جستجوی مقالات مرتبط با کلیدواژه « جنگل » در نشریات گروه « اکولوژی »

Today, livestock outflows from the forests of the north of the country have created environmental and social challenges and problems that have caused concern to natural resource policy makers.  The re-emergence of livestock and ranchers illegally in the forests for various reasons has created disputes and tensions with conservation systems. In this regard, the present study was conducted to analyze the key drivers affecting the return of livestock in the forests of Golestan province. The sample population in the study consisted of 20 ranchers returning to the forest and were purposefully selected. After collecting information, using the cross-effects technique and using MicMac software, 27 indices extracted from the Delphi method were analyzed. The results of the dispersion of indicators in the axis of impact and effectiveness, indicate the instability of the livestock exit system from the forests of the province and its organization, based on which five variables were identified. Findings obtained from the effect-matrix direct dependence and dispersion of indicators showed that the lack of accurate implementation of the provisions of the plan in the forest, lack of support from government agencies in the area of ​​housing, lack of alternative job opportunities and diversification of income sources, lack of pasture Natural resources for livestock and the high cost of complementary inputs, non-timely payment of salaries by people subject to the plan by the government, various procedures and instructions contrary to the plan, lack of proper planning in housing and livestock farms, as the most important effective indicators and Strategies were evaluated in the return of livestock to forest areas. According to the obtained results, the compilation and preparation of a 10-year transformation document in order to organize the settled forest households is the most important proposal with a forward-looking approach to the subject under study.

Fire is an integral part of many terrestrial biomes and one of the main causes of destruction in nature. This study investigates the cause and characteristics of wildfires in the middle Zagros ecosystem for two consecutive years. There have been recorded to conduct this research, whole fire events that occurred in the natural areas of Gilan-e Gharb in 2019 and 2020 during the fire season from late May to early December. The gathered data in this study include the region name, type of affected area by the fire (forest, non-wooden rangeland, wooden rangeland, and mixed forest-rangeland), the cause of the fire, date, duration, area, and its location. The results showed that the fire rate includes 11% in the forest, 47.8% in non-wooden pastures, 26.5% in wooden pastures, and 14.7% in mixed forests and pastures in 2019. The fire frequency was 50% in the forest, 38% in non-wooden pastures, 2% in wooden pastures, and 10% in mixed forest and pasture in 2020. The lowest and highest amount of burnt area in 2019 contains the forest (9.4%) and non-wooden pasture (53%), respectively. Furthermore, the lowest and highest portion of burned area in 2020 includes forest (7%) and mixed forest and pasture (42.6%). According to the available evidence, nearly 72% and 50% of the human causes of fire in 2019 and 2020, respectively. There are recreational factors, disputes, and conflicts. Duration of less than one hour for extinguishing fires has the highest frequency, the amount of which is about 36% and 14% in 2019 and 2020, respectively. The highest frequency with 12 and 11 events includes the Cheleh in 2019 and 2020, respectively, among the common burned areas. In addition, among the factors compared in the study years, human factors of fire under the influence of different conditions have significant differences from each other (p=0.05). Therefore, it is essential to consider the structural causes and motivations of fire-causing factors that affect fire to reduce and avoid fire as much as possible.

Destruction of oak forests in Zagros and its impacts on the economy of Iran have motivated experts of natural resources to study its affecting factors. Researchers have found the most important of destruction is climate changes. Because of the importance of the subject, a proper method for data analyzing, decision making and recognition of potentials of the oak forest decline is needed. In this study, to map the respective susceptible zones, RS/GIS and hierarchical-fuzzy analysis techniques were applied. For this purpose, the slope, aspect, elevation classes, temperature, rainfall, dust and soil were considered as governing factors. Hence, physiographic and climatic maps were initially prepared. Due to the different impact of each factor, they were valued based on the expert judgements and and FAHP. The fuzzy maps were developed using the linear ascending and descending fuzzy and Gaussian distribution functions. Also, through the overlaying of various layers, the areas exposed to drying were mapped and classified. This research suggests that the map prepared by the fuzzy gamma distribution with a precision of 70% has the highest correlation with field data . Furthermore, southern and western areas are most susceptible to severe forest drying.