crowns, which may consequently facilitate the timber volume and above-ground biomass recovery after selective logging. [ABSTRACT FROM AUTHOR]