هادی کیادلیری

Fires are among the most significant natural disturbances impacting plant ecosystems worldwide. Despite their destructive nature and considerable influence on forest ecosystem dynamics, forest fires are an inherent component of many ecosystems. Over millions of years, the interdependent relationship between fire and vegetation has led to their mutual adaptation, making fire an inevitable and inseparable part of these ecosystems. The bark of trees serves as a protective barrier for young trees and seedlings, shielding internal tissues from fire and preventing damage to all tree tissues below 60°C, which is the critical temperature for cambium death. This study aimed to assess the fire sensitivity of two tree species, beech (Fagus orientalis Lipsky) and hornbeam (Carpinus betulus L.), by examining bark thickness and determining cambium death times across trees with similar diameter classes.

The study was conducted in the Lalis Forests of watershed No. 45, located in Mazandaran province, northern Iran. The area covers 2,127 hectares, and the climate is classified as very humid based on the De Martonne method. Random sampling of tree bark was conducted across diameter classes ranging from 5 to 120 cm for both beech and hornbeam species. A total of 192 trees (96 beech and 96 hornbeam) were sampled, with eight trees selected from each diameter class, resulting in 384 bark samples. At breast height, a 10×5 cm section of bark was removed using a knife, and the thickness was measured with a caliper to the nearest millimeter. The bark samples were then exposed to controlled burning at 60°C and 400°C. To compare species vulnerability to fire within the same diameter classes, a paired t-test was used. Bark thickness was entered into the formula  to examine cambium death times.

Significant differences were observed in bark thickness between the two species, with hornbeam exhibiting thinner bark compared to beech in the same diameter classes. A notable difference (P<0.05) was found in the time to ignition between beech and hornbeam bark at the fire environment temperature of 400°C. However, hornbeam bark demonstrated greater heat resistance. In both smaller and larger diameter classes, hornbeam exhibited higher survival rates than beech, despite beech having thicker bark in all diameter classes. One key factor contributing to the species' fire resistance is the physical and chemical structure of the bark, with light-demanding species typically exhibiting higher fire resistance. At 60°C, the cambium is destroyed, and hornbeam showed higher resistance, with its cambium changing color over a longer period. Beech cambium, despite having thicker bark, was destroyed more slowly than hornbeam cambium. This suggests that species with thicker bark tend to have longer cambium death times. Although the  formula is linear, it does not account for all factors affecting tree resistance (such as the physical and chemical properties of the wood), limiting its accuracy in assessing tree mortality.

Bark thickness plays a crucial role in determining the time it takes for bark to burn and for the cambium to die, and this varies between species. When comparing burning times and cambium mortality within a species, bark thickness is a primary influencing factor. However, when comparing between species, factors such as species type, fire resistance, and the physical and chemical characteristics of the bark become more significant. Therefore, in the event of a fire, to protect the forest and minimize further damage, priority should be given to supporting younger, more vulnerable stands.

The occurrence of disastrous consequences of climate change is a manifestation of the intensification of climate instability in a wide area of ​​the planet. This study has been carried out with the aim of evaluating the relationship between the category of international conflicts and the extension of the cancellation of climate treaties. In addition, it is stated that the demand for peace by the subjects of international law will enable the acceptance, synergy and realization of climate justice. The development of mechanisms based on climate justice will be an effective and fair way to achieve the right to have a sustainable climate for all governments and subjects of international law. From this point of view, this study has been done in three operational research phases. Also, in this research have been conducted a review of climate law texts and a survey of experts. In the results of the research that in recent years, it was concluded, the occurrence of international conflicts and the lack of peace among governments have a high impact on the failure of climate treaties. Commitment to the implementation of mitigation and adaptation mechanisms through peace and climate justice legislation is effective in mitigating the risks of climate change.

Adaptive planning and water allocation in the conditions of climate change is facing deep challenges due to various uncertainties. In this situation, decisions should be made that are more stable and maintain their function in different climatic scenarios. This study was carried out with the aim of planning agricultural adaptation measures in the conditions of climatic uncertainty in the Karun 3 watershed using the robust decision-making (RDM) approach. To achieve this goal, GCM models under two emission scenarios (RCP4.5 and RCP8.5) and WEAP model were used to simulate the current situation of water resources and uses in the basin. Runoff and cultivated area were considered as parameters with uncertainty.

