جستجوی مقالات مرتبط با کلیدواژه « skid trail » در نشریات گروه « جنگلداری »

Forests as a renewable resource play an important role in the economic and social activities of the society. In the principled exploitation of the forests of northern Iran, the existence of a suitable road network along with skid trails the most fundamental role. Skid trails in the forest are one of the most difficult and costly operations. The purpose of this study is to design the proposed Skid Trails Planning in the forest using AHP and GIS for various operations.

For this purpose, the parcels 18 and 19 of district 4, part 2 of Neka Zalemarud with an area measuring 97 hectares have been selected. According to effective factors in skid trail planning such as slope, soil, geology, stand per hectare, streams, aspect, forest type, elite trees, and altitude, we have attempted to design a questionnaire and filled by some experts. These factors were weighted in Export Choice (EC) software via the pair-wise method. Finally, the status of the designed skid road and the existing skid road were compared. Then, on the map, the ability to pass lands in Arc view environment was designed using PEEGER software, three options. Finally, the specifications of the proposed routes were compared with the existing route. The Chi-square test was used for statistical comparison between the most appropriate option and the available path.

Analysis of different layers based on the opinion of experts, showed that the longitudinal slope with a relative weight of 0.366 has the highest score, followed by the waterway 0.115 and finally the height above sea level with a relative weight of 0.026 has the lowest score. . The results of evaluating the existing routes and proposed variants on the land passability map showed that the percentage of passing the existing route length over the area with suitable power is less than the proposed variants (22.87) and the percentage of crossing the existing route on the area with Inadequate power is higher than the designed variants (24/99).

The results of the Chi-square test showed that the proposed routes were significantly (at 95% level) better than the existing route in terms of crossing suitable areas (p = 0.0001). Therefore, according to the results, if the percentage of the desired longitudinal slope is reduced; it is suggested to consider a longer route because, in such a long route, the topography cannot be shown precision.

Logging operation by skidders can lead to soil compaction, rutting and erosion of skid trails. Therefore, in order to restore the soil physical properties of skid trails, it is necessary to perform improvement treatments. In this study, four compaction improvement treatments were investigated on one-year-old skid trails with two slope classes of low slope (0-20) and high slope (over 20) and 5 replications. 360 soil samples were taken, half of them before applying the treatments and the other half a year after the treatments application, and were analyzed to evaluate the improvement effect of the treatments. Results of low slope class showed that there was a significant difference between soil bulk density and porosity percentage in improvement treatment plots and control plots of forested area. Treatments of orthogonal groove, diagonal groove and logging residuals showed no significant difference with the control skid trail, and only the use of the combined treatment was able to significantly reduce bulk density and increase porosity percentage compared to the control skid trail. For high slope class, all soil improvement treatments showed a significant difference with control plots; however, compared to the control skid trail, none of the mentioned treatments could cause significant differences. Among the studied treatments, the combined treatment had the best performance in restoring soil physical properties in both low and high slope classes

The skid trails in this study are the routs that logging has been finished. These routes should be able to infiltrate water to decrease soil erosion and hydrological cycle disturbance. In this study four treated samples were selected in order to soil recovery. The treatments were: mulching with residual slash, diagonal water bar to skid trails axis, perpendicular water bar and finally mixed treatment (includes perpendicular water bar plus residual slash). Of course there were two control samples including soil bulk density in stand and skid trail. Totally 61 soil samples were taken before and after treatments from 0 to 10 cm depth. The results showed that, only the mixed treatment causes to decrease compaction in skid trail significantly, although there was a difference between in treatments and control samples (1.06 gr/cm3) after 18 months. Also the results show that, the recovery on ruttings was more than log trace in the middle of skid trail.

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.

Skid trails are considered as a completion of wood transport network and are closely related to the condition of road network, silviculture practices, logging methods, topography, slope, soil mechanical capabilities and other factors. The purpose of this study was to design skid trails in parcels No. 22 and 23 in Darabkola forest using GIS with AHP in order to cross paths on sustainable areas and a convenient access to the forest area. For this purpose, maps of slope, inventory per hectare, stream density, inaccessible areas (outcrop and regeneration), pedology, aspect, geology, forest type, and altitude, which are important factors in designing of skid road network, were used as layers of information and Evaluation of designed skid trails. The results of AHP showed that slope with a relative weight of 0.301 and altitude a relative weight of 0.029 had the most and least effects on designing of skid road network; the acceptable incompatibility was 0.08 in this case. Finally, two variants were designed for the study area. The first variant had a length of 2957.51 m and a density of 25.06 m/ha; the second variant had a length of 3853.85 m and a density of 32.66 m/ha. The situation of variants passes through different areas showed that 83.54% and 84.81% of the length of the skid trail was passed from very proper and proper areas in the first and second variants, respectively; 16.46% and 15.27% was passed from poor and very poor areas in the first and second variants, respectively. Compare designed variants using the nearest route showed that the average distance of each node to the track for the first variant was 64.77 meter and for the second variant was 45.56 meter. The results of this study showed that by considering the skidding distance of 140 m and with a maximum longitudinal slope of skid trail (% upward and -35% downward) the second variant was preferred due to the more passing percentage (84.81) on proper and very proper areas and lesser passing percentage (15.2) on poor and very poor areas and a cover percentage of 48.47% than the first variant with a passing percentage of 83.54% on proper and very proper areas and 16.46% on poor and very poor areas and a cover percentage of 32.18%. The evaluation results of the nearest path showed that the second variant had the best distribution because the average distance between each node to its path was lower.

