جستجوی مقالات مرتبط با کلیدواژه « مسیر چوبکشی » در نشریات گروه « جنگلداری »

Forest harvesting operations, especially logging, are activities that cause interference and tampering with nature. Tractor-operated systems are the most common type of small-scale equipment used in the north of Iran. Due to the direct contact of wood with the forest soil, land logging has always been associated with a wide range of destructive effects on the forest ecosystem, including changes in the soil's physicochemical properties and damage to the natural regeneration and remaining trees. After logging, deep grooves are visible in the remaining logging roads, which can cause soil erosion, landslides, and soil fall due to the high longitudinal slope of these roads. Changes in the soil's physicochemical properties are among of the most important effects caused by the exploitation and removal of wood from the forest mass. Numerous studies report the long-term recovery of the soil's physicochemical properties. A major management goal in forest exploitation is the need to minimize the effects of vehicle traffic on the forest soil because these negative effects can be significant in the long run. The soil characteristics (appearance, compactness, and texture) and chemical properties in terms of soil elements, organic matter, and pH in two control and forest exploitation areas were studied to provide solutions to reduce these effects.

The Kohmian forestry project is located in the 89th watershed of the northern forests of Iran in the area of Natural Resources of Golestan-Gorgan province. This research was conducted in Parcel 27 of the Kohmian Azadshahr Forestry Project located in Golestan, Iran. To investigate the soil's physicochemical changes due to logging with agricultural tractors, soil was sampled in two control areas and on the crossing paths by metal cylinders at three depths (0-10, 10-20, and 20-30 cm) of the soil in a completely randomized design with three replications. These samples were dried in the laboratory in an oven at 105 °C for 24 h and then weighed using a digital scale (EK4000, Japan) with an accuracy of 0.1 g. After recording the soil dry weight, the physical properties (compaction, apparent specific gravity, moisture, and texture) and chemical properties (organic matter, cation exchange capacity, nitrogen, potassium, phosphorus, calcium, magnesium, iron, zinc, manganese, copper, and acidity) were studied using standard methods.

Logging with an agricultural tractor significantly impacted both the soil's physical and chemical properties. The most notable effect was observed in the soil depths sampled from 0-10 cm and 20-30 cm. The alterations predominantly pertained to physical changes in the soil, with no significant modifications detected in the chemical properties. Notably, soil compaction in the trafficked areas at depths of 0-10, 10-20, and 20-30 cm was respectively 46.2, 3.04, and 1.73 times higher than that of the control area. Furthermore, the increase in soil specific gravity at these depths ranged from 20% to 36% compared to the control area. Chemical properties such as cation exchange capacity and the concentrations of elements (e.g., phosphorus, nitrogen, and iron) exhibited reductions of 37.62%, 63.91%, 10.2%, and 73.05%, respectively, in the top 0-10 cm depth. At a depth of 10-20 cm, only organic matter was significantly impacted by tractor traffic, with a reduction of approximately 64% compared to the control area. Chemical properties at a depth of 20-30 cm remained unaffected by tractor traffic.

The study highlights the detrimental effects of using an agricultural tractor for primary forest plot transportation. The uneven contact surface of its tires, particularly the lower contact surface in the front tire, along with the absence of a winch, leads to soil disturbance along the logging path. This disturbance includes soil compaction, increased specific gravity, and alterations in soil texture, nitrogen, phosphorus, and iron content, reduced organic matter, and decreased soil exchange capacity. To mitigate these adverse effects, it is recommended to employ specialized logging machinery, such as skidders with rakes, instead of agricultural tractors. Other measures include implementing surface protections on logging paths, restricting logging activities to periods when the forest soil is dry and less prone to damage, and proper disposal of excess logs along the logging route.

Assessment and management of environmental impacts imposed by forest harvesting activities are one of the key factors that are increasing important. The purpose of this study was to investigate the effect of ground-based system on soil physical and chemical properties and the recovery process of these properties over the course of seven years. Hence, the compartments no. 316, 318, 310, and 309 of the Gorazbon District in the Kheyrud educational and research forest were selected. In this study, a completely randomized factorial design was applied and the treatments included duration (years) from timber extraction (one, two, five, and seven years), three traffic intensities (low, medium, and high) and soil depths (0-10 and 10-20 cm). The soil bulk density after seven years has not yet returned to the original state. There is still a significant difference between the control area and the skid trail. The amount of organic matter after seven years showed a recovery process compared with the first year after timber extraction, so that in the seventh year no significant difference was observed between the amount of organic matter in the control area and timber extraction track, while the amount of organic matter in the first year of timber extraction track is much lower than that of adjacent control areas. The recovery of some soil properties such as organic matter occurs faster than other ones like bulk density and porosity.

