وحید اعتماد

Given that the majority of Iran's land area consists of arid and semi-arid regions, the use of plants resistant to salinity and drought stress can provide a new opportunity for harnessing the potential of the country's highly stressful climates. Therefore, this research aimed to investigate the effects of different levels of drought and salinity on the survival and morphophysiological characteristics of one-year-old Russian olive seedlings. An experimental pot study was conducted in a completely randomized block design with three replications and three observations, at three levels of drought (control 100%, 66%, and 33% field capacity) and four levels of salinity (zero as control, 4, 8, and 12 dS/m), in the greenhouse of the Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, from August to November over a period of 4 months. In this study, the content of chlorophyll and carotenoids was examined and measured. The results of this study showed that the main and interactive effects of drought and salinity stress on the measured traits were significant. The main and interactive effects of drought and salinity stress led to a decrease in chlorophyll and carotenoid content. The lowest levels of chlorophyll a (19.1 milligrams per gram leaf weight), chlorophyll b (44.0 milligrams per gram leaf weight), total chlorophyll (94.0 milligrams per gram leaf weight), and carotenoid content (39 milligrams per gram leaf weight) were observed.

A key effect of reforestation is its impact on the hydrological cycle which can change the quantity and quality of rainfall. The aim of this research was to compare the nutrient elements, pH and EC of rainfall compared to TF of a natural stand of Carpinus betulus L. and a man-made Pinus taeda L. plantation located in the western Hyrcanian region, Astara, north of Iran.

Rainfall and throughfall samplings were done using nine and 18 man-made plastic collectors installed randomly under the canopy and open space of each stands, respectively,. The amounts of EC and pH were measured using EC meter and pH meter. The nutrient amounts of calcium (Ca++) and magnesium (Mg++) were measured by the Titration method and potassium (K+) and sodium (Na+) elements were measured by Flame photometer for three rainfall events during the summer season, 2022. Comparison of means was done by one-way ANOVA and LSD at 95% confidence level.

pH in TF of C. betulus stand was 7 and 6.8 and P. taeda 6.4 and 6.6 in two events which were significantly different from those measured for rainfall (6.6 and 7.1). EC of TF of C. betulus and P. taeda increased by 126.4 percent and 113.2 percent, respectively. The amounts of Ca++ in the TF of the C. betulus stand for three events were 24, 19.6 and 12.5 ppm (mean: 18.7 ppm), respectively, while for corresponding rainfall were measured 11.6, 6.7 and 6.2 (mean: 28.8 ppm), respectively, statically different for all events. Mg++ showed the least change compared to other nutrients elements. The K+ in TF of C. betulus in July rainfall (21.2 ppm) had increased by 11.9 ppm compared to rain (9.3 ppm). The amount of Na+ in TF of man-made P. taeda plantation in the first event (15.6) showed a significant difference with that of Na+ in rainfall (9.3 ppm).

When rainfall hits the canopy of the C. betulus natural stand, in 85 to 90% of the samples of TF, nutrients as well as the pH and EC were significantly changed compared to rainfall. However, this percentage of significant change was 70 to 75% for P. taeda man-mad plantation. In this way, replacement of C. betulus with P. taeda altered the nutrients elements of TF as well as pH and EC by 55%. Understanding the change in the amount of nutrients inputs to the forest ecosystems via TF is essential for choosing the appropriate species for the reforestation of degraded forests since planting new species in an area, in addition to changing the amount of rain that reaches the forest floor, it changes the quality of rainfall.

Certain structural elements of forests, such as habitat trees, serve as crucial habitats and environmental modifiers for a multitude of organisms. This leads to an enhancement in the structural richness and resilience of ecosystems. The focus on habitat trees and biodiversity conservation in forests entails the management of specific elements inherent in the forest’s natural evolutionary cycle. Consequently, this study aimed to examine the structural characteristics of habitat trees in mixed and transition forests within some managed stands in the Kheyrud forest, Nowshahr County. 

