Identification of Critical Land Using Geographic Information System : A Case Study in Poleang Langkowala Sub-Watershed Southeast Sulawesi Province

Abstract

Critical land in Indonesia is about 36,317,857 ha of which 22,250,160 ha are outside forest areas. One of the regions with the most extensive critical land in Indonesia is Southeast Sulawesi Province. Based on the forest statistical data, critical land in Southeast Sulawesi Province during Five Year Development Plan (1995 -1999) is 2,808,648 ha, including estimated 1,004,327 ha (35.76 %) critical land outside forest areas. The objectives of the study are to (1) identify the distribution of critical land in part of Poleang Langkowala Sub-Watershed Southeast Sulawesi Province, (2) provide data on critical land to decision makers as a basis to establish critical land rehabilitation planning, and (3) to provide a methodology to identify critical land effectively and efficiently. The methods employed in this research project contain several steps involving Remote Sensing and Geographic Information System. The steps were determination of critical land criteria, image analysis, and GIS analysis to identify critical land. Three-category areas were used to determine critical land: (1) protection forest area, (2) cultivation area for agriculture effort, and (3) protection area outside forest area. The parameters used to determine critical land were land cover, slope, erosion, and management. The steps of image analysis are preparation, field checking, and classification. GIS activities including a process of spatial data analysis, tabular data, overlay, and smoothing. All of these spatial data were overlaid to produce polygons that were used to valuate the level of critical land. The procedures for spatial analysis consist of establishment the objectives and criteria for the analysis, preparation of the data for spatial operations, spatial operations (union, dissolve, reclassify), and evaluation and interpretation of the results.