فهرست مطالب جعفر فتحی

In order to investigate the factors affecting damage caused by early snow in the compartment no. 10 in Patom district of Kheyrud forest research station, the sampling was conducted on a random grid (100 × 100 m) with 46 m 1000 circular sample plots. In each plot, effective factors including slope gradient of the plot, aspect, altitude (elevation), soil depth, diameter at breast height, and height of all tree species greater than 7.5 cm were recorded. Damages to trees were classified into four types including uprooting (tree throw), trunk fracture, crown fracture, and bending. The results showed that 28.1% of the trees were damaged, with damage of 3, 4, 10 and 11% for each type including uprooting (tree throw), trunk fracture, crown fracture, and bending, respectively. The results showed that there was a significant difference between the types of tree damage and some factors including aspect, slope, elevation, and soil depth. The highest percentage of tree damage occurred in the northern aspect, slope less than 15%, altitude of 330-380 m, and shallow soils depth, and the lowest occurred in the southern aspect. The damage on the eastern and western slopes was approximately similar. The highest and the lowest percentages of damage were related to alder and maple tree species, respectively. Thinning treatments affected the horizontal and vertical structure of the stands by reducing the slenderness coefficient of trees, which has a key role in reducing the severity of snow damage on trees, and improves tree and stand stability.

One of the main and important knowledge for forest management and its optimal and sustainable utilization is to determine its trees volume and number and its production potential. Actually, future forest management is based on its inventory and information. Thus for a precise planning its required to have information about forest standing stock volume and increment, distribution of diameter classes curve and spices structure. Determination of annual allowable cutting is required for wood utilization planning and management, based on stands volume increment data. The research was conducted in Gorzbon district (934.24 ha) at Kheyroud Educational- Experimental Forest (Caspian region of Iran), using 258 permanent sample plots and applying the directed method of inventory to measure volume increment and trees number two times with nine year interval. Results showed that average trees number and stocking volume per hectare were 298.15 and 335.8 sylve in 2003 and 290.14 and 367.7 sylve in 2012, respectively. Although 31% of the forest tree number belonged to Fagus orientalis, but 57% of the standing stock volume belonged to this species. Volume increment was 4 sylve/ha/year and average trees number growth was 5.8 ha/year. Overall, the beech species had the greatest volume increment. In fact, such huge research area and data analysis was carried out for the first time in Khyroud forest and the results showed that applying permanent sample plots method provides essential and precise information and data for measuring forest increment

Tree cutting can affect different aspects of forests. To investigate the changes on snow accumulation, density and temperature due to tree cutting in the forest, two forestry regions were selected, one control and the other the cutting region. For measuring snow accumulation, 10 pickets in cut area and 10 pickets in control area were installed and snow height was measured every 5 days. For determining the density, a snow profile was dug and sampling was done with 500 cm3 sampler from different depths every 5 days. Finally snow temperature was measured in different depths with thermometer. The results indicate that the average of snow density in cutting region and control region are 0.178gr/cm3 and 0.151gr/cm3, respectively and there isnt any significant difference between them. Also decreasing in canopy due to tree cutting has a significant relation with snow accumulation and its depth, which increases and they all together result more snow accumulation. So average of snow height in control region was 13.88cm and after cutting increased to 21.15cm. Snow temperature increasing is significantly related to the decreases in canopy. Therefore the average of snow temperature in control region is -3.3°C which decreases to -10.3°C by cutting the trees.

Despite the cost of forest roads, they are essential infrastructure to provide access for resource management. The quality of roads pavement depends largely on the material used, particularly type of pavement that sometimes includes up to 70% of total cost. The purpose of this study was to use the DCP for CBR assessment of a newly completed road segment. Therefore, a DCP and a penetrometer were used to assess penetration resistance. Then penetration index of DCP was converted to field CBR. The results showed that bearing ratio of sections with clay material (which treated with Ionic stabilizer) was significantly lower than sections with clay and gravel material. There is a significant positive correlation between values of DCP and penetrometer. CBR values of the investigated road were less than expected and improper for passing traffic, which road destruction and wheel rut caused by traffic pass at the end of summer, confirms the achieved result. Regarding the lack of CBR tests in forest road projects due to its cost-time consuming and road surface destruction, using DCP as a simple, efficient and non destructive tool is suggested for estimating field CBR

The present research was performed in Patom, Namkhaneh, Gorazbon, Chelir and Baharbon districts in Kheyrud forest. Due to existence of forest typology map and extension of study area, this study was confined to beech dominated forests. A stratified sampling method based on landform is used to locate 1000 m2 circular sample plots. The number of Fagus orientalis Lipsky trees ≥ 7.5 cm in DBH within each plot is recorded along with elevation, aspect and slope of the ground. Furthermore, at the center of plot, soil samples from A horizon are taken for analyzing soil texture. Gaussian response function was used. Instead of direct estimation of Gaussian parameters, it is customary to fit an equivalent polynomial model. This can be easily fitted as a generalized linear model (GLM) with a logarithmic link function. This function showed beech has 1347 and 464-2231 m a.s.l for its optimum and ecological amplitude, respectively. North-facing slopes (optimum 43 degree) are the most suitable slope for Fagus occurrences. Beech tree can distribute from gentle to steep slopes in the study area, but this species in 39% slope has the best performance. Using generalized linear model showed Fagus can tolerate slopes from 3 to 74%. In light of sand, clay and silt, Beech tree has 25%, 43% and 35 % for optimum and 4-46 %, 25-60% for clay and 15-55 % for silt for ecological amplitude, respectively.

