نشریه علوم و فنون منابع طبیعی
سال ششم شماره 3 (پاییز 1390)

Today flood is a destroying natural disaster that sometimes damages natural ecosystems in large scale that are uncompensable. Increasing current of flood occurrence and its financial and human damages has been the cause of studying this subject in regional scale in different areas. It is necessary to simulate hydrologic behavior of watersheds in order to combat flood risk. This study aimes to prioritize of effective zones on peak flood discharge or to distinguish the areas that have more flooding potential in Sheikh Bahaee dam basin located in Esfahan province, kashan township, using HEC- HMS hydrological model. Results showed that areas located near basin outlet play the most important role in flood production and so should have more priority in watershed management practices. The obtained results can be very much helpful to region monitoring system.

For advancing the efficiency of control, reclamation, reconstruction project and for preventing of wasting limited resources, it is clear that in desertification projects, a method is needed to cover different benchmarks and alternatives and provide optimal solution basea on systematic structure and group aspects. It is observed that the alternatives provided based on the view of the experts, partial, de-systematic and non-multilateral. There is not enough background in using systematic models such as: Multiple Attribute Decision Making (MADM) in combat desertification. Because, this study tries to use Analytical Hierarchy Process (AHP) and systematic model Technique for Order Preference through Similarity to Ideal Solution (TOPSIS), to provide optimal alternatives in combat desertification. In this study the opinion of experts about alternatives and criteria were assessed by using Delphi method and Pire wise comparison and with the application of EC software, Then final preference for the alternatives was obtained with forming decision matrix in the framework of TOPSIS method. On the basis of obtained results unsuitable land use alternative with relative convergence of 0.766, vegetation cover development and reclamation with relative convergence of 0.576 and modification of groundwater harvesting with relative convergence of 0.403 were determined as the optimum combat desertification alternatives in the study area.

Wind erosion is one of the most important and serious problems in most regions of the world and Iran. Measurement of wind erosion is always difficult and there are a time and a local limitation for it. Therefore, using models for its estimation is an important subject. In this study, the IRIFR model is applied for the investigation of wind intensity erosion and estimation of potential sedimentation, which the is result of wind erosion. The area of study region is 88350 ha, located in Sistan and Balochestan Province. Results showed that about 0.88, 6.73 and 25.52 percentage of areas under study are located in 3 classes of medium, high and very high wind erosion intensity, respectively. Furthermore, the potential sedimentation is about 24171.76, 19254.5 and 633.46 ton/km2/yr for each class, respectively.

Lack of proper maintenance and garbage collection gathered in the forest area In addition to making the area ugly will cause soil, air and water poltution. Based on this study, the forests in the series 2 Palhamkooti and Chalous landfill were chosen to evaluate the effect of wastewater on forest trees. Thus, the first five zones were selected in the region and in each zone about 20 meters in width with one hundred percent characterization in diameter, height and health of classes of healthy, drying and try were measured. The results show that in zone two the largest volumes and percentage of species are related to dry Hornbeam and highest volume and percentage of species in dry category is related to the oak. In the third zone the highest percentage is about hornbeam and oak. Highest percentage of species in four the zone is the dry Hornbeam, Maple and Ironwood. In the fifth zone the most species which are drying are Hornbeam. In sum, in zones four, two and five respectivel, most trees are dry or drying while in zone three most trees are healthy in the study area.

In order to modify kiln drying schedule for Beech (Fagus orientalis) lumbers of 7.5 cm thickness they were commercially cut from Sari region Nekachoob forest management plan. Three schedules namely (T4-D3, T4- D4and T5-D4) were adopted for drying the Lumber down to the final moisture content of 8±2 %. Dry bulb temperature of first two schedules was adjusted at 43˚c and 49˚c (for first and second kiln load respectively), while the final dry bulb temperature of all tree kiln schedule was adjusted at 71˚c respectively. Specific gravity (based on oven dry weight and green and dry volumes) of test materials were0.52&0.61, and radial, tangential and volumetric shrinkage were measured 5.8, 10.2and 16.46percent respectively. Physical characteristics, surface checks and warp of the lumbers were measured before and after the drying process and quality control methods were used to analyze the wood defects. Results showed that drying of Beech lumber using each of the three schedules was satisfactory; however the second schedule (T4-D4) had better drying characteristics than the others. At the end of this schedule, it is recommended to use 24 hours conditioning treatment if required.

