Nutritional process and nutrients return in pure and mixed plantations of oak (A case study: lowland forests of Chamestan, Noor)

This research was performed in Chamestan Forest and Rangeland Experimental Station since 1994. In this research chestnut leaved oak (Quercus castaneifolia) was planted at pure and mixed plantation, including Siberian elm (Zelkova carpinifolia), maple (Acer velutinum), hackberry (Celtis australis) and hornbeam (Carpinus betulus). The aims of this research were as follows: 1. investigation on nutritional elements of the leaves and their return by senescent leaves at both pure and mixed plantations, 2. litter production of the species and nutrient fluxes in the two plantation types. For these reasons, sampling was made from the fresh leaves in August and for the senescent leaves in November, and the elements were measured in laboratory. Litter traps were located within the treatment's plots for litter collection and litter dry weight was measured and recorded. The results showed that the mixed plantations produced more amounts of nutritional elements than the pure plantations. Dry litter production was 5.02 to 6.14 ton per hectare per year, which was more than the European temperate broadleaved forests production. The concentration of elements in the mixed oak- maple plantation was more than the pure oak and the other mixed plantations. It can be concluded that investigation on nutritional behavior of forest trees is very important for sustainable forest management