نوع مقاله : مقاله کامل علمی پژوهشی
1 استادیار پژوهشی، عضوهیات علمی مرکز تحقیقات کشاورزی و منابع طبیعی مازندران
2 دانشیار پژوهشی، موسسه تحقیقات جنگل ها و مراتع کشور
3 کارشناس ارشد اداره کل منابع طبیعی مازندران- ساری
عنوان مقاله [English]
Background and objectives: Applying of plant and animal diversity as well as natural regeneration are the common methods of assessing the ecological potential of forest stands. The objective of this study was ecological assessment in 20 years old plantations of Chestnut leaved Oak (Quercus castaneifolia C. A. Mey.), Velvet Maple (Acer velutinum Bioss.) and Brutia Pine (Pinus brutia Ten.) in term of quantitative and qualitative characteristics of trees, natural regeneration, plant and soil invertebrates. The study area is located in District 2 of Neka’s lowland forests, east of Mazandaran province.
Materials and methods: Nine sample plots with 1500 m2 were selected in each plantation. In each sample plot, 3 micro-sample plots, each 49 m2 were selected random-systematically including 27 micro-sample plots for each plantation and overall 81 micro-sample plots in 3 plantations. Study of quantitatively and qualitatively survey of trees (diameter at breast height, height and quality of tree) was performed by a fully inventory in three plantations including 6088 trees. Also all of the plants were recognized in 81 micro-sample plots and their coverage percent were estimated. Diversity indices were calculated by Simpson and Shannon-Wiener indices. Also, richness and evenness were obtained by Margelov and Menhinick indices. Mean analysis of quantitative characteristics was performed by the analysis of one-way variance.
Results: Analysis of the quantitative and qualitative characteristics of trees indicated that Brutia Pine plantation with the least density had the highest quantitative and qualitative results followed by Velvet maple and Chestnut leaved oak, respectively. Also the mean number of regeneration per square was higher in the Brutia Pine followed by Velvet maple and Chestnut leaved oak plantation. Shannon-Wiener index indicated that the plant diversity was higher in the Brutia Pine plantation, whereas the lowest Shannon-Wiener index was calculated in the Velvet maple plantation. On the other hand Shannon-wiener and Simpson indeces indicated that the soil invertebrates was higher in the Velvet maple plantation, whereas the least index of Shannon-Wiener and Simpson were calculated in the Chestnut leaved oak plantation.
Conclusion: In general, one can conclude that the quantitative and qualitative characteristics as well as plant diversity and natural regeneration in the Brutia Pine plantation are higher than that of other two plantations. We should emphasize that this result might be affected by less density in the Brutia pine plantation, where the trees had more growth space and the forest ground receives more light which advances to higher plant diversity. This research emphasizes the use of conifers compatible species in degraded areas as well as thinning operations in plantations. Otherwise, increasing the growth of trees per unit area can lead to reduce the quantitative and qualitative characteristics of trees as well as plant diversity and natural regeneration.