محمود بیات

Biodiversity analysis in northern forests of Iran is very important due to its importance as one of the most valuable forest ecosystems in the country. In this study, the indexes of Margaleph and Menhink, Simson, Shannon Wiener and Pilo, Hip in two forest areas of 10 Chafrood and 7 Nav Asalem of Gilan province were used. 31 and 30 0.1 hectare plots in a 150 * 200 m survey network in 10 Chafroud and 7 nav forests, respectively, were permanently taken and measured and the indices mentioned in each sample plots were estimated. One-way ANOVA and Duncan analyzes were used to compare the two regions in terms of biodiversity indices. Then, altitude, slope and slope direction factors were determined in two regions and their effects on biodiversity indices were evaluated by correlation coefficients and analysis of variance. The results showed that the diversity indices of Simpson, Shannon Wiener, Pilo and Hip homogeneity indices were significantly different at 95% probability level. Margaluff and Mannhink richness did not show significant differences between the two regions and the 10 Chafrood region, was higher than all 7 Nav region, in all indices. The altitude factor had a significant negative correlation with almost all biodiversity indices. Slope and geographic direction were only significantly correlated with some indices. The beech species was the dominant species in both regions, so that the percentage of abundance of the beech species compared to the total species was 83 percent in the area of 7 Nava Asalem, and this ratio was 37 percent of the total species in the area of Chafrood.

China's foreign policy in recent decades has emphasized international prestige and credibility as desirable values, striving toachieve these through the strategy of "peaceful development." However, the Western world, particularly the United States andJapan as transregional and regional powers, view this strategy with suspicion, perceiving it as a threat. In contrast, Chineseofficials regard this process as natural, emphasizing China’s inherent role and position in Asia and beyond.In this context, the key role of social power as a foreign policy tool emerges in normalizing China’s peaceful developmentstrategy. Here, China seeks to complement its hard power with social power to frame its policies as both favorable and normal.More importantly, it aims to portray its policies as natural. The main question of this article is: what is the role of social power inChina's foreign policy?The hypothesis of this article, developed through an analytical-descriptive method, is that China, by emphasizing the role ofsocial power in its foreign policy and utilizing its tools—Confucian thought, public diplomacy, and economicinstitutions—creates opportunities to introduce alternative norms and desirable standards in foreign policy. This enables China tonormalize its "peaceful rise" and "peaceful development" strategies in the realm of foreign policy.

In this research, the continuity of land landscape was analyzed from the perspective of land landscape metrics (10 indicators) and graph theory indicators (12 indicators). First the correlation between correlation indices and water quality parameters was performed using Spearman and Pearson correlation coefficient and then with the help of stepwise linear regression method and through power, exponential and logarithmic regression models and using Akaike coefficient, the best model was chosen. The results showed that there was a significant negative correlation with water quality parameters between the land quality measures of CONIG and FRAC and the length of the corridor and most of the continuity indices of graph theory. Also, the highest coefficient of explanation or R2 belonged to CO3 models with a coefficient of explanation of 0.818, water flow with a coefficient of explanation of 0.733, Ca with a coefficient of explanation of 0.772 and TDS with a coefficient of explanation of 0.704. Almost all selected models are nonlinear models. Significant correlation of land feature continuity indicators, especially graph theory continuity indicators and corridor length with water quality indicators, shows the effect of structural features of land landscape on water quality in watersheds.

Global forest area has decreased by nearly 180 million ha in three decades. So, many ecosystem services provided by forests have been threatened. Reforestation and afforestation are the most effective strategies for mitigating deforestation. Therefore, in a variety of countries worldwide, including Iran, several afforestation projects have been implemented; however, the quantity and quality of many afforested lands have decreased over time under the influence of catastrophic factors, environmental stress, and different management methods. Awareness and continuous monitoring of forest programs are some of the most fundamental forestry policies. Therefore, the monitoring of annual afforestation in the eastern Golestan province using Google Earth software was put on the agenda to prepare an afforestation map and identify the reasons for the success and failure of the implemented plans. According to the findings, 19,377.39 ha of afforestation have been planted in Golestan province. Of these, Maraveh Tappeh city has the highest amount of afforestation with more than 9,256 ha with C. arizonica L, C. sempervirens L. var. horizontalis (Mill.) Gord. and P. brutia Ten, mostly. The presence of suitable climatic and edaphic conditions in the Golidagh of Maraveh Tappeh City and the ArabDagh area of Kalaleh City played a prominent role in the success of artificial forests in these areas. It should be noted that wood smuggling, the presence of livestock, the occurrence of fires, the presence of natural and human obstacles, and continuous monitoring have been other factors affecting the success or failure of afforestation programs in the eastern Golestan province.