Parcels 305, 306, 309, 310, and 311 in the Gorazbon district were chosen for the study. Gorazbon is a part of the mixed broadleaf forests of the Caspian region, situated within the Kheyrud educational and research Forest of Tehran University. It is located seven kilometers east of Nowshahr city in the Hyrcanian forests of Iran. For this research, all trees exhibiting specific characteristics were measured for their diameter with 100% accuracy across all the mentioned parcels. The conditions sought included broken trees, fungi, hollow from the stump, uprooted, broken stems, deformed, curved, tuberous, with nests, dead trees, old trees, and with witch’s broom. A variety of criteria and methods were employed to identify and recognize each of the qualified trees as a habitat tree, enabling the most favorable evaluation of each. For instance, to identify trees with bird nests, special cameras were utilized alongside human observation. The number per hectare in diameter classes was calculated for all habitat trees in each parcel. Furthermore, the average number and diameter of microhabitat types per hectare were determined across the five study sites.

The findings indicated that the highest frequency per unit area in hollow trees is from the stem and roots, equating to 10.95 trees per hectare, while the lowest is in trees with witches'-brooms, amounting to 0.55 trees per hectare.

The objective of modifying policies in the management of Hyrcanian forests is to emphasize sustainable management practices, enhance forest protection methods, and conserve the forests’ natural values. These endeavors aim to ensure that forest ecosystems persist in providing a diverse array of services to society, such as recreation, water supply, food, wood, clean air, and carbon sequestration. Accordingly, in the study management units, there exist various types of habitat trees, which exhibit diverse quantities and abundances based on the type, developmental stages, and vegetative stage, and are distributed across different diameter classes.

The mechanical characteristics of roots can serve as a significant factor for selecting trees in the plantation of arid regions for soil bioengineering. This research aims to evaluate the mechanical characteristics of Tehran pine roots at various vegetative ages (one-year-old, three-year-old, and five-year-old seedlings) and under different water stress levels (light, medium, and severe) in Robat Karim. The mechanical properties of the roots were studied after estimating the water requirement of the studied seedlings at different ages for one year and based on the water stress levels. Then, five seedlings from each treatment (equal to 9 treatments) were selected and coded completely randomly to evaluate the water stress on the mechanical characteristics of the roots of Tehran pine. Initially, some root parameters such as root diameter, length of the whole root, length of thin roots, and length of the longest root were measured. Then the tensile force, tensile strength, and Young's modulus of the roots were measured and recorded using a standard Centam device. The results showed that with the increase in root diameter, the tensile force of the root changes based on the positive power relationship, and the tensile strength and Young's modulus of the root changes based on the negative power relationship. Furthermore, laboratory examinations showed that at any age, the length of the whole root and the root length densities are higher with the increase in water stress. The use of covariance analysis showed that the results of the average comparison between one-year-old age and mild drought stress, three-year-old age and moderate stress, and five-year-old age and severe stress are significant with a probability of 95%. The results of this research show that the mechanical characteristics of the root can be used as an important factor for the selection of pine seedlings in the afforestation of arid areas for soil bioengineering purposes. Therefore, it is recommended that these properties be considered in soil reinforcement modeling.

Investigating forest structure is an important and necessary topic, especially in line with the goals of close-to-nature silviculture. This research aimed to quantitatively analyze the complexity of stand structure during the transformational phase of understory formation in the oriental beech (Fagus orientalis Lipsky) forests of Kheyrud, Nowshahr. After field inspections, three one-hectare sample plots in the transformational phase of understory formation were selected, and a full inventory of all stand parameters, including tree diameter at breast height, natural regeneration, size and distribution of gaps, and deadwood, was carried out. To analyze the structural complexity in forest stands, the structure complexity indices, Cox coefficient, coefficient of variation, and Gini coefficient of tree diameter were used. According to the research results, in this evolutionary phase, the highest frequency is in small diameter classes, while the lowest frequency is in large trees. The distribution curve of trees forms a decreasing exponential with a steep slope in small diameter classes. The average deadwood volume was 30 m³, and the average gap factor of crown coverage was 6.4%. Additionally, the mean Gini coefficient and diameter change coefficient were 0.7 and 6, respectively. These values, along with the Cox coefficient, indicate optimal complexity in the stand structure during this phase. In the understory, the average abundance was 306 stems per hectare, with beech being the most abundant species. Based on these results, to maintain heterogeneity in the managed forests while preserving large trees in the stand, it is suggested to implement operations to increase the complexity of the forest stand structure and perform thinning from below.

