نشریه حفاظت و بهره برداری از منابع طبیعی
سال چهارم شماره 2 (1394)

In hydrology, numerous variables serve as representative for system behavior to model processes. Assuming these variables as independent may question accuracy of modeling final results. On the other hand several variables may involve in some of the hydrological issues and phenomena (floods, droughts, etc.), and affect the phenomenon in a manner that these variables can be interrelated. Applying statistical distribution for such variables regardless of this correlation increases uncertainty. Therefore, understanding the correlation between the marginal distributions of different variables in order to perceive the laws governing these dependences may be very promising to identify the observed hydrological events. Therefore, In order to increase reliability of analysis results, the multivariate statistical approach must be applied. Conventional methods for multivariate analysis involve classical multivariate distribution functions. But while using such functions, marginal distributions should be known and equal. Hence, applying such methods is limited to some extent. More suitable method for multivariate analysis that has overcome the limitations of classical multivariate functions is the utilization of Joint (Copula) functions. Recent developments in applied mathematic's studies have shown that Joint functions are useful tools to study the statistical behavior of dependent variables. Hence, the present paper aims to shed lights on the history and usages of common Copula functions in stochastic hydrology for multivariate analyzing of hydrological processes.

This research aimed to identify issues and problems of Eucalyptus wood cultivation in Golestan province. The descriptive research method and survey technique were used. The study population consisted of all Eucalyptus growers in Golestan province. The sample size was estimated by Morgan-Krejcie’s table. A total of 100 Eucalyptus growers were selected through stratified random sampling method in three counties of Golestan province including Gorgan, Bandargaz and Kordkuy. Data was gathered using a questionnaire. The questionnaire validity was confirmed by specialists and experts. The reliability of questionnaire was confirmed by calculating Cronbach’s Alpha coefficient (α=0.92). Research findings revealed that the most important problems in wood cultivation were: lack of enough irrigated water for wood farms, low resistance of seedlings to cold weather and frost, shading of Eucalyptus trees on crop plants, low price of wood in markets, lack of enough economic profitability of wood cultivation and lack of a proper system of pricing for wood trading. The results of mean comparison showed that there are significant differences between the answers of different respondents about issues and problems in wood cultivation based on the distance of their living place to Gorgan city (the capital of the province), cultivation type and farm size. Based on the findings, some recommendations are presented as follow: introducing the fast-growing species which are compatible to weather condition for different regions, establishing plant nurseries in different regions to produce seedlings compatible with region conditions to solve the problem of seedlings’ low resistance to cold weather and frost.

This research has been done in order to review and introduce the technical, economic and services criteria in regional and watershed level. First, the road network components in form of graph theory (node, link, sub-graph, and buckle), road network (planar and non-planar graphs), link structural characteristics (connectivity, chain, length of link, cycle, circuit, clique and cluster), network structural characteristics (connectivity, complementarity, tree networks, root and articulation node) were investigated. Then economic criteria (Turker cost-benefit , value cost), services criteria of importance (replacement, security-defensive, social, rescue, welfare and recreational-pilgrimage) and technical (α, β,ɣ indices, detour Index, network density, π, η, diameter and number of cycles) were identified. Result showed that regarding the common characteristics between forest road networks and public roads all of the economic and services criteria and some of the technical criteria such as α and β indices, diameter and network density are suitable criteria for comprehensive evaluation of forest road networks.

Increasing distribution of horse hoof fungi leads to significant losses on broadleaf and coniferous trees. Finding the appropriate method to manage and control of these fungi due to their abundance in the northern forests is necessary. The present study was carried out for mechanical controlling of horse hoof fungi in an area about 80 ha of Shast-Kalate forest of Gorgan via transects sampling method. In this research, for evaluating the effect of mechanical control on horse hoof fungi, the caps of fungi were isolated from tree trunk during the growth season. Then, in the next growth season, all specification of infected trees (complete control and wound healing, regrowth of fungi, latex exiting and decaying the fungi establishment) were recorded. The results showed that the identified fungi were belonged to Polyporaceae and Ganodermaceae families. Also, the method was applied to a significant effect in reducing the frequency of horse hoof fungi found in the study area. As the further growths of fungi were not observed on the trunk of infected trees, but the only exception was the fungus of the Rigidoporus ulmarius family.

One of the important issues in regional and national planning is information about land use, land use based on their capacity and the discovery of land use change procedure. By knowing the land use change procedure it would be possible to manage the ecosystem toward balance. This study is to investigate the changes in land use and land degradation in Garmsar Plain. In this study the images of Landsat satellite in the year 2002 and 2011 were reviewed. For producing the land use map of Garmsar plain NDVI index was used. Then, using different methods of supervised classification the land cover map were prepared based on satellite images. Land use in the region from 2002 to 2011 has changed and agricultural land in the study area decreased by 2.49% due to the possible expansion of residential areas in western and north western parts and degradation of agricultural lands in southern parts of the study site.

The main objective of this research is to estimate economic valuation of Geno thermal spring in Hormozgan province. Total Geno thermal spring value includes indirect market (recreation) value and non-market (preservation) value. Contingent valuation method (CVM) and double dichotomous choice (DDC) questionnaire are used to measure willing to pay (WTP) for Geno thermal spring in Hormozgan province. Logit model is used to calculate WTP and the model parameters are estimated using maximum likelihood method. Indirect market value is calculatedby the mean of willing to pay for recreation in Geno thermal spring and isestimated 3613.3 Rial/person and 22113.5 Rial/family. The mean of WTP for preservation value of Geno thermal spring is calculated as 656888 Rial/person. Non market value of Geno thermal spring calculated using mean of WTP for preserve the thermal spring and found to be 4042268.1 Rial/person. Results show that Geno thermal spring has considerable non-market and market values and this value can be an important reason for policy and decision makers to try forpreservation of Geno thermal spring and to prevent the loss of water resources.

