Effects Of Selective Logging Research Articles

Long‐Term Impacts of Selective Logging in a Tropical Rainforest in the East Region of Cameroon

ABSTRACTAlthough selective logging has become the primary cause of degradation in many African countries, little is known about its long‐term effects. This study investigated the long‐term effects of selective logging on forest tree species diversity and dynamics in the East Region of Cameroon. Six permanent monitoring plots of 1 ha each in unlogged and logged forests were established in 2005 and a recensus in 2011. Each 1 ha plot was divided into 25, 20 × 20 m quadrats. Each 20 × 20 m quadrat was further divided into 16, 5 × 5 m subquadrats, where the diameter at breast height (DBH) of all trees ≥ 2 cm was measured. There was a decrease in plant species density and richness in all forest types. Sloetiopsis usambarensis was the most important species in the unlogged forests and forests logged 21 years ago. The most important family was Putrangivaceae, Euphorbiaceae and Violaceae in the unlogged forests and forests logged 11 and 21 years ago, respectively. The frequency distribution of stem size classes indicated a reversed J‐shape of tropical forests. The above ground biomass (AGB) recovered more than 50% in all forests, and the unlogged forest had the highest AGB (961.8 Mg/ha). Larger stems indicated a forest at a stage of recovery from disturbance. Silvicultural management should be considered.

Variable shifts in bird and bat assemblages as a result of reduced‐impact logging revealed after 10 years

Abstract Selective logging is the most widespread driver of land‐use change in biodiverse and carbon‐rich tropical forests. However, the effects of selective logging on biodiversity are less than those associated with other drivers of forest degradation. A suite of recent research has shown that reduced‐impact logging (RIL) results in few or no changes to biological assemblages. But because this logging technique is relatively new, most studies have only considered short‐term impacts. We address this research gap by quantifying changes in biodiversity assemblage as a result of RIL over the longer term. We comprehensively sampled bird and bat assemblages pre‐logged, 1 year after, and 10 years after RIL in Guyana, using a before‐after control‐impact (BACI) sampling design. We compared bird and bat assemblages in each timeframe, and additionally appraised the impact of time since logging, and the number of trees harvested across the suite of species which we further divided between different feeding guilds, disturbance sensitivity and vertical stratification of forest use. We found that 1 year after logging only minor changes could be detected, but 10 years later richness had slightly declined in some groups, while others had shown complete recovery. Nectivorous and insectivorous birds, and carnivorous bats declined in richness, while carnivorous birds, showed a clear recovery to a state akin to pre‐logging. This indicates that for some niches a subtle, but long‐term relaxation effect may be occurring, whereby extinction debts are realized long after the initial disturbance, while other groups have either recovered or not changed after logging. Assemblage changes were also predicted by vertical stratification of forest use, with avian species using the understorey and mid–upper levels of the forest being most affected. Synthesis and applications: Our study demonstrates how best practice forestry and logging can maintain healthy vertebrate populations over the long term. Forestry concessions that adopt techniques of low‐harvest RIL and are managed for their long‐term timber provision through extension of regeneration times beyond 10 years after harvest, are likely to benefit from the ecosystem services provided by biodiversity, while also making a valuable contribution to the global conservation estate.

Effects of selective logging on genetic diversity and population structure of a keystone mistletoe

AbstractThe effects of habitat degradation remain not fully understood. A recent study reported low effects of habitat degradation on plant genetic diversity but indicates that reduction in habitat quality could impact it as well as gene flow indirectly via ecological interactions. Selective logging is a way of habitat degradation, but studies examining its effects on plant genetic diversity on non‐logged forest plant species are relatively scarce. Using 3470 single‐nucleotide polymorphisms, we assess the effects of different selective logging intensities on the genetic diversity of 66 individuals of a keystone mistletoe (Tristerix corymbosus). We also examined the possible relationship with its seed disperser (Dromiciops gliroides) abundance in three sites of the temperate rainforests of southern Chile, with different levels of selective logging intensity. Our results show that selective logging increases allelic richness and inbreeding in this mistletoe; inbreeding increased with selective logging intensity, and heterozygosity decreased with D. gliroides abundance. While wood extraction seems to positively affect T. corymbosus genetic diversity, its long‐term consequences—such as increased inbreeding—are yet to be assessed in future studies.

