نشریه علوم و فنون منابع طبیعی
سال ششم شماره 1 (بهار 1390)

One way for decreasing flood damages, particularly in the case of soil and water loss, is the design of water spreading system in the low slope regions of watershed. This is more suitable for regions that are located in the arid and semi arid climate. Many studies show that the sediments that are transported by flood from other regions of watershed to the water spreading site cause variation physical and chemical properties of soil in the water spreading site. The study area was located in Jajarm، the northern khorasan province. For measuring variation properties, 20 samples were selected from inside and outside of the site (none water spreading site) separately. Depth of sampling was 0 -20 centimeters. Results show that there is a significant difference for the increase of clay، silt، saturation percentage،Ec، organic matter،N،P،K and the decrease of Sand and pH، inside the site in comparison to the outside. Hence, it can be said that water spreading system will be suitable for the improvement of some physical and chemical properties of soil, particulaly for soil texture and the increase of soil fertility.

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.

Little is known and studied about the effects of single selection method on the biodiversity of Hyrcanian forests. In this research after ten years, the effects of single selection method on tree species diversity were studied in 2 parcels with 105 ha of Asalem-Nav forest area. Systematic sampling design at the begining (2000) and the end (2010) of forest management plan with 100m grid dimension and 1000m2 circular shaped plots were used for data collection. Species diversity indexes in each plot were calculated and those averages in two sampling were compared through ANOVA and t- test. The results showed that species diversity index increased slightly in the four layers of seedling, large sidling, sapling and tree, but this amount of increase was not statistically significant. The increase of species diversity index in seedling and large seedling layers were due to the increase of richness index of those layers, but in sapling and tree layers were created due increase of evenness index of those layers. Index of species richness was decreased in tree layer. Therefore, SIV (species importance value) of Fagus orientalis and Carpinus betulus decreased, but SIV of Acer velutinum, Acer cappadocicum and Alnus subcordata increased. Cosequently, we can conclude from the result obtained that selection method is suitable for these stands, but tree species diversity can be conserved in the future along with timber production when enough attention is paid to the index of tree richness and tree SIV at the time of tree marking.

The objective of this paper is to evaluate Leaf Area Index at Robinia Pseudoacacia. in affrostration area of about 89 hectares located in the northern part of Malayer was selected as the study region. The leaf area index was determined by direct method and by collecting all the leaves from the 20 samples (from medium diameter of each diameter class) and measuring the mean leaf area, the crown cover area of each sample was calculated. To determine the soil properties and its relation with the leaf area index, samples from the depth of 0 - 10 and 10 - 30 cm were selected. Physical and chemical properties of soil samples were determined in the laboratory. As a result, the leaf area index of Robinia Pseudoacacia species was 3.78. which the diameter class increased, the Leaf Area Index increased too. The significant relations were statistically observed between the slope and Leaf Area Index. Considering the stand and soil characteristics, the aboveground biomass, diameter at breast height, height, percentage of nitrogen, organic carbon and silt showed the maximal correlation with the leaf area index.

To control landslide phenomenon in a catchment, one of the fundamental tools is identifing and zoning the hazards that affect this phenomenon, to select the most suitable and applicable options. To achieve this purpose, the current study was designated to identify the affecting factors which cause landslide phenomenon and the potential areas to prevent the occurrence of this phenomenon in district 3 from catchment 48 Galandrod forests, Northern Iran. The most important factors involved in the occurrence of landslide hazard regarding the previous studies was identified. The input data included preparing slope, aspect, elevation, fault, river, road network, geological and soil maps as well as precipitation and temperature diagrams based on geographic information system (GIS). Then, using geographic position system (GPS), 10 locations on landslide and control areas were delineated in the field. For the next step, these areas were layout in GIS. The results showed that soil texture of the study area was consisted of three textures; loam-clay; loam-sandy and loam-clay-sandy. Results show that threshold bed slopes susceptible to landslide in disturbed and control areas were 20 and 50%, respectively. These results suggest that human interference had been more effective in causing mass movement of landslide than natural factors such as slope, hydro-climate, vegetation or soil properties.

