Reduced-impact Logging Practices Research Articles

The reasons great ape populations are still abundant in logged concessions: Environmental drivers and the influence of management plans

Negative short-term impact of logging on great ape distribution has been investigated but very little information is available on the long-term impacts of selective logging and management plans on ape habitats at a broader scale. We carried out a habitat suitability analysis using the presence data of great apes to identify the spatial relationships between their locations, logging activities patterns, and other human impacts (due to activities in rural communities) in an FSC-certified forestry concession (388,949 ha) in Cameroon. First, field data showed that the two great ape species, gorilla (Gorilla gorilla gorilla) and chimpanzee (Pan troglodytes troglodytes), did not differ in habitat type selection and they particularly appreciated highly dense rainforests which also lie within selectively logged zones. Second, we used MAXENT software to relate ape presence data to a set of predictor variables which represent environmental conditions and human disturbance factors (poaching, farming, trees felled to collect honey, logging roads). The model predicted that half of the whole concession may be suitable for the two primate species. Disturbances stemming from rural communities mainly correspond to poaching in the framework or not of usage rights. Road density was the strongest predictor of habitat choice by the great apes. Whereas the great apes tend to avoid zones with high road density, their population abundance increases in areas with a certain level of old logging roads. The vast majority of the predicted suitable habitats corresponds to areas logged less than 17 years ago (46.8% of the whole suitable area) where sustainable management practices have begun to be implemented, and unlogged areas (34.30%). Unsuitable habitats were mostly located in areas exploited before 2003 (45.46% of the unsuitable zones) with no reduced-impact logging practices, and in unlogged forests (41.51%). Our findings tend to confirm that selective logging combined with reduced-impact logging techniques which were more prevalent in FSC-certified concessions, may maintain or increase the spatial distribution of great ape habitats.

Reduced-impact logging practices reduce forest disturbance and carbon emissions in community managed forests on the Yucatán Peninsula, Mexico

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.

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.

Effects of directional felling, elephant skidding and road construction on damage to residual trees and soil in Myanmar selection system

SUMMARY Reduced-impact logging (RIL) is widely expected to maximize conservation values of selectively logged tropical forests; however, there remains a lack of supporting data to confirm the effectiveness of individual RIL practices. This study evaluates the extent of damage to residual stands and soil caused by directional felling, elephant skidding, and road construction in a tropical mixed deciduous forest under the Myanmar Selection System (MSS). The felling damage number was consistently larger for bamboo clumps than for trees over the range of felled tree size and felling intensity. Soil disturbed by road construction made up 4.6% of the 9-ha study area, but no visible damage to residual trees and soil from elephant skidding was found three months after the operation. Directional felling toward bamboos and elephant skidding of MSS are effective as RIL practices, producing the lowest level of damage to residual trees and soil as compared with other RIL studies.

Harvested wood products and REDD+: looking beyond the forest border.

BackgroundThe focus of REDD+ is sensu stricto on maintaining forest carbon stocks. We extend the scope of sustainable management of forest from forests to timber utilization, and study carbon offsets resulting from the utilization of harvested timber for bio energy or harvested wood products (HWPs). The emission budget of harvesting operations depends on the loss of standing biomass by timber extracted from the forest site and logging losses on the one side, and on the other on the wood end use and the utilization of processing residues. We develop two scenarios to quantify the magnitude of CO2 emissions by (1) energetic utilization, and (2) energetic and material utilization of harvested timber and compare the substitution effects for different fossil energy sources.ResultsThe direct energetic use of harvested timber does not compensate for the losses of forest carbon stock. Logging residuals and displacement factors reflecting different wood use constitute by far the most important factor in potential emission reductions. Substitution effects resulting from energetic use of mill residuals and from HWPs have only a subordinated contribution to the total emissions as well as the type of fossil fuel utilized to quantify substitution effects. Material substitution effects associated with harvested wood products show a high potential to increase the climate change benefits.ConclusionsThe observation and perception of REDD+ should not be restricted to sustainable management and reduced impact logging practices in the forest domain but should be extended to the utilization of extracted timber. Substitution effects from material and energetic utilization of harvested timber result in considerable emission reductions, which can compensate for the loss of forest carbon, and eventually contribute to the overall climate change mitigation benefits from forestry sector.

