In order to maintain biodiversity in the integrated management of forest ecosystems, there is a need for basic information on habitat trees. Regarding the challenges in assessing the level of animal diversity in forest ecosystems, the status of habitat trees can indicate the level of species diversity. This research was conducted to evaluate the abundance of different forms of habitat and dead trees within beech stands in eastern Gilan. Three one-hectare study area were selected in the Shirgalayeh forest management plan area and in each area the characteristics of all living, dead and habitat trees were measured. The mean of dead volume was 43 cubic meters per hectare. More than half of the dead volume were recorded log form and advanced stages of decay. A total of 81 trees with a sign of microhabitat equal to 15.4 percent of the total trees were recorded. Beech trees with cavities (n = 29, 35.8%) was the most frequent habitat trees after that Cracks and Fruitbodies of saproxylic fungi were the most frequent habitat tree, respectively. The minimum diameter and perimeter for habitat trees were 35 and 110 cm, respectively. Based on the results of this research, it is recommended that at least 15% of the total trees with a diameter of at least 40 cm (especially trees larger than 150 cm) should be selected and maintained in the forests stands. According to this fact that some types of habitat trees, such as hollow trees or trees with outgrowth (Burr) created in the long term, need to be given sufficient attention to keep them in compare with renewable habitats such as cavities.

One of the main problems in Zagros forests is oak trees dieback. What is certain and important is that the tree dieback crisis caused the declining of oak in oak forest of Zagros. Oak decline is characterised by crown thinning, foliar necrosis and progressive death of primary leaf-bearing branches and the emergence and subsequent decline of foliage. A range of biotic and abiotic factors has been shown to contribute to the decline. However, no satisfactory investigation has been established to explain the distribution.
The aim of this study was to investigate the spatial variability of Oak decline and it’s relation to tree properties in Zagros Forest of Kermanshah (Gahvareh). In this order, 150 hectares of Gahvareh forest was selected and then 67 sample plots (400 m2) were used in a 100 × 100 m sampling grid. In each of the plots the the number of healthy trees and their canopy cover, the dieback and trees with dieback features including diameter, height, crown diameter, average canopy cover, the number Search trees were recorded. Then the spatial continuity, using geostatistics (variogram) were described.
The results of the Pearson correlation coefficient indicates that dieback has a significant positive relationship with the feature tree dieback including diameter ¡height, crown diameter, canopy cover is a significant and positive relationship between the number of sprouts. As well as between the dieback and features healthy tree such as the number of trees and average canopy cover and there is a significant negative relationship variograms of variables revealed the presence of spatial autocorrelation except for the number of shoots have the spatial structure.
Overall analysis of the spatial structure of healthy and dead tree dieback and features show that the structural component of the variance components of random variance prevails. The variables studied occurred in a relatively large area, indicating the spatial structure of large, uniform distribution and continuity in the desired location in variable amounts. The similarity in the effect of dieback and features trees with dieback (collar diameter, height, crown diameter, average level of cover and canopy cover) and also a significant positive correlation between them, represents the close spatial relationship between the dieback and trees have been dieback features. Given the significant negative correlation between the dieback and characteristics of healthy trees (number of trees and average level of cover), it can be stated that the spatial variability characteristics of healthy trees, the dieback affects as photos.

The aim of the study was to investigate the effects of terbinthine exploitation on bark redress and longevity of wild pistachio (P. atlantica Desf subsp. mutica (F.&M. Rech.F.) under statistical design of split plots with four replicates and at three year period. The treatments consisted of stem diameter at four classes (20-30, 31-40, 41-50, > 50 cm) and bark slits at 10 different numbers (5, 10, 15, 20, 25, 30, 35, 40 and 50). The trial was conducted in the pistachio Experimental Forest at Fars province of Iran. The bark slits were made twice a year (the first two months of summer). After measuring terbinthine production at each treatment, mechanism of bark redress was also studied. The mechanism of bark redress was significanty different at various stem diameter classes, in which the highest and the lowest rate of bark redresses were found in young or middle-aged and old-aged trees, respectively. It might be concluded that terbinthine exploitation from wild pistachio trees of the studied forest will negativly affect the growth and longevity of the trees, due to inadequate scientific and technical method of bark wounding, ecologicaly hard environment condition and high percentage of old-aged trees at the studied site. For this reason, terbinthine exploitation is not recommended at such forests.

