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Background and objective: Sustainable exploitation of natural resources plays an important role in providing livelihoods to rural and nomadic communities. Nowadays, indiscriminate exploitation of natural resources has prompted policy makers to adopt guidelines for their sustainable management. Among the factors influencing the rangeland degradation, is an imbalance between the number of livestock per hectare and the grazing capacity of the rangeland due to the production capacity of the rangeland. However, many livestock balance plans have been implemented in different parts of the country, it has not been studied much whether these plans actually have acceptable effects or achieved the desired goals. Therefore, the general aim of this study is to identify the effects of balancing livestock numbers and Identifying the Effects of balancing livestock numbers and rangeland carrying capacity from the view point of ranchers, the case of Central District of Kohgiluyeh County.
Materials and methods: The present study was carried out using a mixed method. In the qualitative section, sampling based on the principles of qualitative research continued until data saturation and then, started coding through content analysis. Using the data of qualitative section, a structured questionnaire was prepared. The face validity of the questionnaire was confirmed by subject experts and distributed among the studied samples. In addition, data analysis was performed using SPSSv21 software to categorize the concepts obtained from the first section
Results: The findings showed that from the respondents' view point, the implementation of the mentioned plan had several effects. Analysis of the data collected through content analysis and open coding indicated that these effects included 63 items. Then, to categorize the effects and to reduce the number of known variables and form new structures for them (based on the correlation between variables), exploratory factor analysis method has been used. The findings of factor analysis showed that only 39 of the indicators were extracted from the seven categories and explained 56.243% of the variance of variables used in factor analysis. Among these categorizes, the most effect was due to the psychosocial-educational factor, which explained 14.437% of the total variance.
Research constraints: Factors such as the lack of villagers at the time of the Census, the immigration of some ranchers and the severity of some areas were the research constraints.

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Background and Objectives: Plant ecology is the scientific study of the interactions between plants and environmental factors that determine their distribution and abundance. Ecology provides the necessary framework for an accurate understanding of vegetation dynamics and species distribution, emphasizing the essential role of vegetation within ecosystems. The biodiversity of any habitat plays a crucial role in the stability and health of the natural environment. The assessment of different plant species and their distributions allows important steps to be taken towards biodiversity conservation. Researchers use parametric distribution models, also known as abundance distribution models, to evaluate vegetation diversity and evaluate species diversity. The four main models developed by ecologists include the geometric series model, the lognormal series model, the logarithmic series model, and the broken-stick model, which are used to adjust the distribution of species diversity. The application of parametric models in riparian forests - one of the most diverse and complex plant communities in the world - has provided a new perspective on methods for assessing ecological diversity. Therefore, the aim of this study was to measure biodiversity in the riparian forests of Maroon River in Behbahan district using biodiversity distribution models.

Materials and methods: In this study, transects were laid at 100-meter intervals across the study area to record vegetation. We surveyed 79 sample plots and recorded and analyzed the percentage of tree cover, number of individuals and species composition. The TWINSPAN analysis classified the sampled plots into two ecological groups based on the indicator species Populus euphratica Oliv. and Tamarix arceuthoides Bunge, resulting in 56 and 23 sample plots, respectively. Using the species abundance data and the chi-square test for goodness of fit, we tested the fit of the Geometric, Lognormal, Logarithmic and Broken-Stick parametric models for each ecological group.

Results: The results of the chi-square test showed significant differences between the observed and expected abundance of species in both ecological groups (Populus euphratica and Tamarix arceuthoides), leading to the rejection of the parametric models. However, no significant difference was found between the distribution curve of the observed data and the lognormal distribution curve.

Conclusion: The lognormal model provided the best fit for the distribution of species abundance in both ecological groups, suggesting that these communities are heterogeneous and stable, characterized by species with moderate abundance.

