زهره کریمی - Assistant Prof., Department of Biology, Faculty of Sciences, Golestan University, Gorgan, Iran

Different species of the Fagaceae family are the principal components of the broad-leaved forests in North of Iran. Because of the large size of trees and their commercial value of the wood, they are considered to be economically important for use as lumber. Despite its economic importance, a review of the systematic studies of this familyshows that, several species have been interpreted differently by various authors due to high variations in morphology and the existence of probable hybrids. The objectives of this study are to elucidate specific characteristics of the wood of the family to obtain evidence regarding taxonomical and ecological relationships among the species occurring in the area. For this purpose, ۱۸ quantitative and qualitative characters from wood were surveyed. Cluster analysis and principal components analysis (PCA) were performed based on Euclidean distance and covariance characteristics, respectively. PCA obtained the same result of the cluster analysis. Results showed that, wood characteristics such as shape and size of vessel elements and fiber and tracheids, growth rings, wood porosity, vessel arrangement together with its grouping, solitary vessel outline, perforation plates and intervessel pits arrangements along with their shape and wood density, varied from species to species. These findings are not only useful for species identification but also showed that, differences and similarities among species are related to ecological environment and habitat conditions.

cluster analysis, PCA, Pit, Quercus, VESSEL