مجله جنگل ایران
سال هشتم شماره 1 (بهار 1395)

The purpose of this study was to compare the amount of dust deposited on the leaves surface of Fraxinus rotundifolia, Platanus orientalis, and Robinia pseudoacacia in urban areas of Kermanshah Province, west of Iran. Kermanshah, Ravansar, and Paveh regions with different climatic features were selected for sampling. Leaf samples were randomly collected from different heights of individual trees in four main directions and washed and dust particles of the solution were dried in an oven and weighed. The leaf area was measured by Image J software. The results indicated that the amount of dust per unit leaf area of P.orientalis (0.10 mg.cm-2) was significantly different with those of F.rotundifolia (0.045 mg.cm-2) and R.pseudoacacia (0.04 mg.cm-2) (F=66.703). Significant difference was observed between the amount of deposited dusts in Paveh (0.087 mg.cm-2) (F=16.624) and those of the other sites (Kermanshah: 0.041 mg.cm-2and Ravansar 0.053 mg.cm-2). The results of this study will open up an avenue for identifying suitable trees for dust filtration in the west of Iran. Biological activities are underlyingstrategies against dust storms. The leaves, because of the larger surface in comparison with other parts of plant organs, are considered important for atmospheric dust filtration.

The aim of this research was to study the effects of seed origin on morphology, survival and growth of Persian oak (Quercus brantii). For this purpose, acorns were collected form three habitats, Chehlzarei, Choghasabz and Lamerah, which are located in Zagros forests of Ilam province. Morphological characteristics of acorns including size, diameter and weight were measured and compared. In order to determine the effects of seed origin on seed survival and seedling growth, acorns from three origins (seed sources) as treatments were planted as completely randomized design with four replicates and 30 pots in each replicate in Eivan nursery. During the first season of growth germination of seed, survival, collar diameter, vigor index, height growth of seedling, root and shoot lengths, and their dry mass ratio were measured. Results demonstrated that seeds source significantly affected morphological characteristics of acorns, seeds survival and seedlings growth (p

In order to break dormancy and germinate the seeds of Caucasian maple, they were collected from altitude of 1900 m of Googli Forest located in Savadkooh (north of Iran). Following pre-treatment of warm stratification (0, 4, 8, 12 weeks with 20°C), the seeds were soaked for 24 hours in two separate examinations 1) GA3 (0, 250, 500, 1000 mg/lit) and 2) H2O2 (0, 1, 2, 3%) and immediately moved into cold stratification environment (4°C, for 41 weeks, with consideration of warm stratification period). Both examinations were carried out as factorial with three replicates based on completely randomized design. Water absorption test revealed that in spite of the hard coat, the seeds were permeable to water. Results emphasized the positive effects of warm pretreatment on germination characters, whereas seed germination increased from 13 to 76% and germination speed from 1.4 to 3.8 unit/week. However, the lag time decreased from 20 to 13 weeks and germination period of 50 percent of seeds (T50)from 10 to 6 weeks. Influence of GA3 and H2O2 increased with increase of concentration as well as warm stratification period, whereas GA3 in 500 and 1000 mg/lit was 64% and H2O2 in 2 and 3% was 56 and 73%, respectively. With increasing warm pre-treatment period, the general trend of germination speed enhanced in all concentrations of both promoters. Generally, stratification (warm-cold) without using the promoters mentioned here is easier and more economic for dormancy breaking of Caucasian maple seed.

According to the few basic and applied research related to the structure characteristics of Juniper (Juniperus excelsa)stands in the Irano-Turanian forests and the need for early recognition and proper management of these forests, the present study was carried out to evaluate the structural characteristics of J. excelsa forests located on south facing slope of Alborz mountain chain, Atashgah area, Karaj. For this purpose, systematic network with dimensions of 50×50 m was laid out and coordinates of all trees were determined by distance-azimuth techniques. Canopy diameter was measured in an area about 15.9 hectare in this stand. In order to study the structural characteristics of the stand, nearest neighbors distance index (density of trees), Clark and Evans index and uniform angle index (a variety of location), Mingling index (species diversity), size differentiation index (variety of trees), crown competition factor (competition of canopy trees) between J. excelsa and S index were used in this stand. The results showed that spatial pattern and arrangement of trees were regularly together and variety of trees, was found to be pure without any mixture. The crown competition index was 0.48 (non-unit) representing low crown competition in this stand. Three different aspects of the S index (diversity of spatial pattern, species diversity, and size variety) were 0.227 indicating low levels of tree diversity. The results of this study can be usefully employed for management, preservation, restoration, and development of sensitive and fragile J. excelsa forest ecosystems.

In order to increase wood production, selection of suitable tree spacing and cultivation of different crops between tree rows, especially at early years would increase productivity and poplar cultivation area. In the study Populus alba seedlings were planted in a randomized complete block design with three replicates and fourth mixed poplar and alfalfa treatments with tree spacings including 3×4, 3×6.66, 3×8, and 3×10 m also two control treatments. We investigated some important attributes during 2009-2013. Tree diameter and dry weight were measured. The data were analyzed using combined analysis of variance. Results showed that there were not significant differences between treatments in average of height growth. First and second years revealed most amount of height growth. Of course for diameter growth, first and fourth years revealed best results. Mixed 3×4 treatment showed highest wood volume growth. Also the most amount of dry weight production of alfalfa belonged to pure alfalfa and 3×10 treatments. All of the attribute amounts revealed differences among treatments were significantly different at 5% level of probability. For the some attributes there were significant differences among years and interaction between treatments and years. As a final result until this stage the suitable planting spacing of tree in Poplar/alfalfa intercropping system in Azarbayjan province is 3×8 m according to the site conditions.

