نشریه حفاظت و بهره برداری از منابع طبیعی
سال یکم شماره 2 (1391)

Compartment 7 of Vashmard was a part of watershed 38 of Sardabrood which is located in landscape of the most famous touristic plan and in minimum distance from the high-traffic Chaloos to Tonakabon coastal road through which millions of passengers pass or stop by every year is less than one kilometer. In this paper, we have provided a model for preparatory zoning for tourism development based on multi-agent evaluation approach. In the mentioned model weighing to criteria has been used with analytical hierarchy process in AHP and spatial analysis in GIS in order to provide an optimum display of the land ability for tourism development at three categories of very favorable, favorable and unfavorable. Results have shown that 51.11 percent of the entire compartment belongs to the favorable zone for tourism and 11.61 percent belongs to the unfavorable zone for tourism. Also distribution of the zones showed that unfavorable zones are mostly found in steep parts and field studies have shown that they are not recommended for tourism.

Major challenge in today's world, especially in arid and semi-arid regions are warming and climate change, caused by greenhouse gases. One of the known solutions that reduce atmospheric carbon and help to improve the situation, is carbon sequestration in vegetation cover and soil. In order to estimate the sequestered carbon in forest stand and soil of Pinus eldarica plantations in Taleghani and Chitgar Forest Parks (in Tehran) sampling points were chosen after the sampling network were determined on map, then 10 circle plots were considered with the radius of 4 m in both parks and the Sequestered carbon were measured in trees (trunks and roots), grass cover and soil (0-20 and 20-40 cm), in addition some of the most important soil properties, soil texture, acidity, Soil bulk density, electrical conductivity, organic carbon, total nitrogen and carbon were measured in the laboratory. Results showed that the amount of sequestered carbon in both 20-0 and 40-20 cm depth was significantly (P <0.01) more in Taleghani Forest Park (25.51 tons per hectare and 20.00 ha respectively) than Chitgar Forest Park (21.06 ha and 9.61 ha), also the amount of activated Carbon, which is the most important effective components on soil organic carbon, in both studied depth in Taleghani Forest Park were more than Chitgar Forest Park. According to the results of this investigation it can be stated with confidence that in forest ecosystems, soil is considered as the most important organic carbon reservoir and its appropriate management increases fertility and productivity and land protection and utilization in order to create an appropriate strategy to reduce atmospheric carbon dioxide.

In order to study the relationship between diameter and dependent variables and to determine the percentage of industrial and firewood volumes of beech species, compartment No.2 of Asalem forests was selected. The 10-year data of beech volume measurement were extracted from cut and volume renewal permits. The number of measured trees was 1163. The volume percent of industrial and firewood was calculated for various diameter classes of sampled trees during 2001-2009. Also the mean of percentage of industrial as well as firewood volume of sampled trees was calculated for each year and for all years altogether. Different models were fitted and then the validity of the models was evaluated using SAS software. The results showed that among the suggested models, the parabolic model had the highest correlation. Results also showed that the percentage of industrial volume with DBH less than 35 cm has decreased and with increasing in diameter classes up to 80 cm, the percentage of industrial volume increased and then decreased.

Iran is one of the most important habitats of Astragalus growth in the world. Astragalus spp are valuable for their forage, medicinal and industrial usage and soil conservation. In this study quantity factors were investigated by measurement of vegetation parameters (canopy cover, production, density and height) and quality factors were evaluated by measurement of crude protein, crude fiber, acid detergent fiber, dry matter digestibility and metabolic energy. Data were analyzed using SPSS software package and means comparison was performed by Duncan multiple range test. Results showed that the species of Astragalus podolobus, Astragalus lilacinus, Astragalus sumbari, Astragalus rawlinsianus and Astragalus jolderensis have the best quantitative and qualitative factors such as: production (71 to 1049 kg/ha), crude protein (12.5 to19.2 percent in flowering period), metabolic energy (5.9 to 8.6 MJ/kg) and high palatability. So this species were suggested to increase quality and quantity of forage in adjacent regions of Golestan Natural Park, similar rangelands of Golestan province and the country.

Rangelands enclosure is an important management tool in protection and restoration of rangelands. Enclosure can improve rangelands’ status and trends and also its capacity. In case of time there are three types of rangelands enclosure which include short-time, medium-time and long-time enclosure. The aim of short-time and medium-time enclosures is to revitalize natural establishment of palatable plant species. Long-time enclosure is used for conservation of genetic resources and monitoring of range succession and trend. This research investigated the long-time and short-time enclosures adoption among pastoralists of Bozdaghi region located in Ashkhaneh of North Khorasan province. Survey research was used in which 60 pastoralists were studied. The results showed that the adoption of long-time enclosure could be evaluated at low to moderate level. In this regard, the adoption of short-time enclosures was at high to higher level. The reasons for opposing long-time enclosure were: shortage of forage for livestock, lack of rangelands for grazing and the shortage of land for agriculture. Most pastoralists believed that long-time enclosure should be done when the shortage of forage for feeding pastoralists’ animals be compensated, agricultural lands located in high lands be available by the government for cultivation or pastoralists receive some other lands for cultivation instead of their ranges enclosure and low interest loan be available for pastoralists.

Successful fish embryo cryopreservation has not been achieved. Cryopreservation of fish embryos is replacement of cryoprotectants with water inside embryo. Cryopreservation of fish embryos requires an optimal concentration of cryoprotectants inside all embryo compartments. In researches on cryopreservation of embryo, information on relative toxicities of cryoprotectants is of key importance. Cryoprotectants are less toxic at lower temperatures. Cryoprotectants can neutralize the toxicity of other cryoprotectants. Generally the hatching rate decrease with increase in concentration and expose time. Reduced hatch may be a result of osmotic shock, ionic imbalance or consequence of cryoprotectant toxicity. As the progress of embryonic development, sensitivity of embryos decrease to the different concentration of cryoprotectants and can tolerate high concentration of this materials better.

Forest inventories that are implemented based on systematic random sample design, are the base for all forestry planning and management in northern forests of Iran. Unfortunately, there is no effective and flexible system for analyzing and processing of this huge inventory information that are collected by Forests and Rangeland Organization of Iran. Therefore, there is an urgent need for the forestry sector in Iran to organize its activities of data collecting, analyzing and distributing and the inventory information under a unified system. To facilitate the storage, processing and presentation of inventory information of northern forest, a database for inventory data was designed using Entity – relationship data model. Access software was used to implement the entity- relationship data model or physical design of database system. The designed system was included several components or sub-system (such as inventories, plots, stand status, trees, control trees and regenerations) which can provide data requirements and inventory information for forestry surveys and can be used as a base for providing forestry plans.