عنوان مقاله [English]
For determining of suitable poplar clones for utilizing in cellulose industries on the basis of maximum wood production in hectar ,15 clones of Populus deltoides, P.euramericana and P.nigra were studied in three exploitaion period (2,3 and 4 years) in chamestan of Mazandran province.
In order to homogenize the material, all the shoots were cut at the bottom after the first growth year. At the end of each exploitation period, all stems and shoots were cut and weighted two times; 1) wet wood product and 2) dry biomass after six months of drying in the open air.
Some parameters such as survival, number of total coppice stems per collar, number of shoots over 2 m height, mean diameter and mean height of shoots over 2 m height, diameter and height of the highest stems and resistance to pests and diseases were studied and compared at the end of the project. Results were analized on the basis of randomized complete block design.
Results showed that :
a) In 2 years short rotation system, P.d. 69/55, P.e. triplo and P.d. 73/51 produced the highest amount of dry biomass of 20.05, 17.52 and 17.19 ton/ha/year,respectively.
b) In 3 years short rotation system, P.d.77/51, P.e. triplo and P.d. 69/55 produced the highest amount of dry biomass of 16.70, 15.75 and 14.73 ton/ha/year, respectively.
c) In 4 years short rotation system, P.d. 69/55, P.d. 77/51 and P.e. triplo produced the highest amount of dry biomass of 19.00, 17.77 and 16.96 ton/ha/year, respectively.
The diffrences between dry biomass production of poplar clones in each rotation system were significant.