Selective logging effects on plant functional traits depend on soil enzyme activity and nutrient cycling in a Pinus yunnanensis forest

Selective logging has a wide impact on the remaining trees and soils which in turn influences total ecosystem function. Lots of studies focus on effects of selective logging on changing of plant functional traits, but the mechanism underlying these effects is still unclear. Thus, we studied 6 plant functional traits including leaf N concentration (LNC), leaf P concentration (LPC), leaf N:P ratio (N:P), wood density (WD), specific leaf area (SLA), and leaf dry mass content (LDMC) typically associated with resource acquisition and allocation. We measured these traits across 13 tree species in 52 plots under 5 selective logging intensities in a Pinus yunnanensis forest and aimed to test how selective logging and soil factors affect community weighted mean (CWM) of plant functional traits. The results revealed significant positive correlations between LNC and LPC, LNC and SLA, LPC and SLA, N:P and LDMC. Significant negative correlations were found between LNC and LDMC, LPC and N:P, LPC and LDMC. Only soil β-glucosidase activity (SGA), soil phosphatase activity (SPA), soil total nitrogen (STN), soil total phosphorus (STP) and soil hydrolysable nitrogen (SHN) had a significant relationship with one or several of the 6 plant functional traits. Compared with the control group, there was little significant difference in all plant functional traits across the different selective logging intensities. However, for plant functional traits, selective logging significantly increased the LNC, LPC and SLA. For soil factors, selective logging significantly increased the SGA, soil urease activity (SUA), SPA, soil moisture (SM), STN, STP and SHN. Based on structural equation models, we found that although selective logging has no direct effect on plant functional traits, it can indirectly affect plant functional traits through soil factors, mainly soil enzyme activity and nutrient cycling. Meanwhile, the mechanism of selective logging affecting different functional traits may be varied. Our findings provide a theoretical basis for the scientific management of P. yunnanensis forest.

Effect of selective logging on the genetic differentiation of Juglans pyriformis Liebm. populations

Juglans pyriformis Liebm. (Juglandaceae) is a threatened and endemic tree that grows in the cloud forest of Mexico. Natural populations of this species have been reduced due to, among others, changes in land use, overexploitation, and logging, with probable effects on its genetic diversity and structure. To determine the levels of variation and genetic structure of two populations with different silvicultural regimes, six inter-simple sequence repeat (ISSR) primers were used to amplify DNA from 35 individuals from a high-logging population and 32 from a low-logging population. The results show a higher polymorphism in the low-logging population (81.5%) compared to the high-logging population (77.4%). The genetic differentiation coefficient (PhiPT) values (0.109), genetic distance (0.134) and STRUCTURE analysis (Fst = 0.2271, P = 0.04) show significant genetic differentiation between populations. Rare, private, and monomorphic bands were detected in both populations. These results confirm the trend of reduced genetic variation due to logging.

Effects of selective-logging, litter and tree species on forests in the Peruvian Amazon: seed predation, seed pathogens, germination

