باریس مجنونیان

Tourism development by planning the principles of access roads can help the management and development of villages in natural and protected areas. This study aimed at planning and developing the access roads to achieve the tourism and rural areas as the recreational attractions in Arasbaran protected area. For this purpose, the road network options were designed for three different scenarios to access the recreational and rural areas in GIS environment and evaluated in terms of technical, environmental and socio-economic aspects. In the next stage, the existing road network was modified according to the optimal-designed road options. Finally, the modified versions of the existing road network were proposed for tourism development and management in the region. Thus, the variants of the existing road network, the optimal-designed road network and the modified-road network were evaluated and compared. Moreover, among the designed options, the 10th option in three different scenarios to access the recreational areas and the minimum, medium, and maximum villages with densities of 4.17, 4.93, and 5.86 mha-1, respectively, was chosen as the optimal option to modify the existing road network. Finally, the modified road networks with densities of 3.98, 4.66, and 5.55 mha-1 and accessibilities of 72.7, 76.19, and 78.33 percent were proposed for these three scenarios. According to assessment and comparison of the variants, the optimal-designed road networks and the modified road networks were identified as the better alternatives compared to the existing road network. Tourism management and development in Arasbaran by principled planning and development of access roads can lead to prosperity of economic activities and improve the rural development in this area.

Recreational use of the area must be performed conforms to its ecological capability. Therefore, this study was carried out with the aim of providing a method for modelling and ranking the areas with ecotourism capability. For this purpose, Makhdoum systemic method, regarding to the region specifications, and multi-layer perceptron artificial neural network (MLP) were used to evaluate the ecological capability of Arasbaran protected area. At first, ecological and socio-economic resources were identified and maps of them were provided. Then, ecotourism capability map was prepared by analyzing and overlaying of data in ArcGIS. In the next step, using the results of the systemic method, neural network was trained and its various structures were evaluated. Finally, map of the suitable tourism areas was modeled based on neural network output. In the end, using the socio-economic criteria and recreational attractions, prioritize and final evaluation was performed. Regarding to the systemic analysis, the area has the capability for intensive recreation class-2 (0.06%), and extensive recreation class-2 (10.33%). Topology 7-9-3 was selected as the best classifier with an overall accuracy of 98% for recreational regions classification. The best and the lowest of neural network application were shown to belong to intensive recreation class, and extensive recreation class, respectively. Based on modeled map, 0.17%, 10.09%, and 89.74% of the area were shown to belong to intensive recreation-class 2, extensive recreation-class 2, and unsuitable for recreation, respectively. This study showed artificial neural network has potential for classification of the suitable tourism areas with high accuracy.

The road network is an important element for sustainable forest ecosystem management. On the other hand, efficiency and quality of road design can be improved by considering of environmental and technical principles. Therefore, this study was performed to determine the capability of Arasbaran protected area for road passing and communication routes in order to use in the area management. For this purpose, criteria of the slope, aspect, height, soil texture, lithology, erosion susceptibility, vegetation density, distance to stream, and distance to existing road as the effective criteria for road design were identified by literature review, and their prepared maps were standardized with the fuzzy logic method. Then, the criteria were weighted using of analytical hierarchy process (AHP) and finally were combined to prepare suitability map for road planning by weighted linear combination (WLC) method. According to results, the highest weight (0.289) and the lowest weight (0.033) were belonged to slope and height criterion, respectively. Finally, the area was classified into four classes with the capability of low, medium, high and very high for road network passing, that region with medium passing capability has the highest percent (49.83%). The study proved GIS and AHP capabilities considering to economic and environmental problems for developing the road capability map in order to use for road locating in Arasbaran area.

