Collection of appropriate qualitative and quantitative data is necessary for proper management and planning. In this research, a region with 457 ha area was selected in northwest of  Khoram Abad. An inventory grid with 200 × 400 m size was designed and established in the study area. Then, 40 control plots with 1 hectare area were laid out. Samplings carried out by diagonal transects with 50, 75, 100, 125 and 140m length on square control plots. Finally, the results of sampling by different lengths of transects were compared with control plots using analysis of variance and (E %) ^2×T criterion. The results of ANOVA showed that different lengths of transects had no significant differences (at confidence level of 95%) with control plots for estimation of species number per hectare and crown cover parameters. Transects with 140m length had the most precision for estimating the above-mentioned parameters. Also, comparison of results for different lengths of transects with (E %) ^2×T criterion showed that transects with 75 and 140m lengths are more appropriate for estimating the crown cover and species number per hectare.