This study investigates the effect of drought stress on water requirement and morphological characteristics of Eldarica pine and Chinaberry species at different vegetative ages in Robat-Karim region of Tehran province. This study was conducted as a factorial design with three factors: species type, age, and drought stress with a completely random basic design in 10 replications. The factors included the plant component i.e. Tehran pine and bitter olive species and age in three levels (one, three and five years) and drought stress in three levels: mild, medium and high (0.3, 0.5 and 0.7). A total of 18 treatments (9 treatments for each species) and considering the number of 10 repetitions, a total of 180 microlysimeters were obtained. This research was defined according to its objectives, i.e. determining the water requirement, determining the plant factor and examining the effect of drought stress on the water requirement and plant factor. In the phases of determining irrigation planning, there was moisture monitoring in drought stress levels and the measurement of water requirements of species, the phase of calculating reference evaporation and transpiration and vegetation coefficient, and the phase of evaluating the effects of different drought stresses on water requirement and vegetation coefficient. The amount of water consumption in Eldarica pine seedlings during the plant growth period and in different treatments applied including drought stress treatments of 0.3, 0.5, 0.7 at age 1, drought 0.3, 0.5 and 0.7 at age 3, drought 0.3, drought 0.5 and 0.7 at age 5, including 239.3, 258.3, 307.13,

Climate change has the potential to alter the natural distribution of species and reduce biodiversity in forest ecosystems. This study aimed to investigate the effects of climate change on the geographical diversity of Brant's oak (Quercus brantii L.) to identify the suitable area for this species' occurrence and manage its conservation.

The distribution of Quercus brantii was studied under current and future climate conditions (2050, 2070) using two climate change scenarios, RCP2.6 and RCP8.5, HadGEM2-ES General Circulation Model, the Maxent model, and topography data of Fars province.

The results showed that the current potentially suitable areas for Q. brantii constitute 7.8% (9794.5 Km²) of the total area of the province. Under the RCP2.6 scenario, this will decrease to 6.6% in 2050 and increase to 13.3% in 2070. Also, under the RCP8.5 scenario, the suitable area will increase to 8.1% in 2050 and 10.2% in 2070. Areas with moderate, high, and very high suitability, currently at 1.8%, 1.5%, and 1.7% respectively, will decrease to 1.1%, 0.6%, and 0.3% in 2050 according to the RCP2.6 scenario, and then increase to 2.9%, 1.6%, and 1.2% in 2070. According to the RCP8.5 scenario, these values will decrease to 1.6%, 0.6%, and 0.3% in 2050, and finally change to 2.5%, 0.9%, and 0.2% in 2070.

The study demonstrated that the distribution of Quercus brantii is affected by climate change based on both scenarios. Also, the Maximum Entropy model has proven highly effective in predicting the distribution of this species.

Studying petrified wood from the second geological period is a rare endea vor in Iran. In the pursuit of promoting palaeobotanical research, particularly focusing on fossil trees, an extensive investigation was conducted in the Qeshlaq coalfield, situated within the Eastern Alborz structural zone and Golestan province. The findings of this study led to the discovery of over a hundred fossil wood samples, including standing trees and scattered pieces. These samples have been systematically collected and documented. Given the substantial presence of fossil trees surrounding active coal mines and the palaeobotanical significance of Mesozoic trees within the ancient Hyrcanian forests, this region possesses significant potential for identifying numerous geosites. We propose the initiation of mineral tourism in the mining area through active collaboration with relevant organizations. This strategic approach aims to safeguard and study these valuable geological treasures while simultaneously fostering sustainable geotourism in the region. Furthermore, conducting additional research on the biological structure and preservation conditions of petrified woods will contribute to our understanding of Iran's second geological period forests.

The growing and diverse trend of human social needs has led to a change in people's attitudes about the environment and natural resources. As a result, the importance of ecological and environmental functions of forest resources is increasing. This change of attitude has led to the development of the philosophy of sustainable and multi-purpose management of forests. The aim of the present study is the spatial zoning of the environmental capability of Kheyrud forest ecotourism based on special environmental model with a sustainable management approach. The ecological, socio-economic and environmental capability models presented for Hyrcanian forests were used as the basis of the present study. After preparing the required layers, the evaluation of the environmental capability was done based on three scenarios of high, medium, and low severity, and a spatial zoning was done. In this research, the smallest planning unit was selected based on the hydrological response units (HRU). The results of the implementation of the special model of the environmental capability of ecotourism, which is the integration of ecological and socio-economic models, showed that the integration of layers in scenarios with high, medium and low severity, for determinitig of suitable areas for ecotourism in the study area is appropriate.

