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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.

To investigate some effective causes of beetle attack to Amygdalus scoparia in Bagh Shadi Harat, Yazd 80 sampling plots were randomly selected. In each plot number of infected tree, percent of dryness for each tree, height, diameter at root collar and crown diameter of each tree, elevation, slope and aspect of each plot were measured or recorded. Results showed that beetle infection were positively correlated to dryness of Amygdalus scoparia, Loranthus Grewinkii and negatively to tree sprouting. Beetle infection were also positively correlated to density of Amygdalus scoparia, density and coverage of accompany species, number of dried Amygdalus scoparia and negatively to percentage of slop. It is concluded that beetles prefer habitat with denser and more coverage population of Amygdalus scoparia in flat area and on trees with less sprouting. Since the study area is an important conserved place in Yazd province, research to control the pest can be very important. Elimination of effected and old trees may limit growth of pests in this area.

Background and purpose: In recent years, forestry projects have gained increasing environmental, economic and social importance as an indicator of development. These projects are one of the most important international activities. Since the establishment of a natural forest in arid and semi-arid regions is a long and complicated process, it is difficult and necessary to restore a deforested forest in these areas. The harsh conditions and nature have reduced the forest ecosystem, so this study aims to present a picture of the status of the current forestry plans with Amygdalus scoparia Spach in four regions of central Bazoft. The intention was to compare the qualitative and quantitative status of forestry in these areas and tested the viability and adaptability of tree and shrub species cultivated in the valleys around the Bazoft river and in the central Bazoft region.
Materials and methods: In this study, the centers of sample plots were 400 m² ((20 × 20 m) in a completely randomized design. In total, there were 153 plots, and in each sample plot, quantitative characteristics such as mean area of ​​canopy, average height and qualitative characteristics such as vitality and the most important characteristic and survival was estimated. Kaplan-Meier estimator was used to estimate Survival Distribution Function, average survival rate and drying risk in each forest area. The same survival function tests associated with this estimator were also performed to ensure probable segregation of the areas. Analysis of variance was performed in regard to classified factors of the region (in four classes), planting time (in four classes: 1385, 86, 87, 88), Front (in four classes: Four main directions), slope (in two classes: more than 25 Percent and below), elevation and density of primary seedlings. Mean values ​​were compared by Tukey test.
Findings: The results of the comparison of survival rates showed that at a small spatial distance, a significant difference was observed in forestry with a singletree species. The highest survival rate after one decade was 0.88 and the lowest was 0.64. Even two identical tests of survival function i.e. Log-rank and Wilcoxon showed that there was a significant difference between forested areas with Amygdalus scoparia species. Cox Proportional Hazards Model using topographic factors (slope, front and sea level) as covariance using Wald statistic showed that the highest Amygdalus scoparia cultivation risk ratio were the western and northern fronts and then low slope regions.
Conclusion: There was a significant difference between forested areas with Amygdalus scoparia species. Based on the average canopy area, height and freshness of the trees, the southern slopes were perfectly suitable for cultivation, and the western and northern slopes were inappropriate for cultivation of these trees. The other topographic factors that probably influenced the success of the Amygdalus scoparia cultivation (slope and elevation) had not significant effects on the outcome of the Amygdalus scoparia cultivation.