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1057. Human Impacts on Tropical Forest Degradation Are Greater than Expected

1057. Human Impacts on Tropical Forest Degradation Are Greater than Expected
Selective logging, forest fires, and the edge effect in tropical forests are major causes of carbon emissions and biodiversity loss. However, there is also a great deal of uncertainty about the actual and long-term impact across the global tropics.
A paper published in the journal Nature estimates the canopy height and biomass of trees from satellite remote sensing data using satellite-mounted LiDAR (light detection and ranging), a technology that measures the distance, direction, position, shape, etc. to the target by irradiating the laser beam while scanning the object to be measured and measuring the time until the light is reflected and returned. The study aimed to quantify changes in tropical humid forests.
The analysis revealed that forest heights had decreased by 15% and 50%, respectively, due to selective logging and fires, and that the recovery rate remained low even after 20 years. Due to agriculture and road expansion, the biomass within the canopy height and forest boundaries has decreased by 20% to 30%, and measurable impacts have been observed up to 1.5 km within the forest. Eighteen percent (approximately 206 Mha) of the remaining tropical moist forests had an edge effect, representing an area more than 200% larger than previous estimates.
Degraded forests with a tree crown loss of 50% or more are significantly more vulnerable to subsequent deforestation. Overall, the findings indicate that greater efforts are needed to prevent forest degradation and protect already degraded forests in order to meet the commitments made in the recent United Nations Framework Convention on Climate Change and the Convention on Biological Diversity.
Reference
C. Bourgoin et al, Human degradation of tropical moist forests is greater than previously estimated, Nature (2024). https://www.nature.com/articles/s41586-024-07629-0
Contributor: IIYAMA Miyuki, Information Program