To realize the research goal, the WEAP model was used to simulate the current situation of the basin's water resources and uses. Because under the effect of climate change, the precipitation and temperature parameters of the area will undergo changes in the future from three models - EC-EARTH, CNRM-CM5 and GFDL-ESM2M under two scenarios RCP4.5 and RCP8.5 to investigate the amount of temperature changes and future period precipitation was used. Also, in this research, the IHACRES rainfall-runoff model was used to simulate the runoff of the Karun River in the future. Measures such as 10% increase in irrigation efficiency (S1) and changing the cultivation pattern (S2) were considered as effective adaptation measures in the agricultural sector. Finally, by using the robust decision-making approach (RDM), the strength of the presented strategies under the existing uncertainties for the future period was examined and evaluated. Based on two approaches, RDM minimizes the effect of uncertainty. The Regret Method, which is obtained by minimizing the amount of deviations in performance caused by uncertainty compared to the ideal state, and the robustness approach or the satisfactory boundary, which calculates the fraction of scenarios that meet the designed criteria.

The results of runoff simulation for the future period (2055-2030) show that the amount of Karun river runoff will decrease by 22-8% in different months compared to the base period. Evaluation of the simulation results of the WEAP model in the current situation, the drinking water needs are almost completely provided in most of the sectors and only in the A8 sectors, which is the study area of 2301 (Khorramshahr) and A6 (the study areas of Lali and Indica). ) are facing water shortage. Also, the results showed that there is no shortage in the industry sector. Meanwhile, sectors A1, A2 and A3 are facing a shortage of water resources in the agricultural sector. The results show that due to the deficiencies in the existing conditions, the Behesht Abad watershed will not have the necessary potential to transfer water to the volume of 580 million cubic meters per year through the Behesht Abad tunnel to the Zayandeh Rood watershed. Also, the results showed that the satisfaction index of strategy 2 and strategy 1 is 0.78 and 0.65, respectively. Also, the comparison of the results of the regret index shows that strategy 2 is stronger than strategy 1.

Finally, based on the research approach and the definition of stable decision-making, the results showed that the strategy of changing the cultivation pattern can be put on the agenda as a stable strategy, so that it can work in a wide range of uncertainty and climate scenarios. Maintain within the current status of the basin. The main strength of this study is its systematic methodology, which helps to make more informed decisions and design comprehensive adaptive programs. It can also be applicable to other basins by considering different goals and indicators. However, future studies on climate change uncertainties and socio-economic evaluation of adaptation measures are other areas that could improve the analyses.

The forests of the Zagros region in western Iran have experienced notable environmental shifts in recent years. Investigating the vertical and horizontal forest structures across different timeframes offers a window into these transformations.

Remote sensing methods, alongside satellite imagery, present a cost-effective and accurate means to monitor temporal changes in forested areas. In this study, image integration techniques and spectral indices were employed to assess the scale of these variations.

Initially, Gram-Schmidt integration was used to enhance the satellite imagery to the fourth order of spatial resolution. Subsequently, changes in the horizontal forest structure of the Sardasht region were examined by evaluating three vegetation indices (NDVI, EVI, and LAI) over a decade (2011, 2015, 2018, and 2021).

The findings highlighted the efficacy of image integration in detecting pixels with small tree presence on the forest floor, with NDVI emerging as a particularly suitable index for discerning changes in the forest's horizontal structure.

The southern mangrove forests are considered to be one of the most important forest habitats in Iran due to the presence of indanger and rare, and problems from pollutions. If lack of attention and destroyed, their reversibility is very difficult and sometimes impossible. The aim of this study was to investigate the relationship between aquatic and soil ecological characteristics and morphological variables in 4 vegetation areas of these forests (Goater, Qeshm, Assaluyeh and Mahshahr).   

Ecological parameters including soil texture, equivalent calcium carbonate content, soil EC, soil pH, water sodium and potassium percentage, and morphological parameters of mangrove trees (height, diameter at breast height, collar diameter, diameter and length of pneumatofers, leaf area) with ground measurements were taken randomly by linear method (transect). In the laboratory, measurements were performed with specific devices for each parameter. Using ANOVA and Pearson correlation tests, the relationships between them were examined.