Felling operations in poplar plantations in Iran usually is performed with a chainsaw and by cutting workers. In connection with such dynamic work with repetitive work components, it is necessary to pay attention to the possible pressure on the musculoskeletal system of the workers, the evaluation of the work posture, and the calculation of risk index. To achieve the goals of the study, the Nordic questionnaire was used to study musculoskeletal problems in 9 felling workers in a poplar plantation in the Shanderman region of Guilan province. In the next stage images related to the evaluation of workers' postures during a 4-hour felling operation recorded by a video camera analyzed. The postural evaluation was performed by The Ovako Working Posture Analysing System (OWAS) method. In this study, 55 postures related to tree felling operations were obtained. The most discomfort of workers was related to the waist. The postural risk associated with felling operation was relatively high (I=251). Postural assessment of different felling work tasks indicated that the highest risk was incurred during back-cut (I=313), under-cut (I=303), delimbing (I=295), and bucking (I=281) respectively. 56.41 percent of categories need further assessment necessary soon and now. Back bent forward or backward, standing position and both knees bent, both hands below shoulder height and, force/load 10-20 kg (code:2142) were the most important ergonomic problem in logging operations. These findings indicate the need to provide training solutions among felling workers. In this regard, appropriate training techniques and methods of tree felling and work safety are recommended.

Among the various components of vegetation, root system plays an important role in stabilizing, soil reinforcement and preventing erosion. This study aimed to investigate the effect of oak decline phenomenon on root mechanical characteristics of Brant`s oak (Quercus brantii Lindl.) in Dinarkuh forests, Ilam province. Considering DBH distribution of the trees in the study site, five trees were randomly selected in small DBH (15 to 35 cm) and large DBH (35 to 55 cm) classes within three treatments of healthy, moderate decline, and severe decline. Root samples were collected from each tree by digging near the tree and then tensile test were performed in the laboratory. The results showed that the root diameter-force strength relation was positive power-law and the root diameter-tensile strength relationship was negative power-law. Results of the covariance analysis for tensile force and strength showed that there is no significant difference between tensile force and strength among treatments of small DBH class, while in large DBH class, root tensile force and strength of healthy trees were significantly higher than trees with severe decline. Based on the decline, tensile force of the trees in the treatment of severe decline compared to the healthy trees, so force decreased by 11.3% in the small DBH and 22.7% in the large DBH classes. Also, these values ​​for tensile strength showed a decrease of 13.4% and 19.7%, respectively. The findings of this study show how the effect of forest decline on the root tensile force and strength values ​​leads to a better knowledge of the controlling soil erosion in the Zagros ecosystems.

The role of forest engineering is crucial for restoring and reclaiming of skid trails, one of these being to reduce sediment yields along the trails. This study aimed to measure sediment yield in the skid trails covered by different organic mulches and to compare it with an untreated trail and control plot (i.e., undisturbed forest). This research was conducted for 13 months (from September 2017 to October 2018) in the Namkhaneh district, Kheiroud forest, Nowshahr under the natural rainfall condition. Six-square-meter plots were used in three replications to determine the amount of sediment. Three natural mulch treatments were used in this study, including sawdust, leaf litter, and straw, and there were mulched at three different rates (based on material weight). The highest and lowest amount of sediment was obtained in the untreated skid trail and undisturbed forest, respectively. Our results demonstrated that the application of sawdust, straw, and leaf litter mulches reduced the sediment yield by 13.1, 10.2, and 7.3 times compared to the untreated trail, respectively. Overall, it can be concluded that the application of mulches, especially sawdust, has a significant impact on sediment reduction.

The aim of the study was to provide an intelligent artificial neural networks-based method for modeling the capability of Arasbaran protected area for road crossing, in order to design, modify, and appropriate development of existing road network and communication routs in the region. First, using Analytical Hierarchy Process (AHP) and Weighted Linear Combination (WLC) method, and utilization the effective informative layers on routing, the suitability map of road construction was prepared to provide training samples in ArcGIS. In the following, Multilayer Perceptron (MLP) network was used to estimate the suitability value of road crossing. In order to evaluate the neural network’s model performance, the results were compared with the results of multivariate linear regression. According to the results, artificial neural network and statistical method of regression were shown to be useful in determining the suitability value of road crossing with coefficient of determination (R2) 0.908 and 0.901, root mean squared error (RMSE) 0.0385 and 0.04, respectively. Neural network results were relatively better than regression. Also, according to the results of sensitivity analysis of input variables, four criteria of slope, bedrock, erosion susceptibility, and soil texture showed the highest influence in estimating the model, respectively.

