Comparison of fixed area and distance sampling methods in open forests: case study of Zagros Forest, Iran

Abstract

The main aim of this study was to evaluate methods for fixed area and distance sampling in the Zagros open forest area in western Iran. Basic forest management and planning required appropriate quantitative and qualitative information. Two sampling methods were compared on the basis of the actual means of characteristics derived from the 100 % survey. In total, 37 sampling plots were systematically installed with a grid of 100 m × 100 m in the study area. Density, crown canopy, and basal area of the stands were measured. The 100 % survey showed that tree density above 12.5 cm diameter at breast height was 68.04 stem ha⁻¹, basal area was 15.16 m² ha⁻¹ and crown canopy percentage was 35.71 % ha⁻¹. The values for the traits determined by the two sampling methods differed significantly (P = 0.05). When the time required for the methods was compared, transect sampling required less than systematic-random sampling. Therefore, the transect sampling method was the more economical method for the Zagros open forests. The transect sampling method was statistically defensible and practical for quantitating characteristics of the Zagros open forests.

Keywords

Ilam / Systematic random sampling / Transect sampling / Zagros Forest

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