Land Suitability Identification for a Production Forest through GIS Techniques Data and Required Information The topographical map sheets of 1: 10000 prepared by the Survey Department of Sri Lanka (1993) were used to identify the topography of the area. The land use/ cover map prepared by the Forest and Environment Conservation Division of Mahaweli Authority of Sri Lanka (1991) was used to obtain the land use and road network. Criteria for analysing land suitability for a production forest has been identified through a literature survey. Accordingly, highly accessible, high soil depth low fire hazard land of between 30% to 60% slopes with no perennial vegetation have been identified as the most suitable for a production forest. In order to be economically viable the size of the land parcel should not be less than of 10ha though it was not considered in this study. GIS Analysis & Map Preparation The maps were scanned & screen digitised and the thematic layers of land use, slope, accessibility, fire hazard were prepared with the help of GIS. Land use/ cover classes of ‘mana’ grassland and scrublands were identified as suitable, scattered pines and open woodlands as moderately suitable and other perennial vegetation and built up areas were identified as not suitable. The slope map was prepared with the contour information and is presented in Figure 02.  Figure 02: Slope map of the area Considering the size of the study area and the limited information availability on soil, it was decided that the climate and the soil depths are constant. Fire hazard zonation and the accessibility maps were prepared according to the proximity to existing road network. In this process, five meter distance from the roads were identified as highly vulnerable to fire, 5-10m as moderately vulnerable and >10m as not vulnerable. Up to 40m distance from an existing road was taken as highly accessible, 40-80m as moderately accessible and >80m was taken as poorly accessible. The criteria were analysed to give suitable weightings to the thematic layers to prepare the final suitability map. The Figure 03 presents the complete flow of the methodology adopted in this study. Finally, the suitability was identified using three categories namely, highly, moderately and not suitable for a production forest.  Figure 03: Flow diagram of the methodology |