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Background and objectives: Primary information about different methods of vegetation sampling is important to researchers to decide about their sampling.
Materials and methods: In this study we applied five distance methods (closest individual, nearest neighbor, second nearest neighbor, joint-point and point- centered quarter method) to estimate plant density and canopy cover based on different inventory net (100×100, 150×150, 200×100 and 200×200)m in Manesht and ghalarang ilam province were compared according to their accuracy.  
Results : The result showed that among the distance sampling methods mentioned with different inventory net according to accuracy for density second nearest neighbor in 200×200 inventiry net and for canopy cover respectively point- centered quarter method in 200×100 and 150×150 were more suitable methods  for this region. Because this formulas could provide an acceptable estimate based on ±10% accepted accuracy.
Conclusion : According to this study distance sampling methods in Zagros forest was relatively good accuracy and can be used in other research and executive censuses.

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Background and objectives: In addition to wood production, forests have many environmental and social resources that most of them are often lacking in the market.
Materials and methods: In this paper five cases of ecosystem services forest ecosystem was considered from an economic perspective and they have been evaluated to various approaches. For this purpose, the recreational value of the area by using a conditional valuation method and the value of carbon sequestration, the maintenance of soil nutrients, the value of water regulation and the value of non-food products in the region were estimated by using the replacement cost method. Then the total economic value of these functions was estimated.
Results: According to the results total economic value and the annual value per hectare of forest ecosystem were 576413505.1 Toman and 17243407.560 Toman in year respectively. The functions of Carbon sequestration with equivalent value 574114967.1 thousand Toman had the most value and Recreational function had the lowest total value among other functions with equivalent value 126618 thousand Toman per year.
Conclusion: The results of the study, as well as other similar studies can be concluded that natural resources with regard to the future exploitation process, they are more under pressure and rarer, So it is necessary that with the optimal using of these valuable ecosystems, this natural heritage has been protected. With understanding the economic value of the whole ecosystem, programmers and policymakers are able to make more comprehensive decisions and determine the precedence between available options  that makes optimal use of it.

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Background and purpose: Various factors affect the occurrence, spread, and controllability of forest fires. A hazard fire zones map can be obtained by knowing the important influencing factors. This map shows fire severity in different zones and stages which provides a suitable tool for managing, preventing, and reducing the damages caused by fires to the natural resources manager. This study aims to prepare fire hazard severity zones based on the range of these environmental factors in the forest areas of Mamsani and Rostam counties in the northwest of Fars province with an area of 2188.7 square kilometers.

Materials and methods: The environmental criteria that were used in this study include elevation, slope, slope direction, distance from the road, distance from residential areas, distance from agricultural lands, average annual temperature, average annual precipitation, and land use. After collecting data from different sources, the fuzzy concept was applied to standardize the criteria by using different fuzzy membership functions. A hierarchical analysis process (AHP) was used to weight the criteria and prioritize them. For this purpose, a questionnaire was prepared, and criteria were scored by experts. All the weighted criteria were overlayed by weighted linear combination method (WLC). To obtain the weights of the criteria, the data obtained from the questionnaires were extracted and analyzed in the Expert Choice software. Each of the selected criteria was also prepared as a map using the geographic information system (GIS) in the ArcMap software environment. Finally, the fire severity risk map was prepared in five categories of very high, high, medium, low, and very low fire severity zones.

Findings: The results show that the burned areas show a high compliance of the implemented model with the existing situation. Among the studied factors, the three main factors of fire in this area are distance from agricultural land, distance from road and distance from residential areas with relative weights of 0.254, 0.1971 and 0.1786 respectively. The results showed that the most fires occurred in the 1500-1900 elevation class and 0-10% slope class. As the slope increases, the rate of fire has decreased. Also, the southern aspect has been prone to fire.

Conclusions: So, it can be concluded that most fires have occurred in areas where human access to those areas is more and easier and other factors are less important. Also, the results of this research showed that forest fire risk zone mapping can help managers prevent fire in different forest areas.