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.

Logging secondary damages on remained trees are one of the challenges in management of uneven-aged stands which have been less studied in the northern forests of Iran. In this research decay frequency and volume of bole trees after 15 years from wound occurrence were studied through systematic-random sample plots with 1000m2 plots in the Nav-e Asalem forests, Iran. The conditions of trees were registered in two types: safe and wounded, the wounds were registered in two types: open and decayed; and volume of decayed bole was calculated by Smalian formula. Results indicated that 16.1% of wounds were led to bole decay. Decay frequency and volume were estimated to 5.5 trees ha-1 and 1.7 m3ha-1, respectively, that includes 1.96% of total trees and 0.72% of total stand volume. Coefficients of decay frequency and volume on the base of frequency of logging primary damage (12.2%) were calculated 0.16 and 0.06, respectively. Decay frequency of wounded trees bole were related with tree species, wound location, diameter at breast height (DBH), situation of wounded tree in stand, and slope aspect. Decay frequency and volume in the trees of lime and oak were more than other tree species. Decay frequency was increased by decreasing wounds distance from ground. Decay frequency and volume in the high diameter wounded trees were more than low diameter wounded trees. The wounds on the trees in edge of skid trails were more decayed than the other wounds. Decay frequency of wounded trees on the northern aspect slopes were more than the southern aspect slopes. In general, minimizing of primary logging damages, reducing harvest intensity, increasing logging period, and harvesting bole-decayed trees in the next logging periods are suggested.

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.

Logging operations is an engineering system with the aim of maximizing efficiency and minimizing negative effects. This study was carried out in two compartments including 220 and 225 in Namkhaneh district of Kheiroudkenar watershed. In this study، damages resulted from skidding operation by Timber jack 450C were evaluated. The results of this study showed that in two compartments 220 and 225، 80. 6% and 72. 7% of scars resulted from skidding operations was happened in low parts of the tree (root and stump area) and more than 40% of scars are with the area of lower than 200cm2، but 57% of scars are accompanied with cambium damage. The results of study showed that with regarding to lower logging intensity in compartment 225 compared to compartment 220، the average size of scars in compartment 225 (10. 43cm) is more than compartment 220 (9. 06cm) that this important note is referred to more skid-trail turns in compartment 225 compared to compartment 220 (around 2 times more). Also، the results of analysis of variance showed that the wound-stem ratio is significant difference between two compartments in 1% level (F=9. 01، P=0. 003، df=1). Generally، concluded that increasing number of turns in skid-trails have more degradation effects in comparison with harvesting intensity on edge trees.

Soil properties affected by passing the machines in skid trails and establishment of natural regeneration and herbaceous palnts in these routes after the harvesting operation could be a suitable opportunity to study the reaction of different plant species to soil conditions. This study has been done in district 1 of Nav forest, Guilan/Iran. The skid trails where have been abandoned without traffic for 10 years were chosen among the available skid trail routes. Soil samples were taken and type and the number of natural regeneration in skid trials and adjacent forests (natural forests) wre recorded. The results showed that among soil physical properties, soil bulk density, porosity, saturation moisture percentage and soil texture differed significantly between skid trail routes and natural forest. The natural regeneration of cappadocia maple, hornbeam and alder showed significant difference between natural forest and skid trails routs, while natural regeneration of beech and Velvet maple did not show any significant differences. The regeneration of alder was significantly higher in skid trail routes compared to natural forests, but for hornbeam and maple this regeneration was better in natural forest. Among soil physical properties, bulk density, porosity and soil texture showed significant correlation with amount of natural regeneration and among tree species, cappadocia maple showed the higher correlation with soil physical properties. This study showed that the natural regeneration of some species is affected by soil physical properties. In addition to the determination of natural regeneration responses to soil physical properties, the results of this study could be used in silviculture and forest management.

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.

The ruts on skid roads are the main factors causing water erosion in northern forests ofIran. In order to evaluate the reasons of this phenomenon, the skid roads in Pahneh Kola and Arzefon forests which are under management of Mazindaran wood and paper industry were selected, then 32 cross profiles were randomly chosen in 10 skid roads. The effects of factors such as stocking volume per hectare, understory vegetation, longitudinal slope, skid roads length, canopy, soil type, basin area of each profile and its slope were measured as soil changed. Results showed that there was no significant linear relationship between water erosion rate and profile distance from starting point, stocking volume and understory vegetation. But there was a significant positive correlation between rate of water erosion and basin area (p-value < 0.001), longitudinal slope of skid road and basin area (p-value < 0.01) and skid road length and tree density (p-value < 0.05). Also, the regions with open canopy, clay soil and litter cover in understory showed the greatest rate of water erosion.