Reduced-impact Logging Research Articles

Larger gains from improved management over sparing–sharing for tropical forests

Tropical forests are globally important for both biodiversity conservation and the production of economically valuable wood products. To deliver both simultaneously, two contrasting approaches have been suggested: one partitions forests (sparing); the other integrates both objectives in the same location (sharing). To date, the ‘sparing or sharing’ debate has focused on agricultural landscapes, with scant attention paid to forest management. We explore the delivery of biodiversity and wood products in a continuum of sparing-to-sharing scenarios, using spatial optimization with set economic returns in East Kalimantan, Indonesia—a biodiversity hotspot. We found that neither sparing nor sharing extremes are optimal, although the greatest conservation value was attained towards the sparing end of the continuum. Critically, improved management strategies, such as reduced-impact logging, provided larger conservation gains than altering the balance between sparing and sharing, particularly for endangered species. Ultimately, debating sparing versus sharing has limited value while larger gains remain from improving forest management. To achieve both biodiversity conservation and timber production in tropical forests, this modelling study finds that improved management has much more impact than the choice between sparing forests or sharing forest land for both purposes.

ESTRUTURA E DINÂMICA FLORESTAL, ANTES E APÓS EXTRAÇÃO DE MADEIRA, EM ÁREA DE MANEJO FLORESTAL NA FLONA DO TAPAJÓS

A dinâmica florestal tem finalidade de analisar o comportamento de uma floresta em relação a sua estrutura, composição, crescimento, mortalidade, regeneração e fatores ecológicos diante de modificações causadas por efeitos naturais ou antrópicos. Neste sentido o objetivo deste trabalho foi avaliar os efeitos da extração de madeira de impacto reduzido sobre a estrutura e dinâmica florestal em uma área de manejo florestal comunitário com 1.600 ha localizada na Floresta Nacional do Tapajós. Os dados coletados são oriundos de 08 parcelas permanentes de monitoramento florestal com 0,25 ha cada mensuradas antes e após a colheita de madeira. Foram observados os seguintes parâmetros: estrutura da floresta, índice de valor de importância, distribuição diamétrica pré e pós-exploração e dinâmica florestal. Os dados coletados em campo foram inseridos e analisados no programa Monitoramento de Florestas Tropicais (MFT). A extração de madeira realizada na área não afetou a estrutura da floresta, pois a vegetação manteve a distribuição de classe diamétrica, alta produtividade com baixo impacto, reafirmando assim que o plano de manejo realizado na área é eficiente.PALAVRAS-CHAVE: Monitoramento, Mortalidade, Impacto reduzido.

Biodiversity Observation for Land and Ecosystem Health (BOLEH): A Robust Method to Evaluate the Management Impacts on the Bundle of Carbon and Biodiversity Ecosystem Services in Tropical Production Forests

The Forest Stewardship Council (FSC) has initiated a new sustainability mechanism, the ecosystem-services certification. In this system, management entities who wish to be certified for the maintenance of ecosystem services (carbon, biodiversity, watershed, soil and recreational services) must verify that their activities have no net negative impacts on selected ecosystem service(s). Developing a robust and cost-effective measurement method is a key challenge for establishing a credible certification system. Using a single method to evaluate a bundle of ecosystem services will be more efficient in terms of transaction costs than using multiple methods. We tested the efficiency of a single method, “biodiversity observation for land and ecosystem health (BOLEH)”, to simultaneously evaluate biodiversity and carbon density on a landscape scale in FSC-certified tropical production forests in Sabah, Malaysia. In this method, forest intactness based on the tree-generic compositional similarity with that of a pristine forest was used as an index of biodiversity. We repeated BOLEH in 2009 and 2014 in these forests. Our analysis could detect significant spatiotemporal changes in both carbon and forest intactness during these five years, which reflected past logging intensities and current management regimes in these forests. Enhancement of these ecosystem services occurred in the forest where sustainable management with reduced-impact logging had long been implemented. In this paper, we describe the procedure of the BOLEH method, and results of the pilot test in these forests.

