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Crown dieback is of the phenomena that mainly has affected Persian oak trees. In order to assess the crown dieback of trees in forest stands of oak trees and its relationship with the individual trees, tree origin and size of tree canopy, Shalam forested area in the northern half of the Ilam province was selected. After dividing the study area into topographic homogeneous units, the biggest unit was selected for assessing the research objectives. Within the selected unit, 6 parallel transects were laid and about relatively 60 healthy and dieback trees were recorded. Then crown dieback, position of tree in stand, origination of trees, minimum and maximum crown diameter and crown height were measured. Data analysis was performed by analysis of variance and linear regression. Results showed that individual trees had healthier crown than the rest of the trees. Standard trees showed less crown dieback than the coppice trees. Effect of crown size on crown dieback depended on the location of trees as single or group and tree form. Totally it can be concluded that oak trees would give different responses to drought in terms of their individual or social characteristics and also it was seen a range of crown dieback with different intensity/pattern within stand in individual to group trees.

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In forest ecosystems espcially riparian ones, individual trees have important effects on soil macrofauna. This research was conducted to study the effect of Populuseuphratica on soil macrofauna in Karoon River Side Forest near Shooshtar. Soil macrofauna were sampled in November 2012. Soil macrofauna under tree crown (in three crown diameter category) on parallel transects with 100 m distance from the river and eachother was sampled. Soil macrofauna in 50 cm× 50 cm plots upto 10 cm depth were hand sorted and identified to family level. Totally 342 plots were sampled. The results of correlation showed that there were negetive relationship between distance to tree crown center and soil macrofauna and this relationship was higher in the case of trees with lager crown. The results of ANOVA also showed that the crown diameter size did not have significant effect on soil macrofauna except on soil macrofauna evenness with low significant level. The correlation of distance to river with soil macrofauna showed higher abondance, richness and diversity in farther distances to the river while evenness were higher near the river. Totally it should be saied that indvidual P. euphratica wereeffective on soil macrofauna and it also should be considered the distance from riverside had massive influence on crown diamere.

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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 aim of this research was study of tree species diversity in the Zagros forests of Iran that known as Ardal’s Chartagh protected forests. The total of the study area was 50 hectares. In this way 50 sample plots (circular shape with 1000m²) were measured based on systematic-random sampling method. In each plot species, DBH, species and number of trees were measured and recorded. To estimate of the tree species diversity, Shannon-Wiener, Simpson, Mc Arthur’s N₁ and Hill’s N₂ indices and for calculation of evenness and species richness Wilson- Smith’s and Margalef indices were used respectively. Also species importance value (SIV) was calculated. The results showed that there are 7 tree species in the study area including Fraxinus rotundifolia Mill., Juniperus polycarpos C. Koch, Cerasus mahaleb (L.) Mill., Quercus brantii var. persica, Pistacia mutica Fischer, Acer monspessulanum subsp. cinerascens and Salix persica Boiss.. Values of Shannon-Wiener, Simpson, Mc Arthur’s N₁ and Hill’s N₂ indices are 1.23, 0.58, 2.40 and 2.16. Also Wilson- Smith’s and Margalef indices showed that the values of richness and evenness are about 0.84 and 0.77. The results of SIV showed that the highest value of SIV belonged to the Fraxinus rotundifolia Mill. (188.63%) and the lowest value was due to Salix persica Boiss (17.59%). Therefore, conservation of forest stands might be suggested as a suitable approach for increasing plant diversity.

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Oak decline is a complex phenomenon that oak forests are faced with it across the world and Iran. Shalam forested area located in north of Ilam province was selectedto determine the role of topographicand some edaphic factors in tree mortality happened in Persian oak forests. The study region was divided into 20 homogeneous topographic units. Within each homogeneousunit,three 0.1-haplots  were randomly-systematically established for measuring the rate of tree mortality and oneprofile was prepared for characterization ofsome  physical and chemical soil characteristics (texture, moisture content, TNV%, OC% and N for each soil layer, and soil depth). In each plot,diameter at breast height (DBH), maximum and minimum crown diameters, crown dieback percent, origination and form of trees and shrubs for all species and site variables weremeasured. Results showed that 15.7% of forest stock had reduced while 97.65% of it belonged to Persian oak species. The results of multiple linear regression and RDA showed that tree mortality was significantly affected by elevation and aspect, but not by slope. The highestrate of tree mortality was observedin high elevation and south and west aspects. Also the results of multiple linear regression and RDA showed that tree mortality was significantly affected by soil depth and texture. So, the highestrate of tree mortality was observed in soils with less depth, less sand% and more silt%. It was concluded that topography and soil have effective role in tree mortality and its expansion across Zagros forests. Identifying the critical conditions in terms of topography and soil in these forests can help and be useful in the management of tree dieback.

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Background and objectives: In addition to wood production, forests have many environmental and social resources that most of them are often lacking in the market.
Materials and methods: In this paper five cases of ecosystem services forest ecosystem was considered from an economic perspective and they have been evaluated to various approaches. For this purpose, the recreational value of the area by using a conditional valuation method and the value of carbon sequestration, the maintenance of soil nutrients, the value of water regulation and the value of non-food products in the region were estimated by using the replacement cost method. Then the total economic value of these functions was estimated.
Results: According to the results total economic value and the annual value per hectare of forest ecosystem were 576413505.1 Toman and 17243407.560 Toman in year respectively. The functions of Carbon sequestration with equivalent value 574114967.1 thousand Toman had the most value and Recreational function had the lowest total value among other functions with equivalent value 126618 thousand Toman per year.
Conclusion: The results of the study, as well as other similar studies can be concluded that natural resources with regard to the future exploitation process, they are more under pressure and rarer, So it is necessary that with the optimal using of these valuable ecosystems, this natural heritage has been protected. With understanding the economic value of the whole ecosystem, programmers and policymakers are able to make more comprehensive decisions and determine the precedence between available options  that makes optimal use of it.