Background: The Amazon basin contains mainly unflooded forests, and they are among the most important ecosystems in the world. Field experiments on seed processes are very important in order to understand the structure, function and dynamics of these forests. Methods: And so tree seeds of three species (Cecropia latiloba, Guarea macrophylla, Socratea exorrhiza) were set out in Amazon unlogged terra firme forest, in Amazon selectively-logged terra firme forest, in Amazon palm forest, and in Amazon white sand forest either on top of or beneath the litter layer, and after two weeks scored for seeds taken by predators, seeds destroyed by pathogens and seeds that germinated. Results: I found both terra firme forests (unlogged and selectively-logged) lost most of their seed to predators and the least of their seed to pathogens, white sand forests lost the least of their seed to predators and the most of their seed to pathogens, and the fewest seeds germinated in both terra firme forests and in palm forest. More specifically (1) within unlogged terra firme forest addition of litter reduced seed predation but increased seed losses to pathogens and germination, and C. latiloba lost the most seeds to pathogens, (2) within selectively-logged terra firme forest seeds showed the same trends as unlogged terra firme forest but without significant effects, (3) within palm forest addition of litter reduced predation but increased losses to pathogens, and S. exorrhiza lost the least seeds to pathogens, and (4) within white sand forests addition of litter increased germination. Combining the results from all forests together, predators took most of the seeds, pathogens took most of the seeds that escaped predation, and most of the seeds that survived predation and pathogens germinated. Conclusion: While such large losses of tree seed to predators and pathogens in these unflooded forests suggest limited recruitment, the variation demonstrated in these field experiments – among forest-types, among tree species, between litter situations on the forest floor – help to insure that recruitment does occur and that these unflooded forests continue to dominate the Amazon basin.

Effects of selective logging, fragmentation, and dominance of bamboos on the structure and diversity of Araucaria Forest fragments

During the colonisation of the South of Brazil, logging of tree species with high economic value was one of the main economic activities. In this process, almost all Araucaria Forest, one of the forest types of the Atlantic Forest that once covered most of this region, was severely fragmented and disturbed. One of the consequences of this disturbance was the population growth of a native bamboo species (Merostachys skvortzovii) that came out of the small patches where it occurred naturally, to dominate the understory of forest fragments. In this study, we evaluated if the fragment size, forest-edge effect, and abundance of bamboos affect forest structure and functional guilds in a region of Araucaria Forest in Parana state, Brazil. We sampled trees (DBH ≥ 4.8 cm) in five fragments (24–270 ha) in two plots (2000 m2 each) located at the edge and centre of each one. We analysed the forest structure (species composition and species richness, abundance, and basal area) and estimated the bamboo cover in each plot. We recorded 1743 individuals of 68 tree species in the five analysed patches. The fragments were very similar in floristic composition and structure (species richness, abundance, basal area). The bamboo cover was the main factor affecting forest structure and species guilds distribution, followed by distance from the fragment edge. These results show a simplification of floristic, structural, and functional attributes of Araucaria Forest remnants suggesting that the selective logging followed by fragmentation and native bamboo overabundance are important factors in the imporishment of this endangered biome.

Carbon assimilation, water consumption and water use efficiency under different land use types in subtropical ecosystems: from native forests to pine plantations

The effects of selective logging in Argentinean native subtropical forests or its replacement by pine plantations on carbon and hydrological cycles is of importance for developing strategies for a sustainable use of water resources and climate mitigation in subtropical humid regions. Ecosystem-level gross primary productivity (GPP), evapotranspiration (ET) and water use efficiency (WUE) were assessed using multi-temporal MODIS remote sensing data and its response to climatic variables were analyzed in well-preserved native forests, degraded native forests by selective harvesting and pine plantations. Field measurements of leaf area index (LAI), tree density, basal area, tree high, diameter at breast height and understory cover was implemented. The GPP was high throughout the year across all three-land use types. Selective harvesting of commercial trees resulted in a significant decrease in tree density and in basal area compared to well-preserved native forests but did not have a negative impact on GPP. Mean annual ET was similar between both native forests because although the degraded forest had a lower tree density they had a greater maximun DBH per tree than the well-preserved forests and therefore high transpiration. The WUE was similar across the ecosystem types. Removal of 5.5 m2 of canopy trees produced a compensatory change in ecosystem structure and function resulting in the maintenance of GPP and ET. Replacement of native forests by pine plantations for wood production did not change annual GPP compared to native forests, but the final carbon assimilation should be lower due to the CO2 released before canopy closure and after harvesting. All climatic variables were linearly and significantly related to monthly GPP, ET and WUE with the exception of precipitation with monthly GPP. Finding forest management techniques for increasing carbon assimilation is of importance for limiting the rise of global CO2 emissions and for regulation of the water cycle.

