Iranian journal of Forest
Year:2013 | Volume:5 | Issue:2|Papers Count:15

Since tree stems are not cylindrical completely, an index called form factor is needed for estimating the real tree volume. The form factor is third effective component in determining the tree volume after diameter and high. The goal of the present study is to investigate the effects of tree growth stages and site components such as aspects and slope on form factors of Beech (Fagus Orientalis Lipsky). This study was carried out in the Shafaroud forests. In total 411 trees were sampled. These trees were sampled in 4 aspects (north, north- east, north -west and east) and also in the four slope class (<30, 30-45, 45-60 and > 60) with four growth stages. Normality and homogenity of variance were done using Kolmogorov-Smirnov and Levene tests, respectively. Mean comparisons were performed using Duncan test for homogeneous variance and Dunnett for heterogeneous variance in 5 and 1 percent levels. Results showed that there is a significant difference between various form factors of tree. Dunnett test showed that there is no difference between real form factor of stem (0.5474) and Hohenadl (0.5446). Form factor values increased on north aspects.

Although the ecological study of lichens in the temperate forests have a long history ، but it is new scientific research and studies in Iran, especially little study has been made in Caspian forests about the diversity of lichen species. This study aims at examining and identifying the curticolus lichens in the south forests of Nowshahr in Quercus - Carpinus type. The sampling frame (60 × 40 cm) was placed at breast height of five tree species including Quercus macranthera, Carpinus orintalis, Acer campester, Acer hyrcanum and Acer campestar. A total of 300 quart of lichens was recorded, then using the diversity indices such as richness, evenness and diversitywere calculated for each tree species in this forest type. Duncan's test showed that Quercus macranthera had significantly higher diversity index than the other species. This stems from the suitable ecological and morphological conditions of Quercus macranthera bark in the establishment of curticulos lichens.

This research investigates the carbon sequestration potential for Pistachio atlantica Desf in Firuzabad Pistacia and amygdalus forest research in Fars province. Using Random-systematic inventory for determining the number of trees in 5-cm diameter classes, 3 trees were selected in each diameter class, they were cut and trunk, branches, leaves and litter were weighted separately. Samples were transferred to laboratory. Organic carbon and its conversion ratio were measured. In order to estimate the organic carbon storage in soil, samples were randomly taken in aspects and flat terrains. Their contents were compared with control samples. The results showed that carbon sequestration potential for Pistasia atlantica Desf is 1.99 tons per hectare and 18654.3 tons in total. Soil carbon storage is 12.78 tons per hectare. Duncan test showed that there is a significant difference among the tree components (p<0.01). The highest and lowest Sequestration belongs to the trunk and leaves, respectively. Leaves and litters have the lowest and highest conversion ratio organic carbon, respectively. These results show that by increasing the density and conserving these forests, much carbon Sequestration can be done by Pistasia atlantica Desf due to their vast distribution.

Pollution can be defined as an undesirable change in physiochemical and biological properties of air, water, or land that can damage human or living organism’s health, survival and activities. The pollution induced by heavy metals due to their stability in environment is important. The purpose of this research was to investigate the phytoremediation ability of Nickel uptake for three species including, ash (Fraxinus rotundifolia), willow (Salix alba), and elm (Ulmus densa) around Kermanshah refinery in 2011. Sampling was performed in two locations during growing season in three times, at beginning (May), middle (August), and end (October) of season. Shahed Park which is near the refinery was selected as polluted location and Farabi Hospital far from refinery as control location were selected. ICP method was used to measure nickel content after extraction. Results showed that distance from pollution source and wind direction had not significant effects on nickel dispersion in study locations. Also there was more nickel content in leaves of willow in sampling locations at the beginning of growing season. In addition, the results indicated that the rate of nickel accumulation in ash and elm had upward trend in growing season.