Dust events are common phenomena in arid and semi-arid areas. The dust storms have harmful impacts on human health. The purpose of this paper is to review recent studies on the nature of dust storms including their main sources areas, frequency, causes, effects and consequences in Iran. At present, 22 provinces of Iran are affected by dust storm phenomenon with different intensities. Someareas in Mesopotamia are the main regions in dust production. In recent years, dust storms occur all year round with the highest frequency at June and July. The main causes of the dust events especially over the western parts of Iran can be atmospheric instability in the deserts of Saudi Arabia, Iraq, Kuwait, and Syria, successive and intensive droughts along with the lack of vegetation cover. The combination of climate and human activities and their habitation patterns which increase soil degradation, aeolian erosion, desertification and degradation of nutrients required for plants, intensify dust storms. Dust control methods are land management practices, tillage and mechanical operations particularly creation of plant barriers. Also, some short- and long-term policies and strategies are needed to improve the infra-structure facilities and management actions in the vulnerableareas of the country. It can be concluded that the consequences of dust storm is a multi-dimensional issue and comprehensive solution is needed to control and mitigate the unwanted effects of dust storm events in vulnerable areas.

This project focused on collecting and planting of the Rosaceae and their establishment in order to protect these species and to enhance species biodiversity of the national botanical garden of Iran. Finally, some of the native and economically valuable species which are able to survive in the National Botanical Garden are introduced. Results showed that 16 genuses of Cerasus, Cotoneaster, Crataegus and Prunus were established in the garden. Seeds and seedlings of Cerasus incana (Pall.) Spach. Transferred from the natural habitat and established in arboretum of the national botanical garden. Other species of this genus were established by transferring seedlings and the time of collection and transmission had no effect on the establishment of them. Crataegus microphylla Koch. and Crataegus myerii Pojark. were established by both seed germination and seedling planting and survived very good but others species of Crataegus, Prunus and Cotoneaster were only established by seedling and the best time of establishment is April to May, before opening of leaf buds and October to November after seed maturation. Phenological studies on 16 established species showed that start time of vegetative and reproductive growth of these species is related to temperature and light. Generally, viability and growth of transferred seed-originated samples is more than planted seedlings.

The program to stop destruction of natural resources at the national level as a strategy requires a detailed understanding of the effective factors and determining the contribution of each of them, therefore this study was undertaken for further clarifying. Thus, viewpoints of natural resources experts were chosen in order to investigate and prioritize the effective factors on rangelands degradation in Mazandaran province. The statistical population of this research was comprised of natural resource experts that 50 of them were selected randomly. The main tool for data collection was a questionnaire that was designed to measure the variables influencing the rangelands degradation based on Likert scale with five options ranging from very low to very high. Questionnaire validity was attained by specialists’ views after correction and revision. Reliability of the factors influencing the rangelands degradation was assessed by a pretest with viewpoints of 30 experts from natural resources based on Cronbach's alpha coefficient and the mentioned coefficient was obtained as 0.761 which indicates the high reliability of the questionnaire. In inferential statistics the Friedman test was used to compare the ordinal variables and Path analysis was used to investigate the relationships between variables. The results of Path analysis show that the most indirect effect is related to the number of utilizers and the most direct effect is related to land-use change from rangelands to agriculture. Total of direct and indirect effects suggest that primarily the change of land use to agriculture has the greatest effect on rangelands degradation and after land-use change, drought has an important direct effect on rangelands degradation.

One of the important issues in regional and national planning is information about land use, land use based on their capacity and the discovery of land use change procedure. By knowing the land use change procedure it would be possible to manage the ecosystem toward balance. This study is to investigate the changes in land use and land degradation in Garmsar Plain. In this study the images of Landsat satellite in the year 2002 and 2011 were reviewed. For producing the land use map of Garmsar plain NDVI index was used. Then, using different methods of supervised classification the land cover map were prepared based on satellite images. Land use in the region from 2002 to 2011 has changed and agricultural land in the study area decreased by 2.49% due to the possible expansion of residential areas in western and north western parts and degradation of agricultural lands in southern parts of the study site.

Loss of water through evaporation is a major consideration in the design and management of water supply reservoirs, water resource management and cultivation pattern. The linkages between evaporation and climate change are still not fully understood and an improved understanding of evaporation processes may assist in more accurately modelling evaporation in general circulation models. Therefore, the province of Hormozgan is determined based on expanded De Martonne climatic classification method, classified into 3 classes of climate and in period from 1974-75 to 2012-13. All data have been checked for normality test with the Kolmogorov-Smirnov test. Time trend of this variable were analyzed normality data and analyzed using non-parametric statistical methods (Mann- Kendall test and rho-Spearman coefficient) and parametric statistics (least squareregression analysis and Pearson correlation coefficient). Result shown significantly decreasing trend while the extremely warm- arid and the extremely warmextremelyarid climates and increasing trend in the warm- arid regions. Further trend analysis was carried out on the summer and fall seasons for all the region similar trend regime was for months (August to November) exhibits downward trend the western and Eastern in Persian Gulf coastal and upward trend for the northern regions. In general, the performance and capability non- parametric tests and parametric tests were consistence at the verified confidence limit.