فهرست مطالب farzam tavankar

In the current study, the quantity, quality, and bole form of trees were investigated in three parcels of selectively logged, protected, and recreational areas in the mixed beech (Fagus orientalis) stands in Nav-e Asalem forests. The quality and bole form of trees were measured and evaluated through systematic plot sampling. The results of the research showed that the abundance of live trees in the selectively logged parcel (268 trees ha-1) and recreational parcel (210 trees ha-1) was lower than that in the protected parcel (389 trees ha-1). The abundance of beech, maple (Acer cappadocicum), and alder (Alnus glutinosa) species in the selectively logged parcel, and the abundance of beech and alder species in the recreational parcel were significantly higher than their abundances in the protected parcel. The abundance of snags in the protected, selectively logged, and recreational parcels was 18, 9, and 8.4 stems ha-1, respectively. The average abundance of stem deformity in the protected, selectively logged, and recreational parcels was 18.3, 9.4, and 8.4 stems ha-1, respectively. Logging operations, although increased the frequency of leaning and bending stems, decreased the frequency of conical and decaying stems. In general, the abundance of high-quality trees and boles in the selectively logged and recreational parcels was higher than in the protected parcel. Regular and long-term monitoring of the quantity, quality, and form of tree trunks may be a good approach to align ecological and economic goals in forest management.

Despite progress in full mechanization, motor-manual logging technologies still dominate in many countries, including in North plantation forest of Iran. Motor-manual timber harvesting is considered to be one of the most dangerous working operations. The physical demands of work are still one of the crucial workload factors in most jobs in the forestry sector, especially those connected to manual loading. The aim of the study was to investigate the physiological workload of a worker during manual loading in a poplar plantation stand in the north of Iran. Physiological responses were assessed on a sample of 12 workers manual loading during a normal working shift. Polar heart rate monitors were fitted over a period of a week in order to record ‘working’ heart rates. The collected data were used for the calculation of heart rate indices that determine the strain of the subjects. The average mean heart rates during work time, rest time, and maximum heart rate were 132.42, 79.42, and 175.16 bpm respectively. The results showed that the mean level of physical workload was 55 which correspond to very heavy work. The study results also showed that age and body mass index of workers is significantly effective on HRw and weight of workers on HRw and HRmax, respectively. The results revealed high physiological demands of manual loading. Increasing the mechanization level with investment in modern equipment may be proving beneficial in enhancing workers health and safety.

In this study, the physical, chemical and biological characteristics of compacted soil due to tracked skidding (LTT-100A) after 35 years (from 1986 to 2021) of clear cutting operation were investigated in an even aged mixed deciduous stand in Masal forests, Guilan province, northern Iran. Three levels of machine traffic intensity (TI) (low, LT; medium, MT; and high, HT), two levels of skid trail slope (SC) (Gentle, <10%, GS; and steep, ≥10%, SS), two sample locations(SL) (Between track, BT; and On tracks, OT), and two soil depths (SD) (0-5 cm, and 5-10 cm) were considered as independent variables affecting the process of soil profile recovery. The values measured from the abandoned skid trails were compared with those of undisturbed areas to estimate the soil profile recovery rates. Results showed that TI had significant effects on all soil physicochemical (except for soil moisture) and biological properties (i.e., leaf litter, above-and below-ground biomass); all physicochemical and biological properties (except for soil moisture and leaf litter) were affected by SC; the effect of SL on soil texture, density and moisture was significant; and soil texture and density were the only characteristics affected by SD. The values of soil bulk density and penetration resistance on the skid trails were 35% and 49% higher than those of the control area, respectively, while total porosity value was 17.5% lower than that of the control area. Furthermore, soil organic carbon on the skid trails was 20% less than that of the control area. The amount of soil biomass on the skid trails was not recovered after 35 years, so the above and below ground biomass on skid trails were 42% and 46% less than the control area, respectively. The value of leaf litter on the skid trails was 31% less than that of the control area. Overall, the results of this research revealed that the soil of the studied forest is sensitive to the activity of timber harvesting machines. Thus, sustainable forest management needs to reduce the impact of logging within the context of best management practices (BMPs).

