Assessment of Carbon Sequestration in Private Forests across Two Different Physiographic Regions of Nepal: Implications for Conservation and Climate Change Mitigation

Abstract

Private forests offer diverse ecosystem services, including carbon sequestration and biodiversity conservation, which are crucial for Nepal. However, there is a notable absence of comprehensive research on these services. Assessing carbon sequestration in private forests can have economic advantages for forest owners by promoting resource conservation and contributing to greenhouse gas reduction. This study aims to estimate and compare carbon stocks in private forests located in two distinct physiographic regions of Nepal while also identifying the factors influencing these carbon stocks. The analysis focuses on 16 private forests (with 0.1 to 0.5 hectares) each from Chitwan district (Terai region) and Kavrepalanchok district (Hilly region). Field data collection involved direct measurements of tree and sapling diameter at breast height (DBH), as well as height and class of trees and poles, utilizing a total enumeration method. These collected values were utilized to calculate aboveground biomass (AGTB), aboveground sapling biomass (AGSB), belowground biomass, and carbon stock. Private forests of Terai region were dominated by Shorea borneensis, Tectona grandis, and Dalbergia sissoo, whereas the Hilly region was dominated by Pinus patula, Alnus nepalensis, Schima wallichii, and Quercus leucotrichophora. The aboveground biomass carbon in the Terai region's private forests was estimated to be 83.53 t·ha−1, while in the Hilly region, it was 37.32 t·ha−1. The belowground biomass carbon in the Terai region's private forests was found to be 21.72 t·ha−1, compared to 9.70 t·ha−1 in the Hilly region. Consequently, the estimated total carbon stock in the Terai and Hilly regions' private forests was 105.25 t·ha−1 (386.26 t·ha−1 CO2-eq) and 47.02 t·ha−1 (172.57 t·ha−1 CO2-eq), respectively. Carbon sequestration in the Terai region's private forests was discovered to be 2.24 times higher than that in the Hilly region. These findings underscore the significant potential of private forests, which can generate economic benefits through carbon trading and leverage mechanisms such as REDD+/CDM to promote sustainable conservation practices.