Stand structure and spatial pattern of sweet Chestnut (Castanea sativa L.) trees in the Guilan forests, North of Iran

摘要

The aim of this study was to examine forest stand structure and spatial pattern of chestnut trees in the Guilan forests. 68 lozenge sample plots with 2500 m2 area were selectively taken of 9 chestnut sites. In each plot, diameter at breast height of all trees = 10 cm and total height of whole trees were measured. To determine spatial pattern, distances of chestnut trees were measured using T-square method. In order to analyze spatial pattern, distance methods of T-square and Byth and Ripley were applied. Results indicated that the highest value of mean tree basal area was in the Malianbar site and its lowest value was in Doroudkhan site. In addition, the highest and the lowest values of mean basal area of chestnut tree was obtained in the Visroud site and in Doroudkhan site, respectively. The highest value of basal area of chestnut dead tree was in the Visroud site and its lowest value was in Malianbar site. The highest percentage of chestnut dead trees (42.11%) was gained in the Doroudkhan site, while its lowest value (5.88%) was in Malianbar site. Number of whole trees per hectare and its height curves based on diameter breast height (DBH) were plotted, indicating that trees have irregular and uneven-aged structure. The spatial pattern of chestnut trees was found random in Galehroudkhan, uniform in the Kishkhaleh, and clumped in the Shafaroud, Visroud, Malelab, Doroudkhan, Siahmazgi and Malianbar sites.