Afforestation projects and forest parks in arid areas require detailed studies of basic resources. These include climate studies, soil conditions, water resources, determining minimum and maximum temperatures, pests and diseases, etc. Forest parks are forest ecosystems of natural, semi-natural, or man-made origin and are used for various purposes such as recreation, nature conservation, and, in exceptional circumstances, wood production. Selecting suitable species in forest reserves and parks is particularly important, especially because of the sensitivities to considering all aspects, such as water, climate, and soil requirements. As a result of this study, suitable species are suggested for desert areas and hot, dry areas based on ecological requirements for rehabilitating and utilizing the benefits of the reserve and forest park in the southern region of Varamin. According to the climatic and soil characteristics and other conditions of the study area, Spartium junceum, Morus, Salsola, and Atriplex species are suitable for planting in these areas.

The arid and semi-arid areas in the south of Varamin city are one of the areas that are prioritized for the implementation of tourism development and conservation programs due to soil erosion conditions, excess livestock grazing and destruction of pastures and vegetation. Therefore, the purpose of this research is a comprehensive evaluation of the ecological conditions to evaluate the environmental potential of recreation in this area. For this purpose, first, soil and vegetation samples were taken from sample plots from all three areas of Dolat Abad, Shokar Abad and Fakhr Abad in Varamin, and the required data and maps were prepared. Soil samples were collected and important soil parameters were determined in each sample and maps of these parameters were prepared. Then, the evaluation of the environmental potential of tourism was done by the method of intersecting ecological maps. For this purpose, the mapping of ecological factors, including slope, aspect, height, density of vegetation, precipitation, and temperature, as well as soil texture, was done. They were classified and coded according to the degree of desirability for wide recreation and then superimposed, and finally, the 1st and 2nd grade capacity classes and the unfavorable classes were created from the combination of these layers. In terms of totality and summation of ecological factors affecting the potential of tourism, Shakarabad region has more potential than the other two regions of Fakhrabad and Daulatabad. In general, what has caused the difference and superiority of tourism in Shakarabad region compared with the other two regions is the soil factor, which has caused the development of tourism in Shakarabad region to be higher than the other two regions. Another important factor is the land use and the proximity of this area to the desert protected area, which itself provides a high potential in the Shakarabad region for the development of outdoor recreation. The results of this research showed that by combining the multi-criteria evaluation method and the geographic information system and considering all the ecological factors, the real potential of outdoor recreation in forest areas and reserves can be determined.

Biodiversity is an important structural feature of dynamic and complex forest ecosystems. One of the most challenging and important issues in assessing the structure of forest ecosystems is understanding the relationship between biodiversity and environmental factors. Hyrcanian Forests are considered a biodiversity hotspot in the world and have special and unique features that have led to an emphasis and importance of biodiversity conservation in these forests. The aim of this study was to investigate the effect of biotic and abiotic factors on the diversity and richness of tree species in Hyrcanian Forests from the west of Gilan province to the east of Golestan province. For this purpose, using 655 fixed sample plots (0.1 hectare), the diversity of trees in 3 provinces in the northern Iran from east to west of the Caspian Sea was analyzed. A combination of non-parametric models including random forest (RF) and support vector machine (SVM) and linear regression models were used to investigate the relationship between tree diversity and biotic and abiotic factors. Biotic and abiotic variables included the number of trees per hectare, diameter, respectively. Basal area (BA), Basal Area in Largest tree (BAL), slope, aspect and elevation. Evaluation statistics including the coefficient of determination, RMSE and percentage RMSE error showed that the random forest model was the best model to determine the relationship between biodiversity and environmental factors and has suitable accuracy for determining biodiversity changes in the northern forests of Iran.

Urban green space has a very important role in the sustainability of the city. Green space per capita is one of the main factors to planning and management of a city. In this study, green space per capita estimation of Khomein city was investigated.

Satellite imagery was used to measure green space and parks per capita. For this purpose, using Sentinel-2 imagery, land use map was developed in four classes including: Bare lands, habitat, urban parks and farmlands. The urban park layer was extracted and combined to the four district of Khomein city layer. Then, the green space per capita of each area was calculated.

Green space per capita survey using remote sensing approach shows a severe shortage of urban green space in this city, especially zone 3 in the southeast of the city with 1.66 m2 per capita, meanwhile, this zone had the lowest value among all zones. In this city, green space has an inappropriate distribution and the highest green space per capita value was 3.43 in zone 1. Zones 2 and 4 had an average of 3.22 and 3.27 m2, respectively.

the results show that the green space per capita of the city is very low compared to the standards and requires special attention of decision makers to increase and expand the green space in the city. So in the near future, a comprehensive analysis of the green space and the reasons for this shortage should be addressed.