In order to study morphological and physiological responses of Persian oak trees leaves، one of the dieback affected stands in Melah-Siah region in the northern half of the Ilam province was selected. Oak trees were divided into 4 groups with 6 replicates based on the severity of crown dieback. Leaf samples were randomly taken in South directions of trees crown in spring and summer during two consecutive years and were transferred to the laboratory for analyzing of some morphological and physiological traits including leaf area، wet and dry leaf weight، SLA، LMA and RWC. Results showed that the interaction effect of season and crown dieback degrees on morphological and physiological traits was not significant. But all of the studied traits had significantly ascending or descending temporal variations. Results showed that the dry leaf weight of dieback trees in spring 2014 was more than that of healthy trees. The leaf area of dieback trees in spring 2013 and in spring and summer 2014 was less than those of healthy trees. The amount of leaf water of dieback trees in spring and summer 2013 was less than that of healthy trees. The leaf moisture weight of dieback trees in spring and summer 2013 and spring 2014 was less than that of healthy trees. The RWC amount of dieback trees in spring and summer 2013 and spring 2014 was less than those of healthy trees. It was concluded that drought has more severe impact on the morphological and physiological status of Persian oak dieback trees leaves and responses of some traits in the dieback trees is for resistance to drought condition and possibly performance of vital activities.

The formation of gall is one of the various types of vegetarianism, and gall producing insects cause stress in their hosts. The present study aimed to investigate the changes of some biochemical and photosynthetic indices due to the gall in Persian oak trees in Forests of Middle Zagros. Sampling was performed from trees infected by gall and healthy trees in Blouran forests. The results showed that the amount of lignin, proline and anthocyanin were increased significantly in infected trees compared to healthy trees (P≤0.01). Moreover, the indices of chlorophyll a, chlorophyll b, total chlorophyll and carotenoid content were decreased significantly in infected trees (P≤0.01). According to the results, it can be concluded that the presence of insects producing gall on Quercus branti trees is considered as a pest. The increasing presence of these insects and the consequent changes in trees declare the necessity of the control of the pest and the prevention of the creation of critical spots.

Oak decline is an eminent factor, which has a significant role in degradation and change in Zagros forests. The goal of present study was to assess the crown surface area of oak trees in Sarableh forests, Ilam province. For this purpose, permanent sample plots were used. Eighty sample plots with 10 Ar area were applied based on systematic-random method in a 150×200 survey network in 120 ha. The crown diameters and oak decline were measured. Oak decline was classified in five classes (very high, high, medium, no decline). The inventory was conducted in 2012 and 2014. The Mann-Whitney test was used to compare the oak decline in two inventory times. The results showed that the trees in very high and high decline classes (total of two classes) were 13.6% in 2012 and it is increased to 25.4% in 2014 (to be an 11.8% increase). The changes in forest decline were significant at decline classes (P≤0.01). The highest oak decline was observed in two m2 crown area and the maximum healthy trees were found in 14 m2 crown area. Our result revealed that trees with small crown area are more engaged by forest decline. In order to managing the forest engaging to oak decline in Ilam province and the rehabilitation of these forests , it is recommended the trees with small crown area (up to seven m2) should be more considered in terms of forest rehabilitation and tending.