Forest soil conservation as a production base during the harvesting and skidding operations is necessary, until the amounts of damage and recovery time of soil characteristics after the operation are minimized. This research was carried out in two districts; Patom and Namkhaneh of Forest Kheyrud in order to assess the environmental impact of slope, traffic and rutting location on soil physical properties and recovery them over 20 years compared with the controls. Fourabandoned skid trails were selected in downward direction and different ages and in each of these skid trails, three traffic classes and in each traffic class, two slope classes were specified. For measuring the soil moisture, sample plots of 10×4 m were located in the treatments. The results showed that in 15-20 year skid trail, soil moisture in slope, traffic and rutting location were not significantly different with control area, but the values ​​were still higher than the control area. Over 20 years of skidding operations, soil moisture was 9.7% lower than control area. However, these differences were not statistically significant. The results indicated that with increasing abandoned age of skid trails, the soil moisture tend to have more recovery rate.

Each skid trail construction affects the trees located on the road margins in various extents. The present study was conducted with the aim to assess the changes in annual ring widths of Beech and Alder trees compared to the control trees inside the Nav District in Asalem forests. To this aim, 40 samples from previously felled Alder and Beech even-age trees were randomly drawn alongside and inside the forest stands. Disks were acquired from the trees and were perfectly polished with sanding machine. They were finally used to measure annual ring widths with an accuracy of 0.01 mm. Effect of species (Alder and Beech) and location (along the skid trail and inside of stand) on the average width of annual ring were analysed using a two-way ANOVA test in a complete randomized design. Results indicated larger average annual ring width of marginal trees (0.20mm and 0.38mm for Beech and Alder trees, respectively) compared to those located inside the stand. Moreover, ANOVA results indicated highly significant main effect of species and location on the average of annual ring width, while their interaction was shown to be insignificant. It can be concluded that this increase of trees growth in marginal trees may compensate the loss of volume caused by skid trails construction.

Logging operation due to soil disturbance and compaction changes soil physical and chemical properties. On the other hand، there is a paucity of data on the time required for recovery of disturbed soil properties. This research was therefore carried out to investigate the effects of ground-based skidding on organic matter، which is one of the important chemical soil properties، and it''s process of recovery over a period of 10 years after timber skidding. Changes in organic matter was quantified at three traffic levels including low، medium and heavy on a skid trail that has recently been established. Three skid trails have been left without skidding and traffic for one، five and ten years. The results indicate that skidding with regard to traffic intensity، when compared with the control، significantly decreased organic matter by 32. 5، 53. 5 and 58. 5% at low، medium and heavy traffic، respectively.. Furthermore، the rate of recovery with regard to traffic intensity varied depending on degree of soil disturbance، where low traffic showed more recovery than medium and heavy traffic. The results revealed that soil organic matter removal by skidding was beyond the disturbance threshold and even after a ten-year period، no complete recovery was observed.

Control of logging damage is important for sustainable timber production in Caspian forests. Methods often recommend to control damage levels including directional felling and pre-felling design of skid trial. Directional felling needs felling crew with the ability of leading the trees to an accurate falling path. The present study is an experimental evaluation of felling crew ability for directional felling that carried out in compartment 207 of Nav district in Asalem watershed. A total of 25 trees were randomly selected from the total harvested trees by four felling groups. Falling path of selected trees was specified by paint on the trunk of trees and recorded by using a compass prior to and after tree’s falls. The difference between the intended and actual direction of tree's fall was then calculated for each felling group and an average margin of felling error was calculated for each felling group. Comparison of mean directional error for felling groups indicated that none of felling crew could direct the marked trees to desired path. The result showed that current felling is not according to goals of directional felling. Results suggested that felling worker in study area need more training program for reaching to the goals of directional felling.