Effects of forest degradation on the moonrat Echinosorex gymnura in Sabah, Malaysian Borneo

Commercial timber extraction and agricultural expansion lead to substantial degradation and loss of tropical rainforests, posing a severe threat to biodiversity in South-east Asia. Although the impacts of these disturbances are well understood for some species, they remain largely unknown for most species, impeding any directed conservation efforts. One of these little known, presumably forest-dwelling species is the moonrat Echinosorex gymnura, an insectivorous mammal ranging from southern Myanmar and southern Thailand to Sumatra and Borneo. While the moonrat is currently listed as Least Concern on The IUCN Red List of Threatened Species, large parts of its range have been severely degraded due to unsustainable logging practices and the conversion of forest to oil palm plantations. We conducted a systematic large-scale camera trap survey in three forest reserves under different forest management strategies in Sabah, Malaysian Borneo. We recorded a total of 67 independent moonrat detections at 22 of 180 camera trap stations over 12,281 camera trap days. We analysed moonrat habitat associations using occupancy modelling and a set of 9 different environmental covariates. Canopy closure and forest quality were positively associated with moonrat occurrence and were the most important determinants of the species’ occurrence in our study area. Proximity to plantations (oil palm and industrial timber) and elevation negatively affected moonrat occurrence. Our results thus indicate that the moonrat strongly depends on high-quality lowland forest and is unlikely to occur close to plantations. Moonrat occupancy was highest in the sustainably managed forest reserve, suggesting that this species responds much better to reduced-impact logging compared to conventional logging practices. Our first ecological survey indicates that the moonrat may be more threatened by the continued conversion, degradation, and fragmentation of tropical lowland rainforests than previously assumed.

<i>Cedrela odorata</i> L. TEM POTENCIAL PARA SER UTILIZADA NA SILVICULTURA PÓS-COLHEITA NA AMAZÔNIA BRASILEIRA?

Avaliou-se o desempenho de mudas de Cedrela odorata L. (cedro), plantadas em clareiras causadas pela exploração florestal de impacto reduzido, no município de Paragominas, no Estado do Pará. Analisou-se a sobrevivência e o crescimento das mudas para estudar a possibilidade de utilizá-las em enriquecimento de clareiras, na Amazônia brasileira. Em 200 ha foram selecionadas 400 clareiras, divididas em três classes de tamanho: pequenas (200–400 m²), médias (401–600 m²) e grandes (> 600 m²). Em 236 dessas 400 clareiras foram plantadas 470 mudas de cedro, em 2005, quando também foi realizada a primeira avaliação da sobrevivência e do crescimento das mudas. Outras avaliações foram realizadas em 2006, 2008 e 2010. Constataram-se, após os cinco anos de monitoramento, altas taxas de sobrevivência, em torno de 81,8%, e de crescimento com média de 70,0 cm em altura e 0,23 cm em diâmetro. Portanto, pode-se inferir que Cedrela odorata se adapta a ambientes de clareiras e poderá ser indicada para plantios de enriquecimento de florestas após a colheita da madeira. Há a necessidade de continuar o monitoramento.

Selective logging causes the decline of large-sized mammals including those in unlogged patches surrounded by logged and agricultural areas

Legal and illegal logging is prevalent throughout the tropics, impacting on natural habitat and wildlife. This study aimed to investigate the sensitivity of forest mammals to selective logging in the lowland dipterocarp forests of South-West Peninsular Malaysia and identify the underlying factors that determine species occurrence. A total of 120 camera trap locations were deployed within selectively logged and unlogged forests. We found that unlogged forest had greater wildlife occurrences compared to selectively logged forests, including two endangered mammal species not found in logged forest. Forest vegetation structure characteristics such as the abundance of lianas, large trees, saplings, palms, bamboo and seedlings were associated with mammal species richness. Mammal species richness increased with number of forest trees, particularly those with a DBH of >45 cm, but this was limited to high altitude forest. Worryingly, we did not detect any large mammalian apex predators such as leopards or tigers in either unlogged or selectively logged forests. The absence of these animals may be the result of poaching, habitat degradation or other pressures; these mammals are expected to be present in intact forests in Peninsular Malaysia. Restoring logged forests and preserving the remaining unlogged lowland dipterocarp forests are critically important to safeguard mammalian biodiversity in the region. Besides that, we recommend that conventional logging practices are replaced with reduced impact logging methods.

