Showing 10 results for Forest
Maryam Sisakht Nejad , Roghayeh Zolfaghari ,
Volume 1, Issue 2 (3-2015)
Abstract
Drought is the major environmental stresses that it can have a negative impact on plant growth. The study of gas exchange under drought stress can help to identify factors affecting stress resistant. Due to this fact that Zagros forests has Mediterranean and dry climate, with the aim of this study was to assess the impact of drought on leaf gas exchange in two oak species (Quercus brantii and Quercus libani). Water stress consisted of four levels of water stress (100%, 70%, 50% and 30% FC) in the greenhouse situations. Those seedlings were intended for water stress weren’t irrigated to reach to the desired field capacity (70%, 50% and 30% of field capacity), but control seedlings were irrigated every day in order to soil water content at field capacity shall be kept 100%. Results showed that water stress treatment has a significant reduction of stomatal conductance, photosynthesis, conduct mesophilic, carbon dioxide emission, and transpiration. Also Quercus libani showed higher level of photosynthesis, water use efficiency and transpiration than Quercus branti. Overall, results in both species, showed stomatal and non-stomatal limitation would cause of photosynthesis reduction. Also, due to higher water efficiency and lower gas parameter variations, Quercus libani would gain better mechanism of waster stress and Quercus brantii would gain the use drought avoidance mechanism.
Babak Pilehvar, Zahra Mirazadi, Vahid Alijani, Hamzeh Jafari Sarabi,
Volume 1, Issue 2 (3-2015)
Abstract
Considering the importance of forest structure and interaction among different tree species, this study conducted aimed to determine and compare spatial pattern, heterogeneity, and dimensions of Hawthorn and Maple trees with other neighbor trees. For determining Hawthorn and Maple trees structure, 30 individual of each trees were identified and studied. Based on the results, uniform angle index for Hawthorn and Maple trees were 0/744, and 0/733 respectively, which would propose a clumped pattern for these two species. Computed mingling index values for Hawthorn and Maple were 0/877 and 0/955 respectively that show a high tree species mixture. Also, the average of crown canopy differentiation and crown canopy dimension were 0/582 and 0/322 respectively, for Hawthorn tee and it was 0/42 and 0/656 respectively for Maple tree. Based on mean values, these results show that Hawthorn had high level of differentiation but was inferior in comparing to its neighbors whereas Maple has intermediate differentiation and is dominant to the other neighbors. The average distance to nearest neighbors for Hawthorn and Maple were calculated 7/374 and 6/278 respectively. The results of an absolute discrepancy algorithm (AD) showed a high differentiation of Hawthorn and Maple mixture in comparing to the other indices. It is concluded that maple is superior to hawthorn in dimension and because of low frequency of these two species, they hold high values of mingling indices.
Mehdi Heydari, Ali Mahdavi,
Volume 2, Issue 1 (9-2015)
Abstract
In this study, the impact of land use change of forest areas to forest parks on species diversity indices in Chaghasabz Park (Ilam city) has been investigated. For this purpose, three regions in 30-hectare areas were considered, including the area, without, medium and intensive recreation. The field data were obtained using 20 sample plots with each plot covering an area of 400 m2 in a systematic random design (150 m×100 m) in each region. In order to record the herbaceous species, cover percentage for each herbaceous species was recorded in four micro-plots (1.5 m× 1.5 m) that were defined with Domin criterion. In order to evaluate plant diversity, biodiversity indices e.g. Shannon and Simpson and Maguran richness indices were computed. Also, for studying the comparison between the averages of plant diversity indices, Dunken analysis was used. The results showed that in areas without, average and intensive recreation, there were 29, 45 and 21 species respectively. Therophytes were dominant vegetative forms in all three areas. Asperula odorata, Centaurea irritans Wagentz. Marrabium vulgare L., Phlomis olivieri Benth. and Picnomon acarna (L.) Cass were not observed in intensive recreation region. The least shannon and Simpson diversity and richness indices were observed in intensive recreation region, but on the contrary, evenness index was substantial in intensive recreation. We concluded that intense increase of recreation in forest region might cause a loss species diversity.
