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Highlights • Floristic composition tends to recover to a pre-logging status after 25 years. • Shifts in floristic composition mainly driven by sharp increase in pioneer species. • Little or no change in abundance of late-successional and non-exploited species. • Forest ability to recover following low to moderate levels of disturbance (<65 m3). • Tropical forests under selective logging retain important environmental value. Abstract Selective logging is one of the most prominent land uses in tropical forests and although it involves harvesting a limited number of trees, the impact on forest structure, composition and aboveground biomass can be significant. Although these impacts are well documented, what is little known is the extent to which selective logging affects tree floristic composition and its recovery process. Understanding how floristic composition is affected by logging activities is essential for determining subsequent cutting cycles, for the maintenance of carbon stocks and for biodiversity conservation. This research investigates the effect of logging on long-term trends on the recovery of species composition in a tropical forest using a unique logging experiment where measurements have been taken annually over a period of 25 years. Changes in 12 long-term 1-hectare (ha) permanent plots were assessed where different selective logging intensities occurred. In the first years after logging, floristic composition differed widely between intact and selectively logged forests, with exploited areas deviating from pre-logged composition. Over time, exploited areas shifted towards the original composition, with more pronounced changes in this trend after ∼13 years. Shifts in floristic composition were caused mainly by a significant increase in light-demanding fast-growing pioneer species and their subsequent continuous high mortality rates after 13 years of the recovery process. In contrast, the control plots showed similar shifts in composition over time, suggesting external factors such as long-term climate changes may be driving these shifts. The results suggest that 25 years after an experimental selective logging has taken place, floristic composition tends to recover closer to the pre-logged status. Thus, in the absence of further human disturbances, experimental selectively logged forests in low to moderate intensities are compatible with biodiversity conservation, at least during the first cycle of exploitation. Reconciling conservation strategies with the recovery of stocks of commercial timber species would be greatly improved by using these results and lead towards more sustainable forest management plans. [ABSTRACT FROM AUTHOR]

In the present study, we aimed to map canopy heights in the Brazilian Amazon mainly on the basis of spaceborne LiDAR and cloud-free MODIS imagery with a new method (the Self-Organizing Relationships method) for spatial modeling of the LiDAR footprint. To evaluate the general versatility, we compared the created canopy height map with two different canopy height estimates on the basis of our original field study plots (799 plots located in eight study sites) and a previously developed canopy height map. The compared canopy height estimates were obtained by: (1) a stem diameter at breast height ( D ) – tree height ( H ) relationship specific to each site on the basis of our original field study, (2) a previously developed D – H model involving environmental and structural factors as explanatory variables ( Feldpausch et al., 2011 ), and (3) a previously developed canopy height map derived from the spaceborne LiDAR data with different spatial modeling method and explanatory variables ( Simard et al., 2011 ). As a result, our canopy height map successfully detected a spatial distribution pattern in canopy height estimates based on our original field study data ( r = 0.845, p = 8.31 × 10 −3 ) though our canopy height map showed a poor correlation ( r = 0.563, p = 0.146) with the canopy height estimate based on a previously developed model by Feldpausch et al. (2011) . We also confirmed that the created canopy height map showed a similar pattern with the previously developed canopy height map by Simard et al. (2011) . It was concluded that the use of the spaceborne LiDAR data provides a sufficient accuracy in estimating the canopy height at regional scale. [ABSTRACT FROM AUTHOR]

Tree mortality is a critical process in forest ecosystems, as it influences floristic composition, structure, dynamics, carbon storage, and forest nutrient cycling. However, the mechanisms behind tree death in tropical regions are still poorly characterized. This lack of information is mainly because tree mortality data come from long-interval inventories and studies that measured tree death seasonally are scarce. Here we offer novel insights into the power of fine temporal scale observations and we use a natural history approach to understand the processes and mechanism of tree mortality. We monitored tree mortality every month during one year, in 10 ha of terra-firme forest. To determine the pathways of mortality, we considered the state of the tree at the start of the investigation and the pre and post-mortem characteristics. From November 2010 to October 2011, 67 out of 5808 trees died. Despite the 2010 drought, mortality was highly correlated with monthly rainfall (r = 0.85). In total, six pathways of mortality were assessed. Storms were the main cause of mortality, killing 45% of all dead trees, followed by Biotic/abiotic factors accounting for 30% of tree mortality. The high mortality registered in the rainy season was mostly (78%) due to healthy trees dying uprooted or snapped. Finally, we would benefit from studies that assess mortality on a monthly basis and in combination with quantitative long-term data, we can substantially improve our understanding of the mechanisms behind tree death in the tropics. [ABSTRACT FROM AUTHOR]

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Presents an unbiased model of the relationship between trunk base diameter and tree mass using data from trees harvested in the central Amazon. Model's comparison with other theoretical and empirical models; Estimated tree damage per year of litter production; Hypothesis that tree damage in old-growth forests accounts for a significant portion of age related decline in productivity.

Studies the effect of experimental logging on two species of termites of the genus Syntermes in Central Amazonia, Brazil. Increased effect of logging on Syntermes chaquimayensis; Reduction in forest litter breakdown owing to decrease in density of the species.