The results showed that the ecological conditions of the four regions, as well as the morphological characteristics of the trees, had significant differences. The amount of clay, pH and EC, sodium and potassium of water and height, d.b.h, collar diameter, leaf area and pneumatofer diameter in Guater showed the highest values and the decreasing trend of many parameters from east to west was quite evident. Ecological variables showed the highest correlation coefficient with the root length, while the leaf area parmeter showed the lowest dependence. 

The results of this study show the unique differences of each mangrove habitat in southern Iran in soil and water parameters and morphological characteristics. It also shows the great impact of ecological parameters (water and soil) on the establishment and growth of mangrove trees in sites in the forest ecosystems of the south of the country.

Drought is one of the natural phenomena caused by the decrease in rainfall and reduces vegetation and increases dust. The common method of drought monitoring is based on observational data from meteorological stations and calculates a drought index. Knowing the amount and intensity of drought in a region and planning to reduce its effects is one of the most important principles of management in regional planning fight against drought. Monitoring and management of drought is a region using remote sensing data and satellite images as a suitable tool in the temporal and spatial monitoring of agricultural drought has always been  of interest to regional managers.

This study investigates the efficacy of remote sensing data and satellite images in delineating agricultural drought zones in the southern watershed of Kerman Province from 2001 to 2022. For the purpose, three indices, including the Vegetation Cover Index(VCI),Temperature Condition Index (TCI), and Vegetation Health Index (VHI), were extract from MODIS satellite images, and TerraClimate extracts data for growing season months based on remote sensing of vegetation cover from early March to late August (2001-2022), and the resulting indicators are compared with standard precipitation index (SPI) values. It was compared in one, three, six, nine-, twelve-, twenty-four-, and forty-eight-month time series. In this study, the correlation method between stations was employed to reconstruct the incomplete station data, and the stations with the highest correlation with the incomplete station were utilized for reconstruction. After organizing the data, the reconstructed information was entered into the SPIGenerator software as input, and the SPI indices for 1, 3, 6, 9, 12, 24, and 48 months were generated for the selected stations.

In this article, the results of calculating the SPI index in various time series based on the average data from existing stations and remote sensing data were analyzed. To this end, the values obtained from all satellite-based indices, including VCI, VHI, and TCI, were extracted and compared with the ground-based SPI index in 1, 3, 6, 9, 12, 24, and 48- month time series. In other words, the response of vegetation cover in the region to rainfall with 1, 3, 6, 9, 12, 24, and 48- month time legs was investigated. The result of this study shows that the VCI index has a significant correlation at a 1% level with the SPI index in all time series except for the 1-month series. The TCI index has a significant correlation with none of the time series except for the 1-month series. The VHI index has a significant correlation at a 1% level with all time series except for the 1-month,3-month, and 24-month series. Additionally, the drought indices TCI, VHI, and VCI have a positive significant correlation at a 1% level with rainfall and soil moisture.

The overall results of the analysis of the available data showed that among the studies indices, the VCI index has the highest correlation with SPI values in different time series during the growing season, with a significant correlation at the 0.01 level. Therefore, it is selected as the preferred satellite index for monitoring agricultural drought in southern Kerman Province. The results of this study provide a basis for a better understating and evaluation of drought conditions in southern Kerman Province, and can guide optimized management and provision of drinking water and agricultural resources, leading to increased and optimized agricultural production, and ultimately, proper environmental protection.

Hydrological models are an effective tool for managing water resources as well as understanding the impact of land use changes and climate change on the water cycle and flow characteristics. The aim of this research is to evaluate the relative performance of integrated and conceptual rainfall-runoff models AWBM, Sacramento, SimHyd and Tank in the RRL software package in simulating the daily runoff of the Fasa Bridge watershed from the sub-basins of Maharlu Lake in Fars province. 23/9/2002 to 31/12/2003 for the model warming period, from 01/01/2004 to 31/12/2014 for the calibration period and from 01/01/2015 to 22/9/2021 for the period Validation was used. After the implementation of the models, a quantitative evaluation of the simulated monthly flow values was presented for the calibration and validation stage. Then, by trial and error method and based on the characteristics of the watershed, the optimal values of the model parameters were determined in the calibration period . Comparison of statistical indicators in the calibration period for AWBM, Sacramento, SimHyd and Tank models, efficiency coefficient 0.79, -0.02, 0.6, 0.41 and determination coefficient 0.82, 0.59, 0.79, 0.41, respectively and efficiency coefficient 0.53, -0.19, -0.44, 0.002 and determination coefficient 0.65, 0.61, -0.65, -0.36  were obtained for the validation period. The calibration results for AWBM and SimHyd models show the good performance of the model in simulation of discharge. Although the results of validation for AWBM and SimHyd models have provided weaker results compared to the calibration period, they have provided acceptable results, which may be due to the recent droughts of the validation period compared to the calibration period. The results of calibration and validation for Tank and Sacramento models indicate the poor performance of the model in simulating runoff. Also, the models have a lot of error in peak discharges.

