1- Agricultural Research, Education and Extension Organization (AREEO
2- Department of Forest, Rangeland and Watershed Management, Ilam Agricultural and Natural resources Research
Abstract: (3083 Views)
Introduction and objective: One way to study the problems of forests, to study its changes over the years and access to accurate information, is to use remote sensing technology and satellite data. The use of GIS as one of the most important tools for analyzing the extent, location of degradation and auxiliary factor to identify the cause and factors in the solution of the phenomenon of deforestation. Research shows that between 1990 and 2000, an average of 6.8 hectares of forest area in Ilam province decreased. On the other hand, the phenomenon of oak tree droughts and deforestation has intensified due to severe droughts and land use changes, especially constructions that have been done in forest areas. Therefore, this study was conducted to investigate the distribution of oak tree drought with physiographic factors and also land use change in Zagros forest areas in Ilam province.
Materials and methods: In conducting this research, first the digital elevation model of the province was prepared based on topographic maps, then based on this model, information layers of slope class, geographical directions and elevation classes were extracted. In order to prepare the oak tree drought site location layer, in addition to processing satellite images, the location of oak tree drought trees was collected at 100 points in the province. To ensure the accuracy of the obtained maps, the accuracy assessment method was used, which is based on comparing the map extracted from satellite data with ground reality information such as field perceptions and visits, existing maps and the expert knowledge of the interpreter. In the following, the location map of the distribution of dry masses was overlapped and integrated with slope classes, geographical directions, altitude classes and land use. Then the frequency of dead trees in the units of the mentioned layers was calculated and presented as a percentage.
Results: According to the physiographic units of the region, the highest amount of dry masses is related to the altitude of 1200 to 1600 meters, slope class of 0 to 15% and the geographical direction of the southwest. The lowest of them are in the altitude floor less than 400 and more than 2400 meters, the slope class is more than 30% and the geographical directions are northeast and southeast. The highest frequency of oak tree drying in Ilam province is in the classification of forest areas related to thin class 42%, medium 39% and dense forest areas 5%, respectively.
Conclusion: In general, it can be stated that physiographic factors (slope, geographical directions and altitude) as well as land use changes in different forms and different intensities and weaknesses can contribute to the destruction of temples. Zagros and especially in the area of Ilam province to be effective. Based on the obtained results, dried oak trees have different distribution in physiographic units. In the study of this distribution, the use of satellite images, especially in the study of forest areas, both in terms of the phenomenon of oak tree drying and in terms of deforestation due to land use changes or other natural factors, has many applications.
Type of Study:
Research |
Subject:
General Received: 2019/06/19 | Accepted: 2020/02/9