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In 2006, the Brazilian Forest Service (SFB) started an ambitious program to establish forest concessions so as to provide a legal framework for long-term sustainable timber production in Amazonian forests. Forest concessions in the Brazilian Amazon currently cover only 1.6 million ha (Mha) but we estimate the area of all potential concessions as 35 Mha. This paper assessed the conditions under which the present and potential concession system can ensure an annual production of 11 Mm3. yr−1 to meet the estimated present timber demand. For this we used the volume dynamics with differential equations model (VDDE) calibrated for the Amazon Basin with a Bayesian framework with data from 3500 ha of forest plots monitored for as long as 30 years after selective logging. Predictions of commercial volume recovery rates vary with location. We tested 27 different scenarios by using combinations of initial proportion of commercial volume, logging intensity and cutting cycle length. These scenarios were then applied to the current area of concessions and to the area of all potential concessions (35 Mha). Under current logging regulations and the current concession area (mean logging intensity of 15–20 m3.ha−1, a harvest cycle of 35 years and an initial commercial timber volume proportion of 20%), timber production can be maintained only for a single cutting cycle (35 years). Only the scenario with a logging intensity of 10 m3ha−1 every 60 years with a 90% initial proportion of commercial timber species can be considered as sustainable. Under this scenario, the maximum annual production with the present concession areas is 159,000 m3 (157–159), or less than 2% of the present annual production of 11 Mm3. When considering all potential concession areas (35 Mha), under current rules, the total annual production is 10 Mm3yr−1 (2–17 Mm3yr−1, 95% credibility interval) but is not maintained after the first logging cycle. Under the most sustainable scenario (see above) and a concession area of 35 Mha, the long-term sustainable annual production of timber reaches only 3.4 Mm3yr−1. Based on these results we argue that the concession system will not be able to supply the timber demand without substantial reforms in natural forest management practices and in the wood industry sector. We argue that alternative sources of timber, including plantations linked with forest restoration initiatives, must be promoted.

The prosecution of illegal logging crimes is hampered by a lack of available forensic timber identification tools, both for screening of suspect material and definitive identification of illegally sourced wood. Reputable timber traders are also struggling to police their own supply chains and comply with the growing requirement for due diligence with respect to timber origins and legality. A range of scientific methods have been developed independently with the potential to provide the required identification information, but little attention has been given to how these tools can be applied synergistically to support the legal timber trade. Here we review the use of visual identification methods (wood anatomy, dendrochronology), chemical methods (mass spectrometry, near infrared spectroscopy, stable isotopes, radio-carbon), and genetic methods (DNA barcoding, population genetics/phylogeography, DNA fingerprinting) each with potential application to forensic timber identification. We further highlight where future research and development are required to identify illegal logging crimes using these methods and suggest ways in which multiple methods can be used together to answer specific identification questions. We argue that a new integrated field of forensic timber identification should be a global investment priority, for which the ongoing collection, curation and taxonomic study of appropriate reference material is a critical part. Consideration of the specific legal requirements for method development and the application of identification methodologies to criminal evidence are also imperative to achieve robust scientific support for illegal logging crime prosecutions and prevention.

Using nine microsatellite loci, we studied the effects of selective logging on genetic diversity, mating system and pollen dispersal in a population of the tree species Hymenaea courbaril, located in a 546 ha plot in the Tapajos National Forest, Para State, Brazil. We analyzed 250 offspring (nursery reared seedlings) collected after a logging episode from 14 open-pollinated seed trees. These were compared to 367 seedlings from 20 open-pollinated seed trees previously collected from the pre-logging primary forest. The genetic diversity was significantly lower in the post-logging seed cohort. In contrast to the pre-logging population, significant levels of selfing were detected in the post-logging population (tm = 0.962, P

In this study, six highly polymorphic microsatellite loci and a categorical paternity analysis approach were used to investigate the contemporary pollen gene flow in the neotropical tree species Symphonia globulifera . Data for this study were taken from a 500 ha experimental plot in a dense terra firme forest in the Eastern Brazilian Amazon and included the mapping and genotyping of 161 reproductive trees, representing more than 90% of all adult trees, and the collection of 748 open-pollinated seeds from 56 seed-trees over two field seasons (2002 and 2003). High levels of pollen immigration from outside of the study plot were detected in both sampled seed-years (≥49%) suggesting long distance pollen gene flow. Low levels of self-fertilization were also detected (≤2%). The analysis showed long distance pollen dispersal occurred within the study area in both 2002 ( δ = 907 ± 652 m SD) and 2003 ( δ = 963 ± 542 m SD). Patterns of pollen dispersal distance within the plot were also found to be shorter than the distances between potential male parents and seed-trees. This result indicates that the distance between trees does not explain the identified pollen dispersal pattern. Our results support the hypothesis that animal pollinated species occurring in low-density populations can disperse pollen in long distances, despite the very dense nature of the forest.

