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To evaluate the quantitative and qualitative characteristics of forest park of Shourab's trees, consisting of Pinus brutia, Pinus pinea, Cupressus arizonica, Cupressus sempervirens var. sempervirens, Cupressus sempervirens var. Horizontals, Ailantus altissima, Robinia pseudoacasia and Fraxinus rotundifolia, inventory as a systematic random sampling and in statistical grid 100×150 meter and in 30 circular sample plots (2R) was undertaken. In each sample plot, tree's quantitative and qualitative characteristics, such as diameter at breast height,basal area of tree, tree height, crown coverage percent, h/d factor, regeneration, vitality, crown form and branchiness on the trunk were examined and measured. According to the results, about 75 percent of the species was due to conifers, especially Pinus brutia (45 percent), and 25 percent of hardwood species formed forest park trees. Also the average number of species in whole park was 604.05 per ha. The results shown that the average diameter at breast height, tree height and basal area of tree softwood species-particularly Pinus brutia and Cupressus arizonica, amounted to 23.02 cm, 9.5 m, 0.048 m² and 13.47 cm, 8.02 m and 0.042 m² higher than other species. With the concern of vitality, in softwoods, Cupressus arizonica specie had the most vitality range (85/75) percent and in hardwoods , Robinia pseudoacasia and species had the lowest vitality range (37.27) percent. Finally, we could say Softwood species afforested in terms of qualitative and quantitative indicators of hardwood species, is preferred. Nevertheless, the species of: Pinus brutia and Cupressus arizonica which have exhibited comparatively better performance are suggested for future afforestation expansion in this park.

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The main objective of this study was to estimate the effect of decline disturbance on diameter distribution of coppice oak trees in central Zagros region. For this purpose, two similar stands with equal areas (32ha) in central Zagros (Shorab in Lorestan province and Zarabin in Ilam province) were selected. Diameter at the breast height of declined trees was recorded before and after cutting using 100% inventory method. Following probability density functions (PDFs) Beta, Jonson, Weibull, Gamma, Normal and Log-normal were fitted to the data. The results of goodness of fit tests shown that Beta, Weibull and Jonson PDFs were fitted well to diameter of woody stems in Shorab but Jonson, Beta PDFs were much m ore suitable for Zarabin region. The difference of diameter at hight breast was studied in two stages of before and after declining by means of mortality PDF and using different PDFs. There was a big difference in diameter classes between before and after decline disturbance according to mortality distribution. There was no difference between before and after decline disturbance based upon statistical distribution fitting criteria. Outbreak of decline within this region had merely similar influences on all diameter classes, and as a result, it had not a significant effect on overall diameter fit.