Earth's climate is the result of complex interactions between its effective components and a function of solar radiation, which has a significant role on the afore said components. Among the most important climatic factors that are effective in the vegetation of humid, dry and semi-arid regions, we can mention the variables of vapor pressure and soil moisture, which play an important role in the process of plant photosynthesis. Chlorophyll plays a significant role in photosynthesis of plants, including coniferous. According to the research conducted in Chitgar and Nowshahr, the effect of two different components has been evaluated. The effects of the season on the fluorescence value of two components can’t be denied. The highest value of correlation in soil moisture and its effect on the amount of fluorescence in Chitgar forest park in autumn and winter seasons is estimated with R²=0.44 and 0.56, respectively. The RMSE were calculated 7.4 and 6.7(mg/m2), respectively. In Nowshahr, the highest correlation value with total depth moisture was obtained in summer season. The numerical value of R² is calculated as 0.21. Also, P-Value is estimated at 0.498. The effects of environmental stresses on the amount of soil moisture in different depths are undeniable, especially in the seasons when the plant activity is high and the amount of photosynthesis will be more exposed to drought and salinity stresses. Regarding the effect of vapor pressure in Nowshahr, the highest degree of correlation has been calculated with the fluorescence value in the autumn season. The peak of the rainy season in the north of the country can be estimated in the autumn season, and with the increase in relative humidity, the water vapor pressure will increase.

Drought significantly affects plant growth and causes delays in growth, and disturbance in physiology. This study aims to investigate the effect of drought stress on the morphological characteristics of Tehran pine and Chinaberry. This study was done factorially with the factor of different ages of tree species and different drought stresses in the form of a randomized complete block design with 10 replications. Collar diameter, height and canopy size were recorded as the average of the zero state of the studied seedlings and the evaluated parameters were measured at the beginning and end of the study period. With the increase of drought stress and decrease of humidity at a certain age, the growth amount of each of the studied factors, including collar diameter, height and crown area decreases. The results showed that the collar diameter, height and canopy surface in 0.3 drought stress compared to 0.5 and 0.7 drought stress at 1, 3 and 5 years old have the highest value. The average comparison results showed that water stress on seedlings is not significant in all cases. Water deficiency has a significant effect on the collar diameter and canopy surface in Tehran pine and on the collar diameter and height of bitter olive. The mutual effect of seedling age and drought stress on the crown area of Tehran pine and collar diameter and height of bitter olive has a significant effect. It is better to use drought stress of 0.7 so that the seedlings used can withstand adverse environmental conditions.

Identifying and introducing the plants of a region is particularly and locally important, which includes the possibility of accessing specific plant species in a certain place and time, determining the potential and vegetative capabilities of the region, the possibility of increasing the density of the species of the region, the possibility of obtaining a new plant species or species, and identifying the destructive factors of the region’s plants. The most obvious classification to explain and describe the structure of plants is to specify the life form of each plant species in each different plant community. The purpose of this research is to investigate the flora, life form, geographical distribution and some characteristics of plants in plant communities. in order to analyze the vegetation status at the central Alborz protected area in Alborz province. In this research, 101 plots were collected and a total of 152 plant species were identified. The identified species belong to 103 genera from 30 families. Asteraceae family with 16 genera and 21 species includes the largest existing taxon in the study area, followed by Poaceae and Fabaceae families with 14 and 12 genera and 18 and 17 species, respectively. The genera Salvia with 8 species and Astragalus with 7 species had the highest species diversity among the identified genera. The dominant vegetative form among the identified species was herbaceous, and tree and shrub elements had the least identified form. According to the Raunkiaer system, hemicryptophyte plants with 51.3% (79 species), therophyte plants with 29% (44 species), cryptophyte plants with 9.9%, chamaephyte plants with 6.6%, and phanaerophyte plants with 2.6% were the most abundant biological forms in this range, respectively. Also, the highest abundance of plant species according to the vegetation area is Irano-Touranian (81 species) and Irano-Touranian/ Hyrcanian (33 species). In general, it can be concluded from this study that the plant community in this area is heterogeneous because all the identified species were in presence code class I with an abundance percentage of 0 to 20%. Also, considering that the study area has a relatively high flora, it can be used to evaluate the current situation and predict the future situation of the region.