Trees can cover a wide range of environmental, aesthetic, historical, tourism benefits and social, physiological, as well as economic benefits, however, the trees can cause environmental risks. The aim of current study was to reduce the insignificant variables by methods of index criteria of tree and analysis of the main components and then using the remaining variables in the process of modeling the risk possibility falling of elm tree by Neural Network Method. For this purpose, the quantitative and qualitative variables of elm trees were collected in Seyed Alikhan Street of Isfahan by counting 100% of these trees in 2018. The results of elimination of tree diameter and contact with power transmission lines in predictive models of risk of falling dangerous trees indicated that the variables that were eliminated during the study process did not have a significant effect on predicting the risk of falling dangerous trees. This creates a significant change in the accuracy of the model training data and decrease the number of repetitions of network training to reach the optimal network and reduces the time to reach the optimal neural network. Therefore, we recommended the use of tree fall modeling for management of urban green spaces.

The phenomenon of oak decline is one of the most important current problems in the Zagros forests. Lack of nutrients and differences in nutrient uptake between healthy Brant`s oak (Quercus brantii Lindl.) and trees affected by decline is one of the main causes of dryness of these trees. Tree nutrition can be considered as a management strategy to solve this problem and stop the decay of oak trees. Nutrient spraying is one of the common methods of plant nutrition that meets the needs of the plant in a short time. In this research, the similar trees of two forms (coppice and seed-origin) were selected in the Monj area of Chaharmahal and Bakhtiari province. In each form, trees were divided into three levels of health (Healthy, dieback and crown drought up to 50%). Five similar trees by dimension were selected in each level of health (totally 30 trees). Before and after nutrient spraying, the quality characteristics of the trees were recorded and a mixed sample of leaves was prepared from them. Nutrient spraying were done at full time of leaves from early June to July with an interval of 10 days in three shifts. The results showed that the amount of micronutrients elements in the leaves of trees at the beginning of the growing season was significantly higher than the end of the season. Among the micronutrients elements, the amount of boron in the leaves of healthy trees was more than decaying trees. Qualitative evaluation of trees showed that the progression of dieback has stopped in most of the studied trees. Feeding of decaying trees and increasing the possibility of nutrient uptake from the soil can be effective in stopping the decay of trees.

The Clearwing moths (Lep.: Sesiidae) are important and destructive pests of fruitful and non- fruit bearing trees in different countries of the world. Considering the high damage of sesiid moths in Isfahan landscape, the infestation percentage and intensity were studied on 4768 trees of different species in 14 Isfahan municipality regions, Isfahan University of Technology campus and Nazhvan parks as 15th and 16th regions, respectively. To identify sesiid moth species, DNA was extracted from larvae and adults. Polymerase Chain Reaction (PCR) was used to amplify a 709-bp region of the mitochondrial DNA cytochrome oxidase I and samples were sequenced. Results of COI sequences revealed that the moth Synanthedon caucasica (Gorbunov) is the damaging species on Platanus orientalis, Ulmus carpinifolia and U. carpinifolia var umbraculifera and the sesiid moth Sesia pimplaeformis (Oberthür) (=Eusphecia pimplaeformis) is harmful to Salix alba and Populus alba. Percentage of infestation was calculated based on the number of infested trees divided by total trees and intensity of infestation was determined based on the total number of pupal exuviae, active larval holes and inactive larval holes per 10 centimeters of trunk diameter. The combined analysis was performed in a completely randomized design with 10 replicates. The regions and hosts were considered as main and secondary factors, respectively. Using linear regression between tree diameter and infestation rate, the effect of trunk diameter on the infestation rate was determined. Results showed that 53.8 % of Platanus orientalis, 65.6% of U. carpinifolia, 64.4% of U. carpinifolia var umbraculifera, 52.6% of S. alba and 45.2% of P. alba and totally 53.2% of all trees were infested with sesiid larvae. The highest infestation intensity (4.2) was observed on U. carpinifolia var umbraculifera. The species U. carpinifolia, Platanus orientalis, salix alba and P. alba had lower infestation intensity. No sesiid damage symptoms were observed on Morus spp., Rubinia pseudoacacia and Fraxinus rotundifolia subsp. persica. On all host tree species, the correlation between trunk diameter and infestation rate was positive but a significant correlation (p < 0.05) was only occurred in U. carpinifolia var umbraculifera and salix alba.