Quantitative characteristics of a forest compartment managed under unique-block with a control compartment (Case study: District 3, Sangdeh forests)

The forest management plan of Sangdeh (Mazandaran province) was first implemented in in1969 under a Shelterwood system, which led to final cuttings conducted between 1991 and 1995. This study was planned to compare some of the major quantitative characteristics of compartments managed under a unique block method to a selected control compartment. The forest inventory was carried out in a systematic random sampling with a 100×150 m grid size.The results showed the average growing stock of 464.27 and 240.95 silve per hectare in control and unique block, respectively. In addition, the average number of trees per ha were 232 and 599 trees, the average basal areas per ha were 22.74 and 31.69 m2, the average tree diameters were 39.90 and 21.00 cm and the average heights were 28,30 and 21,27 m, respectively. Furthermore, the vertical forest structure consisted of three and two stories in control stand, while it consisted of one and maximum two layers in the unique block. The average rates for total regeneration accounted for 1487 and 715 tree per ha in control and unique block, respectively. Furthermore, regeneration frequency in unique block showed a reduction compared to the control for all of class except in 7.5-12.5 cm class. Significant differences were observed for the average stock density, basal area, tree height and diameter between the control and unique block stands. All in all, although the unique block was evaluated relatively successful in the light of the majority of measured characteristics, the achieved results are assessed to be still sup-optimal when considering the mother trees and the expected advanced regeneration mixture.