تعيين چرخه بذردهي راش FAGUS ORIENTALIS LIPSRY در منطقه زيازت گرگان

Determination of beech (Fagus orientalis Lipsky) seeding cycle in Ziarat Forest.

The trail was conducted at Ziarat Forest (Longitude: 54° 25ʹ East, Latitude: 36° 43ʹ North, altitude: 650-2350. asl) of Caspian region of Iran in order to identify the seedling cycle of F. orientalis. Twenty seven dominant beech trees were selected for quantitative and qualitative measurment. After soil and ground cover sampling and tree measurment, the trees were cut down and a disc sample was taken from each treeʹs stump. The discs were analyzed to study the annual rings. The results showed that: 1- Fagus orientalis has two seeding types, heavy and light. 2- The minimum age of seeding is about 49 year when is often associated with light seeding. 3- The heavy seeding begin at age of 57 year. 4- At a same site, different seeding cycles were observed during the living period. 5- The light and the heavy seeding repeat at 2-6 and 3-27 year period, respectively. 6- Natural regeneration depends on the light seeding cycles due to their frequent occurance. 7- There was a relationship between the averag decerese of annual ring growth rate and seeding types as follows: a. If decrease of annual ring growth rate is more than lmm, there will be a heavy seeding cycle. b. If decrease of annual ring growth rate is between lmm and 0.31mm, then there will be alight seeding cycle. C. If decrease of annual ring growth rate is less than 0.31mm, there will not be a seeding cycle.