The main object of this research was to distinguish the types and amount of utilizations of the wood and non-wood forest products in three villages including Vezvar, Evard and Aghooz-darreh in the Hezarjerib, Behshahr, Mazindaran province. In this research, statistical society was the head of families of rural people in the studied villages. To collect data, 150 questionnaires were filled out and completed by asking questions from sample people directly. The reliability of questionnaires was obtained with the opinions of experts and examined by using a Cronbach coefficient (0.63). The results showed that the total utilization of forest resources was in an average amount according to people’s answers. The results of multivariate regression indicated that local people living in the studied villages are using the forest wood products for constructions and also as fire woods (%76.6). Rural societies are also harvesting a considerable amount of non-wood forest products as food materials, feeding animals and medicine consumptions. On the basis of the research findings, some suggestions were presented to improve economic situation of the region and also to promote the correct harvesting of forest products toward sustaining natural resources. The most important one is to change life style of rural people in the region.

The current study was done in Patom, Namkhaneh, Gorazbon, Chelir and Baharbon districts in Kheyrud forest. A stratified sampling method based on landform was used to locate 190 0.1 ha circular sample plots in beech dominated forests. The number of Fagus orientalis Lipsky trees with DBH ≥ 7.5 cm within each plot was recorded along with elevation and slope of the ground. Also, at the center of plot, soil samples from first layer were taken for analyzing soil texture, bulk density and saturation moisture. In order to study the shape of response curve and extract the ecological optimum and amplitude in relation to the mentioned variables, beta function was used in the context of generalized linear model (GLM) with poison distribution and logarithmic link function. Gaussian Function were also applied to the data and its performance was compared to Beta Function using Deviance Test and the shape of response whether it is unimodal and symmetric or skewed. Beta function showed the response of beech to altitude is left-skewed, meaning it avoids lower elevations. This species has 1420 and 300-2150 m a.s.l for its optimum and ecological amplitude, respectively. Beech tree can distribute from gentle to steep slopes in the study area. The behavior of beech to slope is symmetric and unimodal attaining its optimum at 40% slope. Using beta function indicated that Fagus have amplitude of 0 to 80% regarding to slope percentage. In light of sand, clay and silt, Beech tree has 25, 43 and 35 % for optimum and 1-48 % for sand, 20-58% for clay and 17-55 % for silt for ecological amplitude, respectively. Using beta function showed the response of Fagus to sand and silt is unimodal and symmetric, but for clay it shows left-skewed shape. It implies that Fagus avoids soils containing low clay contents. The optimum and tolerance of saturation moisture for Fagus have been determined 50 and 17-55%, respectively. Fagus showed right-skewed response to bulk density. It gets its optimum at 1.6 g/cm3 and it can distribute from 1.3 to 2.7 g/cm3. Gaussian function always gives symmetric and bell-shaped species responses whereas the beta function has the advantage of describing either very skewed unimodal responses, or symmetric responses. It can also detect some types of bimodal. The results of this study showed although there is not much difference between Gaussian and beta functions based on deviance explained, but beta function could detect skewed response curve well, compared to Gaussian function. Beech tree has not always showed symmetric responses to the selected variables and the hypothesis implying Beech tree has unimodal and symmetric response to environmental variables can be rejected.

In order to determine the most suitable spacing of ash, (Fraxinus excelsior L.), the effect of three levels of planting spaces ( 1.5×1.5, 2×2 and 2.5×2.5 meters) on quantitative and qualitative characteristics of ash were examined. Statistical design used was random completely block design with three replicates. The site is located in north- west aspect, 250 m a.s.l and 5 percent slope in south of Sari in Mazandaran province. After termination of ten years period, survival, height, diameters and some quality traits of trees were measured and recorded. The results showed that the effect of planting space on tree survival (p<0.05), tree collar diameter and diameter at breast height and volume per hectare (p<0.01) were significant. But the difference between treatments was not significant in tree height. The lowest percentage of survival was related to spacing of 1.5×1.5 meters interval of trees and there was no significant difference between two other treatments. Mean diameters of trees were 2.75, 3.56 and 3.81 centimeters and related to 1.5×1.5, 2×2 and 2.5×2.5 meters spacing of treatment, respectively. The mean volume per hectares increased with decreasing of planting space. The effect of planting space on h/d was significant (p<0.01). But the percentage of forking was not significantly affected by planting space. Maximum rate of h/d and minimum percentage of forking were seen in space of 1.5×1.5 meters.

