نشریه علوم و فنون منابع طبیعی
سال چهارم شماره 1 (بهار 1388)

In implementing inventory design of forest many factors involving human force ,instruments, method, area and form of sample plat are fixed ; and sum other factors such as hindering bushes, average slope, ground's roughness, slipperiness, tree's number at sample plots are considered as variable factors. According to these parameters, the effect of them on measurement time on the tree's diameter and height, filling out the form and the time required for moving between sample plots at watershed 32 Teeroomrood of hyrcanian hard wood forest in north of iran were investigated. The results revealed that the average slops, tree's numbers and hindering bushes would influence on inventory time in sample plots. Approximately 651.97 seconds is required to complete inventory in sample plots: Moreover, the factors such as hindering bushes, average slops of direction, ground roughness and slipperiness, movement on contour lines with slope of more than 60% would influence on time of movement between sample plots. Approximately 310.41 seconds is required to travel each 100 meters between sample plots.

One of the important aspects of vegetation ecology is to be the pattern of spatial distribution of plants, which awareness of that would be the preliminary and necessary condition for vegetation in each region. The order of distribution and the placement of the Deadwood determines the pattern of the location of the Deadwood in forest which is related to the structure of the forest. The present study has been carried out to examine the spatial pattern deadwood in managed and unmanaged stands (the site is located in Kheiroudkenar research forest - Nowshahr). For this aim, two regions with relative identical conditions in physiography in an area of about 10 Hectare in Fagetum community were selected. All the present sampling in this area have gone under statistical examination. Then, Ripley’s M function for obtuine the spatial pattern of deadwood, the general form of Ripply were used. The results showes that the distribution of the deadwood in surface unit in both managed and unmanaged regions are in the cluster form, therefore in the managed region in the distance of 4-40 m shows more difference than that of the managed region.

In order to investigating on the Situation of hardwood and softwood afforestation in Karaj City, moradabe park around 16.5 ha, including (hardwood Species tree of heaven, black locust tree, ash, Mulberry) and Softwood Species (pinus eldarica and arbor have been vitae) have been Selected. In this study, tree Species with more than 7.5 Cm Diameter at breast height full callipering. In addition, for evaluation of afforestation success, the quality and quantity factors maturated from hardwood and Softwood. Quantity Study included the measurements of diameter at breast height, height, crown height and slenderness ratio diameter-height distribution and quality Study included vitality condition color and leaf (Needle) density. (t Test) applied for quantity data analysis as wells as Man-Whitney test for quality data. The results of this study indicated that there are significant different between the quality and quantity Values of hardwood and softwoods species. In terms of total quality and quantities factors, softwoods showed better results than hardwoods. There for, for developing plantation with hardwood species in Karaj city, are Suggest the mixed plantation hardwoods and softwoods which will cover the landscape purpose as well.

The inventories shows that a decreasing trend of vegetal covering in the recent years. This decrease are differs in different areas of land in Iran,where these plants grow in the forests of north of Iran, this phenomenon is not seen only in the mountains areas but also in coastal and Low-level areas so that different species of plants are destroyed. Punica granatum L. which growth on the beach of the Caspian sea, is not exceptional. This study was carried out to specifying the social condition of punica granatum L. species as well as the qualitative and quantitative characteristics of that species. in the west of Mazandaran(from babolsar to ramsar). Therefore, seven areas were specified and the required studies had been done. The results shows that punica granatum L. speoies have better grown from candition babolsar to ward ramsar, Because of the long distance of villages from the sea, decrease in the rains and suitable climate. So, this species can be suggested as the genetic storage in agriculture and also as a protected species which that nobody is allowed to cut them.

