Amphibian responses to conventional and reduced impact logging

Variable species but similar amphibian community responses across habitats following reduced impact logging

The cost of carbon retention by reduced impact logging

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.

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

Financial and ecological indicators of reduced impact logging performance in the eastern Amazon

This paper deals with the results of study on implementing reduced impact logging (RIL) as well as conventional logging (CL), which was carried out in natural production forest under the concession operation of a forest company in Riau in 2001. The aim of this study was to assess the effect of reduced impact logging on possible improvement or securing the stand damage, level of ground exposure, top soil displacement, and cost related skidding productivity. The data collected in this regard were the number of felled trees (stands), number of trees with the diameter of 20 cm or greater, number of damaged trees and poles, ground exposure, top soil displacement, skidding cost, and skidding productivity. The data as such consisted of two main categories, i. e. the one and the other one that resulted consecutively from the implementation of RIL and CL systems. The two-category data were analyzed with respect to their possible differences using at-test. Results of study revealed that the implementation of RIL system brought out more convenient impacts in comparison to the CL, as follows: (1) Level of tree (stand) damage would decrease by about 5.4% (highly significant); (2) Ground exposure decreased by around 9 percent (significant); (3) the decrease in top soil displacement by about 2.4 mm (highly significant); (4) Skidding cost decreased by some Rp 398.98 per m3. With respect to skidding productivity using RIL (compared to CL), there was apparently an increase by about 2.6 m3 per hour. However, such an increase was not significantly different. Based on environmental, technical and economical considerations, the RIL system for future logging operation can be recommended in preference to the CL.

Given the mounting global concerns about mitigating climate change and curbing greenhouse gas emissions, it becomes increasingly crucial to comprehend the effects of logging techniques on biomass dynamics in tropical forests. This understanding is essential for fostering greater carbon retention and sequestration, aligning with the objectives of initiatives like REDD+ (Reducing Emissions from Deforestation and forest Degradation plus sustainable forest management and the conservation and enhancement of forest carbon stocks) and other conservation goals. In this context, this study investigated the effects of two wood harvesting methods, reduced-impact logging (RIL) and conventional logging (CL), on above-ground biomass (AGB) recovery rates 24 years after harvesting. The experimental design was based on three treatments: RIL, CL, and an unlogged control plot, situated in the municipality of Paragominas, State of Pará, in the Eastern Amazon region of Brazil. All trees with diameter at breast height (DBH) ≥25 cm, as well as all trees of commercial species with a DBH ≥10 cm, were monitored in a 24.5 ha plot within each treatment. Additionally, a 5.25 ha subplot within each treatment was designated for the monitoring of all trees with DBH ≥10 cm. The biomass data were generated from 11 measurements carried out from 1993 to 2017 (24-year period). Pre-logging AGB stocks were estimated at 181 Mg ha-1 in the RIL plot, 187 Mg ha-1 in the CL plot, and 174 Mg ha-1 in the control plot. One year after logging, AGB decreased by 19 % under RIL and 30 % under CL, while the control forest remained unchanged. By 13 years after harvest, the RIL plot achieved 102 % AGB recovery, while the CL plot recovered 86 % of the original pre-harvest stock. Over the 24-year post-logging period, AGB stocks recovered to 128 % in the RIL plot compared to only 90 % in the CL plot, while the control forest maintained 93 % of its original stock. The average annual ABG increment rates were 3.56 Mg ha-1 year-1 after RIL and 2.33 Mg ha-1 year-1 after CL. Our findings demonstrate that implementing RIL is a more effective strategy for maintaining post-logging AGB stocks and accelerating AGB recovery rates, serving as a significant mitigation measure against climate change.