Today, the phenomenon of climate change is one of the problems that has always received attention in the world. One of the reasons for climate change is the increase of greenhouse gases, which have a significant effect on extreme phenomena. Drought forecasting is one of the management strategies that helps to plan properly for using limited water resources. It is also important to examine drought changes based on climate changes from various aspects; in many long-term plans, it is necessary to develop a vision of the future state of rainfall and drought periods for the region. The SPEI index can calculate drought in different time scales and can also include the effects of temperature changes in drought assessment and be used to monitor current and future climate changes based on climate scenarios. Also, the Standard Precipitation Index (SPI) is one of the most important indicators in drought analysis. This index is known as the most appropriate index for drought analysis due to the simplicity of calculations, the use of available rainfall data, and the ability to calculate for any desired time scale. The recent increase in droughts in the Karun 3 watershed has caused water shortages and economic and social damages. Therefore, investigating the effect of climate change and analyzing the frequency of drought is very important. In line with this goal, in this research, firstly, simulation of rainfall, maximum temperature, and minimum temperature of eight meteorological stations using three climate models EC-EARTH, CNRM-CM5, and GFDL-ESM2M under two release scenarios RCP4.5 and RCP8 5. It was forecated for the period (2055-2030).

In this research, firstly, the temperature data (maximum and minimum) and precipitation output of EC-EARTH, CNRM-CM5 and GFDL-ESM2M climate models under the CORDEX project for RCP4.5 and RCP8.5 emission scenarios with the help of CMhyd Raz software Scaled and time series of maximum, minimum and precipitation temperatures for eight meteorological stations in the future period (2055-2030) were produced. Then, the temperature and precipitation changes in the future period compared to the base period (1995-2020) were investigated. Finally, the investigation of drought (frequency and continuity) in the future period under two release scenarios of RCP4.5 and RCP8.5 by (SPI) and (SPEI) indicators in three-time scales of three, six, and twelve months using DIP software was performed. To evaluate the efficiency and accuracy of three EC-EARTH, CNRM-CM5, and GFDL-ESM2M general circulation models for simulating climate data, the monthly average of climate variables in the period (1990-2005) obtained from the output of the model was compared with the corresponding observational values. For this purpose, Nash Sutcliffe (NS), bias index and coefficient of determination (R^2) were used.

The results showed that the maximum temperature increase is related to Shushtar station. In this station, the maximum temperature will increase by 1.46 degrees Celsius in the RCP8.5 emission scenario and one degree Celsius in the RCP4.5 emission scenario compared to the base period. Masjid Sulaiman station has the highest increase in minimum temperature. At this station, the minimum temperature increase under the RCP8.5 release scenario is 2.41 degrees Celsius and under the RCP4.5 scenario, it is 1.92 degrees Celsius. Also, the rainfall in the whole range has been decreasing in the coming period. The decrease of rainfall in Kohrang in the RCP8.5 scenario is 146.3 mm and in the RCP4.5 scenario, it is 53.6 mm, which is about 11.7 and 4.3 percent, respectively. In terms of the frequency of drought in the statistical period (2055-2030) on a three-month scale, in the RCP4.5 scenario, Izeh station has the highest frequency with 14 droughts, on a six-month scale, in the RCP4.5 scenario, the maximum number of droughts in Shahrekord with 16 times and on a twelve-month scale, in the RCP4.5 scenario, Kohrang station shows the highest frequency with 15 times. In the RCP8.5 scenario, Izeh station has the highest frequency with 20 drought experiences. Also, in the upcoming period, under the RCP4.5 release scenario, on the scale of three, six, and twelve, respectively, Shahrekord, Yasouj, and Lordegan stations will have eight, 11, and 27 months, and in the RCP8.5 scenario, the drought will continue the most at Masjid Sulaiman, Shushtar, and Lordegan, respectively.

