Impact of Biogas Plant on Forest Community and Carbon Stock in Western Nepal

Abstract

In Nepal, the rural residential sector is highly dependent on firewood energy, which is the major cause of deforestation. Biogas is one of those and has become an important alternative energy source that reduces rural dependence on fuel-wood consumption and helps in forest conservation. These forests play an important role in reducing global warming and climate change by conserving atmospheric carbon dioxide (CO2). Therefore, this study aimed to assess the impact of the biogas plant on fuel consumption in the Kaligandaki rural municipality, Gulmi district, Nepal. Two different community forests users’ groups (CFUGs) were selected for the study namely, Harsa Community Forest (HCF) users’ and Sarsa Community Forest (SCF) users’ group. To assess the Important Value Index (IVI), species diversity, regeneration, and carbon stock, in total 40 sample plots (20 plots in each forest) of 10m radius were sampled using systematic random sampling method. Within the 10m radius plots, 2 subplots of 5m radius were laid for shrubs and 3 subplots of 2m radius for herbs. Tree biomass was estimated using an allometric equation, and regeneration was estimated by calculating the density of each species in seedling, sapling, and tree phases. To know about biogas plant, data were collected from field observation and personal interview. Of 40 households, 20 were selected for each forest user group in the Kaligandaki rural municipality. The carbon stock of HCF was found to be slightly higher (38.46 t/ha) than in SCF (34.46 t/ha) and increased with increasing use of a larger number of biogas plant users’ group. Similarly, total species diversity was found to be higher in HCF, but the diversity of herbs species was higher in SCF. HCF had a very good regeneration status with 12715 seedlings/ha, 6025 saplings/ha and 1230 trees/ha compared to SCF. The open canopy of HCF might have favoured the regeneration of a larger number of seedlings and saplings. This result revealed that the ground vegetation and regeneration was high in the less dense canopy forest and the installation of biogas plants helped in forest conservation.