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Background and purpose: The Sumac shrub is a commonly used species for afforestation in arid and semi-arid areas to reclaim land. Additionally, the fruits of Sumac are used to support the economy of local communities. The purpose of this study is to analyze the type of dormancy exhibited by Sumac seeds, and to determine the effects of different dormancy breaking treatments. These treatments include scratching the seeds, treating them with boiling water, sulfuric acid, cold layer, and gibberellic acid (GA3) to increase the rate of germination.
Materials and methods: A study was conducted at the Forest Tree Seed Technology Laboratory of the Department of Forestry, Faculty of Natural Resources, University of Tehran. The study was conducted in four replicates of 50 seeds using a completely randomized design. The first step was to measure the survival percentage of the seeds using the tetrazolium test, which was found to be 85.5%. The study involved different treatments applied on sumac seeds. The treatments without the presence of gibberellic hormone included: A) Boiling water treatment with three cold layer durations of 2, 4 and 6 months, B) Chemical scraping treatment with 96% sulfuric acid at three levels of 40, 80 and 120 minutes and three cold layer durations of 2, 4 and 6 months, C) Chemical scraping treatment with 96% sulfuric acid in three levels of 40, 80 and 120 minutes and boiling water treatment and three durations of the cold layer of 2, 4 and 6 months. The treatments with the presence of gibberellic acid hormone included: A) Treatment with boiling water and cold layer in three periods of 2, 4 and 6 months and gibberellic acid at three levels of 250, 500 and 1000 P.P.M, B) Treatments with sulfuric acid for 80 minutes and cold layer in three periods of 2, 4 and 6 months and gibberellic acid in three amounts of 250, 500 and 1000 P.P.M, C) Treatments with sulfuric acid for 80 minutes, boiling water and cold layer in three periods of 2, 4 and 6 months and gibberellic acid in three amounts of 250, 500 and 1000 P.P.M.
Findings: The analysis of variance for germination speed confirms that there is a significant variation in the average germination rates between different treatments. The average germination rates for the sulfuric acid treatment, which involved boiling cold water for 120 minutes over a period of two months, was 7.96. This treatment showed a significant difference in growth compared to the control treatment, which had an average growth rate of 96.7. Similarly, the 2-month cold broth treatment had an average germination rate of 7.61, which was significantly different from the control treatment. The Gibberellic acid 500 ppm cold decoction treatment for 6 months resulted in a significant growth rate of 18.75, which was significantly different from the control treatment. Finally, the Gibberellic acid 250 ppm + boiling water + cold treatment for 6 months had an average germination rate of 15.79 and showed a significant difference in growth compared to the control treatment.
Conclusion: According to the results, sumac seeds exhibit both physical and physiological dormancy. The treatment of scraping with sulfuric acid followed by a cold layer did not have a significant impact on dormancy breaking and germination. However, the use of gibberellic acid improved both the percentage and speed of germination, with the best results obtained using a treatment of 500 ppm gibberellic acid along with boiling water and cold storage for six months, resulting in a germination rate of 18.79%.
 

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Background and objectives. By accelerating of the intensity and duration of the drought periods in the Zagros forests, the revival of native tree species, including the brant’s oak (Persian oak), is diminished. Despite the knowledge of the importance of phosphorus in increasing drought resistance in different species, there is little information about the role of this element in brant’s oak seedlings in facing drought.
Materials and methods: For this purpose, the main and interactive effects of two factors of soil phosphorus (at five levels of zero, 25, 50, 75 and 100 mg/kg) and soil moisture regime (at three levels of 60, 30 and 10 percent of field capacity) on performance traits of one-year-old brant’s oak seedlings, with six replications, have been examined. The studied traits include morphological traits (root and stem length, number and area of leaves, fresh weight of roots, stems and leaves), physiological traits (relative water content and electrolyte leakage rate in different organs of leaves, stems and roots, and optimum and maximum yield of photosystem II, and chlorophyll index) and nutrition uptake (concentration of potassium and phosphorus elements in leaves).
Results: The results revealed that with the decrease in soil water content, the traits of leaf number, root and leaf fresh weight, relative water content, photosystem II performance, leaf chlorophyll index and leaf potassium and phosphorus content decreased and root length and electrolyte leakage rate increased. The increase of soil phosphorus in the high irrigated seedlings (60 percent of field capacity) caused the development of aerial organs and leaf surface, and in the seedlings that were in water deficit conditions, it caused the maximum performance of photosystem II to be maintained. Increasing soil phosphorus in all water conditions increased phosphorus, potassium and chlorophyll index, in the leaves of brant’s oak, but it had no effect on reducing membrane damage caused by oxidative stress.
Conclusion: In general, application of phosphorus increased the resistance of brant’s oak seedlings to drought stress by improving nutritional status and protecting the photosynthetic apparatus. Implementing higher concentrations of phosphorus is suggested for future research in order to study the possibility of improving water relations and protecting against plasma membrane injury.

