Effects of stone crushing industry on Shorea robusta and Madhuca indica foliage in Lalpahari forest

One of the various causes of forest decline is certainly the industrial expansion and the resultant air pollution of anthropogenic origin. Gradual and extensive encroachment of the forest area by the quarrying (mining) and crushing activities of the naturally occurring stones since early 1960s is found in the district of Birbhum, West Bengal, India. The aim of this study was to evaluate the effect of stone crushing industry on different foliar parameters of Shorea robusta and Madhuca indica which are two dominant broad–leaved tree species of the forest concerned. Measurement of suspended particulate matter (SPM), dustfall and gaseous pollutants in ambient air were done. Heavy deposition of dust particles on leaf surfaces was noted. Various types of foliar anomalies, both microscopic and macroscopic, were detected externally. Decrease in amount of chlorophyll and total carbohydrate in foliar tissues indicated reduction of photosynthesis. Reduction of protein content in foliar tissues was also noted. Site–wise and season–wise variations of almost all data were found to be statistically significant. Comparison of air pollution status and foliar biochemical parameters with those recorded in a control forest was done along with study of spatial significance between polluted sites at Lalpahari with increasing distance from the source of pollution. A significant correlation was established in many cases between foliar parameters and air pollutants present in ambient air in the highly polluted site of the forest close to the source of pollution.