STRUCTURE AND FUNCTION OF HIGH-ALTITUDE FORESTS OF CENTRAL HIMALAYA .1. DRY-MATTER DYNAMICS

The present study deals with the structure and functioning of three different forest communities, viz., horse chestnut, silver fir and kharsu oak forests, in a high altitude region of Central Himalaya. The tree density and total basal cover of horse chestnut forest was 280 and 76, silver fir forest 355 and 106, and kharsu oak forest 480 trees ha(-1) and 73 m(2) ha(-1), respectively. Allometric equations relating biomass of different tree components to cbh (circumference at breast height) were significant. Total vegetation biomass was 505 t ha(-1) in horse chestnut, 566 t ha(-1) in silver fir and 593 t ha(-1) in kharsu oak forests, of which maximum contribution was by tree layer followed by shrub. herb, sapling and seedling layers. The forest floor litter biomass was 2.1, 4.7 and 4.2 t ha(-1) in horse chestnut, silver fir and kharsu oak forests, respectively. The total litter fall was 7.3, 6.7 and 9.4 t ha(-1) year(-1), of which leaf litter contributed 48, 39 and 64% in horse chestnut, silver fir and kharsu oak forests, respectively. Turnover rate of tree litter was 0.80 in horse chestnut, 0.61 in silver fir and 0.71 in kharsu oak forests. Net primary production of total vegetation was 19.6, 18.9 and 24.9 t ha(-1) year(-1), of which tree layer contributed maximum proportion followed by herb, shrub, sapling and seedling layers. To show dry matter storage and flow of dry matter within the system, compartment models were developed for all forests.