Seed performs a significant role as the most influential factor in the transfer of tree species heritability and forest sustainability. The goal of this study was to examine the effect of altitude from sea level on seed production and regeneration of oriental beech in managed forests. For this purpose, 50 paired sample plots with 2 × 2 m at 1100, 1600 and 2000 m.a.s.l were established. For different experiments were transferred the collected seeds to the seed laboratory. The germinated seeds counted at each sample plot on spring in order to regeneration survey. According to the obtained results, 1600 meters consist of the highest seed, 2000 meters encompass the highest regeneration and 1600 include the un-healthiest seeds. In addition, the maximum seed eaten by insects related to the height of 1600 m. furthermore, 1000 seed weight at the 1100, 1600 and 2000 m were determined to be 207.684, 244.144 and 304.237 grams, respectively. Seed weight appears to be lower in frequently seed years than in regular years. According to the results, the best height for producing and collecting beech seed is at 2000 m.a.s.l. Therefore, the establishment of a seed production station as well as a temporary nursery at this altitude can create a suitable ground for seed reproduction and production in areas of equal height and homogeneity.

As a sustainable forest indicator, biodiversity plays a crucial role in understanding the effects of climate change on forest ecosystems. Measuring the diversity of trees and shrubs in forests is essential for monitoring and evaluating changes in biodiversity. Remote sensing (RS) is an effective tool for collecting such data. To estimate tree and shrub species diversity, we used Sentinel-2 data from August 10 and October 13, 2021. We measured 75 field plots with dimensions of 20 m × 20 m in the Patom, Namkhaneh, and Gorazban districts. In each field plot, the tree species and diameter at breast height of all trees with a diameter greater than 7.5 cm were recorded. We used the Jaccard and Sorensen indices in R software to calculate the beta diversity indices for each sample plot. Preprocessing steps were applied to the Sentinel2 data, and we then performed several spectral transformation approaches, that is, vegetation indices (VIs), principal component analysis (PCA), and Tasseled Cap, and generated texture variables. A vector map was used to extract the spectral and textural values corresponding to each field plot. Correlation analysis between the measured species diversity and spectral and textural variables was conducted at a 95% probability level. Multiple Linear Regression (MLR) analysis was performed using stepwise and Random Forest (RF) methods for modeling. Our regression analysis revealed that texture variables with a window size of 5×5 and spatial resolution of 10 m in Sentinel-2 summer images had the best performance in estimating the Sorensen diversity index( R2= 0.383 and RMSE%= 36.57). However, based on our results, we can conclude that the Sentinel-2 data has a moderate performance in estimating diversity in the Patom, Namkhaneh, and Gorazbon districts.

The beech tree has the ability to produce shoots and form a coppice stands under specific natural climatic and environmental conditions or under unusual circumstances caused by human interference. The current research aims to compare the structural characteristics of coppice and standard stands of beech in the Hyrcanian forests in the Chetan area in Nowshahr. The diameter at breast height of all trees was measured using the full calipering method to determine the stocking volume. Half-hectare sample plots were established using the distance-azimuth method to study the spatial structure. The standing and log stocking volumes were also determined. According to the results, the number of live and dead trees in the coppice stand was 174 and 9.7 per hectare, respectively, and their volume was 146.2 and 3.6 m³/ha, respectively. In the standard stand, the number of live and dead beech individuals was 145 and 11 per hectare, respectively, while their volume was 147.5 and 12.1 m³/ha, respectively. About 55% of the standing dead trees in the coppice stand and 35% of the standing dead trees and 42% of the fallen dead trees in the standard stand were primarily in the first decay degree. The highest number of individuals in a beech coppice group included four, which is 17%. Groups of five individuals and two individuals also accounted for 16.9% and 16.5%, respectively. Spatial structure indices of beech coppice, including the Pielou segregation, Clark and Evans, Mingling, DBH differentiation, DBH dominance, and uniform angle, indicate species continuity, clustering, severe dominance of beech species, moderate differences, small size dominance, and clump distribution, respectively. Traditional uses of forests have influenced the structural characteristics of beech stands. Therefore, it is suggested that these and other similar stands be protected as a forest reserve to ensure the development of these habitats towards a more favorable state and the stability of the landscape in these areas.

