Regeneration of secondary forests in the understory of pure plantations of Quercus castaneifolia and mixed plantations of Quercus castaneifolia and Zelkova carpinifolia in northern Forests of Iran

摘要

The Regeneration structure and biodiversity of trees and shrub species in the understory of pure and mixed Oak plantations were investigated in the Chamestan Forest and Rangeland Research Station of Iran. Species including Quercus castaneifolia (as main species) and Zelkova carpinifolia (as associated species) were planted in five proportions (100Q, 70Q:30Z, 60Q:40Z, 50Q:50Z, 40Q:60Z) 15 years ago in northern Iran, seedlings and saplings of woody plants were divided into two height classes of 15-200cm and more than 200 cm. Berger-Parker dominance index, a Fisher alpha diversity index, Margalef richness indexand Equitability J evenness indexwere used. The results showed more abundance and diversity of regenerated species in the understory of all oakplantations than in the unplanted control plots and also a greater abundance of regenerated species under pure stands of oak than in mixed plantations. The highest species richness was found in the 60Q:40Z treatment. The presence of primary forest species in the understory of mixed plantation can help to restore natural forests.