Abstract

In this study, the relationship between production as an independent variable and small diameter, large diameter, height, canopy cover, volume, average diameter height as dependent variables in Atriplex canescens and Haloxylon ammodendron were evaluated to select the best variables for estimating production in these species. The study site was located in Yousef Abad Neyshabur Rangelands, North East of Iran, Khorasan Razavi Province. Samplings were done random-systematic along Transects with 300 m length and 100 m distance from each other (samplings were done at the first, middle and end of each Transect and in the plots with dimensions of 2 × 4 m² in H. ammodendron  and 4 ×4 m² in A. canescens). Production was measured by clipping and weighting method. Parameters like small and large diameter, height and canopy cover were also measured. To evaluate the relationship between dependent variables and production as independent variable, the multiple variables regression analysis and stepwise regression were performed. The results showed that volume in At. canescens and height in Ha. ammodendron was the most effective factors for estimating production.

Key words: Shrub production, cover, stepwise regression, Atriplex canescens, Haloxylon ammodendron, Yousef Abad Neyshabur, Arid rangelands.