Effect of selective logging on soil microbial communities in a Pinus yunnanensis forest

AbstractSelective logging strongly affects forest structure and functions, which has direct and indirect effects on the soil microbial community. However, the effect of selective logging on soil microbial community composition remains unclear. We analyzed the soil microbial diversity and community composition in a pine (Pinus yunnanensis) forest using the Illumina platform for bacterial and fungal sequencing. The results showed that selective logging significantly altered most soil properties and stand attributes. Dominant phyla abundance varied significantly with change of selective logging intensity, affecting soil microbial community composition. The diversity of bacterial community decreased with the increase of selective logging intensity, whereas the diversity of fungi initially decreased and then increased. Soil properties accounted for most of the variation in the soil microbial communities, followed by stand attributes. Stand density (SD), soil pH, and soil moisture directly influenced the diversity of the bacterial communities, and understory species richness (USR), soil organic carbon (SOC), and soil hydrolysable nitrogen (HN) also directly influenced bacterial community composition. However, selective logging intensity affected the diversity and composition of the bacterial communities indirectly via SD, soil pH, HN, SOC, and USR. Similarly, the intensity of selective logging directly affected the diversity of fungal communities and also showed indirect effect on it via SD, soil pH, SOC, HN, C:N ratio, and soil available potassium. Further, selective logging intensity indirectly affected fungal community composition via soil available phosphorus. Our findings could be used to predict the change in the soil microbial community for the management of P. yunnanensis forest.

Canopy gap dynamics and effects of selective logging: a study in a primary hill dipterocarp forest in Malaysia

Canopy gap dynamics and effects of selective logging: a study in a primary hill dipterocarp forest in Malaysia

Canopy height recovery after selective logging in a lowland tropical rain forest

The effects of selective logging on canopy height were studied in a lowland tropical rain forest in Pasoh Forest Reserve, Peninsular Malaysia. Canopy height was measured in 2003 and 2011 by using an airborne light detection and ranging system and mapped on a 2.5-m grid over logged and primary forest plots. The logged forest plot was in an area where a selective logging operation had been conducted in 1958, whereas the primary forest plot has no trace of any major human-induced disturbances. The average canopy height in the logged forest plot increased from 23.6 m (2003) to 25.8 m (2011), but both of these heights were still significantly lower (P < 0.0001) than in those in the primary forest plot (28.7 m in 2003 and 30.4 m in 2011). The coefficient of variation and canopy height diversity (H′) were also lower in the logged forest plot, suggesting that the highly heterogeneous canopy height commonly seen in the primary forest in this region had not fully recovered even 53 years after the logging operation. Simulation analysis revealed that it will take at least another 16 years from the last canopy mapping (2011) for full recovery.

Fungi decaying the wood of fallen beech (Nothofagus) trees in the South Island of New Zealand