The aim of this research was analysis of the effect of harvest intensity on the volume growth of valuable beech forests in the North of Iran. For this reason, volume growth of stand trees were estimated by permanent sample plots during a 10 year period in three parcels with different harvest intensities of Low, medium, and high (6, 13.1 and 18 m3/ha, respectively), and in a protected parcel (control) in Asalem Nav mixed beech forests. Results indicated the harvest intensity had significant effect on the stand volume growth (P

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.

Single tree selection method needs to an accurate estimation of logging damage to residual stand for ecological and sustainable forest management. In this research accuracy and required time for estimation of frequency of damaged trees due to logging operation were assessed through plot and line samplings in a harvest unit of 30 ha area in Asalem Nav forest, northern Iran. In both samplings with same sampling intensity (10% of total area in plot sampling and equal total line lengths in line sampling) five samples size (plot and line sample numbers) were applied with different grid dimensions of systematic sampling method. The results showed that the sample size had significant effect (P 0.618) with actual damage (100% inventory). Adequate grid dimensions were determined 100 m × 100 m with plot areas of each 0.1 ha for plot sampling and 77.5 m × 77.5 m with sample line lengths of each 60 m for line sampling. Required time for line samplings were about 90% lower than plot samplings. These results indicate the line sampling can be used for accurate and rapid estimation of frequency of damaged trees due to selection cutting and ground skidding.

One of problems in managing of uneven-age forests is logging damages to residual trees and reducing stand quality and quantity in years after logging operation. In this research, trend of bole decay and economic loses by it, following logging damages, were analyzed at a 10 year period in a mixed beech forest in Guilan province. Volume of decayed section on trees bole was measured by Smalian formula, and volume of standing trees bole was estimated by local tree volume tables via plots of 0.1 ha area and systematic sampling design at the start and end of period. Results showed that volume of decayed bole were increased from 0.48 m3/ha at the start of period to 1.71 m3/ha at the end of period (P

Protection of forest soil is one of key factors in having sustainable productive forests. In this research extent and intensity of soil disturbance due to extraction of logs of felled trees (20.5 m3/ha) were studied in Nav-e Asalem forest in Gilan province. After finishing the skidder logging operations, soil disturbance were studied by point-transect sampling method and visual assessing. Results indicated that about 19 ± 6.2 percent of surface soils were disturbed due to winching of logs that 11.3 percent of them disturbed with shallow intensity and 7.7 percent disturbed with deep intensity. The extent and intensity of soil disturbance were decreased by increasing distance from skid trail. The extent and intensity of soil disturbance were increased by increasing of ground slope. Soil bulk density in the shallow disturbed soils (1.29 g/cm3) and deep disturbed soils (1.44 g/cm3) were increased 2.4 and 14.3 percent, respectively, than control soils. Soil bulk density of disturbed areas were increased by increasing ground slope, so in slopes greater than 50 percent soil bulk density was increased 20.8 percent more than control soils. Including ways to reducing soil disturbance during skidder logging in the study area are reduction in harvest intensity, implementation of felling direction and skidder logging limitation to slopes less than 50 percent.

