Effect of Temperature and Precipitation on the Vegetation Dynamics of High and Moderate Altitude Natural Forests in India

In the present study, the high-altitude vegetation dynamics of natural forest cover were analyzed to find the effect of local hydrology for about 10 years. Vegetation dynamics in four different topographical and climatic conditions in India were studied using normalized difference vegetation index (NDVI) data from vegetation sensor of SPOT satellite, and daily temperature and precipitation data from Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation project. The main objective was to understand how and to what extent the natural vegetation reciprocates in various climatic conditions. First, the vegetation data was denoised by using empirical mode decomposition technique. The relation between the vegetation growth and hydrological parameters was studied to find the anomalies. Then, the wavelet analysis of the hydrological data was carried out to find the frequency and extent of the anomalies. Finally, nonparametric Mann-Kendall trend analysis and Sen's slope analysis were applied to find the trend of the vegetation, temperature, and precipitation dynamics. Results indicate that the growth of the vegetation starts when the average temperature is 10 degrees C or higher. Beyond that the increase in temperature may have a negligible effect on growth of vegetation. The vegetation also shows positive change in monthly NDVI with the increase in precipitation depending forest type and local climate. However, with excessive rainfall, a declining trend in vegetation growth was observed. The NDVI data show positive trend in all four sites. In northern region, the temperature showed positive trend, while precipitation had negative trend. In eastern and western regions, the temperature had negative trend and precipitation had positive trend.