Ash is one of the valuable species in the north part of iran, particularly in the arid valleys that has settled on the lowlands to high lands areas. In respect of abundance seedling production of this species, a large amount of seeds is needed each year, but large seed bearing occurs every two years in the stable and optimal environmental condition and also ash seeds have morphophysiological dormancy. Therefore clearly in some years we countered to seed deficiency. Good programming for seed collection has a critical role for obtaining success. Because delaying of seed collection cause serious decrease in seedling production amount. In this study effect of humidity losses evaluated in immature seeds on germination percent and humidity losses cause deeping seed dormancy and decrease of germination percent(P

Fish breeding plays an important role in economic factors and health system of community as nourishment and economic point of views. Thereby, in order to increase efficiency, regarding breeding parameters, such as biological, environmental and hydraulic characteristics are of great concerned. In the present paper, hydraulic and hydrodynamic such parameters of fish habitat for its optimum designing are concerned. Thereafter, hydraulic efficiency coefficient as an effective factor were investigated. In order to calculating hydraulic efficiency, a three dimensional flow solver in fishery Lake for obtaining flow filed characteristics is utilized. Navier-Stokes governing equations in Cartesian system by means of finite volume techniques are used for three dimensional modeling. In addition k-ε two-equation turbulence model is exploited for calculating stresses due to turbulence.

In this study, the effect of immersion temperature on the short-term water uptake behavior of lignocellulosic fillers- HDPE Composites were investigated and then compared with the wood based commercial panels. panels of wood plastic composites (WPCs) were manufactured from different lignocellulosic materials of wood sawdust, rice hull flour and sawdust of particleboard (as filler) and powder of high density polyethylene( as polymer) at 60% by weight filler loading with constant temperature and pressure using a dry blend/hot press method. The nominal density and dimensions of the panels were 1g/cm3 and 35×35×1 cm, respectively. Specimens of the panels of wood plastic composites, medium density fiberboard and particleboard were immersed in distilled water at 20, 40 and 60ºC to measuring water absorption and thickness swelling after 2 and 24 hours immersion. The results showed that by increasing the immersion temperature, the water absorption and thickness swelling increased. So the water absorption and thickness swelling were affected exponentially by immersion temperature. Maximum values of water absorption and thickness swelling at various temperatures showed in particleboard and minimum values showed in HDPE/rice hull flour plastic composites.

Cypress tree is one of the species with unique natural durability and there are in a lot of natural and planted forests in Mediterranean region in Iran. In this study, three trees from two species of natural and planted cypress tree were randomly cut down in Hasan-Abad region of Chalous city. Then from each tree three disks were slected, then and wood flour and prepared and the extractives were measured according to TAPPI standard. The results showed that the extractives decrease in the longitudinal direction. Of tree The average of extractives in natural and planted cypress tree are 7.52 and 2.57 percent respectively. Then wood flour was washed by toluene – ethylic alcohol with the 2:1 ratio, and the extractives residue was added BSTFA reactor and samples kept in Ben Marry Bath in 70oC for an hour, then analyzed by GC/MS. For the identification of component the GC diagram which shows abundance and retention time of each compound, calculation of quartz index and Adams table were used. Generally, 14 compounds in natural and 12 compounds were definited in planted cypress tree. The isophyllocladene, 9-octadecenamide, cinnamaldehyde-2-hexyle, bourbonanone and 1h-naphtho[2,3-c] pyran-3-acetic acid were the important components in either species and these compounds are very important role in durability of cypress tree.

Grazing management and the balance between domestic animal and rangeland need to complete information about rangeland ecosystems and identification of relation between vegetation and livestock. Thus, this research have been studied on the effect of different utilization intensities on vegetation changes in winter rangelands of Miankaleh. After identifying the utilization units, sampling was done in each area with transect-quadrate and systematicrandom method. Number and size of plot identified by statistical and minimal area method, respectively. Then, canopy cover percentage, Frequency, production and palatability of species was recorded in the plots. At last, data analysis was done with variance analysis and means comparison. The results showed that the Gramineae family had more frequency in different grazing intensities, which shows that the Miankaleh rangelands have high vegetative potential to this family nevertheless changes of grazing intensities and dominant species changes from critical to reference area. Also, the effects of low grazing cause to appearance of Trifolium pratense in reference area.