During Ahmadinejad's government, along with the growing conflict between the goals of the Iran and the Israel in the region, especially in the wars of Israel with Hezbollah and Hamas, there has been an intensification of Iran-US. Hence, in view of the special relationship between the US and Israel on one hand and the growing conflict between the goals of the Iran and Israeli during the Ahmadinejad era, the role of the Israel as an important factor in intensifying the confrontation between Iran and the US can be evaluated. Accordingly, this article aims to examine the role of the Israel in the intensification of the opposition between the Iran and the United States during the Ahmadinejad’s presidency. This study (with a descriptive-analytical approach) concluded that: Israel has played an important role in increasing the aggressive policies of the US and, consequently, the escalation of Iran-US confrontation by: linking Ahmadinejad's nuclear program to his policies toward this regime, "securitizing" of Iran's nuclear and regional activities, presenting the idea of its “existential threat" to the international community and with "announced" and "action" policies and scenarios in line with the plan, imposing the threat of attack to Iran and following Iranophobia.

Lack of up-to-date, documented and scientific information on the current situation (area and distribution) of Zanjan poplar plantation is one of the main problems of wood production managers for planning and management of wood supply in the province and the country. In this study, Sentinel-2 satellite data with spatial resolution of 10 m in spectral bands were used and the ground truth map of existing poplar fields with 600 points was plotted in all cities and villages from field surveys. From the beginning to the end of the poplar growing season (first half of March to December 2018), at least 6 time periods of 30 to 40 days were used in the SVM classifier. Post-test and calibration of SVM model based on the phenology of poplar genus and field samples were extracted, populated area distribution map of province was extracted. The results showed that the total area of ​​poplar areas is 2744 hectares which covers 0.12% of total area of ​​Zanjan province. One percent of the total polygons were randomly selected for field control and after field control, the overall mapping error was obtained and calculated. In this study, the exact location and area of ​​poplar mills were estimated with acceptable accuracy (96%). So that using extracted information (distribution map of poplars of the province) can provide studies on comprehensive planning of poplars and sustainable management of wood production from the poplars of the province.

