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Articles by Yahya Kooch
Total Records ( 9 ) for Yahya Kooch
  Ardalan Ahmadi , Asghar Fallah , Hamid Jalilvand and Yahya Kooch
  In order to determine the best form factor formula for Zarbin (Cupressus sempervirence var. horzontalis) in Kordkoy region (Golestan province-North of Iran), a number 54 trees were selected based on their distribution in diameter classes, from 8 to 28 cm (in a 2 cm diameter interval). First, several quantitative factors including diameter at breast height, diameter at 0.65 m of height and diameter at stump were measured using diameter tape, just before the trees being felled. After cutting the trees, the heights and diameter from breast height up to the height where diameter is 5 cm was measured using a diameter tape in a two meter interval. Finally, diameter at 0.1, 0.3, 0.5, 0.7 and 0.9 m of the total height was measured, respectively. As a consequent, each trees volume was precisely calculated as the real volume. Next, the real form factor (fr) was calculated and its average was statistically compared to the averages of natural (f0.1), artificial (f0.5) and hohenadel, s (fh) form factors using pair sample t-test. Results showed that there is no significant difference between the averages of Real and Natural from factors (at = 0.05 level). Hence, just Natural form factor is capable to replace the real form factor of Zarbin over the study area.
  Majid Lotfalian , Yahya Kooch and Nosratollah Sarikhani
  The aim of this research is to consider roads network quantity by reviewing the effective factors and finally determining the optimal road density. Sangdeh forests of Farim Wood Company were selected for this research that located at Savadkouh region of Mazandaran province (in Iran). In this research it is assumed that the effective factors in costs can be determined by using the mathematical model, as well as by the help of graphical model, less costs of skidding and road construction can be obtained; therefore, optimal road density can be evaluated. Harvesting methods, different types of roads, the ratio of each road to the whole network, stand per hectare, slope, geological conditions, presence of sand mine for constructing surface of roads, capital interest rate, wood exit costs, type of skidding or yarding machinery, slope and length correction coefficient, routes, type and number of load, allowable winching distance, brush and underbrush, condition of the roots, silvicultural methods (cutting form), regional soil, regional height, direction of the slope and morphology of the forest are factors which have been mentioned in this research as affecting determination of roads network density. For this, the model of evaluation and calculation of the time of skidder movement, which determines the skidding costs under the existing conditions in Sangdeh Forest, is as follows: Y = -25.05 + 1.20 X. For the forest region of Sangdeh with 353 cubic meters stand per hectare and skidding in contract method, the roads network density is 23 m in hectare and for skidding by the company, the roads network density is 19 meters in hectare; these numbers are the optimal ones.
  Majid Lotfalian , Zeinab Zadsar , Yahya Kooch and Masomeh Soleiman Nejad
  The objectives of this study were to estimate the quantitative damages on regeneration, comparison of industrial and traditional skidding operations and determine how to reduce utilization damages on regeneration and selection of the best method in North of Iran. In this research, the damages to the regeneration were investigated and compared by using of industrial skidding and traditional methods in Kheirood-Kenar forest (North of Iran). Also, according to this research, rates of damage to the increment groups (cores) of seedling, juvenile and sapling was surveyed. Results from this research showed that the rates of damages were 6.48, 5.34 and 9.57% in industrial skidding and 3.78, 5.34 and 2.13% in traditional skidding, respectively. As perceived, the largest rates of industrial skidding were on sapling group and also rate of the damage to the whole regeneration was 6.45% in industrial skidding and 3.48% in traditional skidding. In these two states most of the damages were in the shape of destroyed and the percentages of wounded samples were the same.
  Hossein Khalilpoor , Seyed Ataollah Hosseini , Majid Lotfalian and Yahya Kooch
  Forest road construction is including high costs as if in operations of road construction the saving be inappropriate thus, it is following more damages. Therefore, this study was performed for estimate of annual sediment mean in a forest road network of forest watershed in southeast of Sari city (North of Iran) using a sediment prediction model with considering to the effective factors. In order to, different data includes: topography, roads and also, precipitation mean were recorded. Result of this research showed that the SEDMODEL model with GIS is appropriate compound for using by road construction managers for prediction of sediment total. This result of it can be used for expansion of road construction in future.
  Asghar Fallah , Fazl Allah Emadian , Ali Akbar Rostaghi and Yahya Kooch
  In order to investigation of afforestation operation, Pinus brutia Ten. (Red pine) in Ghapan region (Golestan province-North of Iran) was selected. Planted stands were classified to three altitude classes of 200-400, 400-600 and 600-800 m. Mentioned afforestation was located in northern aspect with 16 years old, plantation distance of 2x3 m and with 232 ha-1 areas. In this study diameter at breast height, height, form factor, diameter increment and stand volume parameters were calculated. Statistical analysis was done by SPSS and EXELL software's in order to study the distribution of trees in diameter and height classes. Results of this research showed that diameter mean of trees were 12.40, 12.96 and 14.42 cm at the first, second and third classes also, height mean were 7.06, 7.22 and 8.02 m at the first, second and third classes, respectively. This study showed distribution of diameter mean at breast height and height was similar to normal distribution and also, volume of Pinus brutia Ten. were estimated 41, 47.41 and 95.80 silve ha-1 at the first, second and third classes. Mean annual increment of diameter were 0.91, 0.98 and 1.15 cm at the first to third classes, respectively. Totally, Quantitative characteristics showed regular changes with respect to different altitudes and 600-800 m altitude class had best results for quantitative characteristics.
  Yahya Kooch and Hamid Jalilvand
  Earthworms are considered as soil engineers because of their effects on soil properties and their influence on the availability of resources for other organisms, including microorganisms and plants. However, the links between their impacts on the soil environment and the resulting modification of natural selection pressures on engineer as well as on other organisms have received little attention. Earthworms are known to have a positive influence on the soil fabric and on the decomposition and mineralization of litter by breaking down organic matter and producing large amounts of fasces, thereby mixing litter with the mineral soil. Therefore, they play an important part in changes from one humus from to another according to forest succession patterns. Consequently, they are also expected to be good bio-indicators for forest site quality and are thus useful when planning forest production improvement. Earthworm`s populations are as indicator that in exploited regions is destruction indicator and reclamation plans is nature return indicator. In this study we summarized the current knowledge in relation to earthworm`s ecology in forest soils as ecosystem engineers.
  Yahya Kooch , Hamid Jalilvand , Mohammad Ali Bahmanyar and Mohammad Reza Pormajidian