To extend present knowledge of communities of wood decay fungi in native forests, basidiomycetes and ascomycetes were isolated from within 15 fallen stems in beech (Nothofagus, Nothofagaceae) forests in the South Island of New Zealand. Fungal species were identified as precisely as possible using traditional culturing and molecular approaches. The internal distribution of species within stems was determined. Common fungi that occupied significant portions of stems were Ganoderma applanatum sensu Wakefield, Australoporus tasmanicus, Inonotus nothofagi, Pleurotus purpureo-olivaceus, and an unidentified hymenochaetaceous species. Richness and diversity of basidiomycete species were greater in stems of red beech (Nothofagus fusca (Hook. f.) Oerst.) and silver beech (Nothofagus menziesii (Hook. f.) Oerst.) than in those of matai (Prumnopitys taxifolia (Banks &amp; Sol. ex D. Don) de Laub.; Podocarpaceae) and tawa (Beilschmiedia tawa (A. Cunn.) Kirk; Lauraceae), as determined from earlier studies in podocarp hardwood and beech indigenous forests. There was greater similarity in the species composition of basidiomycete fungi colonising the three beech species compared with those colonising rimu (Dacrydium cupressinum Sol. ex Lamb.; Podocarpaceae), tawa, and matai. Based on observations in this study and on international research on the effects of selective logging on basidiomycete biodiversity, the decision to restrict to 50% the extraction of wood following storm damage in beech forests on the West Coast of the South Island appears to have been appropriate.

Effects of selective logging on rodent-mediated seed dispersal

Abstract It is generally accepted that selective logging significantly influences the vegetation coverage and habitat structures, but little is known about whether and how low intensity selective logging affects seed dispersal mediated by small rodents. In this study, we compared the differences in seed disperser composition and abundance as well as primary and secondary seed dispersal and predation of Quercus aliena var. acuteserrata by scatter-hoarding rodents in different aged forest (i.e., unlogged stands, stands in the second and fifth year after low intensity logging 150 stems per ha) in Huoditang Forest in the Qinling Mountains, China. We found that the rodent composition of stands in the second year after logging (large-bodied disperser Sciurotamias davidianus was absent) differed conspicuously from that of the other two stands. Selective logging reduced the abundance of rodents, seed removal rate, scatter–hoarded proportion, and seed dispersal distance during the second year after selective logging. However, no significant differences were found in the composition and abundance of rodents as well as their seed dispersal services between the unlogged stands and in stands during the fifth year after logging. In addition, the proportions of initially buried acorns were significantly lower in stands in the second year after logging compared with the other two types of stands, but after seed caching, the seed revisiting rates were lower in stands in the second year after logging compared with the other two types of stands. Rodent–mediated seed dispersal was lower in the second year after selective logging but it recovered to its initial level within five years. The dispersal distance was significantly lower in stands in the second year after logging compared with the distances (3.12 ± 0.23 m) in the unlogged forest stands (5.75 ± 0.41 m) and in stands in the fifth year after logging (4.44 ± 0.36 m). Therefore, selective logging in forests is likely to temporarily alter the composition of rodent communities, change seed dispersal services, and the capacity for plant movements. Number of years after selective logging is important for determining whether seeds are removed rapidly by potential dispersers, which can lead to different rates of seed removal, seed predation, scatter–hoarding, and survival, and eventually influence forest recovery after selective logging.

&lt;b&gt;Effect of selective logging on floristic and structural composition in a forest fragment from Amazon Biome

This study was conducted in one region of a Seasonal Semideciduous Forest located in Tapurah (Mato Grosso State, Brazil) with the aim of studying its floristic and structural composition. The fixed area method was applied to 10 × 250 m clusters, allocating and measuring five clusters with five subunits of 500 m² each. Species with a diameter at breast height greater than or equal to 10 cm were considered, and the sample sufficiency of the floristic survey was verified by a species accumulation curve. The similarities between the sample subunits were calculated by the Jaccard Similarity Index, and the species diversity with the Shannon Diversity Index and Pielou Evenness Index. The horizontal vegetation structure was characterized by density, frequency, dominance and the values of ecological importance, and diametric distribution were assessed by the Spiegel procedure. The families Vochysiaceae, Fabaceae and Sapindaceae were highly represented, and Qualea paraensis , Aspidosperma discolor and Matayba arborescens were the most important species. A high diversity and low ecological dominance were found, and the diametric structure of the trees presented a negative exponential distribution. In general, the structure, floristic composition and richness of vegetation correspond to a forest with stable and autoregenerative community after selective logging.