In recent decades, the population of urban areas has increased dramatically and many vegetations have fallen prey to the onslaught of urbanization. Human beings, regardless of the main factors of the environment and its tolerance, have caused excessive destruction of the environment and endangered the survival, growth and health of current and future generations. On the other hand, in recent years, the ecological approach of Landscape in assessing environmental impacts has been greatly welcomed due to the use of the concepts of spatial integrity as the main basis in environmental planning. The processes and phenomena that exist in environmental systems are often dependent on many variables and there are very complex relationships between components that make it very difficult to analyze. This problem always causes errors in the accuracy and precision of model predictions, so examining the performance of networks and finding the best type of neural network to achieve acceptable and more reliable results is one of the priorities and modeling concerns. As a result of using these concepts to evaluate the appearance of the land, while saving time, the evaluation of the outcome of the activity can be determined cumulatively and in the shortest time. Land degradation model is one of the environmental impact assessment methods that quantitatively represents the effects of human activities in region or watershed scale. In fact, the degradation coefficients that are obtained by this model is an index of the damage done by human activity in a region. the main problem is that this model at some stage of implementation, relying on expert judgment and in addition need to extensive field work. so in this study investigated the relationship between land degradation and landscape ecological metrics that are descriptive index of landscape. Understanding this relationship and identifying metrics that have a strong correlation with degradation coefficients, is very effective to investigation feasibility use of these metrics in degradation model in order to future objectivity. The area of Arak city, using the political border map and in ArcGIS 9.3 software environment was 315 networks (networks 5 km 5 km and 25 km2) on the ground, some of which were full network and some incomplete networks. The degradation, ecological vulnerability and physiological density and then, degradation coefficient were determined. In the next stage, landscape metrics using Patch Analyst software based on the land use map was calculated. Finally, the correlation between the degradation coefficient and landscape metrics using the SPSS 17 software was analyzed statistically. After reviewing the described results, metrics with correlation with destruction numbers that were common to all 4 levels of study were determined in each user. The TLA measure was omitted because all networks are the same in all networks and applications because of the same size. Agriculture: NumP, PScov, TE, AWMSI Range: NumP, TE, AWMSI City: NumP, PScov, TE CA, Barren lands: NumP, PScov, TE, MPE, AWMSI CA, In forest use, there were no measured water areas that had a significant correlation with degradation numbers and were common to all 4 levels studied. The results showed that the metrics that were surveyed, two metrics: total edge (TE) and the number of patches (NumP) had the highest correlation coefficient with land degradation. By changing the scale (network size), the result will not change, so it can replace the degradation model. The findings of the degradation model indicate the destructive effects of industrial and transportation activities in Arak. In this research, artificial neural network was also used. ‌Multi-layered non stero peryspector, in comparison with other methods, has a high accuracy and predictive power and modeling of the factors influencing it. Network estimates were evaluated by MAE, RMSE and R2 criteria. In natural resources, due to the confusion and scatter in the data and the flexibility of the feed-through neural network with two hidden layers, data processing usually begins with two hidden layers. Therefore, network training was performed with four neurons in the input layer, three neurons in the first secret layer, one neuron in the second hidden layer and one neuron in the output layer. The network estimates were evaluated by MAE, RMSE and R2 criteria. Comparing the actual volume output with the network output predicted by the network is another way to evaluate the model. As can be seen, the black dots are the measured dots that indicate how much volume has been added. Based on the results obtained from the implementation of the demolition model in Arak city, it was found that destructive activities such as pollution of factories and various industries, "motor vehicles" and domestic, commercial, etc. heating sources, which were observed in most work units, as well as climatic and geographical conditions of the city. Arak (being surrounded on three sides to the mountain, towards the west and southwest winds and adjacent to Miqan desert) are the main causes of destruction. According to the results obtained in Arak, out of a total of 94 work networks, 37 networks need to be reconstructed due to their location within the boundaries of protected areas, and 22 networks due to high physiological density and high intensity of destructive factors. 21 networks are undevelopable due to faults. Existence of powerful and active faults such as Kooshak, Ensrat, Tafresh, Indes, Tabarteh, Talkhab, and Leopard spring are the most important faults in the province, which indicates the potential for earthquake risk in this province. 35 networks have the first to third development priorities. These networks, which are mainly located in the western and southwestern parts of the city, have low physiological densities and are located farther away from the city of Arak, where the severity of destruction is still high. There is no crisis and the future development of the city should be directed to these areas. Industrial growth has created many job opportunities as a result of the migration of large numbers of people from the cities, villages and villages of Markazi province and other provinces to meet the needs of the growing population. Urban and industrial areas are in this direction. Finally, considering what has been said about the natural sensitivity of the region's ecosystem and the results of the destruction model in this city, it seems that with the continuation of the current trend, there is a possibility that the intensity of development and economic activities will exceed the natural capacity of the region. In which case it will be very difficult and even impossible to restore it to its original state; For this reason, it is necessary to implement large-scale development projects that have a great destructive effect.

The forests of the Caspian region are one of the most important forest resources in Iran, but what is seen as a large gap in research is the need to pay attention to the structural dimensions, especially to maintain the structural connectivity of these forests. The aim of this study was to assess and compare the indicators of forest landscape in the Caspian Sea watersheds. At first, the forest layer was extracted from the land cover map and 25 large watersheds were selected to study and compare the connectivity indicators. The connectivity of the terrestrial landscape was analyzed using landscaping metrics and graph theory indicators, by Fragstats and Conefor softwares respectively. Finally, by standardizing the calculated connectivity indicators, a final connectivity score was obtained for each watershed. The results showed that the indicators of forest patches connectivity in the whole Caspian catchment are very low, so that 80% of the watersheds are in the category of very low and low connectivity. Watershed 9 (Sardabroud, Shalmnroud) and 7 (Chalous) are in a very unfavorable situation, and only two watersheds of 14 (Chalav, Panjab) and 4 (Pasikhan), in the area of Chalav and Punjab, in the Haraz River, and the Shakharz, Pesikhan rivers, are in a better situation in terms of connectivity indicators. Considering the importance of preserving the structure and connectivity of forest patches, the results of this study show the need for special attention to the management and restoration programs of these forests.

Determining and comparing biodiversity in different forest communities is important for accurate identification and forest management. The purpose of this study is an investigation the status of tree species diversity in three forest areas: Gorazbon district of Noushahr Kheyrod forest, Ashkateh Chal of Sefarood Ramsar forest and Haft Khal Neka forest. Species diversity of fixed plots was calculated by Margalf and Manhink (as species richness index), Simson and Shannon-Wiener (as heterogenity index), and Pielou and Hip (as evenness indices) indices. In all of 10R fixed plots, the DBH of alive trees was recorded. Statistically comparisons were done by one-way ANOVA and Duncan test. The results showed that all indices have significant differences at confidence level of 95%. The maximum and minimum of species richness were seen at Kheyroud and Neka forest, respectively. Also, Simpson and Shannon Wiener diversity indices are also maximum at the Kheyroud and minimum in the Neka forest. Ramsar forest has the most uniformity, then Kheyroud forest. The results show that the status of woody species diversity in Kheyroud forest is better than other forest areas in this study. The Neka forest, specially, has poor condition in terms of biodiversity indicators.