The duration of vegetation restoration in the skid trails after logging operations is crucial and fundamental for preserving forests. The purpose of this research is to evaluate the long-term vegetation restoration of the skid trails in Kheyrud forest after logging operations. Therefore, 54 sample plots (1×1 m) were randomly positioned. This included 27 plots on the skid trails with ages of 5, 10, and 15 years at three traffic intensities (low, medium, and high). Additionally, 27 sample plots served as controls with a distance of 10 m from the skid trails parallel to these trails. All the plants in the plots were identified, their abundance was counted, and their species and families were identified. The results of the current research showed that among the three investigated treatments, traffic intensity alone had a significant effect on the recovery of vegetation along the skid trails. However, the age after harvesting and the interaction of traffic intensity and age after harvesting did not have a significant effect. The results also showed that traffic intensity significantly affected the abundance of species. Furthermore, in all three factors (traffic intensity, age after harvesting, and the interaction of traffic intensity × age after harvesting), tree species were more affected by soil changes compared to herbaceous species. Therefore, traffic intensity can significantly affect the variety of species and number of plants in the skid trails, with a greater effect on tree species than herbaceous species.

Understanding the structure of a forest is crucial for detecting forest dynamics, describing ecosystem stability, and designing effective management plans and protection and restoration measures. This study primarily aims to investigate the spatial pattern and structural characteristics of beech forests in the optimal developmental stage using variable area sample plots. In compartment 327 of the Grozban district of Kheyrood forest, eleven variable area sample plots with geometric shapes, exhibiting characteristics of the optimal developmental stage, were selected. The location, diameter, and height of all trees larger than 7.5 cm were measured in each sample plot. The results revealed that the largest contribution of trees among the investigated sample plots was related to mid-diameter and low-diameter classes. The Clark and Evans index and uniform angle results indicated a regular distribution of trees in all studied sample plots. The mingling index averaged 0.19 across all sample plots, suggesting low mixing and a minimal tendency of beech trees to blend with other species. The average diameter and height differentiation index were calculated as 0.31 and 0.30, respectively, indicating an average difference between neighboring trees. Overall, the use of indices based on the nearest neighbor with variable area sample plots and geometric shapes demonstrated that these indices effectively quantify the structural characteristics of forest stands in the optimal developmental stage. Consequently, it is recommended to conduct similar research in other developmental stages.

The Hyrcanian or Caspian Forests in Northern Iran are facing critical forest degradation due to unauthorized harvesting and illegal logging (IL). This study investigates the causes and factors of IL in the Caspian Forest. Open interviews were conducted with 51 stakeholders to gather data, which was analyzed using the Grounded theory method. In the open coding, the text of the informants' interviews was broken into concept codes and then categorized. In the axial coding, the relationships between the extracted codes were specified, and in the selective coding, the connections between them were illustrated. In open coding, 22 codes relating to IL were obtained. Based on the paradigm model, the position and connections between the causes and factors around the central issue of IL are determined. Then, the codes were divided in to five components consisting of causal conditions (one), context conditions (seven), intervening conditions (11), action/interaction (three), and consequences (one). The study found that "the collapse of the forest management system and the lack of plans for forest resources conservation" is the fundamental causality for IL. Further, contextual conditions such as high unemployment, poverty, subsistence livelihood, and intervening conditions such as weakness and absence of a system for monitoring IL have significant roles in intensifying it. The result of these conditions has caused the actions/interactions in which some people's greed in earning money with little effort and enormous profits from IL; avoidance of wood industries from tariffs and taxes by IL and "conflict between violators and forest guards, and legal and social issues. The consequences of these actions/interactions include deforestation, biodiversity loss, floods, and landslides. To address these issues, the study suggests establishing forest management systems in the context of forest management plans and providing the essential equipment, facilities, and human capital. The forest management plans should be prepared with local communities' participation, and reduce their direct dependence on the forest resources. This point can moderately unravel infrastructural, managerial, and supervisory barriers toward IL.

The aim of this research was to identify the optimal habitat areas of ash species (Fraxinus excelsior L.) in Kheyrud Nowshahr forest, which covers an area of approximately 8,224 hectares. We recorded the geographical coordinates of 1004 ash individuals using a GPS device, along with environmental variables such as climate variables and primary and secondary topographic predictors extracted from DEM. We used the predictors with the least degree of correlation as input in the Generalized Linear Model, Generalized Additive Model, Random Forest, and maxent models. We prepared and analyzed the variables in ArcGIS, SAGA, and R software. To compare the performance of the four models, we considered the input variables in all models to be the same. We evaluated the models using kappa coefficient (K), Area Under Curve (AUC), and True Skill Statistic (TSS) measures. The RF model had the highest K (0.973), AUC (0.997), and TSS (0.973), indicating the best performance among the models. According to the RF model, the most important variables were valley depth, profile curvature, slope, and topographic position index. These variables indicate the areas with rich soil, sufficient moisture, proper drainage (non-stagnant water), slope less than 45%, and sufficient light (suitable for the vegetative stage). We identified the most suitable areas in the Baharbon, Chelir, and Menia-Sang districts due to optimal conditions for these effective variables.