Logging is one of the critical operation in forest management that causes damage to remaining trees in forest. Reducing frequency and intensity of damages during logging operation is one of the main goals in section cutting forests. The aim of this study was analysis of effective factors on damage during logging of each tree in Nav forests.
From total of selected trees to cut in the two parcels of the Nav forests, the number of 83 trees (22.7%) were randomly selected and damages to remaining trees were individual-level analyzed during felling, winching and skidding operation.
Results indicated an average 13.3 damaged residual trees per each harvested tree, which 3 trees were damaged at felling stage, 8.9 trees were damaged at winching stage, and 1.4 trees were damaged at skidding stage. Diameter at breast height (DBH) of felled trees were from 25 to 107 with average 68.4 cm, and their heights were from 12.5 to 27.3 m with average 21 m, and damaged trees were increased by increasing of DBH and height of harvested trees. Winching distance were from 3 to 47 m with average 24.5 m, and winching angle were 0 to 47 degree with average 19.1 degree, and damaged trees increased by increasing the distance and angle of winching. Damaged trees were increased by increasing of number of skidd-trail curves and by decreasing of skid-trail radius. Damaged trees due to felling of trees on suitable directions, and winching of the on suitable routes were lower 42.4 and 17.1 percent than unsuitable directions and routes, respectively. The DBH of wounded and destroyed trees at felling stage (63.5 and 34.6 cm, respectively) were more than their averages at winching and skidding stages. Average size of bole wounds was 327.1 cm2, average depth of bole wound was 20.1 mm, and average height of bole wounds from ground level was 0.86 m. The averages of the bole-wound sizes and the bole-wound height from ground level were higher at felling stage, the average bole-wound depths at the winching stage were higher than other stages.
The results reveled that appropriate management of selection cutting forests need to develop of sciences and techniques of logging operation. Implementation of tree directional felling, and limiting of winching operation to areas without standing trees, regeneration and ground slopes less than 50 percent are necessary for reducing logging damages to residual trees in these forests.

In this research resistance of six tree species to logging damages (bole wound) after 12 years were studied in district 1 of Asalem Nav forests. The data of extent and severity of damages on residual trees were collected immediately after logging operation from systematic sampling with circular 0.1 ha plots in the year of 2000. The damaged trees and wounds condition were reexamined in the year of 2012. The results of this study showed the resistance of trees to logging wounds is related to their specimen, diameter and wound size (P

Forest management has a decisive role in decreasing or increasing snow damages on trees due to effects on stands structure. In this research snow damages on trees were investigated and compared in managed and natural stands with selection silvicultural system in Nav-Asalem Forests, Guilan province. Circular 0.1 ha sample plots were established using random-systematic method for studying the effects of snow on different species with various ages. The distance between sample plots were set to 100 m. The results showed that the frequency of snow-damaged trees in managed stand (10.2%) was significantly higher (P < 0.01) than natural stand (7.2%). The occurred changes in the age structure and tree species composition in the managed stand during selection cuts was the main cause of most snow damage in this stand compared to natural stand. The most frequency of damages was observed on young trees with high slenderness coefficient. For fortifying the studied forests against risk of snow damage the following recommendations can be mentioned: increasing the selection cutting period from 10 to 20 years, reducing the removed volume in each logging period, reducing the areas of regeneration gaps, increasing the number of large trees, avoiding the cutting trees in forest edges, implementing the thinning operation in the stands in which previous cuttings caused homogenous, even aged, young stands with high slenderness coefficient, and avoiding tree cutting in the areas that are sensitive to snow damage such as ridges, steep slopes with low depth of soil.

Snow damage is a significant and serious problem in management of mountain forests. In this research snow damage on trees in related to physiographic factors were studied in Asalem-Nav mountain forests in the Guilan province. The ground slope of study area was divided in tow slope classes: lower and upper than 50 percent. The frequency of damaged trees in lower and upper than 50 percent of ground slopes was 10. 5 and 18. 2 percent. The results showed that the frequencies of damaged trees have significantly differences in two ground slope classes (P < 0. 001). The frequencies of tree damage types of crown damage، stem breakage and uprooting in the slopes of upper than 50 percent was higher than slopes of lower than 50 percent. The trees on the northern aspect slopes were more damaged than southern aspect slopes، so frequency of damaged trees on northern aspect slopes was 17. 6 percent but on the southern aspect slopes was 10. 3 percent. The trees of Beach، Hornbeam، Great maple and Cappadocian maple in northern aspect slopes، while the trees of Alder and Oak in the southern aspect slopes have more susceptible to snow damage. In order to strengthening of trees against to the snow damage needs to adequate silvicultural operation in mountain forests.