Growth, mortality, and recruitment of tree species in an Amazonian rainforest over 13 years of reduced impact logging

Forest harvesting causes disturbances in the forest, affecting the dynamics of tree species. In this study, growth, mortality, and recruitment of trees ≥45 cm DBH were assessed in different forests logged along 13 years (2002–2015) in the Eastern Amazon. The data were collected in a control unlogged forest and in four 100-ha working units divided into 20 plots of 5 ha (total of 100 plots in 500 ha sampled) and inventoried at 100% one year before harvesting and again in 2015. A total of 49 species were analyzed in the study. The highest mortality rate occurred in the first five years after harvesting (5.6%), with a reduction from the seventh year (3.2% year−1), a period in which recruitment rate significantly increased for species from all ecological groups. Harvesting reduced both the number of individuals and species in the first five years after logging. Logged areas presented the highest growth rates five and seven years and only stabilized eleven years after logging. Within the range of 3–40 m3 ha−1 of logging intensity no differences were observed in growth rates of remaining trees ≥45 cm DBH. Pioneer, light-demanding, and shade-tolerant species presented higher growth rates in the first five years after logging. From seven years after harvesting, light-demanding presented a higher growth when compared to the shade-tolerant species. Larger diameter classes presented the highest relative growth rates (RGR). All diameter classes increased RGR up to 11 years after logging.

A Natural Forest of Commercial Timber Species: Logging or Not Logging

Most tropical forests outside protected areas have been or will be selectively logged because the timber industry is a main income-generating resource for many developing countries. Therefore, understanding the composition of commercial timber species and logging types is key for sustainable forest management in countries like Vietnam as they move toward fulfilling Reducing Emissions from Deforestation and Forest Degradation (REDD+) agreements. Seven 1-ha plots were surveyed in the Central Highland of Vietnam, and 18 commercial tree species from these plots, whose timber is widely used by local people for housing and furniture making and timber is easily sold at local markets for high prices, were analyzed. In total, 151 tree species with a diameter at breast height (DBH) of ≥ 10 cm were recorded. The 18 commercially valuable species assessed in this study accounted for 33.2% of all stems (total of 524 stems ha−1 for all species), 47.1% of basal area (total of 34.35 m2 ha−1 for all species), and 50.8% of aboveground biomass/AGB (total of 262.68 Mg ha−1 for all species). Practicing diameter-limit harvesting of all commercially valuable species with DBH of ≥ 40 cm, which is widely performed in Vietnam, will reduce the number of stems by 7%, basal area by 31.6%, and AGB by 38.2%. Because such harvesting practices cause severe ecological impacts on the remaining forest, logged forests may require > 40 years to recover the structure status of a pre-logged forest. In addition, the recovery of the 18 commercially valuable species may require a much longer time because they comprised 33.2% of stems. Permission for logging natural forests should be given in Vietnam to sustain lives of local communities, where logging has been prohibited. However, alternative harvesting systems, such as reduced-impact logging systems, should be considered. The systems selected must simultaneously generate economic returns for local people and respect the REDD+ agreements with regard to protecting biodiversity and reducing carbon emissions.

Reducing the deleterious effects of logging on Ephemeroptera communities through reduced impact management

Reduced impact logging has emerged as one alternative to reduce the effects of timber harvesting. However, the effects of this method on aquatic ecosystems still need to be tested. We studied the effects of logging (reduced-impact logging—RIL and conventional logging methods—CL) on the chemical water quality and physical habitat conditions of streams in eastern Amazonia, as well as on Ephemeroptera diversity. Were analyzed control streams (without logging—CONTROL), streams with RIL and streams with CL, located in the Capim River Basin. Specimens were collected using a dipnet, following a standard protocol and abiotic data were measured with a multiparameter probe. Conventional logging in proximity to streams increased the conductivity and pH of the water, reduced dissolved oxygen and canopy cover of the stream’s channel, altering the composition of Ephemeroptera when compared with CONTROL and RIL areas. We verified that specialist Ephemeroptera species within control environments were replaced by species more tolerant to changes in the natural habitat conditions. In contrast, there was species similarity between RIL and CONTROL streams.

