Fire-induced carbon emissions from tropical mixed broad-leaved forests of the Terai–Siwalik region, central Nepal

Abstract

Forest fires are one of the major environmental issues globally. In Nepal, substantial amounts of forest biomass and carbon are lost due to fire. Nepal’s high value lowland forests are particularly vulnerable to fire. However, there are limited studies on the estimation of biomass loss and carbon emissions due to fire. Thus, this research addresses the information gap in the tropical mixed broad-leaved forests of Nawalparasi District. The forests were divided into three strata: Lower Tropical Sal Mixed Broad-leaved Forest, Hill Sal Forest and Riverine Forest, and from these four community-managed forests were selected for estimating above ground biomass. Ninety-two sample plots were set out for above ground biomass estimation in burnt and non-burnt areas. Forest fire incidences from 2001 to 2017 were acquired from the MODIS fire data. Forest biomass and carbon emissions were estimated using standard allometric equations. The fuel fraction consumed during the fire was estimated through field surveys during the forest fire season. The results show that every year, over 3158 ha of forests are burnt, resulting in some 1108 tons of carbon emissions, equivalent to approximately 4066 t CO2, 2581 t CO and 1474 t CH4. Among the forests, the Hill Sal Forest was more vulnerable to fire. Forest management strategies, therefore, should include construction of fire lines and conservation ponds along with capacity building and raising awareness among local communities and stakeholders.