Long-term effects of selective logging on dipterocarp populations in the Pasoh Forest Reserve, Malaysia

Background: Selective logging alters tree growth, mortality and recruitment, and the subsequent population dynamics of trees. However, little information is available on how tree populations reduce local extinction in logged forests.Aims: We evaluated the effects of selective logging on tree performance and population dynamics of five dominant dipterocarp species in the Pasoh Forest Reserve, Malaysia.Methods: We used demographic data derived from a forest that was selectively logged in 1958 as well as those from an unlogged primary forest and constructed population transition matrix models to project the population dynamics.Results: The dipterocarp species studied showed minor differences in mortality and diameter growth, but there was a large difference in recruitment between logged and unlogged forest; populations in the logged forest had 10 times slower recruitment rates into the smallest size class than those in the primary forest. Population size structures differed between the two forest types but, despite a large difference in the recruitment rates, there were only minor differences in both asymptotic- and matrix-projected population growth rates.Conclusions: A single selective logging event had only minor impacts on the growth rates of dipterocarp trees in the Pasoh forest. But at the same time it had a large impact on the size structure of the dipterocarp populations through a reduction in recruitment showing that the impacts of selective logging are still seen on dipterocarp population after 50 years.

Effect of selective logging on soil organic carbon dynamics in tropical forests in central and western Africa

Changes in soil organic carbon (SOC) as a consequence of selective logging activities are often neglected in tropical areas, even within activities that aim to promote the permanence of forest C stocks (e.g. REDD+). In this context, we assessed the magnitude of the impact of selective logging on the SOC levels in three chronosequences in Ghana, Cameroon and Gabon. In each chronosequence, from unlogged forest to forest that was selectively logged at different times in the past, adjacent plots were investigated by sampling the soil at various depths to 1 m. Both SOC concentrations and stocks drastically decrease after selective logging in all sites. The 0–5 cm depth represents the layer with the most evident SOC decreases, particularly in the first and second decades after selective logging. The SOC loss is later stabilised, but the C levels remain lower than those of the unlogged forest 45–50 years after selective logging. In all the investigated chronosequences, the SOC levels are strongly affected by selective logging and the soils continue losing C for many years. In conclusion, SOC measurements should be used to provide precise C emission-removal estimates also for forests managed using sustainable management practices.

Avian responses to selective logging shaped by species traits and logging practices.

Selective logging is one of the most common forms of forest use in the tropics. Although the effects of selective logging on biodiversity have been widely studied, there is little agreement on the relationship between life-history traits and tolerance to logging. In this study, we assessed how species traits and logging practices combine to determine species responses to selective logging, based on over 4000 observations of the responses of nearly 1000 bird species to selective logging across the tropics. Our analysis shows that species traits, such as feeding group and body mass, and logging practices, such as time since logging and logging intensity, interact to influence a species' response to logging. Frugivores and insectivores were most adversely affected by logging and declined further with increasing logging intensity. Nectarivores and granivores responded positively to selective logging for the first two decades, after which their abundances decrease below pre-logging levels. Larger species of omnivores and granivores responded more positively to selective logging than smaller species from either feeding group, whereas this effect of body size was reversed for carnivores, herbivores, frugivores and insectivores. Most importantly, species most negatively impacted by selective logging had not recovered approximately 40 years after logging cessation. We conclude that selective timber harvest has the potential to cause large and long-lasting changes in avian biodiversity. However, our results suggest that the impacts can be mitigated to a certain extent through specific forest management strategies such as lengthening the rotation cycle and implementing reduced impact logging.