Different forms of land use development and human activities in protected areas are considered to be the main drivers of change, which have many effects on habitats, habitats, diversity and richness of species. The purpose of this research is to model the effect of human activities on the diversity of vegetation using the artificial neural network method and determine the impact of ecological and human variables on them. This research was done in the Central Alborz protected area under the management of Alborz Province. To achieve the mentioned purpose, firstly, 101 plots and 101 soil samples were collected and, soil and vegetation analysis were performed on the samples. Finally, using the multilayer perceptron neural network method and using 18 input variables including physical and chemical variables of the soil, physiographic variables, and human factors variables , the effect of human activities on the diversity of vegetation in the study area modeled. According to the results, the vegetation diversity model with the structure of 1-5-18 according to the highest value of the coefficients of determination in the three categories of training, validation, and test data is equal to 0.82. 0.81 and 0.68 show the best structure optimization performance, distance from roads, electrical conductivity, and percentage of organic matter in the soil show the greatest effect on the diversity of vegetation in the study area. The model presented in this research is used as a decision support system in evaluating the effects of human activities on the diversity of vegetation in protected areas and provides the possibility of predicting the extent of these effects on the diversity of vegetation in these areas.

Water use planning for irrigation in arid and semi-arid regions is incredibly imperative. The objective of irrigation operations in these areas is to make favorable humidity conditions for plants. The current study probes the water requirement and plant coefficient of adaptive tree species treated for afforestation and urban green space in the arid region of Robat Karim town. To determine the water requirement of biennial species of Ash, Tehran pine, Tree of heaven, Berry, Black maple, and Black locust, in the period from 1 May to 20 November 2018 for 7 months, in Robat Karim city, soil moisture monitoring daily and on the definite hour was monitored by Soil Moisture Meter tool in the greenhouse. According to the results, among the six studied species, the highest rate of evapotranspiration was related to the Berry (146 mm) in the first decade of July, the Ash (142 mm) in the first decade of July, and the Black maple is in the first decade of July (128.2), respectively. The lowest evapotranspiration rates include the Tehran pine (10.1 mm), the Tree of heaven (11/24 mm), and the black locust (16 mm), respectively, all three belong to the third decade of November. Similarly, the variations trend in plant coefficients was minimal in the initial stage. In the two stages of growth and development and the middle stage, plant coefficient increased along with full foliation and development of stems and aerial parts. The highest plant coefficient for the studied species occurs on average in October, which is about the end of the middle stage. Then, in the final stage, with decreasing photosynthetic activity, aging, and leaf fall (November), the amount of plant coefficient decreases. The quantity of cumulative water requirement of the studied species also shows that the order of cumulative water requirement of the studied

The study of ecological roles of animals that live in forest stands is always considered as a missing link in studies related to forest science and ecology. The aim of current study is to investigate the ecological and socio-economic roles of brown bear (Ursus arctos syriacus) in the forests stands of northern Iran. This study uses library documents that include books on forest ecology, forestry, wildlife science, history, anthropology, environmental sociology, natural resource law and biography, as well as research reviews and sources including related articles and reports, exploration and searches throw internet and obtained relevant information, along with conducting unstructured interviews. Unstructured qualitative content analysis interviews were conducted with experts in the field of forest and wildlife ecology and individuals from indigenous communities who are in conflict with brown bears such as gardeners, beekeepers and ranchers. By releasing informants so that they can explore the issue quite freely from a variety of perspectives, and they can comment in any way they wish on the ecological and socio-economic roles of the brown bear in the forests of northern Iran. The studied documents show that biologically brown bears control populations of insects, invertebrates and small vertebrates, facilitate decomposition and decay of forest dead woods, perform natural pruning, accelerate the natural regeneration of forest trees, playing a scorching role in carnivores and reduce the risk of forest fires. Affects the forest. Socio-economically, it also damages livelihood activities such as beekeeping, horticulture and animal husbandry, thereby creating some beliefs about the animal. Awareness of ecological maps of forest animals such as brown bears in the movement and establishment of seeds of forest trees, soil fertility, natural habitat, etc. leads to the knowledge and awareness of decision makers and indigenous communities of animals and thus helps significantly in wildlife protection.