Proper distribution of urban green space is one of the most important issues in urban planning and especially in management of urban green space. In other words, the physical expansion of cities destroys surrounding natural environments and arable lands. It also results in fundamental changes in ecological structure and functionof urban landscape, along with gradual changesin spatial structure and patterns of this landscape (Wang et al., 2008). Since ecosystem processes depends on its structure, landscape metrics have been accepted as a very useful tool for expressing the structure of urban green space and its human-causedchanges (Hessburg et al., 2013).There has always been discussion onacceptable per capita green space or changes in green space over time and place. Iranian cities are no exception in this regard, thougheven a city enjoying a high ratio of green space per capita may still lack enough green space per capita in some districts. This suggests the necessity of investigating various measures and avoiding studies limited to per capita green space and urban forestry. (Botequilha and Ahren, 2002). If as an ecological structure,green space is proportional to populationcomposition and distribution, ecological performance and land use type of an urban area, it can have important ecological functions. Since most studies on urban green space have primarily focused onfinding a proper location, calculating appropriate per capita green space and introducing suitable species for green space, investigatingthe spatial distribution of urban green spaceseems to be of great importance. Therefore, the present study seeks to investigate the spatial pattern and distribution of public green space in Khomein using a landscape approach.

Study area The study area, Khomein, is bounded by agricultural lands and gardens in its northeast, west, and partly in its south. Only the main area of urban texture is located on barren lands (Abbasi et al., 1986). The study area includes four districts of Khomeinin which the pattern of green space distribution isinvestigated. Methods Sentinel-2 images were used in the present study. Satellite images were processed and then, their geographical effects were extracted inthe first step of classification. Different indices were defined for each patch of the image and using supervised method, images were classified into four classes of agricultural lands, barren lands, urban parks and residential areas in accordance with the training data. Visual method was used to improve classification results. In this method, classification results are matched with the imagesand possible errors are rectified. Google Earth was used to evaluate the accuracy of results obtained from classification of satellite images. In the next step,the base map of the present study was produced and then, the layer containing urban parkswas integrated with the layers prepared for four districts of Khomein. It should be noted that the present study focuses on urban parks prepared by the municipality for public use and does not include other urban green spaceareas such as the green belt or private gardens, etc. To study the spatial distribution of green space, measures of land cover were calculated and analyzed in each of the four districts. Geographic Information System (GIS) and Landscape Measurement Analysis Program (FRAGSTATS) were among the tools used to calculate and measure landusein the present study. Landscape metrics used in the present study included: Landscape Shape Index (LSI) which measures the area of ​​the largest patch in a class divided by the total area of ​​that landscape (multiplied by 100 to convert to percent) Euclidean Nearest Neighbor distance (ENN) which is the average distance between patches in a class. Meter is used as the standard unit of measurement for this index. Perimeter /Area Ratio (PARA) which is the ratio of the perimeter of ​​the patch (m) to its area (m2). This measure lacks a specific unit and for PARA> 0 it is without a limit. Number of Patches (NP) equals the number of patchesof the corresponding patch type (class). Shape Index:sum of patches’ perimeter divided by the square root of the area of ​​the patch (ha) for each class (class surface) or the entire patch (land surface). This index iscalculated for circle standard (polygon), or square standard (grid) and divided by the number of patches. Largest Patch Index (LPI) which measures the area of ​​the largest patch in a class divided by the total area of ​​the landscape (multiplied by 100 to convert to percent) Mean Patch Size (MPS) which measures the average size of a patchin the landscape.  

District 3 ranked highest and district 1 ranked lowest in ENN indexindicating that ​​urban green space patches in this district were closer together, while green space patches in the third district were limited and far apart from each other. Regarding LPI index, the second district ranked thehighest and the third district ranked the lowest indicating that the largest urban parks in this districtwere much smaller than other districts. Other district had a relatively acceptable statusin this respect. In MPS index, district 2 with 697 patches ranked highest and district 1 with ​​564 patches ranked lowest indicating that average green space patches in district 1 were smaller. This was also confirmed by maps prepared based on other metrics.Regarding the LSI index, district 1 ranked highest and district 2 ranked lowest, while districts 3 and 4 had a similar status in this measure. The first district had the highest number of patches (NP), while the third district had the lowest NP. The highestPARA ratio was observed in District 1, and the lowestin District 4, while districts 3 and 2 ranked near the middle. In Landscape shape index which increases with the heterogeneity of patches,district 1 (with 13.12) ranked highest and District 3(6.64) ranked lowestwhiledistricts 2 and 4 ranked near the middle.This indicates the heterogeneous shape of green space patches in district 1, while showing that patches of green space in district 3 are very simple and homogeneous.Finally it should be noted that calculating landscape metrics for the four districts ofKhomein indicated a very low per capita green space in this city and also absence of a proper and equitable spatial distribution.  

