مجله جنگل ایران
سال هشتم شماره 3 (پاییز 1395)

In order to investigate the decline of oak trees in Zagros forests in relation to forest soil characteristics and topographic conditions, Ghalaje Forests with an area of 500 ha in Kermanshah province were selected. For forest classification, systematic-random sampling was used with a 200×150 m grid by 50 m transects. Work units were specified based on the land form, aspect, altitude, slope degree and rate of oak decline. Soil samples were taken within work unit to analyze soil texture by hydrometer, soil nitrogen by Kjeldahl, bulk density by clod method, organic carbon by Black and Walkey method and lime percentage with Calcimetri method. The results of analysis of variance showed that the number of dieback trees was significant (P

Drought stress is one of the most important environmental factors affecting the photosynthesis and plant growth performance. This study aims at evaluating the effects of water deficit on growth and physiological characteristics of mahaleb (Prunus mahaleb L.) and hawthorn (Crataegus aronia L.) seedlings in 60 days. For this purpose, an experiment was performed as completely randomized design in two irrigation treatments (50% field capacity, and control based on field capacity) with 5 replicates. In both species, water stress decreased the photosynthesis, stomatal conductance and transpiration rate (respectively, 64%, 68%, 62% for Crataegus, and 61%, 47%, 61% for Prunus). This is while that, in both species, particularly Crataegus, the electrolyte leakage increased (31% for Crataegus and 23% for Prunus) following the decrease of relative water content of leaf. Water deficit caused the decrease of stem growth (44%) and diameter growth (39%) in Prunus compared to control. Such a trend more or less was found with Crataegus seedlings. Contrary to Crataegus, in Prunus, significant correlation was detected between physiological parameters and total plant biomass. Likewise, in both species the most morpho-physiological characteristics of seedlings were declined under drought stress.

Previous studies have shown that vegetation enhances the soil shear strength and the stability of slopes through soil reinforcing. The amount of reinforcement mainly depends on the density and tensile strength of the root. The objective of this study was to assess the impact of pollarding on tensile strength of Quercus persica roots. For this purpose, five treatment and five control tree samples were randomly selected. Some root specimens for each tree were collected and tensile strength was measured by a standard Instron. 150 successful tensile tests were conducted on roots withdiameter ranging from 0.9 to 5.5 mm, force range of 3-374.5 N and tensile strength range of 1.22-217.80 MPa. The relationship between root diameter and force was following a positive power one but the power relationship between the root diameter and tensile strength was not statistically significant. The results of Wald Chi square test showed there was no significant difference between the tensile strength of treatment and control sample trees, although the root diameter (as covariate) had a significant effect on tensile strength. It can be concluded that no significant differences may relate to short history of pollarding (3 years) in the study area, and therefore it is suggested to assess the stands with longer history of pollarding.

This research aims at investigating the feasibility of Landsat8 images for poplar plantation mapping. Three areas in Talesh and Sumehsara regions, Guilan province, with a total 1025.35 ha with different vegetation mixtures were chosen as study area. Five image-sets were selected from growth and autumn seasons. Studying the images showed no radiometric and geometric distortions. The image enhancements like rationing, PCA and Tasseled-Cap transformation were performed. By preparing training samples in each region and choosing the suitable band-sets, the images were classified using maximum likelihood algorithm. The ground truth was prepared for Hefzabad and Toularoud in Talesh using GPS. It was extracted for Haft-Deghnan and Sheikhneshin from available update-maps. To ensure suitability of the training samples, assessing the accuracy of classification were performed in the training samples. After ensuring this, the accuracy of classification was assessed in whole areas of all images. The results in all areas and dates were almost close to each other. However, the best results were always obtained in growth season, especially in June 2013. Using calculated enhanced bands along with the original bands in classifications in Talesh region showed slight improvement in accuracies, with overall accuracy and Kappa about 95% and 71%, respectively. In Sumehsara region, the best results were obtained in June with 83% overall accuracy and the relatively low Kappa 0.43. While, the results of accuracy assessment in training samples in all cases were about 0.89 to 0.99. It could be stated that the Landsat 8 images had medium capability for poplar plantation mapping. More investigations are needed to create better poplar plantation mapping.

DPSIR (Driver-Pressure-State-Impact-Response) is an analytical process, which is based on cause and effect relationship for making policy and management programing. The aim of the present study is to investigation of the local utilization of northern Zagros forests using DPSIR framework. For this purpose, three villages including Gandoman, Mirhesam, and Kokh-Mamo around Baneh city, west of Kurdistan province, were selected. Forest, Agrosilviculture, Silvopastoral and Agrosilvopastoral management were the main types of land use in the region which mapped according to satellite data, digital maps and GPS data collected from the field. The classified maps of slope and aspect were extracted of 1:25000 digital maps. In addition, DPSIR was applied to investigate the current state of the region and its management responses. The results showed that Agrosilviculture (44% of forested area) and Pollarding (42.3% of forested area) were more developed than other local utilization systems. These land use types are main drivers shaping local landscape and ecosystems features i.e. have made the current state of the region. Forest administration, NGOs and other organizations presented various management responses including banning the pollarding in recent years, to control deforestation in order to develop agriculture land, to plan and implement Tuba and agroforestry projects, to restrict the hunting of rare wild species, organizing and management of pollarding, introduce of alternative sources of revenue to local people, to extend the use of renewable energy (solar water heater), to develop LP gas project and issuing the special certificate allowing small trades from Iraqi borders. Analyzing consequences of the responses showed that in most cases, driving forces (key factors) have been neglected. Thus along with the above mentioned responses we suggested allocation of encourageous and supportive policies in order to proper performance of local forest management practices and holding workshops to improve local communities’ awareness of their surrounding environment as well as techniques to modify traditional forestry.

