3Agricultural and Natural Resources Research Institute of Khuzestan, Ahvaz
We studied litterfall dynamic of tree plantations in Dez River floodplain, at 14 to 15 years old. The plantations consist of Populus euphratica Oliv., Eucalyptus camaldulensis Dehnh., E. microtheca F. Muell, Acacia farnesiana (L.) Willd., A. salicina Lindl., A. saligna (Labill.) H. Wendl., A. stenophylla Benth. and Dalbergia sissoo Roxb. Litterfall was different between the tree species, and leaf litter fall was the dominant part, while reproductive and woody parts have considerable amounts in some species. The results also showed that most of the everegreen and deciduous trees litterfall were in Jun and October, respectively. Day length and maximum and minimum temperature controlled the litterfall of some species. Totally we could state that although leaf litter is the most part of litterfall, reproductive and woody parts have also considerable amounts in some species e.g. woody parts in Eucalyptus species. Also the obvious differences of litterfall fractions between the different species confirmed that the litterfall fractions should be considered in studying nutrient cycling.