Knowledge of soil chemical properties is important for understanding its engineering characteristics in road construction. Reflectance spectrometry is a non-destructive, fast and environment friendly method, but unfortunately no research has been conducted to use this tool to estimate the forest soil characteristics in Iran. The present study was conducted to investigate the ability of VNIR spectrometry to estimate some chemical properties including organic matter, CaCO3, pH and EC in the forest soil. For this purpose, 45 soil samples were collected from Namkhaneh series in Kheyroud Forest and those properties were measured by standard methods. The reflectance of sample was measured in dark room using Fieldspec ASD spectroradiometer. PLSR (Partial Least Squares Regression) method was used to predict soil properties in reflectance and first derivative mode. The results of RPD shows that OM has a very good estimate in two modes of reflectance spectra and derivative reflectance spectra (PRD>2) and pH, EC have acceptable estimate (1.42), but CaCO3 has poor prediction in two modes of reflectance spectra and derivative reflectance spectra (PRD<1.4). In general, based on the results of this study, spectrometry can be used to predict the above-mentioned properties except CaCO3 as a fast and an acceptable method and this method can simultaneously estimate several soil properties.

Forest machinery traffic on forests causes significant changes in increasing the bulk density, reducing porosity, ventilation and reducing water infiltration rate which resulted in an increasing surface runoff. According to the results of previous studies on the effect of mulch on reducing runoff in laboratory conditions, The aim of the present study was to determine and compare the amount of runoff produced in untreated skid trail, undisturbed forest (control area), and the skid trail plots covered by sawdust, under natural conditions in Namkhaneh District, Kheyrud Forest to find useful strategies to reduce the effects of forest utilization in order to maintain the function of forest water protection and reduce runoff. In this study, the runoff plots (6 m2) were triplicate established and runoff collected by pipes in the outlet plots were measured based on natural rainfall conditions. The results revealed that applying sawdust mulch to the skid trail decreased runoff compared to the untreated skid trail, and the runoff amount in undisturbed forest, untreated skid trail and sawdust mulch treatments were 0.40, 1.44 and 0.71 mm, respectively. The highest and the lowest amount of runoff were found for untreated skid trail and undisturbed forest treatments, respectively. Also, by application of sawdust mulch, the amount of runoff produced reduced by 48.4%, while the amount of runoff before the use of mulch in skid trail was 72.2% higher than the intact forest. Also, the runoff produced in skid trail control treatment was 51.1% higher compared to sawdust treatment.

The Landslide is one of the natural hazards that causes a lot of mortal and financial losses in high-altitude and seismic mountainous areas annually. Considering the importance of roads as a pillar of sustainable forest management in this study, we have tried to estimate the sensitivity of landslide occurrence in 8 forestry series with using frequency ratio approach. Initially, the slip position in the series occurred with ground scrolling by GPS, then the effective factors in the occurrence of landslides were determined for the study area. Raster maps of the effective factors were prepared and classified. Considering the distribution of landslides recorded in the field and the categories of effective factors, the frequency ratio for each class of each factor was calculated and their relationship with the occurrence of landslide was investigated. The results of the relationship between positioning and slipping showed that the highest amount of landslides occurred on the lower side of the road, and by increasing the age of the roads, the amount of landslides is reduced. The relationship between soil and slip occurred on the class with the code 2.2.3, which represents the soil texture of loamy, loamy clay and clay that the highest number of slides was observed. Elevation class 300 to 600 meter has the highest number of landslides. The relationship between the slope and slip showed that with increasing the slope up to 40%, the number of landslides was increased, but then the trend was decreasing. The relationship between geological and landslide showed that the highest number of landslides was observed in the class with L-PLL2 ​​code representing relatively high peaks with moderate slope, average soil depth, stability and permeability. The relationship between rainfall and landslide factors showed that the greatest slip is occurring between 600 and 800 mm. In the northern, northeastern and northwest directions, the highest slip occurred. The evaluation results of the model with the ROC method indicated that the area under curve (AUC) was 0.688 (68.8%).