Calculatinglandscape metrics in the four districts of Khomeinindicated thatcompared to other districts, district 1, located in the southern part of the city, has a more desirable status in indices such as PARA, LSI, NP, and ENN. At the same time, district 3, located in the southeastern part of the city, has the least appropriate status regarding these metrics indicating the necessity of a comprehensive analysis of green space areas in this district in near future. Urban managers and planners need to focus on this district and its green space, and if possible find appropriate sites for future green space areas in this district.Although the status of districts 2 and 4, located in the west and north of the cityrespectively, were not very desirable, theyranked higher than districts 3in NP, LPI, and MPS. Using GIS in combination with satellite imagery, and land use metrics provided an innovative way to study the gradual spatial changes in urban green space. Results of landscape metrics analysis indicated an unbalanced distribution of land use in the four urban districts in this study.

Diameter at the breast and height of trees are the most important components in the forest inventory. Measuring the diameter of trees is simpler and less costly than height; hence, some equations are used to predict height by diameter of trees. In the present study, the ability to use different diameter-height models for estimating the height of beech trees (Fagus oriantalis Lipsky) in uneven age and mixed stands in Hyrcanian forest, North of Iran. In this study, a systematic-randomly sampling method with 150 × 200m network (0.1 ha) was used. Diameter and height of the thickest and nearest trees (690 individuals) to the center of circular sample plots (345) was measured. 70% of the data was used for modeling and the remaining 30% was used for evaluating estimated models. Using 20 nonlinear regression models including 11 two-parameter models and 9 three-parameter models, the relationship between height as a dependent variable and diameter as an independent variable was considered and analyzed. In order to evaluate the models and select the best model, the validity of the statistical models was evaluated using RMSE and BIAS. The results of the model evaluation criteria did not differ significantly. Korf, Ratkowsky, Naslund and Weibull models with root mean square error of 4.17, 4.19, 4.21, and 4.23 and BIAS of 0.17, -0.38, -0.55 and -0.1, respectively had a good ability to accurately estimate the height of beech trees. According to the region conditions, these models can be used to estimate the height of beech trees in broadleaved and mixed forest of northern Iran.

In this study, the effect of climate variables (temperature and precipitation) on diameter growth, basal area and volume of trees on the surface of Permanent sample plots in North of Iran were investigated. In this research, 313 permanent sample plots were used for correlation modeling. These sample units are located in the Jojadeh district, farim Forest. Using growth data obtained during 2003 and 2013 in this section, the growth model was obtained during a ten-year period in permanent sample plots, Also, the mean diameter, basal area and volume were used as variables related to the model. The results of this research showed that the model of growth, diameter basal area and volume with 83%, 94% and 90% correlation, respectively, have good accuracy. In addition, diameter at breast height, basal area at ​​breast height, basal area of the thickest trees, volume and climatic factors were the most important characteristics in the variation of growth in the plot area of ​​the specimen. Finally, the results showed that by using growth models, we could determine tree growth and its effective factors with proper accuracy.

In this research, which was done in Ramsar forests in Mazandaran province, the forest increment was estimated using artificial neural network and compared with the actual increment of the forest which was directly measured in 20 sample plots of 1 hectare in 2002 and 2012. The annual volume growth of beech was 4.52 and 4.35 m3 in hectare for direct inventory and estimation by artificial neural networks. Then regression analysis was performed to compare the results, stepwise, and the best models were selected. After selecting the best model for forecasting growth, the sensitivity analysis of inputs was investigated.The results showed that the neural network with relatively good accuracy can estimate the annual growth and cutting. The value of R2, RMSE and MAE were 0.75, 17 and 13.6 (for 20 sample plot of one hectare) respectively in the multi-layer perceptron network. Results also showed that the MLP neural network had the highest accuracy in predicting and estimation. In the analysis of multiple linear regression, the coefficients of detection were 0.610 and 0.679, respectively, and RMSE was 1.5 and 1.42, respectively, for the first and second models respectively. The volume at the beginning of the period and the diameter at breast height had the greatest impact on the amount of wood produced. Comparison of the models showed the use of neural network can predict the growth rate with proper accuracy.

