Document Type : Research Paper


1 Research Institute of Forests and Rangelands, Range Research Division , Karaj , Islamic Republic of Iran

2 PhD student of Combat Desertification, Hormozgan Universit

3 Young Researchers Club, Ardestan Branch , Islamic Azad University , Ardestan , Iran

4 Dep. of Forest & Rangeland, Zanjan Research Center for Agriculture and Natural Resources


In this study the effect of month, place and different years on the preferencevalue of Bromus tomentellus in semi-steppe region was studied. The preferencevalue of the Bromus tomentellus was studied in two years and four months in three sites as cheshme anjir (Fars), Badamstan (Zanjan) Firuzkuh (Tehran). To determine the preferencevalue of species the two methods of as preference index and timing method was used. To compare preferencevalue in different sites times the factorial completely randomized design was used. Mean comparison was performed using Duncan's Multiple Range Test at 5% level. And to compare two methods whit each other the T test was used. The results of preference index showed that sites were significant at 1% level. But the other factors were insignificant differences according to the results of timing method all the factors were insignificant. Comparison of two methods by T test showed that the two methods were different.