Regarding to special situation of northern forests in Iran, chainsaw is a unique cutoff. Nevertheless, study to evaluat operation efficiency is imperative. Present study was carried out with the aim of time study of cutting operation, estimating the productivity and costs of chainsaw, and developing a regression model. According to the results of this study, the hourly production of cutting by chainsaw with and without delay time were 51.6 m3/h (9.6 trees/h) and 86.2 m3/h (16 trees/h), respectively. Cutting productivity was increased related to DBH as power model and on the other hand the unit cost was decreased. Total cutting cycle time with and without delay time were averaged 6.24 and 3.74 minutes, respectively.

Measurements of gross rainfall (GR)، throughfall (TF)، and stemflow (SF) were conducted during the summer 2009 beneath a natural pure stand of oak (Quercus castaneifolia C. A. M) forest canopy located near the southern border of Kheyrud Forest Station of Tehran University. Measurements were made inside a plot with an area of 0. 12 ha. GR was collected by means of three manual collectors placed in a neighboring open area away from the study plot. Thirty five TF manual collectors were randomly positioned underneath the tree canopies. SF was collected from nine oak trees with different diameters by the spiral-type SF collection collars installed at diameter at breast height. All the measurements were performed on a rainfall event basis using a graduated cylinder. Interception loss (I) was calculated indirectly as the differ rence between GR and the sum of TF and SF. During the study period، 10 events were recorded. The cumulative GR، TF، SF، and I depths were 257 mm، 192 mm، 0. 7 mm، and 64. 3 mm، respectively. At the event scale average ratios of TF: GR، SF: GR، and I: GR were 72. 2%، 0. 2%، and 27. 6%، respectively. A weak correlation was observed between SF: GR and GR (r2 = 0. 43) while a fairly strong positive correlation was observed between I: GR and GR (r2 = 0. 65). Interception loss contributes a remarkable amount of incident rainfall in the studied oak forest and its measurement is an essential element in assessing water balance on a catchment scale.

Abstract Economic evaluation and optimization of various aspects of forestry project will guarantee the continuation of forestry project. Meanwhile, an exploitation operation as the most expensive part of a project is specially important. The purpose of the present research is to study the production and cost of skidding by Timberjack 450C skidder in Namkhaneh district of Kheyroudkenar forest. In this study, after determining the components of a skidding turn from cutoff place to the place where timber is accumulated along the road, 53 samples were recorded. In addition, variables such as skidding distance, skid trail slope, the number of timber at every turn, load and tree species were recorded. Data analysis and mathematical equation to predict skidding time was determined. Production rate with and without delay were 7.92 and 12.1 m3/h, respectively, and the vehicle cost was estimated 66.13 dollars per hour. Skidding cost based on the cost of finding the proposed agenda of the operational plan of the watershed, range and forestry organization per cubic meter taking into account the number of delays and without it were 11.3 and 7.7 dollars respectively. Total delays, departure time with and without load component constitute the most of skidding time by Timberjack 450C. The effect of variation of each variable on skidding time by Timber Jack 450C indicated that the increase of each variable will increase the cost as a power subject.

Tree felling is one of the most important component among tree harvesting components which consists of cutting and felling, limbing and bucking sub-stages. Tree limbing using chainsaw in hardwood forest is much effective and important. This research was carried out in two compartments of Namkhaneh district, in Kheyrud Forest for assessment of limbing sub-stage. The objectives of this study were time study of tree limbing operation, estimating the productivity and costs of chainsaw and developing regression model. Factor affecting total limbing time regression model was dbh of harvested tree. The hourly production of chainsaw limbing with and without delay time were 11.1 m3/h (4 tree/h) and 14.8 m3/h (5 tree/h), respectively. Productivity of chainsaw tree limbing is increasing with dbh as power. The unit cost of chainsaw limbing with and without delay time were 14710 and 11020 Rials/m3, respectively. Total tree limbing cycle time without delay averaged 12.37 minutes and with delay time averaged 16.51 minutes and also with reducing personal delay, work efficiency can be increased.

At forest ecosystems, gross rainfall (GR) is partitioned into throughfall (TF), stemflow (SF) and results in canopy interception loss (CIL). In the present research, CIL, which is considered a major component of the water balance, was measured at the midland of the central Caspian forests, Kheyrud forest research station of University of Tehran. Measurements were carried out in a sample plot of pure oriental beech (Fagus orientalis Lipsky) stand with an area of 5625 m2. GR was collected using three manual collectors in an open area approximately 160 m apart from the study plot. Thirty six TF manual gauges were randomly placed beneath the beech canopies and SF was collected from six beech trees with different diameters by means of the spiral type SF collection collars installed at diameter at breast height. GR, TF and SF were collected on an event basis using a graduated cylinder during the summer season of 2008. The amount of cumulative GR depth of 19 events was 206.8 mm allocated to TF, SF and CIL, 135.5, 4.2 and 67.1 mm, respectively. At the event scale, the mean values of TF, SF and CIL were accounted 64.7, 1.6 and 33.7% of GR, respectively. Regression analysis suggested a strong positive relationship between CIL and GR. There was also observed a fairly weak negative relationship between CIL/GR and GR. We concluded that CIL contributes a remarkable amount of incident rainfall in the pure oriental beech forest of the study site and therefore should be considered in assessment of water balance.