Adaptation of a spatially explicit individual tree-based growth and yield model and long-term comparison between reduced-impact and conventional logging in eastern Amazonia, Brazil

Sustainable forest management is vital for the persistence of sun bear Helarctos malayanus populations in Sabah, Malaysian Borneo

A key driver of rain forest degradation is rampant commercial logging. Reduced-impact logging (RIL) techniques dramatically reduce residual damage to vegetation and soils, and they enhance the long-term economic viability of timber operations when compared to conventionally managed logging enterprises. Consequently, the application of RIL is increasing across the tropics, yet our knowledge of the potential for RIL also to reduce the negative impacts of logging on biodiversity is minimal. We compare the impacts of RIL on birds, leaf-litter ants, and dung beetles during a second logging rotation in Sabah, Borneo, with the impacts of conventional logging (CL) as well as with primary (unlogged) forest. Our study took place 1-8 years after the cessation of logging. The species richness and composition of RIL vs. CL forests were very similar for each taxonomic group. Both RIL and CL differed significantly from unlogged forests in terms of bird and ant species composition (although both retained a large number of the species found in unlogged forests), whereas the composition of dung beetle communities did not differ significantly among forest types. Our results show little difference in biodiversity between RIL and CL over the short-term. However, biodiversity benefits from RIL may accrue over longer time periods after the cessation of logging. We highlight a severe lack of studies investigating this possibility. Moreover, if RIL increases the economic value of selectively logged forests (e.g., via REDD+, a United Nations program: Reducing Emissions from Deforestation and Forest Degradation in Developing Countries), it could help prevent them from being converted to agricultural plantations, which results in a tremendous loss of biodiversity.

Impacts of tropical selective logging on carbon storage and tree species richness: A meta-analysis

The REDD+ scheme of the United Nations Framework Convention on Climate Change is a carbon-based compensation for projects that resulted in reducing carbon emissions or enhancing carbon sinks or both in tropical forests. However, estimating such emissions and sinks remains challenging, and thus making it impossible to estimate carbon revenues from managing tropical forests. Here, we estimated the reduced emissions and sinks by developing models for setting Reference Emission Level (REL) and Project Emission Level (PEL) for REDD+ projects in concession forests taking emissions under conventional logging (CVL) scenario as that of REL, and emissions under reduced impact logging (RIL) and RIL with liberation treatment (RIL+) scenarios as that of PEL. By choosing Cambodia as a case study, REL under the current logging system of 25-year cutting cycle was estimated at 23.1 TgCO2 year -1 . To determine an appropriate cutting cycle, we tested our models with four cutting cycles and found that a 50-year cutting cycle is more appropriate. Taking this 50-year cutting cycle for REDD+ project, PELs were estimated at 0.4 TgCO2 and -3.3 TgCO2 year -1 under RIL and RIL+, respectively (- means sinks). After subtracting REL with PEL and leakages, annual carbon credits from managing 3.4 million ha of concession forests in Cambodia were estimated at 15.9-18.5 TgCO2 depending on chosen scenario. With a carbon price of $5 MgCO2 -1 , total revenues from the sales of carbon credits alone are $79.5-92.5 million annually. To ensure continued flow of wood supply from tropical forests while mitigating climate change, we suggest that new climate agreements adopt RIL or RIL+ for sustainable forest management in tropical countries.

Carbon emissions from selectively logged forests in the tropics are strongly affected by logging practices. Although tropical forests are mainly managed under the concession system, only a handful of studies were done to assess the impact of logging practices on emission reductions and future timber supply. In this report, carbon stocks, timber supply, and carbon emission reductions under conventional logging (CVL), reduced-impact logging (RIL), and RIL with special silvicultural treatments (RIL+) were assessed in 3.4 million ha of concession forests for a 55-year project time span. Carbon emissions under a 25-year CVL practiced in Cambodia were estimated at 12.4 TgCO2 year-1 for 55 years. We then tested four cutting cycles of selective logging and our results suggest that a 45-year selective cutting cycle was appropriate for managing concession forests in Cambodia in terms of maintaining commercial timber supply and reducing carbon emissions. By considering RIL or RIL+ as a new logging practice for improving forest management in the tropics, carbon credits from selective logging in Cambodia were estimated at 6.2 - 7.9 TgCO2 or about $31.0 - 39.5 million annually if carbon is priced at $5. It is concluded that RIL or RIL+ should be adopted for “sustainable management of forests” element of the REDD+ scheme.

Recovery of biomass and merchantable timber volumes twenty years after conventional and reduced-impact logging in Amazonian Brazil

Forest biomass recovery after conventional and reduced-impact logging in Amazonian Brazil