Rangeland suitability for exploitation of gum tragacanth as a subsidiary product(Case study: Shwishe, Kurdistan)

Presenting a new spatial model for suitability of gum tragacanth exploitation was the aim in this study. After preparing basic information including topographical 1:50000 maps, aerial photos, vegetation types, as well as local exploiter’s comments, useful criteria were determined. To estimate the gum yield per cover area, 100 m 2 circle quadrate was used in different types, totally. Total yield for the studied site was estimated exceeding 18000 kg that should be exploited in a rest-rotational system during 5 years. Gum-productive Astragalus species form the average of 3% of vegetation cover. Using GIS, maps of land form (slope, aspect and elevation from sea level) were absorbed from Digital Elevation Model. Then the specified classification conducted to gain the land form submodels. The map of distance from village prepared using buffer option and the gum yield submodel created by applying the type yield categories on vegetation types map. The least value identified for the final land units in integrated map of suitability model. In these processes, the submodels aspect (4 classes), hypsometry (2 classes), slope (2 classes), distance from village (3 classes) and gum yield (3 classes) were crossed to gain the final model. Comparison of submodel's maps implied that the aspect submodel affected the most various categorization because of its important ecological role in mountainous ecosystems.Emong the submodels, the distance from village was the most effective one in categorization so that about 53% of the study area identified as S3 from the view of this criterion. The traditional exploitation and camping with family near the village is the reason for this phenomenon. Eventually, 3%, 15%, 27%, 55%, of the study area were determined as S1, S2, S3 and non-suitable for gum exploitation, respectively.