The Brazilian Atlantic Forest is considered one of the world's most important sites for biodiversity conservation, and within this biome there are regions with diVering levels of species richness, species composition, and endemism. The present study was undertaken in southern Bahia, Brazil, and employed a standardized sampling method to compare the density of arboreal species in this region with other areas throughout the world known for their high tree species density. A total of 144 tree species with DBH > 4.8 cm were sampled within a 0.1 ha plot of old-growth forest (OGF), and these data were then compared with 22 other world sites that had been sampled using the same methodology and likewise demonstrated high densities of arboreal species. Only one site of ombrophilous forest in Colombia demonstrated a higher tree species density (148 spp. in 0.1 ha) than was encountered in southern Bahia. Other areas of Brazil, including other Atlantic Forest sites, showed signiWcantly inferior tree species densities. These results indicate that this region of southern Bahia has one of the greatest numbers of tree species in Brazil and in the world. These results, associated with the high levels of endemism there, indicate the high biological importance of this region. It is therefore fundamental

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The impacts of logging on Amazonian ecosystems has been the focus of considerable attention both within and outside of Amazonia. However, the impacts of logging on individual timber species has not been at all adequately investigated. Logging affects timber species by: (1) removing mature individuals that are important sources of seeds; (2) damaging seedlings and saplings (i.e future generations of canopy adults); and (3) creating conditions that favour fire by opening the canopy and leaving slash as fuel on the forest floor.In this study we summarize information on the ecological characteristics of 305 timber species in Brazilian Amazonia. We identify seven ecological parameters that are useful in evaluating a species' ability to resist the negative impacts of logging. These characteristics are: (1) effective long-distance dispersal ability; (2) abundance of saplings in forest regeneration; (3) rapid growth; (4) ability to resprout; (5) capacity to withstand fire; (6) broad geographic distribution; and (7) high density of adults. We hypothesize thai species with characteristics opposed to these parameters and subjected to intense logging pressure will have difficulty in maintaining their populations in logging regions.We use a simple scoring system to rank species with regard to their hypothesized ability to withstand logging impacts. Among the species that are potentially susceptible to logging impacts are Euxylophora paraensis (‘Pau Amarelo’) and Swietenia macrophylla (American Mahogany). The sawn lumber from these two species goes principally to European and North American buyers, revealing a direct link between First World consumption and possible biodiversity impoverishment in the Brazilian rain-forest. These two species, and others that might experience population reductions as a result of logging, merit special study.