Global forest area disturbance from fire, insect pests, diseases and severe weather events

Abstract

Reliable global data on forest degradation and disturbances due to fire, insect pests, diseases and severe weather are important to understand ecosystem health and condition, safeguard production of goods and services and avoid negative impacts on human livelihoods. This paper presents a global analysis of forest area affected by fire, significant insect pest outbreaks, diseases and severe weather reported by countries as part of the Global Forest Resources Assessment 2015. Between 2003 and 2012, approximately 67million hectares (1.7%) of forest land burned annually, mostly in tropical South America and Africa. In a similar reporting period, in total 142million hectares of forest land were affected by other disturbances than fire. Insect pests affected more than 85million hectares of forest, of which a major part was in temperate North America. Severe weather disturbed over 38million hectares, mostly in Asia. About 12.5million hectares were reported to be disturbed by diseases, mostly in Asia and Europe. There were strong correlations between burned forest area and the area of partial canopy cover reduction, as well as between burned forest area and net forest loss. Partial canopy cover reduction is used as a proxy for forest degradation, although it also includes land under management that is not degraded. A decreasing trend in burned forest area was found, largely accounted for by decreased area burned within the last ten years in tropical South America. However, an increasing trend in burned forest area was found in the boreal climatic domain. The data on other disturbances was not suitable for determining any year on year correlations and should be improved in future data collection exercises.