Efficiency of Canopy Cover Measurement of Artemisia sieberi Stands by Two Sampling Methods in Different Lengths (Case study: Steppe Vegetation of Baft Region, Iran)

This research has been conducted to establish a wheel-point device and evaluate its efficiency (precision, accuracy and time) with respect to the estimation of canopy percent in a pilot Artemisia stand in Khabr region of Baft, Kerman province, Iran in 2015. Several transects with different lengths (30, 60, 90, 120, 150 and 180 m) were established using the randomized sampling block with 5 replicates. Measurement of canopy percent of dominant species and the associated ones was done by transects as linear-contact (control treatment) and wheel-point device. Data standard deviation of each treatment, relative error of each treatment to control and time criterion have been considered as precision, accuracy and time indices for sampling and evaluating the efficiency Results indicated that in the sampling by the means of linear-contact method (control method), the optimum sampling length was given as 30 m concerning three statistical states involving the dominant species, associated ones and total species population. Also, results have shown that in sampling by wheel-point device method in order to consider the statistics of dominant species, the optimum transect length was estimated as 60 m; when the statistics of associated species and total species population are regarded, the optimum length was 120 and 150 m, respectively. According to the results of regression model with respect to data given by wheel-point method and transect (control), determination of coefficient was computed as 57 and 67% for the dominant and associated species, respectively.