Investigation on phenological stages of some trees species in the Caspian Region

In this investigation, the phenological stages of six important tree species in four elevations of three zones (east, west and central part of Caspian Region) have been studied. Twenty well developed crown individual trees of beech (Fagus orientalis), Oak (Quercus castaneifolia), Hornbeam (Carpinus betulus) and Iron wood (Parrotica persica) as well 10 trees of Caspian Alder (Alnus subcordata) and Maple (Acer velutinum) were selected at each site. The results are as follows: 1- The flowering and leaf flashing time depend on climatological conditions, but differ between one or two weeks every year. 2- The phonological stages, according to the temperature, beginn earliar at eastern parts of Caspian Region. 3- About 67% of tree flash between 21 and 30 of March. The rest flash before this data. 4- Trees with dbh of 40 to 80 cm, showed the highest rate of flowering and seed production.