Not the harvesting removal of mature trees, but the damage to remaining trees and subsequent thinning have the strongest influence on tree species composition of a lowland Amazonian rainforest.

This is one of the important results that Angela de Avila, PhD candidate at the Chair of Silviculture, and her German and Brazilian colleagues have published as a result of their analysis of a unique long-term experiment.

In this study, tree species dynamics was documented through 8 repeated inventories over 31 years in an experiment examining the impacts of different management intensities in the Brazilian Amazon. Tree species diversity was not impaired by silvicultural interventions, but high intervention intensities substantially affected the recovery in species composition. Moreover, the reduction of basal area through harvesting damage and thinning had a stronger effect on species composition than logging of mature trees itself. These findings indicate that maximum harvesting intensities under current Brazilian legislation will likely not cause substantial changes in tree species composition in the long-term. In addition, the results demonstrate that strong thinning interventions should be avoided and they point to the importance of reduced impact logging for easing damage to retained trees and hence lessen possible unintended changes to tree species composition. These measures may enhance ecosystem recovery and maintenance of biodiversity at other trophic levels

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