GROWTH, BIOMASS, CARBON SEQUESTRATION AND SOIL NUTRIENT DYNAMICS UNDER PINE FOREST IN NORTH-WEST HIMALAYAS.

Pinus roxburghii is the most dominant forest type present in North-West Himalayas. Pine forest accounted for the total vegetation biomass of 156.7 Mg/ha/year during present study. Total carbon stock in pine forest was 69.52 Mg/ha/year which accounted for carbon sequestration of 255.13 Mg/ha/year. Carbon allocation in different components of Pinus roxburghii was 54.22 per cent, 53.74 per cent, 53.07 per cent and 50.75 per cent in stem, roots, branches and leaves, respectively. Phyto-sociological studies revealed that Parthenium hysterophorus had lowest frequency (0.3%) while Chrysopogon montanus (1.35%) had maximum frequency. Species abundance varied from 1.0/25m2 or 400 herbs or shrubs/ha to 3.28/25m2 or 1312 herbs/shrubs or grasses/ha. A/F ratio ranged from 1.11 (Rubus ellipticus) to 10.0 (Partheniumhysterophorus and Veronica cinerea). Soil organic carbon, N, P, K, pH, Electrical conductivity and bulk density were analysed from top soil profile (0-15 cm) to sub-soil profile (30-60 cm). Soil organic carbon varied from 0.24% to 0.77% and it decreased depth wise.Nitrogen, potassium and electrical conductivity at various soil depths varied from 194.32 to 280.0 kg/ha, 128.1 kg/ha to 269.2 kg/ha and1.09 dSm-1 to 1.22 dSm-1, respectively and they also decreased depth wise. Soil pH was acidic and it ranged from 6.50 to 6.72. Available phosphorus and bulk density varied from 0.18 to 0.30 kg/ha and 0.43-1.23g cm-3, respectively and increased depth wise.