Assessing Patterns of Forest Disturbances in the Pan-Tropics Using RADD Alerts

By Jari Tibboel

Abstract
This thesis studies the spatial and temporal patterns of forest disturbances on a pan-tropical scale, assessing the RADD alerts, their drivers and their implications for future disturbances and conservation strategies. Tropical forests are the biggest part of the world’s primary forest and sustain a variety of life but face huge pressure from human activities.

We use Sentinel-1 C-Band Synthetic Aperture Radar (SAR) data detected by the RADD alerts, which provide near real-time, consistent, 10-meter resolution forest disturbance alerts for the pan-tropics. Forest disturbances from 2020 – 2023. We assessed data annually, quarterly, and for all years. Additionally, we mapped these patterns mapped and linked with forest fragmentation, accessibility and other drivers from literature.

All continents face more disturbances in the dry season, in Central America in 2023 extended and strengthened by El Niño. This situation left forests more vulnerable to disturbances, especially during small-holder slash-and-burn practices common in Central America and Africa. Additionally, whole-year forest disturbances were evident in Brazil, Indonesia, and Cameroon. Brazil saw a decrease in forest disturbances from 2022 to 2023, coinciding with the election of their new President.

We didn’t find a clear relationship between forest fragmentation and disturbance patterns, travel time to cities and forest disturbances showed a weak negative relation, suggesting that areas closer to human-dense or more accessible areas face greater human pressure in shaping forest disturbance patterns.

Our findings show how climate changes, socio-political factors, and human actions together shape spatial and temporal forest disturbance patterns in the pan-tropics and are very region-specific.