The results showed that the annual long-term average of the maximum and minimum temperature in the future period compared to the base period in all eight stations had an upward trend. Also, the results showed that the maximum temperature under the 8.5RCP scenario increases more than the 4.5RCP release scenario. Also, the results showed that the Kohrang station affected by climate change will have the largest decrease in rainfall in the study area during the coming period. Also, the results showed that in all three-time scales of three, six, and 12 months in the future period, compared to the base period, there are many fluctuations in the time series of SPI and SPEI drought indices. Also, extreme drought conditions will increase in the coming period. It is expected that in the coming period, the number of dry months will be less than the number of months with normal and wet conditions. Also, when examining the drought situation using the SPEI index, it can be seen that, like the SPI index, the pattern of changes in the drought period can be recognized in the stations. It should be mentioned that the intensity of droughts calculated using the SPEI index is rarely higher than the numerical value of two. By comparing the duration and frequency of drought in the studied stations and in different time comparisons, it was found that the SPI index shows the continuity and frequency of drought in most cases compared to the SPEI index.

Road ecology studies are very important and valuable for monitoring the impact of forest roads on biodiversity. This study was conducted in order to investigate the effect of forest roads on the biodiversity of herbaceous species, tree regeneration and lichen in the Kalardasht forests. Sampling was done in the sample plots at distances of 0, 15, 45, 75, and 105 meters from the roadside in two controlled and harvested areas. The indices used were Margalf's species richness, Shannon-Wiener's biodiversity and Pielou's evenness index. The effects of roads on vegetation diversity in relation to soil characteristics were also investigated. The results showed that road construction in the harvested stand caused the destruction of tree regeneration, herbaceous and lichen, but the physical and chemical properties of the soil were not affected. By increasing the distance from the road, the diversity and richness of regeneration in both control and harvested areas has increased and the evenness index has decreased. On the other hand, the diversity and richness of herbaceous species has shown a significant decrease. This study reports the distance of 15 to 45 meters of the buffering effect of the roadside on the indices of biodiversity and the richness of tree regeneration, herbaceous cover and lichens. Most of the physical and chemical properties of the soil have also increased with increasing distance from the road. Also, there was a significant correlation between most of the physical and chemical properties of the soil with the regeneration of trees and herbaceous species.

The aim of this study was to investigate the spatiotemporal dynamics of trees distribution patterns in a ten-year period following disturbance caused by decline in the oak forests of Lorestan province in the west of Iran. For this purpose, the quantitative characteristics and the spatial patterns of trees in 5-hectare sample plots in four different regions without decline, which were surveyed in 2010, also surveyed in 2020 which three regions had conditions of decline and one region without decline). The results showed that the mean of density was decreased in declined areas and increased in the non-declined area during the period. During the ten-year period, there was a significant difference between the tree density and canopy percentage in the areas with and without decline. The spatial patterns of Persian oak (Quercus brantii) trees in the decline areas showed that during the period, the spatial patterns in the pure and low-density stands were clustered, while in the mixed stands with the dominance of oak with relatively high density, it was a random distribution pattern, which with increasing of distance, changed to clustered. The disturbance due to decline in the mixed stands caused the clustering occurred in a smaller radius (40 meters and more), but in the mixed stands without declined clustering observed in a radius of more than 60 meters. The results of this study showed that the trees decline affects the spatial patterns of trees which can be an effective guide in the management of decline stands.

Improving decisions in fire management requires a complete understanding of the spatio-temporal relationships between droughts and fires. To achieve this, the natural areas of Lorestan province were selected as the research site. The fire data from MODIS satellite products and monthly rainfall data of the province were extracted to estimate SPI drought index for the statistical period of 2000 to 2022. The spatial and temporal relationship between the frequency of fire occurrences and the spatial and temporal distribution of droughts in terms of annual and monthly scales was investigated with the Pearson correlation model in the province. The results showed that the trend of fires in the region is increasing. The months of June and July have experienced the highest frequency of fires in the natural areas of the province. Poldokhtar city has had the most frequent fires in natural areas. The whole region has tended to be dry, but the eastern parts mostly included classes with higher degrees of drought. The results of the correlation matrix showed that only the drought events in spring to summer had a significant but moderate negative correlation with the fire events in spring and summer. Despite the obtained results, this study emphasizes that the connection between fires with drought needs more studies and it is not possible to prove the real relationship between the two phenomena with just one calculation index.