Sustainability of wood harvesting in tropical rainforest of Nigeria

Over the years, Nigerian tropical rainforest has become the main source of timber supply to many countries which were in critical need of timber to feed their wood-based industries. The increase in population has led to increase in the demands for forest products, specifically wood for construction. Improper harvesting practices has substantially degraded the tropical forest that future timber values may be reduced. Sustainable wood harvesting focuses on the trees that are remaining rather than on the trees that are to be fell. Proper wood harvesting and management method must be adopted to facilitate the regeneration of the forest. Efficient wood harvesting in Nigeria requires the construction of landing sites as collection points for the harvested timbers and adequate training must be provided to the operators of the diverse harvesting equipment. With proper timber harvesting techniques, the damages caused by logging can be minimized. Functional forest policies that guide against over-exploitation of timber should be enacted. Reduced impact logging should be incorporated into sustainable forest management to reduce devastating damages to the residual trees in the forest.

Trade-offs between carbon stocks and timber recovery in tropical forests are mediated by logging intensity.

Forest degradation accounts for ~70% of total carbon losses from tropical forests. Substantial emissions are from selective logging, a land-use activity that decreases forest carbon density. To maintain carbon values in selectively logged forests, climate change mitigation policies and government agencies promote the adoption of reduced-impact logging (RIL) practices. However, whether RIL will maintain both carbon and timber values in managed tropical forests over time remains uncertain. In this study, we quantify the recovery of timber stocks and aboveground carbon at an experimental site where forests were subjected to different intensities of RIL (4, 8, and 16trees/ha). Our census data span 20years postlogging and 17years after the liberation of future crop trees from competition in a tropical forest on the Guiana Shield, a globally important forest carbon reservoir. We model recovery of timber and carbon with a breakpoint regression that allowed us to capture elevated tree mortality immediately after logging. Recovery rates of timber and carbon were governed by the presence of residual trees (i.e., trees that persisted through the first harvest). The liberation treatment stimulated faster recovery of timber albeit at a carbon cost. Model results suggest a threshold logging intensity beyond which forests managed for timber and carbon derive few benefits from RIL, with recruitment and residual growth not sufficient to offset losses. Inclusion of the breakpoint at which carbon and timber gains outpaced postlogging mortality led to high predictive accuracy, including out-of-sample R2 values >90%, and enabled inference on demographic changes postlogging. Our modeling framework is broadly applicable to studies that aim to quantify impacts of logging on forest recovery. Overall, we demonstrate that initial mortality drives variation in recovery rates, that the second harvest depends on old growth wood, and that timber intensification lowers carbon stocks.

Using multimetric indices to assess the effect of reduced impact logging on ecological integrity of Amazonian streams

Multimetric indices are considered a low-cost and rapid means of assessing ecological integrity in streams. The present study aimed to develop and validate multimetric indices that permit evaluation of reduced impact logging (RIL) effects on the ecological integrity of streams in the Eastern Amazon. We sampled 47 stream sites, 13 of them in reference areas and 11 in conventional logging (CL) areas, which were used to develop indices. The remaining 23 stream sites were sampled in RIL areas and used for validation of the developed indices. In each stream site we measured metrics relating to habitat structure and ecological features of fish assemblages, which were used to develop a habitat integrity index (HII), biotic integrity index (BII), and a general multimeric index (GMI). The values of the indices obtained for the RIL areas were compared and tested both in relation to the values observed in the reference and CL areas, and in relation to temporal gradients (i.e. time since logging) in RIL areas. All developed indices differed between RIL and CL, however only the HII differed between RIL and reference areas. We also detected a decrease in the GMI in recently logged RIL areas compared with streams in older RIL areas. The lack of distinction in GMI and BII indices between reference and RIL areas demonstrates the benefits of RIL practices for fish assemblages compared to conventional logging methods. However, the intermediate values obtained from these indices in RIL areas for all developed indices, the distinction of HII between reference and RIL, and the temporal variation of GMI in RIL areas can be considered as an important warning regards the possible impacts of RIL practices on ecological integrity in Amazonian streams. In summary, the multimetric indices were shown to be good indicators of ecological integrity in Amazonian streams subject to RIL. Even where the deleterious effects of logging are controlled by technical guidelines, indices presented a high sensitivity to anthropogenic disturbance, reinforcing their value as tools to evaluate and monitor ecological integrity of streams in human-modified tropical landscapes.