Chainsaw and cable skidder are two main logging machines for wood harvesting in the Caspian forests. Selection cutting is the main silvicultural method in these forests. Harvesting in the Caspian forests has the potential to damage the trees that are left standing. Damages to residual trees during the selection cutting operation may decrease the quality of residual trees and increase stand mortality through insect and disease infestation. The wounds can cause stem deformity and significant losses of the final crop volume and value. The wound characteristics such as size, location, and intensity are the main factors that influence on the future quality of damaged trees. Logging damages to the residual trees increase as the time passes. The literature review shows that minor damage to the stem of residual trees during logging operation can have a major impact on the final stand volume as future saw logs. In the Caspian forests, many studies focused on the primary logging damage (immediately after logging operation) and a few studies were done on the secondary logging damage (after years). The objective of this research was to study the condition of logging wounds on residual trees after 12 years elapsed in the Caspian forests. Materials and methods The study was carried out in two adjacent compartments (35 and 42) of the district No., one of Nav watershed in Guilan province in the Caspian forest of Iran. The Nav watershed is located between 37° 38' 34" to 37° 42' 21" N and 48° 48' 44" to 48° 52' 30" E. The elevation of the study area is ranged from 1350 to 1600 m and the mean of annual precipitation and temperature are approximately 950 mm and 9.1°C, respectively. The original vegetation of this area is an uneven-aged mixed forestand is dominantly covered by Fagus orientalis and Carpinus betulus stands. These compartments selectively logged by ground-based logging operation during December and January of 2000. The characteristics of wounds (size, intensity, and location) on the residual trees were measured immediately after logging operation. The condition of wounds was restudied after 12 years from logging operation in the year of 2012. Results and discussion The results of this study showed that 67.1% of wounds were closed and 32.8% of the damaged trees were not able to improve their wounds. About 4.2 percent of wounds caused to tree mortality as shown in Table 1.

Minimizing of logging residuals is the first and basic rule of forest harvesting. In this research effect of ground slope, stump diameter and species on stump height and volume were studied district 2 from Nav-Asalem forest area in the north of Iran. For this reason 68 felled trees from each three ground slope classes (< 20%, 20-50% and >50%) were selected using random sampling design and stump heights and volumes were calculated from Newton formula. ANOVA and Duncan test were used for analysis of data and compare means. The results showed that mean of stump height in the study area were 37.9 cm. Besides, 77% of stump heights were more than 32.5cm. 37 percent of stumps, ratio of stump height to stump diameter (H/D) were lower than 0.5. Each three studied factors (ground slope, tree diameter and specie) were significant effect on stump height. Stump height were increased Whit increasing of ground slop and tree diameter. Stump heights in beech, hornbeam, maple and alder were measured 38.7, 39.9, 26.5 and 25.6cm. 4.34±0.75 percent of selected trees volume were remained in forest as stump waste volume. Education and control of felling operation personnel can be useful to reducing stump height and increasing timbers.

Prediction of volume and characteristics of logging residuals before logging operation is one of basic information about decision and residual management. In this research, volume and characteristics of logging residuals were studied in parcel 237 with 41ha from Guilan-Nav mountainous Fagetum forest area. Silviculture and logging method in these forests is selection cutting and assortment (short and long log) method. Systematic sampling design with twenty 100m sample lines were used for estimation of volume, weight and characteristics of residuals in parcel and volume of each piece of residuals were calculated by Huber formula. The volume, weight and number of logging residues per hectare were estimated 3.6m3, 2.5 ton and 233 pieces, respectively. The averages of volume, weight, length and middle diameters of pieces were calculated 0.02m3, 15kg, 1.5m and 10cm, respectively. About 65% of residual volume was compounded by woody materials that had first class quality and without decay and knot. Ratio of logging residue volume to number of tree felling was 0.58m3. This ratio for each 100 sylve of selected trees was 17m3. Also, volume of logging residual for each 100cm diameter at breast height of harvested trees was 1.08m3. These amounts of logging residuals are considerable and useable in wood industries. So export of those can have economic value.