In order to quantify the response of canopy to environmental changes, leaf area index (LAI) and canopy cover characteristics are used, which are known as canopy photometric characteristics. Road construction in the forest, will change the photometry characteristics of the canopy. Therefore, this study aimed to investigate the LAI values and canopy cover along the secondary forest roads and compare with the value of mentioned characteristics in the Beech-Hornbeam forest type.

 This study was conducted in district 1 of Langa Forestry Project in Kelardasht. In the logged parcel, 10 transects were established randomly and perpendicular to the road at fillslope was constructed on 1984. On July 2019, the canopy was photographed by hemispherical photography at distances of zero (road edge), 15, 45, 75 and 105 meters. Then, the values of the mentioned characteristics were processed in GLA software based on the fourth ring of this software.

According to the ANOVA test, the values of canopy cover and LAI are different between different distances of forest roads and according to the Tukey test, the values of the mentioned characteristics at the distance of zero meters from the road (road edge) is significantly lower than other distances (p < 0.001).

Due to the fact, this road is one of the secondary forest roads, so traffic is rare on this road, and on the other hand, a single selection cutting method (with low interference intensity) was used in this forest. Therefore, the forest in this area over time has been able to mitigate the negative effects of road construction and only at the road edge has a significant effect on the values of these characteristics.

Liliaceae include 73 species that covers about 1 percent of Flora of Iran. In addition approximately 27% of mentioned taxa are classified in endemic flora of Iran. Gagea with 31 species is the largest genus liliaceae in scale of Iran. These taxa were categorized based on topographic zonations including basins (less than 300 m a.s.l.), lowlands (300–1000 m a.s.l.), semi–mountainous (1000–1500 m a.s.l.), mountainous (1500–2500 m a.s.l.), alpine (2500–3500 m a.s.l.), and subnivale (3500–4500 m a.s.l.). Iranian Liliaceae included critically endangered (CR): 22 spp, endangered (EN): 5 spp., near threatened (NT): 37spp), vulnerable (VU): 1 spp.), In addition, the Kurdistan–Zagros range and the Atropatenian phytogeographical units feature the highest richness of mentioned taxa and form the first class in conservation value and priority. Several endangered species in this family, a wide range of which is located outside protected areas, so In situ as well ex-situ conservation actions seems to necessary for their conservation.

Due to the weakness of the ecosystem in the Zagros forests, which is due to human and livestock pressure over the past decades and the occurrence of recent droughts, most of the forest areas have declined. In this situation, it is necessary to study the effects of various management activities in order to design strategic plans. To do this, the current study was conducted in Dinarkuh forest area of Ilam province to investigate the impact of different management activities on tree, soil and biodiversity variables of tree species, taken during the last decade. Experimental treatments included exclosure, exclosure + pruning, exclosure + pruning + afforestation, exclosure + pruning + afforestation + catchment system and control which considering aspect in the form of factorial statistical plan, 19 treatments with four replications were considered for each treatment. In total, 76 sample plots with area of 1500m2 were established in the field. The interested variables were measured and calculated in each sample plot and then compared between different treatments using two- way ANOVA with two factors: management activities and aspect. The results showed that among the biometric variables of trees; DBH, height, crown diameter, sprout diameter and tree density, among physical and chemical properties of soil; percentage of organic matter, silt, sand, bulk density, lime, carbon, phosphorus, potassium, soil depth, erosion and among biodiversity indices; Shannon-Wiener, Pielou and Heip indices were significantly different under management activities' areas compared to the control area. Even though, all management treatments had effective and positive effects on tree biometric variables and soil physico-chemical characteristics, as well as on biodiversity indices and in most cases made improved the current situation, considering the required costs for management treatments and their destruction in the field, exclosure can be introduced as the best management treatment in the region.

Iranian mangrove forests provides valuable information to prevent genetic erosion in the gene pool of these ecosystems. The aim of this study was to investigate the genetic diversity among mangrove forests located in four different regions of Iran, based on morphological characteristics and microsatellite markers. Cluster analysis of molecular data, using neighbor joining algorithm classified the 60 mangrove trees, sampled from different coastal areas, into four groups. Analysis of molecular variance showed that the majority (77%) of the variance explained by among-population variation and the highest values of genetic diversity parameters including number of effective alleles, Shannon’s information index, and Nei’s genetic diversity were obtained for the Qeshm population, indicating that region is the most diverse population among all the studied populations. Baced on the morphological analyses significant differences were observed between all populations in terms of height, diameter at breast height, collar diameter, leaf size, pneumatophore length and pneumatophore diameter. The present study, provides useful information about genetic diversity of mangrove habitats which can be used in evolutionary studies and conservation efforts for these valuable plant ecosystems.

