Evidences of Climate Change and its Impact on Structure and Function of Forest Ecosystems in and Around Doon Valley

Available data on meteorological observation , phytosociological studies , population dynamics and biomass in moist Sal (Shorea robusta Gaertn. f.) forest of Doon Valley and adjacent dry deciduous forest are utilized to understand the structure and functioning of ecosystem. Seventy years mean maximum and mean minimum daily temperature and rainfall were analyzed for each five-year interval (1931-2000). It was observed that there is an increase of O.5°C in mean maximum temperature and decline of 1.1°C in mean minimum temperature. However total rain (monsoon , June to October + local rains , November to May) has declined by 17% during seventy year of period , whereas the local rains has increased by 27% since 1981 onward. Fluctuations in temperature and rainfall have pronounced effect on the distribution of evergreen and deciduous tree species. Further , change in climatic pattern and microclimatic conditions as a result of deforestation have noticeable impact on forest decline. Atmospheric CO₂. enrichment has put a positive response in enhancing productivity of these ecosystems.