Carbon Stocks in Chir Pine (Pinus roxburghii) Forests on Two Different Aspects in the Mahabharat Region of Makawanpur, Nepal

Despite the significant contribution of forests in climate change mitigation, studies to establish the potential of sub-tropical forest ecosystems at different aspects in enhancing soil health indicators are only partly known. The study was carried out to quantify vegetation and soil carbon stocks of a natural Chir Pine (Pinus roxburghii) forest at two different aspects (northern and southern) of a typical sub-tropical environment in Nepal. Stratified random sampling was used for forest inventory and soil sample collection. Aboveground forest biomass was calculated using standard allometric models. Soil was sampled up to 60 cm depth and at 20 cm intervals. Walkey and Black method was used to determine soil organic carbon. Total aboveground plant biomass carbon in southern aspect (140.20 t ha-1) was higher compared to that on the northern aspect (115.34 t ha-1). Similarly, soil carbon stock on southern aspect (46.65 t ha-1) was higher than that of northern aspect (42.14 t ha-1). This resulted to total carbon stock on southern and northern aspect of P. roxburghii forest of 186.85 t ha-1 and 157.48 t ha-1 respectively. The total carbon stock of P. roxburghii forest is significantly higher on southern aspect than on northern aspect with p value 0.001 (p<0.05). Hence, we conclude that the southern aspect of the Mahabharat range favour the growth of P. roxburghii forest compared to the northern aspect. However, the contribution of the entire Chir pine forest ecosystem to carbon sequestration and global climate warming mitigation can’t be neglected.