نشریه تحقیقات منابع طبیعی تجدید شونده
سال دوم شماره 4 (پیاپی 6، زمستان 1390)

Planning and performing preservative programs to revive and reform natural resources decrease the corrosion of these resources, but also guarantee sustainable development and local communities’ partnership. This research’s aim was to study obstructions regarding the reception of grazing management project from the viewpoint of natural resources expert. The statistical subject group included 50 experts (either working or the retired who had experiences of inventory, preparing range management plans, supervising and management of plans. The sample number derived from Cochran relation was determined by 43. The results showed that there is a significant difference between reception obstructions and grazing management project from the viewpoint of experts. The study of each index of reception indicated the scarcity of winter ranges can be the greatest challenge in reception of performing grazing management project. Ranking of the variables based on correlation intensity indicated that forage insufficiency and high price, the inadequacy of low profit loan , reluctance to ownership due to weak control and monitorship have the most correlations with grazing management project. Whereas, there is no major correlation between the grazing management project and the users’ amount of share, and the level of competence and awareness. In addition, the results showed that there is no meaningful correlation between the obstruction of GMP reception and the experts’ experience, education, and the contract model they have signed with their organization.

The reciprocal effect of sustainable and unsustainable ecological resources is considered in the course of assessment of ecological capacity. These resources have reciprocal effects to each other and environment as specifications of each micro ecosystem. So, it is obligatory to utilize nature as it less harms environment and at the same time it benefits human more. This is not obtained unless all effective factors and phenomena in environment are considered. In this research, to assess the ecological capacity for surface expansion of forest based on principles of reclamation of land, one of the sub- areas of Karkheh that is called Dadabad sub- area in Lorestan Province was studied through geographical information system (GIS). At first, the basic studies were done and the theme maps of the area were prepared and then numerated. Then, there were the data analysis and the collecting of layers in the GIS environment and finally the map of environmental units of area with 1581 units were obtained. In the next step, the limited areas were omitted from the map of the primary environmental units, with identifying permanent and absolute limitations in each indicator and through booleen (boolin) logic, and for surface expansion of forest a total of 1110 units with a total area of 17482 hectars were obtained without any limitation for assessing ecological capacity. After that, three separate maps were prepared and coded by differentiation of the map of soil (units and sub- units of lands): the map of measure of the organic materials, texture of the soil. Then, using bipolar distance scale, the coded qualitative values were changed to quantitative measures. These coded qualitative values in the list of descriptive data related to seven indexes included: slope, bearing, altitude, depth of the soil, texture of the soil, measure of organic materials of the soil and susceptibility to erosion that were selected as main indexes for surface expansion of forest. Next, by EC software and the process of hierarchical analysis the hierarchical structure was prepared for the considered indexes, and the objectives and criterions and relation among them were established, and in the next phase, weight of the indexes, distinction to them and studying the logical consistency of judgments were established. Final weight of each index was determined by SAW method. Then, the reciprocal effect of all the indexes related to the record of data as a final value was obtained by collecting all collective values for each record of data. Then capacity of the lands was classified in four classes of capacity for expanding forest (by considering the available values, nine is highest value and 1 is lowest value). Afterward, in the chart of descriptive data based on the available categorization, the final value. At the end, by considering the accomplished researches class of capacity 1 and 2 was selected for p

Development of tourism in preserved areas has many advantages both for their management and for tourists. But we should consider that tourism activities can have negative effects on tourism experiences and tourist resorts qualities and characteristics in the absence of an appropriate planning and management and without determining the capacity and capability of the area. Therefore, determining suitable areas for expansion and development of tourism in preserved areas and national parks is crucially important for sustainable exploitation of natural resources. Golestan National Park, as one of the preserved areas, has many significant tourist attractions. This study used weighted linear method, AHP and GIS to determine suitable ecotourism sites in this area. The criteria used in this study included the distance to the river, to the road, to the village, to water sources, to wildlife habitat, and the distance to slope and vegetation densities. Finally, appropriate areas for ecotourism with different degrees of suitability were determined. According to the classification map, the regions with very high potential have the minimum area of 0.25% and the regions with the high potential have the maximum area of 12.5% of the total study area. The research results indicated that the AHP weighting method and WLC method has high applicability in tourism site selection studies.

