Effective topographic factors in distribution of wild pear (Pyrus glabra Boiss.) trees in the forests of Kermanshah province

The present study was conducted to investigate the effect of topographic factors in distribution of wild pears (Pyrus glabra) in Kermanshah province. The distribution area was classified into three altitudinal ranges including (>1500, 1500-2000, < 2000m a.s.l.), four geographical directions including (north, south, west and east) and also different land forms including (valley, slope, slope edge and flat). Sampling was performed within the 1000m2 plots established at least with three replications. In each plot, variables including number of trees, diameter at breast height (DBH), total height, stem length, and two perpendicular diameters of crown for the wild pears were recorded. The results showed that the study species has the highest crown cover on the west-direction slope and an altitude of 1,500 to 2,000 meters above sea level, and enjoys better growth conditions.