تأثير اجراي شيوه تك گزيني بر تنوع گياهان چوبي (مطالعه موردي: سري جنبه سرا- گيلان)

Effect of single selection method on woody species diversity (case study: Janbe sara district-Guilan)

In this study, variations of woody species diversity were investigated in Beech, Beech-Hornbeam and Horn Beam stands of Janbesara district (located in the west of Guilan province) after the application of single selection method. Random-systematic sampling method was applied in the first and last year of the 10-year period (1993-2003) with 3.3% intensity and 200x150 grid size. Shrubs and trees species were recorded in 0.1 ha circle sample plots. Species richness, Shannon Wiener and Simpson diversity indices were used to evaluate plant diversity in each sampling plot. The means of different diversity indices were calculated and t-test was used to analysis all indices means differences in both sampling. The results showed that species richness, Simpson and Shannon diversity indices both in Horn Beam and Beech-Hornbeam types increased (with non-significant mean differences) after applying the single selection method. Therefore, single selection approach can be applied as a appropriate silvicultural method in northern natural forests for plant diversity conservation together with wood production.