Slow carbon recovery in logged tropical forests.
Tropical forests recover from logging by rapidly accumulating carbon from the atmosphere, at least, that’s the idea. Scientists from Vietnam and the universities of Leeds and Maastricht show that carbon uptake may be much slower than thought.
Regenerating forests are often seen as a natural way to tackle climate change, because trees absorb carbon dioxide from the atmosphere and store it in their biomass. In their climate mitigation plans, governments and carbon markets increasingly count on recovering forests. Therefore, we need to understand how fast degraded forests can recover and how much carbon they can store in a warming world.
Disappointing reality
One of the researchers, Suzanne Stas, at the department of System Earth Science in Venlo explains: “During my PhD we set up 24 permanent forest plots in central Vietnam. Using eight years of measurement data, we calculated how much carbon the forests had recovered nearly twenty years after logging stopped. Individual trees were indeed still growing, but those carbon gains were cancelled out by trees dying, so overall there was no net carbon uptake in these forests. Carbon recovery was much slower than indicated by the Intergovernmental Panel on Climate Change's standard values and slower than what has been reported for comparable forests in the region.”
Further, the study found that hotter peak temperatures went along with lower carbon gains, which suggests that global warming may already be slowing down the forest's recovery. Nevertheless, these forests have maintained their existing carbon stocks despite disturbances and climate stress, without losing net carbon. Further, this study shows the importance of using local data and long-term measurements for understanding how forests function and recover.