One of the major challenges affecting the natural ecosystems and various aspects of human life is climate change. The effects of global warming on the hydrology and water cycle in nature are very serious, and the quantitative recognition of these effects creates more readiness to deal with its consequences. In the present study, the black box model (artificial neural network) and the semi-distributed model (SWAT) were selected and examined according to error and uncertainty. This paper employed the large-scale model (CanESM2) under scenarios RCP2.6 and RCP8.5 to investigate the effect of climate change. The results of climate change in this study showed that runoff (3-59%) and temperature (1.53-6.93 °C) have an increasing trend. In particular, this increasing trend is further exhibited by extreme values and severe floods. Also, the amount of runoff will increase by 7-11% in the upcoming period. For this reason, it is necessary to pay attention in urban studies to the increase of flood occurrence in the future.

Climate change is one of the most important challenges that influening natural ecosystems and have different effects on precipitation, temperature, intensity and frequency of droughts and floods and hydrological parameters of watersheds. The purpose of this study is to investigate the effect of climate change on the trend of changes in temperature, precipitation and solar radiation and also to determine the effect of changes in these variables on the recharge of the Karaj watershed. In this study first using the outputs of the two HadCM3 and CGCM1 global models, and using SDSM micro-scale model, climatic variables were simulated for three decades (2010- 2039, 2040-2069 and 2070-2098). In the next step, using HELP model, the rate of groundwater recharge was estimated and the effect of changing these variables on the amount of natural recharge was investigated. Also the results showed that this model is highly sensitive to evapotranspiration. Result of simulating climatic variables under A2 climate change scenario show that in future decades, amount of temperature, precipitation and solar radiation will be increase (1.5, 2.8 and 4.55 percent), decrease (8.1, 15.1 and 18 percent) and increase (0.5, 1.4 and 2.4 percent), respectively. Result of simulating the amount of groundwater recharge using model under A2 climate change scenario show that in future decades, amount of groundwater recharge will be decrease (9.6, 15.1 and 15.6 percent). Also research result show that HELP model is highly sensitive to evapotranspiration amount.

Over the past decade, the decline phenomenon has affected the valuable forests of this tree in the Zagros region in western Iran. Persian Oak as the most important tree species has been damaged more than any other species. On the other hand, many parameters are involved in this phenomenon. The purpose of this study is to identify areas with high potential for deterioration and determine the most important parameters affecting it.

For this purpose, in this study, using multi-criteria evaluation methods based on GIS - TOPSIS method - and fuzzy logic, in June 2019 the zoning map of decline potential was prepared for the two selected stand of Dalab and Chaghasabz in Ilam city to reveal areas with high risk of decline. Hierarchical analysis process (AHP) was used to determine the weight of the parameters.

The results showed that in Dalab %25 and in Choghasbz about %60 of the stand area as the center of potential for decline, but both selected stands had the potential for decline at all levels. Chaghasabz is more prone to decline due to socio-economic problems. Also rainfall, pests and diseases and socioeconomic parameters have the greatest impact on Oak decline.

These results confirm the need for greater focus of area management on the design of strategic protection plans.

Fire is an integral part of most ecosystems, which have negative environmental and social consequences. The identification of effective factors in the occurrence of fire and mapping of fire risk in the forest is one of the basic tools to achieve fire control and countermeasures. The purpose of this study is to identify the ecological factors affecting the development of fire and assess the risk of fire in the forests of Sardasht region using a geographic information system. After basic studies, homogeneous environmental units were produced and divided into four classes using the multi-criteria evaluation method. The ecological conditions of the areas with a history of fire were investigated by conducting field studies. Data analysis was performed using a geographic information system and hierarchical analysis. The fire risk assessment was also performed linearly. In conclusion, vegetation and climatic factors are the most important ecological factors affecting the development of fires in the forest ecosystem. Besides, the area was moderate in terms of fire risk, and measures should be taken for high-risk areas, such as building fire stations and watchtowers.