This study was conducted with the objective of investigating the feasibility of making wood-cement using Poplar sawdust and Portland cement. A total of 48bricks were made in the laboratories of Technical Teacher Training Faculty of Somesara based on ratios of sawdust to cement (3:2 and 2:1) and 100×100×100 and 50×50×50mm dimensions. Mass and volume of samples were measured and then density of bricks was calculated. The composites were tested for compressive strength using testing machine. The mean compressive strength values were 1.17 N/mm2 and 1.25 N/mm2 for 100×100×100mm composites with sawdust to cement ratios of 2:1 and 3:2 respectively, and 0.85 N/mm2 and 0.99 N/mm2 for 50×50×50mm composites with sawdust to cement ratios of 2:1 and 3:2 respectively. Soaked composites swelled irrespective of the sawdust to cement ratio. The compressive strength for the soaked bricks was approximately 45% of the dry weight strength. The composite bricks were found to be unfit for paving and medium heavy load wall construction. Due to their light weight, by imparting decorative mosaics they can be used for interior wall paneling and decoration, where minimal wetting is experienced.

This research is to study the ultra sound wave parameters including slowness and attenuation of two Picea abies species as well as defects diagnosis (artificial) through tomography method. For this purpose, two roots of this species were prepared from Ojabit woods of Kelardasht zone in Mazandaran province. To perform the test, 15cm thickness discs were prepared from each root stock in three different states: with bark, without bark and defected (artificial hole). In order to do the measurement, ultra sound wave parameters were used. The measurement technique of this research was direct contact and 55 KHz wave frequency. The results showed that as the ultra sound proximate the wood pith, the wave slowness and attenuation coefficient increase and by moving from pith to the wood bark, both factors show reductions. In addition, the results of tomography showed that it is possible to diagnose the defects through measuring the attenuation factor. Although no impacts of bark existence were found in the pictures, the pictures that were taken by attenuated factors revealed defects and bark.

Effects of immunogen supplementation on growth index, survival and body composition of the Pacific white shrimp (Litopenaeus vannamei) (3.0±0.19g) were investigated for 8 weeks at a stocking density of 15 shrimp per tank. Commercial shrimp diet was supplemented with 0 (control), 0.05%, 0.1% and 0.2% Immanogen in a totally randomized design trial in triplicate groups. There were no significant differences in growth parameters between fish fed control and immunogen supplemented diets (P>0.05).The average increase in body weight, percentage of body weight gain, specific growth rate and net production generally enhanced in shrimp fed on diet containing 0.1% immunogen. Feed intake (%/day and g/shrimp) increased in shrimp fed on diet containing 0.1% immunogen (P<0/05). No significant difference in body composition was observed (P>0.05). The experiment indicated that the immunogen did not the increase of the growth performance of pafific mhite shrimp and it is not appropriate for supplementation in the diet Pacific white shrimp.

Soil organic carbon storage which is mainly considered as a preliminary indicator of soil quality in natural resources, environment and agriculture studies represent the absorption of atmospheric carbon dioxide. Food and Agriculture Organization (FAO), has announced that agriculture and earth lands make one-third of global warming and climate change. This is due to inappropriate management and land use change. In this study, some areas are considered in Semnan province with Artemisia sieberi dominant species which conversion of nature to crop lands is common. Then, in order to determine changes in soil carbon storage in Hordeum fields and its adjacent rangelands a control treatment (Artemisia sieberi shrublands) in every site and two Hordeum treatments in Ivanakey and one treatment in Sorkhe were selected. Soil sampling of treatments was selected in depth of 0-50 cm and with the number of three profiles and five profiles in control areas. The average of carbon storage per hectare of Hordeum lands in Ivanakey was 40.3 and 30.9 ton which make 15.2 and 11.6 % of carbon storage of region. Hordeum cultivation in Artemisia sieberi shrub lands leading to increase 120.5 and 69 % content of carbon storage in Sorkhe region were 35 ton that consist of 13.6 % of total area of region and make decrease 55.2 % of carbon. The average of carbon storage in Ivanakey and Sorkhe were 16.07 and 40.2 ton /ha respectively. Results of independent t-student test imply that there is not a significant difference between carbon storage in two land use (rangeland and Hordeum field) as well as areas separately, Ivanakey. There is significant difference at the level of %5 but there is no significant difference in Sorkhe.

In this research qualitative characteristics of the sapling of 17 regeneration groups within gaps and seven regeneration groups under closed canopy were studied. For this purpose, all of the woody saplings were sampled in 3 gap classes: i) seven small gaps (d/h ≤0/5), ii) seven medium gaps (d/h = 0/5-1) and iii) three large classes (d/h >1). In this classification “d” stands for largest gap diameter and “h” means height of edge trees around the gap. The results showed that the gap size had major effect on qualitative characteristics of maple saplings at confidence level of 95%. The frequency of medium quality class (forked) of maple saplings that is a light demanding species in small gaps was more than those in the medium and large gaps. In addition, the results indicated that beech sapling under crown canopy had lower quality than those in gaps.