One of the most important environmental problems of Toroud region is the influx of quicksand in to the buildings and settlements of the regions which need precise study and presenting the underlying and practical solutions. For this reason, the best plant species of arrow sand in Najar Abad Erg have been selected in this research in Najar Abad Erg in south- eastern of Shahrood city by using 2 method of Multiple Criteria- Decision- Making (MCDM) methods including Analytical Hierarchy Process (AHP) and Group Analytical Hierarchy Process (GAHP) methods. Therefore, after specifying the studied region by satellite images and aerial photos, the field studies began and by using transect and Based on one-dimensional method and longitudinal sampling unit, four plant species of arrow sand including Alhagi mannifera, Seidlitzia Florida, Reaumuria Turcestanica and Zygophyllum eurypterum specified and their morphometric characteristics including arrow sand length, arrow sand volume, maximum width of arrow sand, covering crest canopy diameter and plant height have been measured. Then, the best species have been selected by using AHP and GAHP methods. The results indicate that group AHP method has better efficiency than AHP method to defining the suitable species. The Zygophyllum eurypterum with obtain of 0.57 score in group AHP and with obtain of 0.47 score in AHP method have the most effect on stabilizing the quicksand in studied region. According to results, for implementing the plans of quicksand stabilization in studied region; developing the arrows sand of Zygophyllum eurypterum species and then the Alhagi mannifera species are the most important species respectively. So, they will have the maximum efficiency if developing and implement them. The result of this research about quicksand stabilization plans can utilized by environmental planners.

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