PHYTOSOCIOLOGY OF THE VANISHING TROPICAL DRY DECIDUOUS FORESTS IN DISTRICT SWABI, PAKISTAN .1. A COMMUNITY ANALYSIS

The vegetation of 20 different graveyards in District Swabi was sample d quantitatively. Three main communities: Dalbergia sissoo-Melia azeda rach, Ziziphus mauritiana with 2 subtypes,and Acacia modesta with 5 su btypes, were recognized on the basis of similarity indices, importance values and floristic composition of the stands. A. modesta community was widely distributed in the area. The first two communities represen t secondary succession iii the area. The vegetation of all the stands was stratified into tree, shrub and herb layers. The variation in the dominant species was due to edaphic and biotic disturbance. It is sugg ested that the existing vegetation might further change due to undergr ound seepage of water from nearby Tarbela dam. A vegetation profile of all the communities is given.