Stratification and mapping of Taxus baccata L-bearing forests in Talle Valley using remote sensing and GIS

The yew plant (Taxus baccata L.) has acquired importance because it yields taxol, which is effective in the treatment of cancer the world over. There is great demand for Taxus from pharmaceutical companies and the species is being extracted heavily from its natural habitats throughout the world. Thi s demand has necessitated the preparation of an inventory of Taxus-bearing forests for conservation and sustainable utilization. We have used remote s ensing and Geographical Information system for identifying and mapping yew plants with reasonably good accuracy. IRS 1C LISS-III False Color Composite (FCC) data dated 2 January 1997 having 23.5 m ground resolution were appli ed for this purpose. These forests were visited on ground for a detailed ve getation analysis of the distribution of the yew plants. The raw data was c orrected both radiometrically and geometrically and then enhanced using the standard image enhancement techniques such as linear contrast stretch. Var ious techniques of digital image classification such as hybrid clustering, masking and classification were tested to differentiate and delineate the y ew-bearing forests in Talle Valley area falling in Lower Subansiri district of Arunachal Pradesh. Forests covered with various proportions of Taxus co uld be stratified and mapped with 85% accuracy. The preliminary results obt ained in this study demonstrate that Taxus-bearing forests could be separat ed with a priori knowledge of vegetation types of the area.