The most suitable harvest period of P. deltoides 77.51

Determining of the tree removal age related their usage, is more important to economical harvesting. It is highly significant, when range of fast growing tree plantation is extended for wood demanding. From 25 populus clones planted in Safrabasteh research station in 1965, 14 clones with the highest value in height and dbh were selected only. Between 14 selected clones, clone number Populus deltoides 77.51 was superior in height growth and dbh increament. In order to determining of the appropriate time of harvesting with maximum productivity per area, an experimental designwas stablished in Safrabasteh research station. The experimental design used, is a Split polt. That means that means that the each of four different harvesting period such as 2, 4, 6 and 12 years as a main plot divided into two subplots with different seedling??? Were inceased. Harvesting has been done 6, 3 and 2 time for period of 2, 4 and 6 years respectively. The period of 12 years yield was harvested in the end of period only. All yield were weighted and analyzed. The results are shown as fallow.
1-Total mean yeild per area for period of 2 years was 170.998 tones.
2-Total mean yeild per area for period of 4 years was 274.167 tones.
3- Total mean yeild per area for period of 6 years was 250.546 tones.
4- Total mean yeild per area for period of 12 years was 241.679 tones.
The analysis was indicated that the period of 4 years had most production per area than the others.