This study was carried out to analyse the carbon content in different parts of Alnus nepalensis, and to assess the effect of aspect and altitude in the carbon storage in Alnus nepalensis as well as to quantify the total carbon sequestration (stock) in an Alnus nepalensis forest in the mid-hills of Kaski District. The inventory for estimating above and below ground biomass of the forest was carried out using stratified random sampling techniques. The carbon content in different parts of Alnus nepalensis was quantified using a combustion method in the laboratory. For determining the soil carbon content, six soil profiles from each aspect were excavated and soil samples were taken from up to 1 metres depth for deep soil and up to bedrock for shallow soils at intervals of 20 cm. Mean carbon content in stems, branches, leaves and bark of Alnus nepalensis were found to be 40.52%, 33%, 9.56% and 16.4%, respectively. Total biomass carbon sequestered in the northern aspect was 30.20 t/ha while for the southern aspect it was 39.00 t/ha. In both aspects, higher carbon sequestration was observed at an elevation range of 1200-1300m i.e. 34.8 t/ha and 45.6 t/ha in the northern and southern aspects respectively. Soil carbon sequestration in northern and southern aspects was found to be 113.4 t/ha and 169.30 t/ha, respectively. The total carbon sequestration potential of Alnus nepalensis forest was estimated to be 186.05 t/ha.
