The structure and function of pine forest in Central Himalaya. I. Dry matter dynamics

Abstract

The present study deals with structure and function of four areas of Himalayan chir pine forest. Tree layer was monospecific on all sites with varied density and basal cover in the range of 540-1630 individuals per ha and 25·0-47·2 m²ha⁻¹, respectively. Shrubs having low density were sparsely distributed. All allometric equations relating to biomass of different components, to circumference at breast height (cbh) were significant, with the exception of that for cone biomass. Total vegetation biomass (115-236 t ha⁻¹) was distributed as 113-283 t ha⁻¹ in trees. 0·56-0·82 t ha⁻¹ in shrubs and 1·63-2·57 t ha⁻¹ in herbs. Total forest floor biomass including herbaceous litter ranged between 9·6 and 13·6 t ha⁻¹. Of the total annual litter fall (4·26-7·38 t ha⁻¹), 60·3-75·1 per cent was distributed in leaf litter and 24·9-39·7 per cent in wood litter. Turnover rate of tree litter varied from 0·45 to 0·53, whereas rates for shrubs and herbs were assumed to 1. Net primary production of total vegetation ranged between 9·91 and 21·2 t ha⁻¹ year⁻¹, of which the contribution of trees, shrubs and herbs was 76·5- 88·1 per cent 0·6-1·8 per cent and 11·3-21·5 per cent, respectively. A compartment model of dry matter on the basis of mean data across sites was developed to show dry matter storage and flow of dry matter within the ecosystem.