Black locust wood species is considered to be very durable, which is cultivated asa random tree figure and, as a plantation species in the most of country regions, especially in the semiarid and arid areas (Karaj) in order to create green place and soil nitrogen fixing. Extractives was done using ethanol solvent for 15 days. The percentage average of black locust heartwood extractives was determined 16.6. Identification of chemical components in the extractives samples were done by using GC/MS technique. Generally, fifteen compounds were identified with different percentage in heartwood. The most abundant compounds identified in the heartwood of black locust species was (23S)-ethylcholest-5-en-3.beta.-ol which were observed at about 18.33%. The most important identified saturated and unsaturated fatty acids in the heartwood of this species were Hexadecanoic acid (0.31%) and 9,12-octadecadienoic acid (Z,Z)- (0.47%), respectively. The other main identified sterols in the heartwood of this species, uhich is present in the most plant species, was stigmasterol (13.75%) and campesterol (3.53%).

Analytical Hierarchy Process (AHP) is one of the most extensively used and multi-criteria tools for decision making. Monitoring the management of Khoshkehdaran national and natur area using the AHP method would suppose to be practical by the Expert Choice software in this study. First, the level of hierarchies including goals, criteria, sub-criteria and alternatives were determined. Then, a double-compareison among the complexes was done for scoring. While scoring the complexes, an analysis of the Inconsistency Index was made for decision making to be less than o.1.At the end, all of the mentioned criteria and sub-criteria were mutually compared and were displayed diagrammatically. Khoshkehdaran national and nature area in Tonekabon city was selected in this study as the area under investigation. It has been a protected area since 1355. The goal of the current study was the determination of the most appropriate application for the area by employing the Expert choice software. The criteria consisted of "Geomorphology", "Environment "and "Climate" as well as the corresponding sub-criteria specific for each single criterion. Finally, from among the three alternatives suggested "area protection" was shown to be the best choice with the highest allocated score. "Ecotourism" was ranked the second and finally "optimization "was ranked the third.

Iran has an important role in global biodiversity due to its ecological diversity. This variety creates natural attractions for tourism as an outstanding universal value. due to the effect of tourism on various biodiversity indices including diversity richness and evenness. To do this research in chaldare park tourism region the study area was divided into 3 zones including: low-tourism pressure and medium-tourism and high-tourism pressure. 5 Sample plots with an area of 100m2 with quadrate shape were selected with systematical random concentration of woody spaces. Some micro-plots with an area of 4m2 were selected per sample plots, furthermore; soil samples were collected per sample plots and were analyzed in lab. The results show that high-tourism pressure has significant effect on decreasing the number of plant species, plant richness and diversity and increasing soil density and evenness.

Unfavorable conditions of cities, the shortage and the deficiencies of open and green spaces in large cities of the country require paying attention to parks and green spaces of the city. Ecological and social activities which are the foundations of the city's stability have elevated the quality and the livability of the cities, while being effective in its beautification in order to make the city's living environment more desirable. The elimination of the current deficiencies in these parks is often known as their restoration. In this research, the ParkShahr as the first public park of the city of Tehran has been studied because of its environmental values, its functionality, culture and beauty and the study was done on the basis of descriptive-analytic method. Thus, all the current physical, biological, social, cultural and functional specifications of the ParkShahr in the current conditions have been analyzed. Then the analysis of the outlook and the view as a pictorial-analytical method (Simon Bell) and the analysis of behavioral patterns of visitors by utilization of questionnaires have been done. Finally, the results showed that the principles related to the techniques of restoration and reclamation of ParkShahr will put emphasis on improvement of ecological and social quality. SWOT method was used for the restoration of ParkShahr.

Management activities like land cultivation will crucially affect rangeland characteristics. For sustainable utilization of rangeland to have information of these changes is needed. The aim of this research was to investigate the effect of land use exchange from range land into land farm so that soil physical and chemical properties were included. The study area is Kohne lashak 65 km from nowshahr. In order to analyse effects land use exchange on physical and chemical properties, 63 soil sampies from 0-30 cm depth were gathered and transported to laboratory. Soil properties such as; soil texture, PH, EC, bulk density , organic material, organic carbon, calcium, mg, phosphor and lime were measured in laboratory. Afterwards, data normalization and analyses of data were carried out using SPSS statistical packages. Results showed that EC, bulk density, organic matter, organic carbon, calcium, magnesium, phosphorus and lime decrease as a result of land use exchange, PH did not change by land use exchange and the changes have further changed soil texture from loam into clay loam.