Natural regeneration of Popolus caspica has serious problem in Caspian region of Iran. In this research, characteristics of P. caspica’s saplings were evaluated using hormone and different diameter of cutting treatments. Annual cutting ranging from 18 to 20 centimeters in three diameter classes (5, 10, 15 millimeters) were used. Also (IBA) Hormone has been prepared in 5 volumes (Control, 1250, 2500, 5000 and 7500 ppm). This study was carried as randomized completely blokes design in Shalman station, Guilan, north of Iran. Results showed that 10 millimeter cutting is the best one for asexual reproduction of Popolus caspica Bornm. Using up to 2500 ppm Indole Butyric Acid volume is appropriate only for 5 diameter cutting. Other sizes of cuttings or hormone volumes are not appropriate.

In order to analyze the quantity of Juniperus stands spatially and statistically and their relationships to topographic and edaphic features, an area of 4700 ha was selected in the Chahar-Bagh region at the Gorgan. The maps of slope, aspect, elevation and geology in GIS environment were overlaid to generate homogenous landform units. In each unit, some 0.1 ha sample plots were randomly selected in GIS environment. 149 sample plots were established in the field. Within each sample plot, diameter at breast height, number of trees, canopy cover and height of trees were recorded. Analysis of variance (ANOVA) and Duncan comparative analysis were used to compare the properties among landform unites. The results showed that landform units were different significantly in terms of number of trees per hectare, canopy cover percentage, mean diameter of basal area and basal area at breast height. Results of nonlinear regression model showed that aspect and wetness index were the best predictors for the number of trees per hectare (R2adj= 0.57). Also a nonlinear component of aspect, stone and wetness index were the best predictors for modeling the canopy cover (R2adj=0.49). In addition, a nonlinear component of variables containing aspect, stone, wetness index and stream power was the best model for basal area at breast height prediction (R2adj= 0.56). A nonlinear component of variables including the aspect, stone, stream power and wetness index were also the best predictors to model the diameter of basal area at breast height (R2adj= 0.50).

To investigation inter- and intra- population genetic diversity, three natural populations of Buxus hyrcana (Pojark.) in north of Iran (viz. Chashmeh Bolbol in Bandar Gaz, Sisangan in Nowshahr and Gharnabad in Gorgan) were investigated using RAPD markers. Results showed that there was a relatively desirable genetic variation among populations, ranging from 22.9% in Gharnabad`s poppulation (Gorgan) to 28.3% in Siasngan’s population (Nowshahr); Contribution of intra-population gene diversity in overall genetic diversity was estimated higher than inter-population gene diversity (90% vs. 10%). Also Investigation of Nei's genetic similarity coefficient showed that three studied populations had a high genetic similarity (between 92.9 to 96.2%). Least and highest genetic distances (3.9% and 7.4%, respectively) were observed between Bandar Gaz's and Nowshahr's populations, and between Gorgan's and Nowshahr's populations, that was confirmed by UPGMA-based cluster analysis. Investigation of Hardy-Winberg genetic equilibrium of populations showed that there were equilibrium at most loci, although there wasn't allelic equilibrium at some loci in some or all populations; highest genetic disequilibrium was observed for Gorgan’s population, probably due to decreasing genetic resources, It suggests that this habitat must be added to the list of Buxus hyrcana reservers. Altogether, on the basis of results of this research, it could be concluded that RAPD markers are efficient and reliable markers for studying the population genetic of Buxus hyrcana species in forests of North of Iran.