Using CLASlite to Map Deforestation in Makira Natural Protected Area, Madagascar

Abstract:

Makira Natural Protected Area in northeastern Madagascar houses high levels of biodiversity, but is currently threated by encroachment of agriculture and the illegal logging of hardwoods. The Wildlife Conservation Society currently works with local communities in running a Reducing Emissions from Deforestation and Forest Degradation (REDD+) project in Makira. High cloud cover in humid forests and seasonal variations in vegetation make temporally consistent classifications difficult, affecting the estimates of deforestation needed for REDD+. Carnegie Landsat Analysis System lite, or CLASlite, is a free software tool designed to pre-process and analyze remotely sensed data, creating forest and deforestation maps, between other outputs. This study was performed in collaboration with WCS using fifteen Landsat 5, 7, and 8 images to determine the performance of CLASlite in comparison to previous mapping work using a conventional mapping approach.

A combination of CLASlite and expert interpretation created four forest vs. non-forest maps from 1994, 2001, 2010, and 2014 with 92% overall accuracy in the 26,956 km² study area. Over the twenty year period, 7.9% of the 11, 464 km² of original forest was lost. Visual comparisons with the previous mapping work revealed that CLASlite was better at detecting small patches of forest as well as connectivity in riparian areas. Various cloud masking settings within CLASlite allowed for adjustments specific to cloud and sensor types. Cloud contaminations were minimized by utilizing Landsat tiles from the dry season. CLASlite is well designed for conservation practitioners and performed well in this forest type.