SummaryWhile around 20% of the Amazonian forest has been cleared for pastures and agriculture, one fourth of the remaining forest is dedicated to wood production [1]. Most of these production forests have been or will be selectively harvested for commercial timber, but recent studies show that even soon after logging, harvested stands retain much of their tree-biomass carbon and biodiversity [2,3]. Comparing species richness of various animal taxa among logged and unlogged forests across the tropics, Burivalova et al. [4] found that despite some variability among taxa, biodiversity loss was generally explained by logging intensity (the number of trees extracted). Here, we use a network of 79 permanent sample plots (376 ha total) located at 10 sites across the Amazon Basin [5] to assess the main drivers of time-to-recovery of post-logging tree carbon (Table S1). Recovery time is of direct relevance to policies governing management practices (i.e., allowable volumes cut and cutting cycle lengths), and indirectly to forest-based climate change mitigation interventions.

Forest logging reduces population density and increases the distance between co-specifics and so can cause the loss of alleles, and affect the genetic diversity, spatial genetic structure (SGS), mating system, and pollen flow of the population. These factors were studied in the tropical tree species Bagassa guianensis Aubl. occurring in a low-density population in the Brazilian Amazon forest. Genetic diversity was compared among offspring, juveniles and adult trees, before and after selective logging. Non-significant differences were observed between these samples. The harvest of 61% of the adult trees caused the loss of three alleles in the reproductive population. However, these alleles were present in juveniles and offspring and so were not lost from the population. SGS was detected up to 300 m before logging in the overall and adult populations. After logging, significant SGS was not observed. Deviations from random matings were evident throughout biparental inbreeding ( 1 − t ˆ s = 0.067 , P r ˆ p ( m ) = 0.193 , P Φ ˆ ft = 0.081 , P

Levels of genetic diversity, inbreeding, and spatial genetic structure were investigated at different ontogenic stages for a population of Hymanaea courbaril , before and after Reduced Impact Logging (RIL) was applied, in a 546-ha plot in the Tapajos National Forest, in the Brazilian Amazon. The multilocus genotype of nine microsatellites loci was determined for 74 juveniles (dbh t -test, P > 0.05), they suggest the occurrence of inbreeding depression. All ontogenic stages showed spatial genetic structure at short distance classes ( t -test, P > 0.05). Logging also reduced the distance of the spatial genetic structure in the reproductive population from about 800 to 200 m. In general, our results indicate that RIL affected the gene pool and spatial genetic structure of the reproductive population.

In the last three decades, Amazon tropical forests have experienced high rates of deforestation, both by clearing for agriculture and by logging. In this study, we use computer simulations to examine the potential effects of forest logging on genetic diversity and demographic recovery (basal area development) of four neotropical tree species over a time frame reflecting multiple logging events. The study species, Bagassa guianensis Aubl., Hymenaea courbaril L., Manilkara huberi (Ducke) Chevalier, and Symphonia globulifera L.f., are all taxa which are commonly exploited for timber in the Brazilian Amazon. The simulations were parameterized using empirical data from field studies in the Tapajos National Forest, Para State, Brazil, including genotypes at microsatellite loci, demography, ecology and growth for each species. Eight scenarios, combining two different cutting cycles and two minimum cutting diameters, were examined for each of the four species. The scenarios represent the actual forest practices used in Brazil and French Guiana (cutting diameter 45 and 60 cm, and cutting cycle of 30 and 65 years, respectively). Logging scenarios were applied for six cutting cycles, and final genetic and demographic data were compared to baseline data from corresponding control scenarios. At the end of the simulated period the basal area was strongly reduced under all conditions in B. guianensis, H. courbaril, and M. huberi. In only two scenarios was a species able to recover its basal area following logging (S. globulifera with both 45- and 60-cm cutting diameters under a 65-year cutting cycle). In the logging scenarios, all species showed a loss of alleles and genotypes and an increased genetic distance (calculated between each population at the start and the end of the simulations). These effects were higher under the most intensive logging cycles (30 years, 45 cm). However, effective number of alleles, expected and observed heterozygosities, and the fixation index were little affected by the logging simulations. Over all, we conclude that, even under very optimistic conditions for growth and recruitment, current logging practices are not sustainable in terms of basal area. Our simulations show that different species respond differently to logging, both demographically and genetically. No single set of logging parameters can be applied to the forest as a whole. Rather, forest management practices must be species-specific, taking into account not only growth parameters but also ecological and reproductive variables, in order to move toward long-term forest sustainability.