Generally in developing countries such as Iran, the studies in soil mechanics are rarely done or even not conducted due to high cost and time of research and conventional laboratory methods, so the lack of information in this field can damage the construction. Today new approaches such as field spectroscopy are being developed in order to dissolve many of these issues, which is a
non-destructive, fast and inexpensive method. Spectrometry is a non-destructive, fast and inexpensive method that has not been applied in estimation of mechanical properties of forest soils in Iran yet. In this study, we estimated the Atterberg limits of soil (Liquid limit, Plastic limit, Plasticity index, and Shrinkage limit) by field spectroscopy. For this purpose, 45 soil samples were collected from Kheyrood forest (NAMKHANE district) to do Atterberg Limits and VNIR. Partial Least Square Regression (PLSR) was used to predict the Atterberg limits in both the raw spectra and the first derivative of the spectrum. The results showed that PLSR modeling for the parameters of Liquid Limit and Plasticity Limit in the raw and first derivative is very suitable and for Plastic Limit and Shrinkage Limit is weak and not acceptable. Therefore spectroscopy can be used as a fast, inexpensively and accurately acceptable method for predicting the Atterberg limits.

Land cover is also important factor for protecting the soil against erosion. A fully forested watershed experiences relatively little surface erosion, but timber harvest alters the canopy cover, exposing the soil to water and wind. Forests provide the maximum amount of soil protection. Reduction of vegetative cover by forest harvesting generally increases the average surface runoff volume and sediment While, the hydrologic response of forest harvesting has been rarely considered. Towards this attempt, the present study has been conducted to investigate the effect of vegetation cover on hydrological components in plot scale (2m*1m) with four replicates in tow slope scale (0-20%, 20-40%) in Kheyrud Forest of Iran during December 2014 until December 2015. The rain depth was measured by using a rain gauge installed in the study area. The runoff volume and sediment yield were also measured through field data collection and lab analyses by weighting and decantation methods. The results of the study showed significant effects of vegetation cover (P ≤0.01) on runoff volume and sediment yield. Natural forest without harvesting, forest with selective harvesting treatments exhibited the lowest amounts of runoff and sediments, with averages of 372.31, 878.96 cc, and 0.08, 0.17 gr m-2 respectively, in comparison to other treatments. Linear regression among mentioned parameters (precipitation, runoff, and sediment) were determined. The results show that there were significant correlation and linear regression among precipitation, runoff and sediment.

e aim of this study was to assess spatial distribution of roots by Carpinus betulus trees in Patom district of Kheyrud forest. For this purpose, five trees at small, medium and large diameter classes were selected randomly (totally 15 trees). In order to measure root area ratio (RAR), three soil profiles were dug at both up and down sides of trees (size 50×100 cm) by wall trench method at the horizontal distance of 1, 2, and 3.5 m from tree stem (totally 90 profiles). 10 cm horizons were identified on wall trenches and all of the root diameters were measured. Finally, RAR was calculated for each soil horizon. The RAR was decreased logarithmically by increasing the soil depth. The results of ANCOVA showed significant difference between roots distribution at small, medium and large classes. The results of t-test showed that the value of the index at first, second and third trenches wall of small class at upside significantly more than down side. At medium diameter class only third trench of upside significantly more than down side. At large diameter class, first trench of upside was significantly greater than first trench of down side. The results of this study increase our information about vegetation role in stabilizing slopes and will improve the modeling of slope stability accordance to the DBH classes.