This research was conducted in Khanikan forests located in lowland of Mazandaran province (North of Iran). Eighteen profiles were dug and several chemical, physical and biological soil properties were investigated. The soil properties evaluated were soil pH, bulk density, saturation moisture content, electrical conductivity, organic carbon, total nitrogen, cation exchangeable capacity, available phosphorous, soil texture, calcium carbonate content, number and biomass of earthworms, litter carbon and litter nitrogen. Principal Component Analysis (PCA) was used to identify the variation of soil properties. PCA, a technique which reduces the dimensionality of multivariate data by removing Interco relations among variables, has a number of useful applications in forest researches. The results showed significant relationships between some soil factors with PC1 and PC2 axes, also, among different soil factors, the distribution of forest types was most strongly controlled with some soil characteristics such as acidity, bulk density, texture, phosphorous, organic carbon, total nitrogen and cation exchangeable capacity.

  Kamran Adeli , Asghar Fallah and Yahya Kooch

In order to make the sampling procedure more efficient and more accurate to study the tree species richness and canopy cover, the appropriate plot size was calculated in the this study. The sampling was carried out using 48 four-hectare plots, each with 13 sub-plots of different plot sizes and 7 one-hectare plots, each with 7 sub-plots. The result of this study showed that 300 ARE plot size was determined as the best area for 1-5% density class, 125 ARE plots for 5-10% class, 150 ARE for 10-25% class, 100 ARE for 25-50% class and 75 ARE plot size to sample >50% density class, in 95% confidence level. Consequently, using 100 ARE sampling plots is suggested for all density classes in central Zagros forests.

  Yahya Kooch , Hamid Jalilvand , Mohammad Ali Bahmanyar and Mohammad Reza Pormajidian
  A TWINSPAN classification of 60 sample plots from the Khanikan forest (North of Iran) is presented. Plant types were determined from field observations and sample plot data arranged and analyzed in association tables. The types were defined on the basis of species patterns of presence, absence and coverage values. Vegetation was sampled with randomized-systematic method. Vegetation data including density and cover percentage were estimated quantitatively within each quadrate and using the two-way indicator species analysis. The objectives of the study were to plant type`s classification for Khanikan lowland forest in North of Iran, Identification of indicator species in plant types and increase our understanding in regarding to one of Multivariate analysis methods (TWINSPAN). Five plant types were produced for the study area by TWINSPAN, i.e., Menta aquatica, Oplismenus undulatifolius, Carex grioletia, Viola odarata and Rubus caesius. Therefore, at each step of the process, the program identifies indicator species that show strongly differential distributions between groups and so can severe to distinguish the groups. The final result, incorporating elements of classification can provide a compact and powerful summary of pattern in the data set.
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