A quantitative study of the forest floor biomass,litter fall and nutrient return in a Pinus roxburghii forest in Kumaun Himalaya

The present paper reports on the forest floor biomass, litter fall, nutrient return and turnover of organic matter in a Pinus roxburghii forest in Kumaun Himalaya. Peak values of fresh leaf litter, partially decomposed litter and wood litter on the forest floor occurred in April, May and September, respectively. The relative contribution of partially decomposed material to total forest floor biomass remained greatest throughout the annual cycle. The biomass of herbaceous vegetation was maximal in September with a total annual net production of 151 g m^-2. The total annual litter fall was 895 g m^-2, of which tree, shrub and herb litters accounted for 82.4%, 0.6%, and 16.8%, respectively. Annual nutrient return in kg ha^-1 through litter fall amounted to 278.6 ash, 73.9 N, 5.5 P, 79.7 Ca, 15.1Mg, 20.7 K and 3.6Na. The turnover rate for tree litter was 48% and that for various nutrients on the forest floor ranged between 40–79%.