Estimating carbon avoided from the implementation of reduced-impact logging in Sabah, Malaysia

SUMMARY The objective of this study was to investigate the design and application of a carbon baseline for commercial timber harvest activities involving conventional timber harvest activities (CNV), relative to reduced-impact logging (RIL) in Sabah, Malaysia. As only RIL is eligible to be practiced in production forests, a baseline of CNV was estimated from the literature. The principle of net present value was applied to the post-harvest accumulation of carbon stocks after RIL to model a conservative ‘crediting’ baseline. Two areas representing opposite ends of a range of anthropogenic disturbance were sampled, with an old growth lower montane forest, and a lowland severely logged-over dipterocarp forest investigated before-, and two- and three-years after harvest, respectively. Areas impacted by CNV were estimated to contain 12–39% of pre-harvest carbon stock, relative to 57–63% under RIL and estimated to accumulate carbon in the range of 0.68–1.25 tC ha-1 yr1, averaging 14–55 years for recovery; in-li...

Corrigendum to “Mortality of stocking commercial trees after reduced impact logging in eastern Amazonia” [For. Ecol. Manage. 401 (2017) 1–7

Corrigendum to “Mortality of stocking commercial trees after reduced impact logging in eastern Amazonia” [For. Ecol. Manage. 401 (2017) 1–7

Optimal selective logging regime and log landing location models: a case study in the Amazon forest

ABSTRACT Reduced-impact logging is a well known practice applied in most sustainable forest management plans in the Amazon. Nevertheless, there are still ways to improve the operational planning process. Therefore, the aim of this study was to create an integer linear programming (ILP) to fill in the knowledge gaps in the decision support system of reduced impact logging explorations. The minimization of harvest tree distance to wood log landing was assessed. Forest structure aspects, income and wood production were set in the model, as well as the adjacency constraints. Data are from a dense ombrophylous forest in the western Brazilian Amazon. We applied the phytosociological analysis and BDq method to define the selective logging criteria. Then, ILP models were formulated to allow the application of the constraints. Finally, 32 scenarios (unbalanced forest, UF, and balanced forest, BF) were generated and compared with real executed plans (RE). Robust results were achieved and the expected finding of each scenario was met. The feasibility to integrate ILP models in uneven-aged forest management projects was endorsed. Consequently, the UF and BF scenarios tested were efficient and concise, introducing new advances for forest management plans in the Amazon. The proposed models have a high potential to improve the selective logging activities in the Amazon forest.

Do responsibly managed logging concessions adequately protect jaguars and other large and medium-sized mammals? Two case studies from Guatemala and Peru

Large areas of tropical forest have been designated for timber production but logging practices vary widely. Reduced-impact logging is considered best practice and third-party certification aims to ensure that strict standards are met. This includes minimizing the number of roads constructed, avoiding sensitive areas and strictly regulating hunting. Large scale camera trap grids were utilized in Guatemala and Peru to evaluate the impact of reduced-impact logging in certified concessions upon the large and medium-sized mammal fauna with special emphasis on jaguars (Panthera onca). Spatial capture-recapture models showed that jaguar density in Peru (4.54 ± 0.83 ind. 100 km−2) was significantly higher than in Guatemala (1.52 ± 0.34 ind. 100 km−2) but in both regions, densities were comparable to protected areas. Camera traps detected 22 species of large and medium sized mammals in Guatemala and 27 in Peru and a multi-species occupancy model revealed that logging had no negative impact on any of the species studied and actually had an initial positive impact on several herbivore species. We found no avoidance of logging roads; in fact, many species, especially carnivores, frequently used logging roads as movement corridors. Our results indicate that well-managed logging concessions can maintain important populations of large and medium-sized mammals including large herbivores and large carnivores as long as hunting is controlled and timber volumes extracted are low. Responsible forest management would therefore be an ideal activity in the buffer zones and multiple use zones of protected areas creating much less impact and conflict than alternatives such as agriculture or cattle ranching while still providing economic opportunities. Logging concessions can also play an important role in maintaining landscape connectivity between protected areas.

