Structural diversity as component of biodiversity in forest ecosystems, case study from population of Persian ironwood (Parrotia persica C.A. Meyer) in the north Iran

Knowledge appropriate quantity information from forest stand structure in the natural conditions is the first step in protecting and restoration the endangered species habitats. The objectives of this study were to contrast the structural diversity of three, native stands of Persian ironwood using common structural indices and measure the range of intraspecies and interspecies competition. For this purpose three one hectare study sites in the Patom district from Kheyroud forests, were selected were selected and within sites 30×30 m gird plot established and in the intersection point of girds diameter at the breast height, tree height, crown diameter, distance and angle among trees were measured for the closest beech to the intersection point as reference tree and other three nearest neighbors the to the reference tree. Our results showed that Persian ironwood tends to be fairly pure in species composition, have slightly heterogeneous diameter distributions, uniform tree height, and the stems have an average distance between trees of 6.0 m. The results indicated that trees in the canopy layer were more vital and decrease of height differentiation and a raise of tree–tree distance caused better vitality classes. It can be assumed that the vitality of the Persian iron wood is better related to inter-specific competition. We conclude that Persian ironwood is successes in the intraspecies competition and the interspecies competition was the most important variable influencing on the trees vitality.