This study was conducted to determine the optimal systematic sampling dimensions in forest using Variogram analysis in geostatistics in Catchment Area 30, Safarood forest of Ramsar, with a total area of ​​100 ha. Sampling was done within a systematic grid (200m×150m) with randomly starting point. To determine the correct spatial correlation between specimens at short distances, from the intersection of the sides of the grid, two other samples were taken at a distance of 50m in two main directions from the central sample plot. Each piece of the sample consisted of two common-centered circular area of ​​300 and 700m2. The analysis of the selected model for fitting the experimental variogram of the total reference sample plots for the variables of growing stock and basal area/ha indicates the existence of a strong spatial structure and a significant relationship between the measured samples in the 700m2 sample plots. The existence of a weak spatial relationship between samples for basal area/ha in 300m2 sample plots indicate a weak spatial structure in these plots.

This study aimed at evaluating the box tree habitat after the occurrence of box blight disease in Buxo-Fagtum orientalis (B) and reference pure Fagetum (S) stands in the district 3, Lesakoty catchment No. 36, southeast of Tonekabon in the Mazandaran Province. In each stand, 60 micro-plots with 25 m2 were established, in which the frequency of herbaceous species was recorded. For sampling lichens, 60 × 40 cm quadrats were used. Raw data obtained from the field were compared and analyzed using an independent t-test and CCA analysis. Results revealed that the Simpson species diversity (B = 0.813 ± 0.07, S = 0.649 ± 0.07) and Shannon-Wiener (B = 0.830 ± 0.05, S =0.577 ± 0.05) of herbaceous species were significantly higher in Buxo-Fagetum orientalis stand (p <0.05). In addition, the independent t-test for lichen species showed that Simpson species diversity (B = 0.477±0 0.03, S = 0.629 ± 0.03) and Shannon-Weiner (B=0.738 ± 0.06, S= 1.067± 0/06) inboxwood-beech stand was significantly lower than those in pure beech site (p <0.05). CCA results showed that the environmental conditions, as well as the variability of the presence and diversity of different species of lichens as forest ecosystem bio-indicators were changed, mainly due to the boxwood blight disease in boxwood-beech stand. Further, stand opening caused by disturbances and increase of light reaching the forest floor was identified as a key factor in changing the composition of herbaceous and lichen communities in Buxo-Fagetum orientalis stands.

This research was started in 1995 in order to investigate the effect of thinning on the young plantations of velvet maple (Acer velutinum Boiss.). The silvicultural interventions comprised three main treatments (medium and heavy thinning), two secondary treatments (3-year and 5-year rotations) in the fully randomized design with three replications. There were 9 sample plots in the experimental design with an area of 0.3-0.4 hectare each. A full calipering of the future trees was done after 20 years and 6 thinning operations. The results for DBH, total height, trunk height and trunk diameter showed significant differences between the control treatment and thinning intensities. However, no significant difference was observed between the secondary sub- treatment (circulation 3 years and 5 years) and the intersection between the main and sub plots treatments for DBH, total height, trunk height and trunk diameter. For the intensive thinning treatment, the largest value of 32.95 cm was observed for the DBH, while the lowest value of 27.39 cm was observed for the slight thinning. In addition, the largest height of 24.42 m was observed for intensive thinning, whereas the lowest rate of 23.63 m was observed for the control treatment.

Tree to tree variation in growth results from compositional complexity, stand structure and competition. Therefore, it is essential to know how trees respond to competitive interactions. This study aims to evaluate of competition indices in order to assessment of management interventions effects in pure beech (Fagus orientalis Lipsky) stands (with 36 hectares) in Lavij- Noor region of Mazandaran province. For this purpose, the positions of all 58 marked trees were recorded as cored trees. Competition plots centered on the cored tree with radius of 3.5 × the cored tree crowns were established. The following attributes were measured for each tree (≥ 7.5 cm diameter at breast height (DBH)) within the plots: X and Y coordinates (m), total height, DBH, crown diameter at the base of the living crown in different directions and crown length. In order to quantify the competition level by each of the cored trees, 4 different distance-independent indices including Gerrard, Bella, Hegyi and Braathe were used. The results showed that the studied stands were middle-aged, the major interventions were in the middle DBH classes, and there was no significant change in the amount of competition indices following the interventions. Accordingly, the management interventions (marking) were not targeted and the process of individual tree competition changes was not measured. Therefore, the process of competition changes is necessary to be considered in stand management due to the high importance of the competition factor and its relation to the stand parameters.