Recently, forest decline has outburst in Zagros forests, west of Iran. Consequently, we aimed considering dried trees and their spatial patterns as well as spatial structure at Bioreh forests in Ilam province, west of Iran. For this purpose, we selected and fully inventoried a 96 ha infected forest. The interested attributes were tree species, diameter at breast height (DBH), crown diameter, origin and number of sprout in coppice trees as well as Cartesian coordinates of dried trees with drying intensity more than 50 percent. For spatial point pattern analysis and spatial structure of interested attributes, O- ring statistics and variogram analysis were used, respectively. Results showed that the density of dried trees was 10 N/ha which more comprised of coppice trees, while high frequency percentage of drying was observed in large diameter classes. The spatial pattern of dried trees was determined as cluster up to 15 m, which implied that dried trees created patches with 4500 m2 surface area. No spatial structure were found for three interested attributes (DBH, crown diameter and number of sprout) which implied that there was no similarity among infected trees. These results can be used as an instruction to manage infected stands based on their spatial characteristics.

Today, a lot of information about the negative effects of cement kiln particle on vegetation exists, but so far the impact of this pollutant on species are poorly investigated. Ziziphus spina-christi L. is present in a wide range of semi-arid areas and has high ecological value and widespread use in folkloric medicine. In this study, the effect of particle depot of Behbahan cement factory on morphological and physiological characteristics of Christ's thorn jujube trees at 0.5, 2, 5 and 7 kilometers northwest of the factory during growing season was evaluated. The results showed that with decreasing distance from the factory from five km the amount of particle depot on the leaves was significantly increased and the amount of leaf area reduced but no changes in leaf dry weight was observed. The frequency of stomata diminished due to cement particle depot in both sides, but this change in adaxial surface was greater than abaxial surface. Content of leaves chlorophyll a and carotenoids also decreased, but there was no significant change in the content of chlorophyll b. Leaf initiation rate of the trees also was not affected by cement depot. The longitudinal growth of the branches of the plant facing to the factory decreased from five km of factory. The results showed that Behbahan cement factoy with current production rate (one million tons of cement per year) causes limitations in photosynthesis and activities of the shoot apical meristem in the trees.

Forests have been threatened by exceed domestic animals in forests. Some plans like the plan of exiting animals from forest and reintegration forest dwellers are implemented to reduce pressure on the forests of northern Iran. But the question can be proposed of how the acceptance of the project among forest dwellers is and what factors affect it. The aim of this research was to examine the relationships between demographic characteristics, socio-economic and psychological factors of forest dwellers and accepting the plan of exiting animals from forests and reintegration of forest dwellers. Using descriptive research and survey technique, 100 forest dwellers were studied randomly in Nekachub forestry plan area of Mazandaran province. Data was collected through questionnaire which its validity and reliability were confirmed by a pilot study. Results of comparing two groups of adopters and non-adopters of the plan revealed that adopters group has less crowded households, less cattle and calves, less income from husbandry, less garden, more income from agriculture and non-husbandry sources, more trip to nearest town each month, more participation in training and extension classes about exiting animals from forests and reintegration forest dwellers. Logistic regression analysis showed that five demographic factors, i.e the number of loans for livestock, the number of trip to nearest town each month, consultation of government departments with forest duelers before the implementation of the plan, respondent’s attitude toward risk and the degree of livelihood vulnerability of the plan are the main effective and predictive factors for the adoption of exiting animals from forests and reintegration forest dwellers plan.

In the current research, the performance of ordinary least square regression model was studied for the task of predicting a key forest structural parameter – tree height – across a study area in Tarbiat Modares University forest research station using a series of edaphic and topographic variables. For this purpose, 123 0.1 ha circular sample plots were established and total height and diameter of Fagus orientalis Lipsky trees with DBH ≥ 7.5 cm within each plot was recorded along with elevation, azimuth and slope of the ground. Also, at the center and four geographical aspects of sample plot, soil samples from first layer (0-10 cm) were taken and mixed for analyzing several soil variables. The results showed the OLS model performed moderately well based on R-squared, but exhibited clear signs of spatial autocorrelation (Moran’s I =0.168). Adding spatial weighted matrix in spatial simultaneous autoregressive models resulted in removing autocorrelation and statistically significant improvement in model fit. Comparison of spatial lag and error SAR models using AIC, log-likelihood and R squared indicated that error SAR model performs better than lag SAR model. These analyses underscore the importance of controlling for spatial autocorrelation in forest ecology studies and furnish guidelines for future modeling of species performance in relation to environmental predictors.

Pistacia khinjuk, from Anacardiaceae family, is one of the important forest species.In order to break the seed dormancy and increase the germination percentage and rate, and early growth of Pistacia khinjuk seedlings, factorial experiment was conducted as completely randomized design in three replicates with Four factors including: scarification with two levels (control and sulphuric acid (H2SO4) 98% for 10 minutes), stratification with three levels (control, moist chilling in °C and dry chilling in -20°C), potassium nitrate (KNO3) with three levels (0, 1% and 2%) and gibberellic acid (GA3) with two levels (0 and 200 ppm) were studied. Evaluation of germination indices and seedling early growth showed that simultaneous effects of three treatments, i.e. scarification seeds with H2SO4 98%, moist chilling and GA3 200 ppm, had the maximum effects on breaking seeds dormancy and increasing the seed germination percentage and rate and also seedling early growth.