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Extended Abstract
Background and Objectives: One of the most important factors of global warming is the phenomenon of illegal emission of greenhouse gases; The most important of which are nitrogen dioxide (NO2), carbon dioxide (CO2), and methane (CH4). However, due to the large amount of carbon dioxide accumulation in the atmosphere, this gas is one of the key gases in the phenomenon of global warming. Therefore, to reduce atmospheric carbon dioxide and balance the content of greenhouse gases, atmospheric carbon must be absorbed and deposited in various forms. Urban forests have a high capacity to absorb atmospheric carbon dioxide and provide many environmental services in urban areas. Therefore, it is necessary to obtain correct and accurate information in this regard to optimally manage these forests in increasing carbon sequestration. This research aimed to estimate the amount of carbon stock of the urban forest in Sari City, the capital of Mazandaran province.
Materials and methods: This research Using selective sampling, 150 samples were taken (50 samples in each region) and an effort was made to distribute these samples in the three regions. First, the information related to the general characteristics of each of the samples, including the height above sea level, the slope, and the direction of measurement, were recorded. In each sample plot, species type, breast diameter, height, and small and large crown diameters of all trees were measured, and the number of each tree and shrub species was counted and harvested. The center of each sample and measured tree was recorded with a GPS device and transferred to the GIS software environment. After calculating the carbon sequestration of trees, the relationship between diameter and carbon sequestration was investigated using linear regression in SPSS software version 21. Then, a carbon sequestration zoning map was prepared in all areas of Sari using the conventional kriging method and in GS+ software.
Results: The highest and lowest amount of carbon sequestration of trees was observed in areas one (60.95 ± 31.10 tons per hectare) and three (13.68 ± 3.84 tons per hectare) of Sari city, respectively. Variance analysis of diameter and carbon deposition relationships showed that linear and power regression models were significant. The evaluation results of the linear regression model (R2=0.74) and power (R2=0.97) showed that both models are highly accurate in estimating carbon deposition on the ground of trees. According to the results, the highest potential of carbon sequestration was observed in the northeastern part and located in an area of Sari.
Conclusion: In this research, a high amount of carbon sequestration was observed in the city of Sari. It can be said that the main reason for the high amount of carbon deposition in Sari city is that, most of the trees in the green space of Sari city are old plane trees The reason for the high level of carbon deposition of the plantain tree is the high density of its wood compared to other trees. In general, young trees have a higher amount and speed of carbon deposition than old trees, but old trees also deposit carbon in a larger amount and for a longer period. Obtaining the results that the trees of Sari city can absorb 200 tons of carbon per hectare is remarkable and promising. Prioritizing the preservation and growth of larger and older trees in urban environments may have significant results for carbon sequestration. At the same time, examining the temporal dynamics of carbon sequestration, combining other environmental variables, or modifying the spatial resolution of the analysis can further increase the accuracy of carbon sequestration estimation. Therefore, obtaining more information in this direction is necessary and necessary.
 

