جستجوی مقالات مرتبط با کلیدواژه « Dieback » در نشریات گروه « جغرافیا »

Crown dieback is a manifest phenomenon that occurred in the Zagros oak forests during recent droughts. Since the effect of crown features on the presence of mistletoe and on the trees have been proven, it is necessary to investigate the relationship between the dieback and the characteristics of tree canopy of the trees with mistletoe. So the investigation of the spatial distribution of parameters related to dieback of trees is important in order to manage and control the mistletoe in The Zagros Forests and prevent damage to trees and. Therefore, the plots (1600 m2) in a 200 m × 200 m sampling grid were established in Gahvareh Forests. Then Data were analyzed using geo-statistics (variogram) in order to describe and quantify the spatial continuity of variables. The range of the variogram for tree height is: 4110, tree height with mistletoe: 4227, average diameter of the tree crown: 4110, canopy diameter of tree with mistletoe: 4110, crown shape ratio of the tree with mistletoe: 5110, crown area of the tree with mistletoe is 2053 and the percentage of crown dieback of trees with mistletoe is 4110. The range of height, tree height with mistletoe, average diameter of the crown tree, tree crown diameter with mistletoe and the percentage of crown dieback of trees with mistletoe are similar proving that these factors have a greater impact on the distribution of this variable.