Today, skeletal musculoskeletal disorders are one of the most important occupational health issues and have a high prevalence in almost all occupations, and preventing it involves evaluating and modifying working conditions. This study aims at assessing the risk factors of musculoskeletal disorders of work by QEC in forestry workers of two regions of Guilan and Mazandaran forests. In this study, statistical population included 51 workers in three jobs of felling and bucking, skidder driver, and manual loading worker were studied by census method. The Nordic questionnaire and QEC method were used for determining the prevalence of musculoskeletal symptoms and assessing the risk of these disorders, respectively. The results showed that the highest prevalence of musculoskeletal disorders was in the waist, neck and back segments, respectively. The significant relationship between weight, body mass index, work experience and smoking with musculoskeletal disorders was observed. Results of QEC evaluation showed that the 72.6 percent of worker are in risk level of 4, while these values for risk level 1, 2, and 3 were 7.8, 9.8, and 9.8, respectively. In vibration exposure, speed of operation and stress about 64.7, 62.7, and 70.6 percent of worker were in high and very high levels. The results indicate a high prevalence of disorder among workers. The main ergonomic problems in study area include inappropriate physical condition, bending and twisting of the waist, lifting and carrying heavy loads, vibration, speed during work and stress.

CEC is the most important soil engineering properties used to determine the swelling potential of soil. Measuring CEC of soil is difficult, time-consuming, costly and consuming of dangerous chemical materials. In this study the ability of spectral reflectance to estimate the amount of CEC were investigated. So 45 soil samples were collected from Namkhaneh series of Kheyrood kenar Forest and their reflectance were measured in the range 350-2500 nm in dark room. Then the relationship between CEC and reflectance and first derivative of reflectance were analyzed by single band Pearson correlation, PLSR and two groups of narrowband soil indices (RI, DI). The results of this study showed that narrowband indices have stronger relationship than PLSR and the DI index in case first derivative have highest correlation (R2=0.82, RMSE=5.01). In the PLSR method between reflectance and CEC strong relationship was observed while the indices of first derivation reflectance and CEC have stronger relationship than row reflectance. So reflectance can be as a nondestructive, fast, easy and Cost effective method to estimate the CEC.

Globally, soil erosion is one of the most important environmental problems which are threats to soil and water resources. Soil properties are the main parameters that affect the runoff and soil erosion processes. Therefore, this study was conducted to investigate the effects of some soil properties on runoff and sediment yield components in plot scale (2m×1m) with eight replicates in four different treatments (control area, harvested area, without canopy cover and skid trail) in the northern forests of Iran during December 2014 until December 2015. The runoff volume and coefficient and sediment yield were also measured through field data collection and lab analysis by weighting and decantation methods. Some of the soil physical and chemical properties consisted of texture, moister content, organic matter, bulk density, pH, and EC were determined. The results of the study indicate that the effect of vegetation cover changes due to harvesting on runoff volume and sediment yield is significant (P≤0.01). There were positive and significant relationships between clay percent and bulk density and negative and significant relationships between organic matter, sand percent and pH with runoff. Also, there were positive and significant relationships between clay and bulk density negative and significant relationships between organic matters, sand and moister content with sediment yield.

Forest roads are constructed to facilitate forest protection, reforestation, logging operations and maximizing the value of forest products. Therefore forest roads are key infrastructures in the development of the region. This study aims to plan forest road network using artificial neural network and GIS regarding forest road technical principles. First the criteria were chosen using Delphi method and then they were weighted regarding their importance in road planning. After that the criteria were combined with corresponding weighs to achieve suitability map based on the degree of suitability for road allocation. Value and coordinates of each pixel were extracted by ENVI software and were normalized in the range of 0-1 for modeling by MATLAB software. In this study two neural networks were used for modeling, including multilayer perceptron (MLP) and radial-bases functions (RBF). The neural networks estimated suitability of different pixels in other districts based on the Patom district results. Using an ArcView GIS extension, PEGGER, two forest road networks were planned. The results showed that MLP provides better ability for estimating suitability of pixels for road passage in comparison with RBF with the R2 of 0.994. A linear regression was also used to compare the results of the proposed neural networks. The results revealed that neural network improves the results in comparison with the linear regression and results showed that the second road alternative was optimum network with regard to the unit cost

