Vegetation Degradations of Wildlife Sanctuary Danau Pulau Besar Danau Bawah Siak District Riau Province

Wildlife Sanctuary of Danau Pulau Besar Danau Bawah is surrounded by a forest conservation area of timber industrial estates and villages inhabited by indigenous peoples where their lives are very dependent on the forest. The consequence of these conditions is that forest degradation is quite serious as the encroachment of trees and forest conversion practices to agriculture and plantations. This study aims to gain estimation on forest encroachment and total loss of trees resulting in a decline in floristic diversity in this region. Data collection on forest encroachment map using satellite imagery analysis was done by using Supervised Classification technique. The area assessed is conservation forest areas which has been encroached upon or degraded areas. Vegetation data were collected by using the plot method that illustrates the potential, type, density values, dominance of vegetation and its importance value index. The results of extensive analysis of vegetation encroachment illustrated the potential value of forest degradation rate. Conservation forests area was degraded up to 2, 339.73 in hectare or 8.29 % of the total area, while the estimated loss due to the encroachment of trees during the period 1998 to 2012 reached 550, 819.24 m3 or equal to 39, 344.23 m3 trees per year, or 3, 278.69 m3 per month and 109.29 m3 per day.