Effects of reduced-impact selective logging on palm regeneration in Belize

To assess the impacts of a low-intensity selective timber harvest on a palm community in Belize, we mapped logging infrastructure (i.e., roads, log landings, skid trails, and stumps) and measured palm regeneration 1year after a timber harvest carried out using reduced-impact logging (RIL) practices. We sampled palms across a gradient of increasing harvest impact severity from areas not directly affected by logging, in felling gaps, on secondary and primary skid trails, and on log landings. We used generalised linear mixed-effect models fitted in a Bayesian framework and applied a non-metric multi-dimensional scaling of the ecological distances between sites to evaluate differences in palm seedling regeneration density and species composition, respectively. The harvest of an average of 2.5treesha−1 caused 0.4% of the forest to be converted to log landings, 0.7% and 3.6% to roads and skid trails, and 2.3% to felling gaps, which left 93.0% of the 350ha harvest block with no direct impacts of logging. The difference in abundance and species composition of palm regeneration in unlogged areas compared to felling gaps and skid trails was small, but log landings had markedly lower densities. These results highlight that the impacts of selective logging are minor at least where harvest intensities are low and RIL practices are employed. If further reductions in canopy opening and soil disturbance are desired, we recommend that logs be cable-yarded (i.e., winched) the final 20m to skid trails instead of driving to the tree stumps. We estimate that implementation of this practice would reduce total skid trail coverage from 3.6% to 2.9% and overall forest disturbance from 7.0% to 6.3%. However, further reductions in disturbance might be inimical to the maintenance of palms and will certainly not favour regeneration of light-demanding commercial timber species (e.g., Swietenia macrophylla).

Carbon emissions performance of commercial logging in East Kalimantan, Indonesia

Adoption of reduced-impact logging (RIL) methods could reduce CO2 emissions by 30-50% across at least 20% of remaining tropical forests. We developed two cost effective and robust indices for comparing the climate benefits (reduced CO2 emissions) due to RIL. The indices correct for variability in the volume of commercial timber among concessions. We determined that a correction for variability in terrain slope was not needed. We found that concessions certified by the Forest Stewardship Council (FSC, N=3), when compared with noncertified concessions (N=6), did not have lower overall CO2 emissions from logging activity (felling, skidding, and hauling). On the other hand, FSC certified concessions did have lower emissions from one type of logging impact (skidding), and we found evidence of a range of improved practices using other field metrics. One explanation of these results may be that FSC criteria and indicators, and associated RIL practices, were not designed to achieve overall emissions reductions. Also, commonly used field metrics are not reliable proxies for overall logging emissions performance. Furthermore, the simple distinction between certified and noncertified concessions does not fully represent the complex history of investments in improved logging practices. To clarify the relationship between RIL and emissions reductions, we propose the more explicit term 'RIL-C' to refer to the subset of RIL practices that can be defined by quantified thresholds and that result in measurable emissions reductions. If tropical forest certification is to be linked with CO2 emissions reductions, certification standards need to explicitly require RIL-C practices.

The effects of reduced-impact logging practices on soil animal communities in the Deramakot Forest Reserve in Borneo

The effectiveness of reduced-impact logging practices on the maintenance of biodiversity in Borneo has been recognized for some organisms (e.g., mammals). We investigated the effects of reduced-impact logging and conventional selective logging practices on biodiversity by using soil fauna as indicators of disturbance. The study sites were the production forests of the Deramakot Forest Reserve and the Tangkulap Forest Reserve in Sabah, Malaysian Borneo (5°14–30′ N, 117°11–36′ E). We compared macro- and mesofauna in a pristine forest with no logging, a reduced-impact logged forest in Deramakot Forest Reserve, and a conventionally logged forest in Tangkulap Forest Reserve.The mean density of soil macrofauna (excluding ants) did not differ significantly among the three forest categories (nested ANOVA, p>0.05). This tendency was also seen in the density and species richness of Oribatida and Collembola, which showed little difference among forest categories. Nonmetrical multidimensional scaling (NMS) ordination diagrams revealed a different community composition in conventionally logged forest sites compared with the other sites. The scores for the NMS first or second axis of soil fauna were correlated with one or more of the values for density, diversity, and species composition of trees. A RELATE test showed the congruence between trees and the Collembola and Oribatida community composition between sites. The results implied that the soil fauna community composition was related to tree communities. In conclusion, the impacts of logging on decomposers in the soil animal communities have been mitigated by the introduction of reduced-impact logging in Deramakot Forest Reserve through the protection of tree vegetation. It is important to consider monitoring the influence of selective logging on soil fauna with regard to the dynamics of the species (or group) composition because total density and species (or group) richness of soil fauna displayed only a marginal response to the different logging practices.