Forest harvesting by cutting off the nutrient cycling processes affects the water quality causes the soluble nutrients in the plant to be washed out and flowing through the soil to the river. The type and method of harvesting are important factors in the amount of nutrients get out from the area. The present study aims at investigating the effect of forest harvesting on runoff quality components in plot scale (2m*1m) with four replicates in tow slope scale (0-20%, 20-40%) in the northern forests of Iran during December 2014, December 2015. The rain depth was measured by using a rain gauge installed in the study area. Statistical analysis was conducted to evaluate the effect of forest harvesting on water quality. Samples were analyzed for EC, TDS, pH, anions (Chlorine, sulfate, bicarbonate) and cations (Calcium, magnesium, sodium, and potassium). Kruskal- Wallis Test at 0.01 significance levels was used. The results of the study showed that there was significant effects of forest cover and slope (P

Access routes are the basic requirements to access recreational areas and tourism planning. The purpose of this study is designing and evaluating of forest road network in order to select the optimal road network for tourism development in Arasbaran protected area. For this purpose, recreational suitable areas were evaluated and identified using Makhdoum systemic methods and Multilayer perceptron (MLP) neural network. In order to prepare the road passing suitability map, effective criteria for road designing have been standardized with the fuzzy logic method and combined according to the relative importance obtained from the analytical hierarchy process. Then, the road network options were designed for access to recreational areas in the GIS environment and evaluated in terms of technical, environmental and socioeconomic. The results of the tourism suitable area assessment showed sections of the region have a capability for intensive recreation class 2 (0.17%), and extensive recreation class 2 (10.09%). According to the weighting results by criteria, slope criterion with a value 0.289 and height criterion with a value 0.033 have the highest and the lowest weight, respectively. Overall, 14 road network variants were designed and based on the final evaluation, variant 7 was selected as the optimal option with density 3.34 m/ha, accessibility (hard) 64.68% and minimum cost and environmental impacts. Therefore, taking into account the cost and environmental impacts and using GIS capabilities, it is possible principle design of the road network, and as a result the development of existing access roads in order to develop tourism in the area.

Forest roads make access for people who want using the gift of forest. Experts believe that one of the ways that can encourage visitors to experience promenade more visible is to use developed, targeted and desirable pedestrians. Using them can access to the most attractive locations of promenade in a controlled way. The study area (Patom district of Kheyrud forest) which is partly faced toward north and has Caspian Sea view is capable of promenade attractions. In this study, first of all, after going through the path in Patom district of Kheyrud forest, we collected information and then by using Arc GIS software, the layer's slope and soil maps were prepared to specify appropriate locations for designing walk ways, and to specify the capability of existed path for tourism usage. Also scenic views were located and the quality and the specifications of views that specified the related table of view's specs, were defined. After data study and making sure that they are normal, SPSS software was used for path widths. The study results were showed that the average width difference with standard was 1.5 meter which was about one percent (p

Vegetation in riparian areas, including trees with various hydrological and mechanical effects has an essential role in soil reinforcement. This is accomplished by increasing soil shear strength and inhibiting the higher layer of soil into the lower layers and reducing erosion by roots. The aim of this study was to evaluate the tensile strength changes of Salix purpurea L. trees in different trunk distances and soil depths. Therefore, five trees were randomly selected for root system sampling, which was done by using the soil core technique. Sampling was taken in three different depths, tree horizontal distances and in four directions of the trees. Finally, 97 successful tensile tests were performed on root samples. The relations between tensile force- diameter and tensile strength-diameter were analyzed and compered. The results showed the average of tensile strength of 57.91, 46.96 and 46.27 Mpa for depths 0-10, 10-20 and 20-30 cm, respectively. Furthermore, the average of tensile strength was 29.18, 76.81 and 28.78 Mpa for 0.5, 0.75 and 1 m distances, respectively. Root diameter and tensile force fallowed positive power and exponential trends. However, the association between root diameter and tensile strength followed a negative power trend. Results of Wald test showed no significant difference between tensile strength of three soil depths and three horizontal distances, though root diameter as a covariate parameter with a significant effect on tensile strength.