Like many other countries, Iran was influenced by the newly emerged capitalism which provided their own raw materials of their factories through plundering the resources of other countries. Not only British and Russian, but also French merchants were ranked as the top clients of Iran’s raw materials. Meanwhile, forests as a significant resource of wood supply were not exceptions. In this study, the form and content of the concessions signed with French merchants to utilize Quercus castanefolia to provide the required supply of wood for constructing barrels (for wine and beers), is investigated in the historical political context of the early twentieth century. For this purpose, the manuscripts and archival documents were used. The results of this study indicated that the French merchants had bought each cubic meter of stand oak trees in Iran almost 180 times cheaper than the same one in France. In addition, the lack of awareness of the Iranian private forest owners of the real value of their properties led to the maximum misuse by the French merchants. Unfortunately, the Iranian government was also unable to support the Iranian subjects.

The use of appropriate building materials for forest road pavement has the important role in deceasing the forest road repair and maintenance. According to the role of forest mines for procurement of building material, awareness of their mechanical properties has a crucial importance. For this purpose, the soil mechanical properties of mixed four forest mines used for forest road pavement were investigated in Nav district in 7TH watershed in northern forest of Iran. Gradation, broken face, plastic properties, durability, and sand equivalent of mixed soil were analyzed. The gradation of mixed mines and soil classification were performed by dry sieving and unified method, respectively. The mean values of the investigated variables were compared with standard values. Final result indicated that soils of mines number 1, 3, 4 are gravel and poor graded (GP) but the soil of mine number 2 was sandy well graded (SW). The best curvature and uniformity coefficient belonged to the mine number 2 with 22.5 and 4.44, respectively. Percentages of fractured particles in four mines were 71.7, 72.4, 74.8 and 72.6, respectively which was consistent with the standard values. Coefficient of friction values for selected mines was consistent with the standard values with 38.55, 42.20, 39.47, and 43.87, respectively. The mean values of sand equivalent for four mines were higher than 0.5. Therefore the soil of mine number 2 is more preferable for use in permanent way while, the soil gradation of other mines should be corrected for using as a pavement material.

This paper aimed at identifying and providing the appropriate criteria and indicators for sustainable forest management in northern Iran, and the comparison between the views of local people and experts and priorities of each of these two groups of criteria and indicators. Four processes including Montreal, Helsinki, Near East FAO and CIFOR criteria and indicators were used as basis among the existing international procedures, Through Multi-criteria decision-making methods a series of criteria and indicators for sustainable forest management was selected. Criteria and indicators of the first stage were separately judged by teams of experts and local people. Finally, through the process of network analysis, creating a model and developing the relationships between the criteria and indicators to calculate the final weight and prioritize them were conducted. The results included a series of 11 criteria and 65 indicators. According to experts, the criteria for the conservation of biodiversity and the protective functions of forests had the highest weights (0.1011 and 0.8944, respectively) and criteria for effective local management of conservation and access to resources had the lowest weight (0.07998). According to the local people, the criteria for the socio-economic functions and the maintenance of the productive capacity of forests had the highest weights (0.9501 and 0.9069, respectively) and criteria for conservation of biodiversity had the lowest weight (0.07994). The results indicated that successful management of forests requires joint decision-making between experts and local people, which in turn depends on the relationship and mutual understanding between the two groups.

Climate change and increasing in mean annual temperature and on the other hand, the human activities increased the fire rate in forests and pastures. It seems that the fire affects the vegetation and changes the forest stand structures. In this study, the changes in woody species composition, structure, viability and regeneration of forest biomass in the forests of Sarvabad, Kurdistan province were investigated. In this study, two burned and unburned stands (control), each of them four hectares with similar environmental conditions and plant community were selected, reticulated in 40 plots and were investigated using 100% inventory method. Fire treatments and control data comparisons were performed using independent t-test. The results showed that 10 years after fire occurrence, the share of oak trees has been decreased, while the proportion of Amygdalus and Crataegus has been increased. No significant difference was observed for Pistacia. Furthermore, pistachio and almond were the more resistant species against fire, compared with Quercus brantii. The coppice number in burned area was more than control one, although the difference was not significant. The average collar diameter of Q. brantii in control area was significantly less than those in burned one, however the total height in control region was more than burned region. Also the significant variations were observed in terms of seedling age and height in control and burned plots, however the number of observed regenerations in plot showed no significant differences.

Drought stress is one of the most important factors reducing the plant growth and yield. Due to the complexity of factors affecting the drought tolerance or resistance in plants and access to relevant mechanisms, researchers are faced with challenges. Studying the root development can be considered as an important indicator in this regard. On the basis of this study how the development of two species of Eucalyptus roots under drought conditions and at different depths in lysimetric conditions were taken into account. Drought stress was applied in three irrigation levels, including: 100% field capacity (control), 70% field capacity (moderate stress) and 40% field capacity (sever stress) in three replicates. Effects of drought stress on root weight development were studied in six deeps, including: 0-20, 20-40, 40-60, 60-80, 80-100 and 100-120 cm. The results showed that increasing drought stress reduced the roots development in both species significantly. E. micortheca produced more roots than E. sargentii in varying levels of drought stress. The roots of E. microtheca had more deep penetration than E. sargentii in all drought stress treatments. Due to the reasons mentioned, E. microtheca is more resistant to drought stress than E. sargentii.