Managing production forests for timber production and carbon emission reductions under the REDD+ scheme

Sustainable forest management (SFM) ensures the continuous flow of wood products and employment while improving the functionalities of forests as compared to conventional management. Until recently, many projects associated with the reducing emissions from deforestation and forest degradation (REDD) scheme focused only on reducing emissions from deforestation and forest degradation, conservation of carbon stocks, or enhancement of forest carbon stocks. REDD+ is an extension of REDD that also includes, SFM, conservation of carbon stocks, and enhancement of forest carbon stocks. REDD+ projects concerned with securing timber production while reducing emissions are very few in number. In this report, we discuss how SFM through the adoption of appropriate logging practices can lead to a reduction in carbon emissions while securing timber in the tropics. Logging practices affect timber production, the structure of forests, and forest-dependent communities because of damages caused by logging itself and the large amounts of logging and wood wastes. By switching from conventional logging to reduced-impact logging practices, International Tropical Timber Organization producer countries could reduce carbon emissions by about 1.5–2.1 billion tCO2 year−1 while still producing about 164.9–280.8 million m3 of end-use wood under a 50-year project cycle, with the results being dependent on the chosen scenario. Study results suggest that a policy of reduced-impact logging combined with a 40-year or longer cutting cycle is appropriate for SFM projects as part of the REDD+ scheme.

Recent surveys in the forests of Ulu Segama Malua, Sabah, Malaysia, show that orang-utans (P. p. morio) can be maintained in slightly logged forests.

BackgroundToday the majority of wild great ape populations are found outside of the network of protected areas in both Africa and Asia, therefore determining if these populations are able to survive in forests that are exploited for timber or other extractive uses and how this is managed, is paramount for their conservation.Methodology/Principal FindingsIn 2007, the “Kinabatangan Orang-utan Conservation Project” (KOCP) conducted aerial and ground surveys of orang-utan (Pongo pygmaeus morio) nests in the commercial forest reserves of Ulu Segama Malua (USM) in eastern Sabah, Malaysian Borneo. Compared with previous estimates obtained in 2002, our recent data clearly shows that orang-utan populations can be maintained in forests that have been lightly and sustainably logged. However, forests that are heavily logged or subjected to fast, successive coupes that follow conventional extraction methods, exhibit a decline in orang-utan numbers which will eventually result in localized extinction (the rapid extraction of more than 100 m3 ha−1 of timber led to the crash of one of the surveyed sub-populations). Nest distribution in the forests of USM indicates that orang-utans leave areas undergoing active disturbance and take momentarily refuge in surrounding forests that are free of human activity, even if these forests are located above 500 m asl. Displaced individuals will then recolonize the old-logged areas after a period of time, depending on availability of food sources in the regenerating areas.Conclusion/SignificanceThese results indicate that diligent planning prior to timber extraction and the implementation of reduced-impact logging practices can potentially be compatible with great ape conservation.

Vertebrate population responses to reduced-impact logging in a neotropical forest

Vertebrate population densities were quantified in lowland central Guyana using line-transect censuses at three forest sites subjected to reduced-impact logging (RIL), and three adjacent unlogged sites. We censused a range of forest vertebrate species including large canopy-dwelling and terrestrial birds, three primates, one rodent and one tortoise. Two 4 km transects at each site were repeatedly surveyed during the wet season of 2008 to derive population density estimates on the basis of a cumulative survey effort of 416 km. RIL had ended within 16 months, and sites had been subjected to a mean extraction rate of 3.9 m 3 ha −1, equivalent to only 1.1 trees ha −1. Three of the 15 vertebrate species examined here exhibited significantly different abundances at forest RIL sites, two of which were negative. Large frugivores such as primates were less abundant in sites subject to RIL, whereas smaller frugivores, granivores, folivores and insectivores were more common in logged sites. We are unable to reliably distinguish between responses of different taxonomic groups, since robust abundance metrics could only be estimated for four mammal species. Despite this, species traits including dietary guild, body mass, home range size and vertical stratification of forest use are used to explain varying responses. Our findings suggest that responsible reduced-impact logging practices in neotropical forests can be considered as a relatively benign form of forest management that can coexist with the requirements of both local economies and biodiversity conservation. However, our study sites experienced comparably low extraction rates, and detrimental effects such as hunting were low. Our results therefore provide an opportunity to scrutinise the effects of best practice logging systems, though do not necessarily represent typical circumstances across tropical forests.