Understanding the ecological niche of the different species is essential in many ecological issues.  Ecological niches of species are one of the important factors in the tree species distribution pattern and for all species, it can be detected by examining distribution of species distribution. Ecological nest models often help to understand more ecosystems. These models are applicable in predicting ecosystem stability and sustainability ratios and ecosystems.

In order to determine the selective pressure of different species, the indicators of the equilibrium level of selected nests, the dominant level of selected nests and the crisis level of selected nests were used and 41.5 hectares of Khirud research and educational forest were fully surveyed (100%). Then, characteristics such as diameter equal to the chest of the trees were measured and using selective nesting indices, the selected pressure and nesting levels of beech, oak, hornbeam and alder species were measured.

The values of the selective pressure were measured for the species on the Fagus orientalis 66.419, Quercus persica 3. 313, Carpinus orientalis 261. 28, Alnus 36. 962 and tilia begonifolia 9. 39 respectively. The final results showed that Carpinus orientalis wasat a Dominates niche level, the Fagus orientalis and Alnus was in the balance niche level and the Quercus persica was in intermediate between balance and critical level and also tilia begonifolia was in the critical niche levels.

The Carpinus species were at the dominant level of selective pressure, the Tilla species were at the equilibrium level and the Quercus species were at the equilibrium level of the crisis nest. The results of this study showed that selective strain quantification is an important factor in determining the current status of endangered species.

There are important species of beech and hornbeam In the Hyrcanian forests. Due to the economic and ecological importance of beech as well as the frequency of mixed beech-sufficient information about the structure and the level of beech and hornbeam and their associated species which will be used by Forest managers. Also in this study, for the first time in the study area, correlation analysis and regression analysis between biodiversity indices and independent environmental variables were performed which are essential steps in forest planning and management.

For this purpose, the indices of biodiversity (Shannon Weiner and Simpson Index) were measured individually in each habitat and then they were compared with each other. In addition, the correlation and regression of these indices with 16 eco-physiographic factors Including seasonal light, average air temperature, high altitude from the nearest drained point, topographic shafts, relative humidity, wind speed, reflection and radiation levels representing the environmental conditions of the region was obtained. Among them, only four factors had a significant correlation with biodiversity index. These factors are air temperature near the surface of the Earth, topographic wetness index, wind speed, and total solar radiation energy in each habitat. Also, t-test was performed to investigate the significant differences between biodiversity indices between the two habitats.

The results showed that both Biodiversity indices were higher in Hornbeam habitat than Rash habitat. The correlation coefficient of the environmental variables mentioned in the Shannon diversity index in each habitat indicated that the correlation coefficients of the variables with the variability index in the hornbeam habitat were higher than the rash except for the correlation coefficient related to the total solar energy variation in the Beech habitat which was higher than beech, with a negative slope indicating the nature of the friendliest shade of beech species compared to hornbeam.

the higher Shannon species diversity and Simpson uniformity index in beech habitat, confirms the tendency for this species to be mixed with its non-homogeneous trees and high competition at this stage of the sequence in beech habitat. In fact, the mass distribution of beech is a factor in the high competition and, consequently, a low index of uniformity. The results of this study showed that biodiversity indices were higher in hornbeam than in beech, which could be due to various reasons. In fact, determining biodiversity indices in forest communities firstly and then, examining and determining environmental factors affecting the biodiversity of tree species, as well as comparing important forest habitats and communities from the perspective of these factors for management purposes. Forests are important and essential.

Hyrcanian forests, which are located mainly on the northern slopes of Alborz are very important in terms of their specific features. Consequently, studying the evolution of these forest communities and their vegetative status can help planners and managers in tending forest stands. Growth and product models, which describe the dynamics of the forest, are widely employed in forest management to predict future products and to study management options. This study was conducted in Jojadeh section of Farim forest in northern Iran. Individual tree growth models including individual tree diameter growth, individual tree height growth, individual tree survival growth and individual tree regeneration growth were investigated in this study using 313 permanent sample plots (0.1 ha) in two 10-year periods. Competition in the stand was investigated by basal area and basal area large in the stand. Results showed that in the diameter model, the increase in diameter up to 90 cm was dependent on the diameter at breast height i.e. the diameter growth increased with the tree diameter; however, it decreased after attainment of 90 cm diameter. Oak and Maple trees had the highest diameter growth. In the height model, species type had no effect on the height model. In the survival model, the survival probability of alder species were lower than other species. In addition, the regeneration decreased with the basal area of stand in the regeneration model. in the present study, we have attempted to present models that estimate and measure theexact diametergrowth, regenerationand survival without regard to age