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Background and objectives: Cold is one of the severe and limiting environmental stresses in forest ecosystems, particularly in temperate regions. With climate change affecting plant phenology and altering cold resistance in spring and autumn (notably in seedlings), it is crucial to identify species and genotypes that exhibit resilience. Therefore, this study focused on assessing the cold tolerance of seedlings from three species: Quercus brantii, Q. infectoria, and Q. libani, and examining how this tolerance relates to their phenological traits, such as bud burst and leaf senescence.
Materials and methods: Seeds from 54 mother trees were collected from the Baneh forest region (located in the Northern Zagros, characterized by higher altitude, latitude, and colder temperatures) and sown in a communal garden in Yasuj (found in the Southern Zagros, with lower altitude, latitude, and warmer conditions) for two years. Various phenological parameters (including the timing, rate, and speed of leaf bud burst and leaf senescence) as well as survival rates and damage of the terminal bud of the seedlings were recorded and analyzed at different time intervals using statistical methods such as repeated measures analysis of variance, Duncan's test, and Pearson correlation.
Results: The results of this research indicated that seedlings of different oak species exhibit notable differences in leaf bud burst speed, damage to seedlings, and survival rates. Specifically, the Q. brantii opened its buds approximately 3-4 days earlier and more rapidly, while, it showed the least damage to the terminal bud and the highest survival rate. In contrast, the Q. infectoria opened its buds later and more slowly than other species and suffered the most damage to the terminal bud and had the lowest survival rate. Additionally, correlation analysis revealed that seedlings with faster bud opening in the early growing season tend to have more terminal bud damage but also higher survival rates. Furthermore, the results of leaf senescence also showed that there was no significant difference among the three species in two years, although a positive correlation between the speed of bud burst and the leaf senescence.
Conclusion: The findings of this research suggest that the Q. brantii exhibits greater resistance to late spring frosts due to its favorable phenology (earlier and faster bud burst) and reduced bud susceptibility to cold. Consequently, it is less affected by late spring frosts associated with climate change compared to the other two species studied. Therefore, it is recommended to planted the Q. infectoria and Q. libani species more in the higher and cooler regions of the Zagros, and to select seeds from genotypes that have a later bud burst in spring for breeding programs.
 

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Background and objectives: The Hyrcanian forests play a crucial role in carbon storage, soil and water conservation, and climate change mitigation. Previous studies on the silvicultural management of these forests have mainly focused on estimating stand volume and structural characteristics, while the impacts of different management regimes—particularly the shelterwood system—on aboveground biomass, as a key indicator of carbon sequestration, remain unclear. The main objective of this study was to quantify and analyze the effects of shelterwood management treatments on tree quantitative characteristics and aboveground biomass in the beech (Fagus orientalis Lipsky) forests of Kelardasht, northern Iran.
Materials and methods: The research was conducted in Compartment 5 of the Kelardasht forest management plan. Five management treatments were selected: control, shelterwood, partial shelterwood, shelterwood with improvement cutting, and unmanaged (outside the management plan). In each treatment, five 0.5-hectare plots were randomly established. Diameter at breast height (DBH), total height, and stem height were measured, and tree volume was calculated. Aboveground biomass was estimated using tree volume, wood specific gravity, and FAO expansion factors. Data were analyzed using one-way ANOVA and independent t-tests.
Results: Mean DBH and total height were significantly higher in unmanaged treatments (control and outside the management plan) than in managed ones. The control treatment had the highest aboveground biomass (613.58 t ha⁻¹), whereas the complete shelterwood treatment had the lowest (272.56 t ha⁻¹), representing a 56% reduction compared to the control. The partial shelterwood and shelterwood with improvement cutting treatments had mean values of 417.13 and 273.61 t ha⁻¹, respectively. These patterns were consistent with structural indices such as stand volume and total height; even-aged stands resulting from complete shelterwood had lower biomass, while uneven-aged structures in partial shelterwood and control treatments performed better.
Conclusion: The findings suggest that the partial shelterwood method is a suitable option for the mid-elevation forests of Kelardasht, as it combines considerable economic benefits with biomass levels closest to the control treatment, while maintaining the advantages of uneven-aged forest structures. For the first time, this study demonstrates that prolonging the shelterwood regeneration period can lead to the formation of natural, uneven-aged stands that exhibit features of sustainable forests, with important implications for enhancing carbon sequestration in these valuable Hyrcanian ecosystems.
 

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