Revisiting forest types of India

Champion and Seth undertook the pioneering work on classification of forests in India. Earlier Sir H. G. Champion had compiled his monumental work 'Preliminary Survey of Forest Types of India and Burma' in 1936. The original work of 1936 was revised by Sir H. G. Champion with S.K. Seth which was published as 'A Revised Survey of the Forest Types of India'. Their work helped the forest managers and researchers all over the Indian sub-continent to prepare management plans for the scientific management of forests. India's forest types are very diverse in their compositions with a long evolutionary and geological history, occurring under many climatic and edaphic conditions. They have been undergoing subtle but significant changes in the composition of forests since the forest types were revised by Champion and Seth. These changes have taken place on account of climatic changes and anthropogenic causes (biotic pressure as well as management interventions). The present study was conducted by revisiting various forest types. It was aimed at assessing the changes that have occurred over a period of time since they were revised by Champion and Seth. The field survey covered more than 200 forest types and subtypes representing very diverse climatic and edaphic conditions across the country. The sample plots were generated randomly across different forest types. Data collected from the field surveys were analyzed for preparing the change matrix of forest types, basal area, importance value index, stem density and diversity indexes including similarity indexes. Impact of climate change on the vegetation was critically examined to see the species level responses to the changes in the rainfall and temperature regimes over the past years. The study has indicated many changes occurring at species and forest subtypes levels. The species level changes were observed largely in Shorea robusta (Sal), Tectona grandis (Teak) and Bamboo forests with regard to their distribution and species density. The study has indicated the absence of teak from very moist and moist teak sub-type and occurrence of many moist deciduous and semi-evergreen species. In central India, the low rainfall regime has shown the decline of Sal and occurrence of dry deciduous species. The study revealed that both positive and negative changes have been witnessed in various forest types. These findings could be used by the policy makers, scientists and foresters for evolving suitable strategies for futuristic management intervention so that the objectives of sustainable forest management are realised. The new classification of forest types has been proposed reflecting the present ecological, climatic, bio-geographic and edaphic influences on the vegetation composition and stand formation. In the proposed new classification, 10 major groups and 48 sub-groups were identified.