Studying the interaction between English yew (Taxus baccata L.) adult trees and its regeneration in Afratakhteh Forest Reserve, Golestan province

Understanding the underlying mechanisms for tree species regeneration, as well as the positive and negative interaction between tree species and regeneration can improve the effectiveness of forest management and restoration activities. English yew, as one of the rare and valuable native species in Hyrcanian forests, Iran, has declined over the past several decades for many reasons such as lack of regeneration in existing populations. This research aims at studying the spatial pattern of English yew regeneration and its interaction with adult trees. For this purpose, the location of all English yew trees and its regeneration was recorded using TP360 device and distance-azimuth method in the Afratakhteh Forest Reserve, Golestan province. Totally, 417 English yew trees and 59 regenerations were recorded in the research area. The minimum and maximum diameter of the English yew trees was 6 and 124 cm, respectively. The results of the univariate analysis O-ring function showed that the spatial pattern of English yew trees is completely random and spatial pattern of regeneration were clustered in < 5 m, and then it is random. The results of the bivariate O-ring function showed that there is strong competition and negative interaction between the yew tree and its regeneration. It seems the density of the mother trees in the forest and a large shadow over the length of the year by yew trees is linked directly to the absence of regeneration in this forest reserve. Also allelopathic influence of parent yew trees could negatively impact on seedling density beneath a conspecific canopy. The areas out of existing English yew canopies are most likely to represent optimal sites for regeneration. Therefore, in order to protect the existing English yew stands, management activities on regeneration should focus on these areas.