Area disturbed and residual stand damage following logging in a Bolivian tropical forest

The area disturbed and damage to the residual stand caused by planned diameter-limit logging was assessed in a tropical humid forest of Bolivia and compared with disturbance and damage reported in other studies in the neotropics with similar harvesting intensities. The forest was logged by a private company under a government concession. The harvest incorporated many reduced impact logging practices including pre-harvest tree inventories, planned placement of roads and skid trails, vine cutting, and directional felling. A total density of 4.35 trees/ha and 12.1 m 3/ha of wood were harvested. It was estimated that logging disturbed 45.8% of the stand including 25% ground area disturbance in the form of skid trails, logging roads, and log landings and an additional 25% in canopy openings due to tree felling. On average, 44 trees were damaged for every tree extracted including 22 trees killed or severely damaged, 6 of them commercial species. The most common types of damage included uprooted stems, stem wounds to the cambial layer, and bark scrapes. Road width was found to be a significant factor determining the number of trees damaged along logging roads but not along skid trails. Damage to trees sustained along skid trails was found to be significantly less than the damage incurred along logging roads. Residual damage in felling gaps was positively related to the diameter-at-breast-height of the harvested trees. Comparisons with other planned operations revealed a higher percent ground area disturbed and a greater felling gap area per tree extracted. Higher ground area disturbance was mostly due to the greater area in skid trails, many of which appeared to be unnecessary. Larger felling gap sizes appeared to be at least partially attributed to the larger size of trees harvested relative to those in other forests. The results of this study suggest that reduced impact logging practices may also need to be accompanied by close supervision of field personnel, monetary incentives and/or disincentives to loggers, and post-logging site inspections to be implemented properly.

Effects of forestry practices on vegetation structure and bird community of Kibale National Park, Uganda

I examined the lingering effects of past timber management practices on the vegetation structure and bird community of Kibale National Park, Uganda. I compared four forest treatments: unlogged native forest (UL), two that were selectively logged at low (LL) and high (HL) intensities in the 1960s, and a conifer plantation (PL). Forest-dependent birds were best represented at UL. LL was similar to UL in both vegetation structure and bird community composition, although some forest-dependent bird species were missing from the former. HL had significantly less canopy closure and lower tree density than other plots as a result of the combination of extensive secondary damage and natural disturbance patterns that prevented the reclosure of the forest canopy. Thirty-one percent of the forest-dependent bird species observed during the study were not detected at HL. At PL, bird species richness and bird abundance were about a third of those observed in other plots. There were significant correlations between heterogeneity of tree distribution (horizontal heterogeneity) and abundance and species richness of birds across plots. Abundance and species richness of all, forest-dependent, and forest generalist birds were highest in plots with intermediate measures of horizontal heterogeneity, which were mostly unlogged or lightly logged. If reduced-impact logging practices are not implemented during selective logging operations in tropical forests, consequent long-term changes in vegetation structure may result in significant declines in the populations of some forest-dependent species, as was observed in Kibale National Park.

Cost and Efficiency of Cutting Lianas in a Lowland Liana Forest of Bolivia1

Liana cutting is a commonly suggested silvicultural practice aimed at reducing the negative impacts of lianas on timber production, but few experimental studies have been conducted to evaluate the cost and efficiency of this practice. In this study, we estimated the cost of cutting lianas in 12 plots of 0.25 ha each in a densely liana-infested forest of lowland Bolivia, and evaluated the efficiency of this silvicultural treatment in terms of the proportion of lianas missed, the density of resprouting liana stumps, and the number of liana-infested trees after two years of an experimental liana treatment.The cost of cutting lianas in this forest by locally hired laborers was 23.6 (SE = 2.48) person-hours/ha. Considering local cost of labor and the U.S.–Bolivian currency exchange rate at the time of the study, this figure translates to ca $15/ha. Liana density decreased from 2471 (SE = 104.3) to 130 (SE = 24.2) liana stems ≥2 cm/ha immediately after cutting, because 5.5 percent of lianas were left uncut (missed). Slender lianas were missed more often than lianas with large-diameter stems. Liana species that grow 2–3 m before they start to twine were also frequently missed. Twenty-two percent of liana stumps ≥2 cm sprouted after cutting. Liana stumps with larger diameters sprouted more than stumps with smaller diameters. Most liana stumps produced only two sprouts. Two years after cutting, 78 percent of trees had no living lianas in their crowns, in contrast to only 13 percent liana-free trees in the control plots. Sixty-four percent of trees still had hanging dead lianas two years after cutting, but only 23 percent of trees were reinvaded by lianas using dead liana stems as trellises.Liana cutting can efficiently reduce the number of lianas in liana-infested forests, and the effects of cutting lianas last for at least two years; however, the treatment is expensive. Thus, we recommend that it is better to view liana cutting as a preventive activity to avoid liana infestation, rather than as a corrective measure after poor management. Liana cutting can be easily conducted along with other reduced-impact logging practices.