فهرست مطالب سید محمد مهدی رضایی سنگدهی

To assess the changes in qualitative and quantitative attributes at the end of a period of forestry plan implementation, a portion of the Jojadeh zone with an area of 1270 ha was selected. Data were collected from 265 permanent plots in a systematic random design (1000 m2 plots and150 × 200 m grid size) in 2004 and 2014 to facilitate a comparison. In each plot diameter, species, quality grade, height of control tress and quality of regeneration (in 100 m2 microplots) weree measured. During the ten-year period, approximately 14000 silve of growing stock was marked within a single tree selection cutting system. The results showed following figures for 2004: the average number of trees per ha=173, volume per ha=318.36 silve, basal area per ha= 25.87 m2, diameter of basal area= 43.93 cm and Lorey’s mean height= 25.31 m. The values in 2014 were 175, 360.24 silve, 28.31 m2, 43.39 cm and 26.40 m, respectively. Apart from number of trees per ha, significant differences were observed between the two measurement times for the other attributes. Furthermore, the species specific regeneration frequency was affected by a significant reduction in seedling and saplings in 2014. However, tree percentages increased in 1st and 3rd quality grade classes, whereas it decreased 2nd class andd remained unchanged in 4th class. All in all, the results showed that the average values of quantitative and partlyy qualitative characteristics were not far from favorable conditions during the period of forestry plan, which indicated the conducted silvicultural practices served the defined goals of the close to nature forestry method.

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.