Study area
The Western Ghats that run parallel to the west coast is endowed richly with different categories of forests. Coffee is an important plantation crop, mainly confined to the hills of South India, where Karnataka, Kerala and Tamil Nadu form the major traditional coffee growing regions with an area of 2.13, 0.84 and 0.31 lakh ha with a production of 2.52, 0.69 and 0.19 lakh tonnes respectively. The investigation included Chikmagalur district of Karnataka and Wayanad and Idukki districts of Kerala, located in the Western Ghats experiencing high rainfall and hot per-humid, hot moist sub-humid and hot humid tropical climates. Chikmagalur district lies in the north-eastern hills of Western Ghats and Balehonnur belonging to the Chikmagalur district receives an average annual rainfall of 2792 mm, mainly from the south west monsoon during the months of June to September. Wayanad and Idukki districts of Kerala receive average annual rainfall of 2517 mm and 2305 mm respectively. Balehonnur, Wayanad and Idukki experience hot per-humid, hot moist sub-humid and hot humid tropical climate respectively and study area is depicted on a location map (Fig.1).