This study aimed to investigate effect of forest roads on amount of soil elements: nitrogen, phosphorus, potassium and pH in the Caspian Forest of Iran. For this purpose, main and secondary forest roads were chosen in second district in Kheyroud forest. 16 transects (8 transects in the main roads and 8 transects in the secondary roads) was established with 100 meters length from roadside into the forest interior. Four plots established at 0, 5, 60 and 100 m distances. The amount of nitrogen, according to the Tukey test, in the main roads and cut slope, was significant in the 60 and 100 m distances and their values were more than 0 distance. However in the edge of secondary roads, there was a significant difference, in both cut and fill slope and its value is less than other distances. Phosphorus only in roadside and on the down slope of the main road was significantly more than 100 m and there was no significant difference for potassium at different distances of the main and the secondary roads, cut and down slopes. pH, in 0 m distance had a significant difference and its value was more than other distances in the main and the secondary roads. The results showed that changes due to soil disturbance caused by road construction affect chemical elements of soil and pH, so that is necessary to reduce degree of destruction and disturbance in road construction as much as possible, with respect to technical principle and following the nature.

Reduction of vegetative cover by forest harvesting generally increases the average surface runoff volume and sediment yield for a given area of land. Forest harvesting in northern forests of Iran is managed using a selective harvesting and logging system. Towards this attempt, the present study has been conducted to investigate the effect of forest harvesting on hydrological components in plot scale (2m*1m) with four replicates in tow slope scale (0-20%, 20-40%) in the northern forests of Iran during December 2014, December 2015. The rain depth was measured by using a rain gauge installed in the study area. The runoff volume and coefficient and sediment yield were also measured through field data collection and lab analyses by weighting and decantation methods. The results of the study showed that there was no significant effects of forest harvesting (P

Now a day, due to applying the close to nature forestry method to manage the Hyrcanian forests and harvest distribution in this method, reducing damage to the residual stand gains more important. The aim of this study was to determine and compare the resistance of the various diameters of tree species against scars or created during logging operation considering to the size, intensity and different locations as well as to study the change in the wound (healing and wound closure) in the species over time. The research was carried out in the Patom and Namkhaneh district in the Kheyrud Forest. The results showed that there were significant differences among scar healing in the tree species. By increasing the diameter of the trees, the healing rate was significantly reduced, while by increasing the size of the wound (the primary area of the wound), scar healing rate was significantly decreased. Also, by increasing the scar height along the bole, the rate of wound healing has been changed significantly. By the increasing severity of the wound, healing rate was significantly reduced. The results showed that scar age has significant effect on the healing rate, but traffic intensity hasn’t significant effect on wound healing rate. Tree position along the skid trail has positive effects on the amount of residual damage trees. Due to the fact that wounds are made in one meter height of the trunk, which is the most valuable part of the tree, trying to control the damage of trees is essential in the ground skidding operations.

In this research two forest plantations (Picea abies and Fraxinus excelsior) with similar site conditions were selected in the near vicinity of each other. Three trees of each species were randomly selected for later analysis. Profile trenching method was then used to analyze and compare their root distribution. Root samples of each species were collected to test their tensile strength using a standard Instron. The results showed that, RAR values and additional root cohesion tend to decrease with soil depth following a logarithmic function for both forest species. Also for both studied species, root tensile strength tend to decrease with increasing root diameter following a power function. According to the results, over 80 percent of roots were found to be within the top 20 cm of soil profile, indicating the highest reinforcing contribution within this layer. The results revealed that the root tensile strength of Picea abies (19.31 ± 2.64 MPa) with roots diameter ranging from 0.32 to 4.93 mm were greater than that of Fraxinus excelsior (16.98 ± 1.01 MPa) with roots diameter ranging from 0.42 to 4.91. Also, the additional root cohesion from Picea abies (0.03 ± 0.008 kPa) was found to be significantly greater than that from Fraxinus excelsior (0.02 ± 0.005 kPa). The results of this work may help us when applying an efficient bioengineering technique.