Drivers and impacts of timber extraction, fires, drought and habitat fragmentation
This review paper analyzed forest degradation processes using existing data that included fire, edge effects, extreme drought, and timber extraction between 2001 and 2018 in Amazon forest. The synthesis focused on causes and impacts, possible futures, and some interventions required to slow these forest degradation processes. The analyses demonstrated that the combined effects of all degradation processes impacts an area larger than the total area deforested during this same period. Forest carbon loss from these processes is also comparable to carbon loss from direct deforestation.
The analysis highlights specific processes that can be targeted to reduce the negative effects of forest degradation processes, including carbon emissions that occur beyond the direct effects of deforestation. Reducing degradation processes will require engaging with a diverse set of stakeholders, the monitoring of different disturbance processes, and the development of appropriate policies and programs.
Degradation processes in the Amazon, including areas degraded by fire, edge effects, timber extraction, and extreme drought are impacting an area equivalent to 38% of all remaining forests in the region, with a related carbon emission of 0.06 to 0.21 Pg C yr-1. This degradation also reduces dry-season evapotranspiration by up to 34%, and results in large losses to biodiversity. Even with reductions in deforestation rates, degradation will remain a dominant source of carbon emissions primarily due continued degradation of forests along the edges of agricultural areas. The quantification of carbon, water and energy balance changes from land-use activities in tropical forests need to be included in Earth system models to accurately account for second order degradation processes.
Jeff Chambers and Charlie Koven from LBNL were supported as part of the Next Generation Ecosystem Experiments–Tropics to participate in the associated meeting in Manaus, Brazil that led to the development of this review paper.
Lapola, D.M., et al. (2023) The drivers and impacts of Amazon forest degradation, Science, 379. https://doi.org/10.1126/science.abp8622.