Yaser Mohammadi, Vahid Etemad,
Volume 2, Issue 1 (9-2015)
Abstract
Rural households’ involvement in forest conservation and reforestation depends on their perception towards forest perceived benefit which is attributed to demographic characteristics of the households head. In order to test this hypothesis, a study was run on rural households surrounded by Chahartagh forest reserve (N=600) which its livelihood was based on forest resources. About 196 rural households were determined as the research sample using Cochran’s formula through Simple random sampling procedure. Also, a researcher-designed questionnaire was used to collect data which its content validity confirmed by expert opinions and its reliability confirmed by Cronbach alpha coefficient. Collected data were analyzed by two software of IBMSPSS21 and LISREL8.5. The results showed that rural households’ perceptions towards forest are directly related to benefits they perceived from the forest. Perceptions towards forest benefits was summarized into three categories of perceptions towards forest economic, environmental and social benefits which economic benefit was recognized as the most important benefit perceived by respondents. From rural households’ perspective, the income gained from timber and non-timber products were the most important economic benefits of forests. Structural equation modeling results also revealed that rural household’ perception towards forest benefits differ among rural households according to their demographic characteristics. It observed that the younger, higher literacy level, had the higher income level and also, they had the more positive perception toward forest benefit. Also, each household’s head that was member of rural local institutions, had a corporation with NGOs and had participation into active groups to conserve forests had more positively perceived forest benefits.
Ahmad Yaghoubi Farani, Marjan Sepahpanah, Farshad Parmozeh,
Volume 2, Issue 2 (3-2016)
Abstract
The purpose of this study was to identify the barriers of local peoples' participation in forest conservation plans. The research population included 240 Local rural households in Gilan – e – Gharb, Kermanshah. A number of 144 people were randomly selected using Morgan's sampling size table. A questionnaire was used as a main tool in this study. The content and face validity of the questionnaire was verified by a panel of experts. The reliability of the questionnaire estimated by Cranach's alpha coefficient (0.737). Factor analysis was used for finding the most important barriers. Four key factors were identified as the most important barriers in people participation programs in forest conservation plans. These factors were socio-cultural, economic, organizational and educational barriers.
Ahmad Hossieni , Syyed Mohsen Hossieni ,
Volume 3, Issue 1 (9-2016)
Abstract
Oak decline is a complex phenomenon that oak forests are faced with it across the world and Iran. Shalam forested area located in north of Ilam province was selectedto determine the role of topographicand some edaphic factors in tree mortality happened in Persian oak forests. The study region was divided into 20 homogeneous topographic units. Within each homogeneousunit,three 0.1-haplots were randomly-systematically established for measuring the rate of tree mortality and oneprofile was prepared for characterization ofsome physical and chemical soil characteristics (texture, moisture content, TNV%, OC% and N for each soil layer, and soil depth). In each plot,diameter at breast height (DBH), maximum and minimum crown diameters, crown dieback percent, origination and form of trees and shrubs for all species and site variables weremeasured. Results showed that 15.7% of forest stock had reduced while 97.65% of it belonged to Persian oak species. The results of multiple linear regression and RDA showed that tree mortality was significantly affected by elevation and aspect, but not by slope. The highestrate of tree mortality was observedin high elevation and south and west aspects. Also the results of multiple linear regression and RDA showed that tree mortality was significantly affected by soil depth and texture. So, the highestrate of tree mortality was observed in soils with less depth, less sand% and more silt%. It was concluded that topography and soil have effective role in tree mortality and its expansion across Zagros forests. Identifying the critical conditions in terms of topography and soil in these forests can help and be useful in the management of tree dieback.
Seyyed Majed Hesami, Saeiid Davazdahemami,
Volume 3, Issue 1 (9-2016)
Abstract
Phenology studies can be appliedin sustainable management, protection, rehabilitation, development, and utilization of forest resources. In this study, the phenology of Persian oak was investigated in three forested areas of Mamasani, Dasht-e-Arjan and Kamfirouz with 2300 m,2100 m,1800 m altitude, respectively in south –west and north of Fars province, Iran. In each area, ninetrees were visited repeatedlyat different times in different seasons during 5 years (1998-2002) and the observed characteristics were recorded. The results showed the stages of growth were completely different at the threementioned areas. The shoots sprouted up in the second week of March to the first week of April. The full leaf formation happened in the second week of April to the fourth week of April. The early flowers appeared in the second week of March to the fourth week April. Pollination occurred in the third week of March to the third week in April. The leaves began to fall in the fourth week of October to the fourth week of December. So characteristics of phenology in Persian oak were affected by climate and environmental factors.