Key drivers of ecosystem recovery after disturbance in a neotropical forest

BackgroundNatural disturbance is a fundamental component of the functioning of tropical rainforests let to natural dynamics, with tree mortality the driving force of forest renewal. With ongoing global (i.e. land-use and climate) changes, tropical forests are currently facing deep and rapid modifications in disturbance regimes that may hamper their recovering capacity so that developing robust predictive model able to predict ecosystem resilience and recovery becomes of primary importance for decision-making: (i) Do regenerating forests recover faster than mature forests given the same level of disturbance? (ii) Is the local topography an important predictor of the post-disturbance forest trajectories? (iii) Is the community functional composition, assessed with community weighted-mean functional traits, a good predictor of carbon stock recovery? (iv) How important is the climate stress (seasonal drought and/or soil water saturation) in shaping the recovery trajectory?MethodsParacou is a large scale forest disturbance experiment set up in 1984 with nine 6.25 ha plots spanning on a large disturbance gradient where 15 to 60% of the initial forest ecosystem biomass were removed. More than 70,000 trees belonging to ca. 700 tree species have then been censused every 2 years up today. Using this unique dataset, we aim at deciphering the endogenous (forest structure and composition) and exogenous (local environment and climate stress) drivers of ecosystem recovery in time. To do so, we disentangle carbon recovery into demographic processes (recruitment, growth, mortality fluxes) and cohorts (recruited trees, survivors).ResultsVariations in the pre-disturbance forest structure or in local environment do not shape significantly the ecosystem recovery rates. Variations in the pre-disturbance forest composition and in the post-disturbance climate significantly change the forest recovery trajectory. Pioneer-rich forests have slower recovery rates than assemblages of late-successional species. Soil water saturation during the wet season strongly impedes ecosystem recovery but not seasonal drought. From a sensitivity analysis, we highlight the pre-disturbance forest composition and the post-disturbance climate conditions as the primary factors controlling the recovery trajectory.ConclusionsHighly-disturbed forests and secondary forests because they are composed of a lot of pioneer species will be less able to cope with new disturbance. In the context of increasing tree mortality due to both (i) severe droughts imputable to climate change and (ii) human-induced perturbations, tropical forest management should focus on reducing disturbances by developing Reduced Impact Logging techniques.

Selective logging effects on ‘brown world’ faecal-detritus pathway in tropical forests: A case study from Amazonia using dung beetles

Abstract While a significant effort has been made to understand how human activities influence biodiversity, less attention has been given to the consequences of tropical forest disturbance on belowground functional processes and its linkages with environmental drivers. Here, we demonstrate how selective logging influenced dung beetle communities and two associated ecological processes – namely, dung consumption and incidental soil bioturbation – in the eastern Brazilian Amazon, using a robust before-and-after control-impact design. We tested hypotheses about logging-induced changes on environmental condition (canopy cover, leaf litter and soil texture), community metrics (e.g. dung beetle species richness and biomass) and beetle-mediated faecal-detritus processing; and on the importance of the environment for beetle communities and functional processes. We show that post-logging changes in canopy openness do not necessarily mediate logging impacts on dung beetle diversity and biomass, which were directly influenced by reduced impact logging (RIL) operations. Although neither environmental condition (leaf litter or soil sand content) nor faecal consumption and incidental soil bioturbation were directly affected by RIL, the relationships between environmental condition and biological components were. By showing that selective logging alters the linkages among belowground ecological processes and environmental drivers, we provide support that logged forests can retain some important functioning processes, in particular faecal consumption, even when the dung beetle diversity and biomass are impoverished. These results provide support for the resistance of functional processes to logging-induced changes in biodiversity.

A preliminary report: does reduced impact logging (RIL) mitigate non-CO<sub>2</sub> greenhouse gas emissions from natural production forests?

A preliminary report: does reduced impact logging (RIL) mitigate non-CO<sub>2</sub> greenhouse gas emissions from natural production forests?

Negative incentives and sustainability in the amazonian logging industry

Abstract: This paper investigates the existence of lock-in of low technology and high environmental impact on Brazilian Amazon logging industry. The research employed evolutionary economics as a theoretical basis, especially the concept of technological trajectories. The duality of decisions involving logging - conventional logging (CL) versus reduced-impact logging (RIL) - was studied. An agent-based simulation model - in which decision-making under bounded rationality is based on a genetic algorithm - was implemented in Java programming language. Results demonstrate the existence of lock-in, producers aversion to risks, greater operational efficiency of sustainable logging, and benefits derived from a policy of environmental bonuses, both in economic and ecological terms.