Effects of selective logging on large mammal populations in a remote indigenous territory in the northern Peruvian Amazon

We examined the effects of selective timber logging carried out by local indigenous people in remote areas within indigenous territories on the mammal populations of the Yavari-Mirin River basin on the Peru-Brazil border. Recent findings show that habitat change in the study area is minimal, and any effect of logging activities on large mammal populations is highly likely to be the result of hunting associated with logging operations. We used hunting registers to estimate the monthly and yearly biomass extracted during timber operations and to calculate the catch per unit effort (CPUE) in subsistence hunting in the community of Esperanza 2 to 5 years before logging activities started and 4 to 7 years after logging began. We also used line transects and the distance method to estimate animal densities before and after logging. We found that 1389 hunted animals and 27,459 kg of mammal biomass were extracted per year from logging concessions. CPUE for ungulates declined; however, it increased for other mammal orders, such as rodents and primates, indicating a shift to alternative prey items. Although collared peccaries (Pecari tajacu) and tapirs (Tapirus terrestris) may also have declined in numbers, this shift may have been caused by a possibly natural population crash in white-lipped peccaries (Tayassu pecari) that coincided with the logging periods. We found no evidence that populations of primates were reduced by the logging activities. Because primates are sensitive to hunting, and their populations were of principal concern as logging commenced, this indicates that these forests remain of high conservation value. The unusual socioeconomic situation of these remote territories may mean that they are compatible with wildlife conservation in the Yavari-Mirin basin.

Selective logging: does the imprint remain on tree structure and composition after 45 years?

Selective logging of tropical forests is increasing in extent and intensity. The duration over which impacts of selective logging persist, however, remains an unresolved question, particularly for African forests. Here, we investigate the extent to which a past selective logging event continues to leave its imprint on different components of an East African forest 45 years later. We inventoried 2358 stems ≥10 cm in diameter in 26 plots (200 m × 10 m) within a 5.2 ha area in Kibale National Park, Uganda, in logged and unlogged forest. In these surveys, we characterized the forest light environment, taxonomic composition, functional trait composition using three traits (wood density, maximum height and maximum diameter) and forest structure based on three measures (stem density, total basal area and total above-ground biomass). In comparison to unlogged forests, selectively logged forest plots in Kibale National Park on average had higher light levels, different structure characterized by lower stem density, lower total basal area and lower above-ground biomass, and a distinct taxonomic composition driven primarily by changes in the relative abundance of species. Conversely, selectively logged forest plots were like unlogged plots in functional composition, having similar community-weighted mean values for wood density, maximum height and maximum diameter. This similarity in functional composition irrespective of logging history may be due to functional recovery of logged forest or background changes in functional attributes of unlogged forest. Despite the passage of 45 years, the legacy of selective logging on the tree community in Kibale National Park is still evident, as indicated by distinct taxonomic and structural composition and reduced carbon storage in logged forest compared with unlogged forest. The effects of selective logging are exerted via influences on tree demography rather than functional trait composition.

The impact of selective logging and clearcutting on forest structure, tree diversity and above‐ground biomass of African tropical forests

AbstractTropical deforestation is well known to have serious negative consequences for biodiversity, terrestrial carbon sinks and the balance of atmospheric greenhouse gases. By contrast, selective logging of tropical forests is often regarded as having a lesser impact on the ecosystem particularly in long terms, even though there have been few critical evaluations of the practice, particularly in Africa. We compared field data from 511 plots in the tropical forest of Sierra Leone, Ghana, Cameroon and Gabon. These plots were subject to different forest management practices: no recent logging (primary forests), selective logging (up to 30 years old) and re‐grown secondary forests post clear‐cutting (at least 20 years ago). Our findings suggest that the vertical structure and plant richness of the selectively logged and secondary forests change in different amplitude from those of primary forests, but stem density and the prevalence of vine and weed species differ greatly. We show that the effects of selective logging are greater than those expected simply from the removal of commercial species, and can persist for decades. Selective logging, unless it is practiced at very low harvest intensities, can significantly reduce the biomass of a tropical forest for many decades, seriously diminishing aboveground carbon storage capacity, and create opportunities for weeds and vines to spread and slow down the ecological succession.