The vegetation on the slopes and hilltops has been cleared earlier by the tribes for cultivation of lemon grass and food crops. The abandoned cultivated areas are devoid of shrubs and trees for a considerable area and the vegetation of that area is dominated with grasses. The lemon grass cultivation is a common practice among tribes and considerable portion of the agriculture land is utilized for this purpose. Teak and eucalyptus plantations in small patches have been raised in the past at Vanchikulam and Ollavayal. The agricultural lands comprise nearly 7% of the area of the Sanctuary.