Masoud Nejabat, Mohammadreza Negahdarsaber,
Volume 3, Issue 2 (3-2017)
Abstract
Background and objectives: Familiarity with the appropriate soil conditions for Pistacia atlantica leads to improve and develop forest vegetation cover in Zagros zone. The main aim of this research was investigate suitable soil characteristics ranges for natural growth of this species in Fars province.Materials and Methods: Field studies and soil sampling was done based on network sampling (20×20 km grid) in wild pistachio forests of Fars province with crucified pattern. The filed study showed mountain and hilly land are the main land types that pistachio species have placed on them. These land types include the displacement of rock, stone and gravel as high and low soil depth with moderate to severe water erosion.Results: Main physical and chemical properties measurement of soil samples showed that the only limiting growth factor has been the low soil depth. The low effective soil depth and light soil texture are the most important limiting factor on soil moisture storage ability (from rain). This deficiency, transition from drought or very dry periods (resulting from an undesirable distribution of rain) makes it difficult. Statistical analysis methods based on principal component analysis (PCA) and cluster analysis (CA) shows that wide ranges in soil characters, even up to about 40% differentiation in the measured properties do not make restrictions for pistachio Natural growth. Ecologically, Pistacia atlantica is a drought-tolerant plant. Wild pistachio (Pistacia atlantica) is one of the high resistance species in wide range of soil condition (soil characteristics) and this feature (desirable survival) make it favorite for Zagros forest rehabilitation.Conclusion: Land and grazing management (land use planning), along with watershed management practices can conserve and improve soil and environment of wild pistachio habitats of the Zagros forests.
Dr Farhad Ghasemi Aghbash, Sara Falahi,
Volume 3, Issue 2 (3-2017)
Abstract
Background and objectives: The recent movements opposing deforestation are indicative of the fact that in most programs carried out, less attention has been paid to the socio-economic status of the local people. In extensive deforestation, rural communities play a significant role. Therefore, this study examines the role of economic and social factors in the destruction of the forests of the Oulad Ghobad regions.Materials and methods: This research was carried out as a field study, using a questionnaire. The population comprised 398 families living on the outskirts of the Saman-e Orfi Forest in the Oulad Ghobad region. Out of this population, 150 families were randomly chosen, using Cochran’s sample size formula. Furthermore, 40 questionnaires were distributed among the officers of Lorestan Natural Resources Office. The validity and reliability of the questionnaire established by a pre-test and Cronbach's alpha were 0.83 for local people and 0.705 for officers, respectively.Results: The findings showed that from the viewpoints of both officers and local people, human factors (such as lack of agricultural lands, conversion of forests into agricultural lands by forest dwellers, poverty and and low income, and high unemployment rate) contribute more to deforestation, compared to natural factors (such as drought and forest fire). As for prioritizing human and natural factors contributing to deforestation, the results showed that according to local people, lack of agricultural lands (mean rank of 7.58), and according to officers, conversion of forests to agricultural lands by foresters (mean rank of 11.25) were the main contributing factors. In addition, the results showed that there was a significant negative relationship between income and the factors contributing to deforestation (P <0.001).
Conclusion: In general, the results showed that human factors have a significant effect on the deforestation of the Oulad Ghobad region of Koohdasht and the role of human factors is more conspicuous compared to natural factors.
Fatemeh Babazekri, Mehdi Nooripoor, Zeinab Sharifi,
Volume 3, Issue 2 (3-2017)
Abstract
Background and objectives: Forests and rangelands are the most important natural resources of a country. In addition, they have a special position in the ecosystem of the earth, and, thus, they play an essential role in soil conservation as well as climate moderation. However, serious and, sometimes irreparable, damage has been ocuured by both natural and man-made factors. One of the areas where degradation of rangelands and forests could clearly be recognized over the past years is the central District of the Dena County. Therefore, the purpose of the current study was to identify and analyze factors affecting the degradation of rangelands and forests in the central District of Dena County.Materials and methods: A mixed research method including qualitative and quantitative methods was used in two phases, using interview and questionnaire as instruments. In the first phase of the study, the population comprised the villagers and officers of the Department of Agriculture, Dena County and also the Provincial Department of Natural Resources in Kohgiluyeh and Boyer-Ahmad Province. In the second phase, the population consisted of the academic faculty members of local universities who were native and were familiar with the region. Snowball sampling technique was adopted in both phases of the study.Results: Factors affecting the degradation of rangelands and forests were identified in the first phase of the study. These factors comprised organizational factors (monitoring, supportive and administrative), infrastructural, socio-cultural, legal, economic and natural factors. Following that, in the second phase of the study, the participants were asked to rank the factors identified based on AHP procedure principles. The results showed that lack of grazing management in monitoring factors, less governmental support for natural resources in supportive factors, administrative corruption in administrative factors, road construction in infrastructural factors, poor cultural patterns in socio-cultural factors, lack of appropriate legal actions when faced with illegal possession in legal factors, rural poverty in economic factors, and finally drought in natural factors were the most important factors contributing to the problem of degradation.Conclusion: Finally, out of the recommendations made to prevent the degradation of forests and rangelands, one can mention the employment of native people to improve the management of rangelands and forests in areas of guarding and conservation affairs of natural resources. In addition, for the purpose of constructing roads, building power plants, etc. it is necessary to seek the expert advice of engineers with expertise in road construction, civil engineering and rural development.