The main pre-request of the forest management and planning program is the availability of quantitative and qualitative data from forest structure. Therefore, the forest inventory plays a vital role in the estimation of the current status and future planning. In this study, spatial pattern of trees in Gorazbon section of Kheyroud forest in northern Iran was simulated to compare the random systematic sampling and complete random systematic sampling method based on the full calipering method. By using the Arc GIS software, the spatial pattern of forest trees was simulated. Buffer function was used to calculate the random systematic sampling and complete random systematic sampling method based on the full calipering method. In order to compare random systematic sampling with full calipering single-sample, a t-test was used. The results showed that there was no significant difference between random systematic sampling and full calipering method to estimate the average diameter of Alnus, Fagus orientalis, and Tilia begonifolia. However, there was a significant difference between two methods in the estimation of average diameter of Carpinus orientalis and Quercus persica. The results of T-test revealed that there is no significant difference between Alnus and Tilia begonifolia but significant difference was observed between the trees of the Fagus orientalis, Carpinus orientalis, and Quercus persica. In addition, paired t-test was used to compare the random systematic sampling and complete random systematic sampling method. Results showed that there is no significant difference between random systematic sampling and complete random systematic sampling method.

Haloxylon is a resistant tree naturally found in some desert areas of Iran, which sometimes faces dieback. This research was conducted to investigate the factors affecting the dieback of this species in Hossein Abad Mish-Mast Qom. Growth and yield traits including the density of trees, number of branches, trunk diameter and height, canopy area, tree age, trunk form, pests, and diseases were recorded in the field. Leaf samples were taken from the trees with varying drying and the amount of sodium, potassium, phosphorus, and chlorine was measured. Soil profiles were dug and soil samples were taken from areas with different drought stress of trees to measure physico-chemical characteristics of the soil at different depths. The results showed that there was a direct relationship between the density of trees and their drying. The results of soil analysis showed that soil salinity was an important factor in the establishment of trees since the density of trees decreased by increasing soil salinity. Also, low concentrations of nutrients have been found to be effective in tree growth and yield. The results of leaf analysis showed that the amount of sodium and chlorine in the leaves was very high and in the older trees the amount of these elements was higher in the leaves. The results showed that salinity was not the only cause of drying of the trees but the higher density was more important in causing this problem. Ecological problems and nutritional deficiencies associated with high density and lack of proper planting intervals were the main causes of drying of trees.

Determination of forest growth is one of the most important goals and tasks in forest management, which has always been accompanied by challenges in the implementation section due to the complexity of volume and growth process determination. Knowing the volume of standing trees and growth is mandatory in an accurate planning. The volumetric growth of forest stands is a basis for determining the annual cutting in planning and management of forest exploitation. Harvest of this amount of wood leads to forest sustainable development and, to some extent, can provide the wood needed in the country without raising a problem for these valuable resources. This study was done in Gorazbon district of Kheyroud forest in Mazandaran province. 258 permanent sample plots were measured in the circle area of 10 R. Then, volumetric growth and number of trees in forest stands were directly calculated. Results showed that the average tree numbers were 298.15 and 290.4 stems per ha in 2003 and 2012 respectively. The growing stocks were 335.8 and 367.7 sylve per ha sustainable forest management. Although beech constitutes 31% of the total number of trees in Gorazbon district, it accounts for 57% of the whole trees in terms of standing volume. Annual volumetric growth is 4 sylve per hectare and growth of tree number is -5.8 per hectare annually. Finally, it can be concluded that preparing an inventory by permanent sample plots provides the necessary information and detailed statistics to determine the volumetric growth and number of trees to contribute to proper management and decision making. Moreover, harvesting this volumetric growth can help the economy and lead to sustainable development of the forest at the same time.

Quantifying forest growth and determination of its affective factors are fundamental for forest management. This study examines the effects of biotic and abiotic factors on the diameter increment of oriental beech (Fagus orientalis Lipsky) in a high-elevation forest in northern Iran using permanent sample plots. The aim of this study was identification and quantifying environmental factors such as potential solar radiation in growing season, topographic wetness index in representing soil water distribution seasonal air temperature, topographic wetness index (as indicator of soil water distribution), wind velocity generated from simulation of fluid-flow dynamic models of complex terrains, temperature and humidity and their relation with diameter increment of beech. On the basis of diameter measurements in a 9 year period (2003-2012) a model was used in order to estimate diameter increment. Also, mean of DBH and basal area of beech trees were implemented in model as biotic factors. The results showed that DBH, combination of topographic and soil water index factors and basal area are the most important factors affecting diameter increment of beech trees, respectively. Eventually, the results showed that by using increment models, it is possible to determine the increment of diameter and factors affecting it with high accuracy.