Dynamics of leaf litter decomposition and nutrient release of selected tree species in Central Nepal Himalaya

Litter decomposition is a fundamental ecological process that regulates nutrient cycling and soil fertility in forest ecosystem.This study compared the litter decomposition rates and nutrient dynamics of dominant tree species at different elevations in the Gaurishankar Conservation Area of Nepal.Leaf litter decomposition was monitored using the litter bag method under natural field conditions for one year.Decomposition rates varied significantly among species, with Pinus roxburghii exhibiting the most rapid decomposition (89% mass loss), whereas Pinus patula had the slowest decomposition rate (33% mass loss).The Himalayan deciduous species, Myrica esculenta, decomposed more rapidly (52%) than the evergreen species such as Quercus lanata (46%) indicating the influence of functional traits on leaf litter decomposition.Overall, the decomposition rates followed the order: P. roxburghii > Pinus wallichiana > M. esculenta > Q. lanata > Rhododendron arboreum > P. patula.Similarly, macro-nutrient release from the decomposing litter followed the sequence phosphorus > potassium > carbon > nitrogen, indicating relatively strong nitrogen retention in litter.Elevation had a strong negative correlation with litter mass loss, indicating decreased the rate of decomposition as elevation increased.The estimated time required for 95% decomposition (t 95 ) ranged from 2.26 and 12.5 years for P. roxburghii and P. patula, respectively, demonstrating the role of elevation in nutrient retention.These findings, therefore, suggest that a combination of factors such as elevation, litter chemistry, and species-specific traits play a key role in nutrient cycling and soil fertility in the Himalayan forests.