Spatial Patterns and Intra-specific Competition of Chestnut leaf Oak (Quercus castaneifolia) using Ripley's K-function (Case study: Neka-Zalemrood forest- Sari)

One of the most visible aspects of a forest stand structure is the spatial patterns of trees. Competition affects on forest structure and its understanding is important, when the purpose of forest management is to imitate the dynamic of natural ecosystems. For this purpose, an unmanaged intact forest was selected with 26 hectares area. All Chestnut leaf Oak (Quercus castaneifolia) trees with a diameter at breast height greater than 7.5 cm were measured and their Cartesian coordinates were determined. Then the measured trees were divided into four classes based on their diameter at breast height as small timber, medium timber, large timber and extra large timber. To investigate the spatial patterns of oak trees in the region and in the each diameter size class, and to examine the intra-specific competition the univariate and bivariate Ripley’s K- function were used, respectively. Results showed that the spatial patterns of oak trees was cluster in short distances due to heavy seed and high frequency of young trees and then changed to random distribution as distance increased. Moreover, interactions between diameter size classes showed that oak trees with different sizes had different positive (attraction) and negative (repulsion) competitive effects which occur at different scales based on the size of trees, influenced by light-demanding, limited seed dispersal and intra-specific competition of oaks with various diameter sizes. Since the Chestnut leaf Oak trees showed random distribution, the silvicultural interventions should be based on individuals and random single selection to create random spatial patterns in the stand.