In this research the vegetation diversity in the managed (under exploitation parcel) and unmanaged (control parcel) forest study of Fagus- carpinetum have been studied and compared regarding species richness, simplexity, and species diversity index in Golband forestry project, series 8 (Laroochal). Data collecting with 100 and 150 system dimension was randomly- systematically accomplished in 60 sample parcels in an area of 400m2 in a 140 hectare land (5 micro plots with 1 * 1 dimensions has been considered in every plot to count the number of grassy species). The number of dendroidal species in every sample plot and the number of grassy species in every micro plot were written. The mean of different diversity indexes in every sample plot was counted to analyze data and the statistical independent T test was used to examine the significant difference between the mean of indexes in two parcels (managed and unmanaged parcels). The results show that in the managed and unmanaged parcels the mean of dendroidal species richness index is,shanon simplexity index,shanon species diversity index,simpson species diversity index is 2.83, 3.37, 0.78, 0.71, 0.57, 0.79, 0.34 and 0.43 respectivly. In addition, the mean of grassy species richness index,shanon simplexity index,shanon species diversity index, and the mean of simpson species diversity index is 12.8, 13.36, 0.56, 0.59, 1.93, 0.2, 0.79 and 0.80 repectivly.

Tending of forest is the most important part of applied silviculture activities, covering all subjects which are related to stand structure tending. By applying tending operation, the resistance and stability of trees will increase against natural disasters, furthermore by preparing a suitable condition for other trees, the diameter, height and finally wood production will also increase. The purpose of this research is comparing and analyzing the quantity and quality of acer velutinum boiss species characteristics in sample stand or non-managed stand in parcel no.2 and managed stand (in parcel no.13) of the second series of "berenjestanak". The area of the parcel is 30 hectars, the statistic method is systematic and random,the net dimensions is looxloom and the area of each sampling plot is 4 Ar. the results showed that the mean in one hectare in the sample stand is 1365 and in the managed stand is 977. The average diameter of trees increased from 13.45 cm in the sample stand up to 16.40cm in the managed stand. Furthermore, the volume average in one hectare increased from 164.2 m3 in sample stand upto 188.5m3 in managed stand. The stability coefficient of sample stand and managed stand was estimated 105.5 and 99.4 respectively. The statistical tests showed that there is a significant differance between the averages of quantitative parameters of two stands in 95% confidence level and equality of averages (zero hypothesis) is rejected. Regarding the quality, the managed parcel trees are in better conditions compared to sample stand trees.

Due to some changes which are created over time in the olive cultivated fields preparing updated map of the olive orchards is one of the most important requirements in the management region agricultural planning of the region. In this research, olive orchards were studied using IRS Satellite images in the region including some sectors of Roudbar, Manjil, Loshan and Abbar, Guilan, Iran. For this purpose, 248 land control points were studied taking into consideration the surface cover. Helping and training points of different land covers were prepared to place on a sample set of color composite (bands 1, 2 and 3). The mean and standard deviation of training and auxiliary pixels of olive orchards was calculated. Upper and lower limits of DN-olive orchards were distinguished by adding standard deviation to mean or subtracting that. In each band, olive limits were introduced to the software and slicing method was used to prepare olive map. Final map of olive fields was obtained by overlapping these three maps. The olive orchards map has been crossed by training point map to calculate the accuracy of method. The results indicate that in the classification of images with spectrum reflex statistics, more than 70% of training points had again been classified in the olive orchards class.

This research was carried out to investigating the effect of bleaching on optical properties of CMP pulp treated with P.Chrysosporium fungi. After preparing the fungi sample, provided chips of Carpinus betulus were treated under 39 °C and 65% relative humidity condition in three distinct times of 1, 2, 4 weeks and untreated as control sample. sample to prepare the CMP pulp from treated chips, pulping temperature was adjusted at 165 °C, pulping time at 80 and 90 minutes, and 14 and 22 percent of chemicals charge (sodium sulphite) were used and the ratio of pulping liquor to chips were 7 to 1. CMP pulps were bleached with hydrogen peroxide and then handsheets with basic weight of 60 g/m2 were made. Thereafter, optical properties of handsheets were measured. Results showed that fungal treatment, time and chemical have significantlyaffected the brightness and yellowness of handsheet paper samples. The fungal treatments caused a significant effect on handsheet paper samples had opacity. But the effects of chemicals and time is not significant on the opacity of handsheet papers.The results show that among all treatments, bleached pulp with 2 weeks treatment exhibited better optical properties than the others.

The Present study is to achieve optimum environmental management state.The study was performed in Safarood forest Park with an area of 55 hectares. Safarood is one of the most important parks in Iran which located in Ramsar provience. In this Study two efficient methods in environment management include of AHP,SWOT were used. In the First step, by using Analytical Hierarchy Process (AHP), the most appropriate function for this area was selected. Then, by using SWOT method. and field studies, the strengths and weaknesses (internal factors) of the region, and the opportunities and threats (external factors), had been specified. Hereafter, some strategies to eliminate weaknesses and threats, and fortifying the strengths and opportunities were adopted. Finally, the strategies were given marks based on their priorities and they were acceted in the Environmental Integrated Management Program of the area.