Signature of logging in the Brazilian Amazon still detected after 17 years

Abstract

Selective logging in the Amazon Biome holds significant importance economically and environmentally. Due to its potential for forest degradation, monitoring these areas is of utmost importance. We assessed canopy openness in sustainably logged forest areas in Eastern Amazonia using hemispherical photos taken in areas that were logged in different years (2004, 2007, 2017, 2019, and 2021), along with one unlogged control area to evaluate the time period over which the effects of logging remained detectable. Timeframes of detectability varied across logging features considered (e.g. log landings, logging roads and skid trails). Canopy openness of log landings used to store logs was still greater than that of unlogged forests controls >17 years after logging had ceased while the impacts of logging roads and skid trails were still detectable at least 5 years after cessation of logging. The detection of the impacts of selective tree harvesting on the forest several years after the end of operations provides confidence for larger-scale quantification of historical low-intensity logging over Amazonia through high-resolution imagery. More generally, the study also highlighted the importance of monitoring selective tree extraction areas to understand their influence on forest disturbance and the occurrence of regeneration processes.