Fire Induced Carbon Emission from Tropical Mixed Broad Leaf Forest of Nepal

Abstract

Forest fire is emerging as a major environmental issue across the world. In Nepal, substantial forest area, biomass and carbon are lost due to fire. The high value lowland forests of Nepal are more vulnerable to fire. However, in Nepal, there are limited studies on estimation of biomass loss and carbon emission due to forest fire. Thus, the present research was carried out to estimate forest fire area in different ecological regions of Nepal, and biomass loss and carbon emission from the Tropical Mixed Broad-leaved Forest of Nawalparasi District. The fire drivers were identified using participatory approaches and were prioritized by scoring method. For this purpose, six Focus Group Discussions, 10 Key Informant Interviews and five Consultation Meetings were performed. For estimating biomass loss and carbon emission, DBH and height were measured in 92 sample plots in the four community forests selected purposively based on fire vulnerability and topography ensuring representation of the Lower Tropical Mixed Broad-leaved Forest, Hill Sal Forest and Riverine Forest. Forest fire incidences and burnt area for 2001-2017 were acquired from MODIS fire data. The burnt and non-burnt area were delineated and analyzed in GIS. Forest biomass and carbon emission were estimated using allometric equation. Loss and damage of biomass was estimated using the stock difference method. Data related to road networks, settlements and topography were obtained from the Survey Department, Government of Nepal, forest type data were acquired from Department of Forests and Soil Conservation and climate data were obtained from the Department of Hydrology and Meteorology, Government of Nepal. The results revealed 29,24,691.05 ha forest (1,72,040.65 ha/yr) to be damaged in Nepal from 2001 to 2017. In Nawalparasi District, 3151.05 ha forest per year were found to be damaged. Among the forest types, the Hill Sal Forest was the most vulnerable in compared to the Lower Tropical Mixed Broad-leaved Forest and Riverine Forest. The study revealed 20 forest fire causing drivers; among them, eight drivers, i.e. precipitation, forest distance from road, elevation, forest fuel, forest distance from settlement, temperature, slope and aspect were identified as the major ones. In terms of emission, 1108 tons/year carbon was found to be emitted due to forest fire in Nawalparasi District that is equivalent to approximately 4066 t CO 2 vi , 2581 t CO and 1474 t CH 4 .With respect to plant forms, higher (>90%) damage was found in leaf-litter, herbs and grass as compared to trees (0.01-0.4%). These findings are useful for sustainable forest fire management in the lowland of Nepal and in the area having similar ecological and socio-economic conditions. Keywords: Active fire data, Burnt area, Biomass loss, Carbon emission, Fire drivers