The study was aimed to assess of the Danish and Swiss methods of thinning in 20 years old plantations of Chestnut leaved Oak (Quercus castaneifolia C. A. Mey.) in terms of quantitative and qualitative characteristics of trees, natural regeneration, plant and soil invertebrate diversity. The study area is located in Neka forests, east of Mazandaran province in the Caspian region. This research was conducted under compeletly randomized block design (CRBD) with three replication and three treatments. Also in each sample plot, 3 microsample plot, each 49 m2 were randomly systematic selected. The quantitative and qualitative parameters of trees were measured in each sample plots by full callipering. In each microsample plot natural regeneration was counted. Also, whole plants were recognized in each microsample plot and their coverage percent were estimated. Moreover, in each microsample plot invertebrates were sampled, using core soil samples (81 cm2 cross section) to the depth of 10 cm. The results of this research has been shown that the tree diameter at breast height, the abundance of quality tree and the number of natural regeneration in the thinned areas was more than the control area. Of course, the positive impact of the Danish method was greater than that of the Swiss method. Also this research has shown the control area created a more favorable situation due to the plant species diversity than the thinning areas. However the positive impact of the Danish method was greater than that of the Swiss method. On the other hand the Swiss thinning area created a more favorable situation due to the soil invertebrates' diversity than the Danish method. Overall this research emphasizes that the thinning operation with moderate intensity in Danish method is better than the Swiss method for forestations.
