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Changes in four rainforest plots of the Western Ghats, India, 1939–93
Marsha Pomeroy, Richard Primack and S.N. Rai

A major question of concern to forest ecologists in India is how well the forests have withstood the impact of human activities, and if they will be able to recover their stand characteristics, including number and size of trees, biomass and species composition, once they are protected from further disturbance. To examine the process of forest disturbance and possible recovery, four research plots in the evergreen forests of the Western Ghats of Karnataka State were analysed for stand characteristics and species composition starting in 1939 when they were remote and had minimal human impact. In these plots, all trees were identified and measured for diameter at breast height. The original trees continued to be censused at approximately five-year intervals. New recruits were first censused in 1984, and their size in the past was estimated from average growth rates. The plots were not treated differently from the surrounding forest, so they serve as a sample of the status of the surrounding forest. These forests then experienced increasing levels of human activity in the form of clearing for roads and power lines, fires, grazing by cattle, collection of forest products and low-level selective logging in the 1970s and 1980s, during which time forest censuses continued. At all four forests, there was a steady decline over time in the number of trees, with sharper declines associated with periods of logging and clearing. At the point of greatest decline following logging, only about 70 per cent of the original numbers of trees were present; however, the number of new trees increased after logging stopped in 1988, compensating to some degree for the loss of the original trees. Aboveground biomass also declined over time, with only about 70 per cent of the original.