مهدی پورهاشمی

Cold plasma is an innovative technology in the food industry that has significant potential for extending the shelf life of fruits. This technology can effectively increase the longevity of fruits due to its capability to kill microorganisms and deactivate spoilage enzymes. This research investigates the effect of cold plasma with argon gas on the shelf life of red guava fruit (Psidium guajava L.). In this study, guava fruits were contaminated with a microbial strain of Aspergillus niger and subsequently treated with various cold plasma treatments for different durations (ranging from 150 to 1200 seconds). The results showed that the use of cold plasma significantly reduced the number of molds and improved the physical and chemical properties of the fruits. Additionally, sensory evaluations indicated an increased acceptability of the cold plasma-treated fruits. The changes in pH and fruit firmness also improved, indicating better quality in the treated fruits. Based on obtained results, cold plasma is an effective, non-thermal method for preserving quality and extending the shelf life of red guava. It can serve as an alternative method in post-harvest management of horticultural products. The application of cold plasma may contribute to the development of new technologies for the preservation and storage of agricultural products, particularly in international markets.

The dynamics of spatial structure play a major role in understanding the mechanisms of forest structure and the formation of biodiversity, and largely determine the sustainability of the forest and its productivity. As part of a long-term monitoring project, the present study was conducted to assess the structure of juniper (Juniperus excelsa M.B.) stands in the Parvar protected area of Semnan province in the Irano-Touranian vegetation zone. Two permanent sample plots, each one hectare, were randomly selected, and the quantitative characteristics of woody species were measured and recorded using the full calipering inventory method. The structural characteristics of the stands were calculated based on the nearest neighbor indices. In sample plot one, juniper was the most abundant species, accounting for 49.7% (94 stems), while Rosa canina was the least abundant, with 4.8% (9 stems). Berberis integerrima and Cerasus microcarpa accounted for 39.7% and 5.8% of abundance, respectively. Sample plot two, with 75 stems per hectare, consisted of only two species: juniper (54 stems, 72%) and barberry (21 stems, 28%). The Clarke and Evans index and uniform angle indices indicated a clustered spatial distribution pattern of trees. The species mingling index for the entire stand in sample plots one and two was 0.46 and 0.38, respectively, indicating moderate mixing. The combined structural diversity index value was 0.47 and 0.48 in sample plots one and two, respectively, suggesting high diversity in the investigated stands. This study demonstrated the effectiveness of these indices in estimating the horizontal structure of forest stands, providing valuable information essential for management and decision-making processes.

Forests are one of the most important carbon sinks in the world and play an important role in mitigating climate change. The Zagros forests due to the coverage of oak and other species stands provide a wide range of important and key environmental functions, including carbon sequestration and storage. In this research, the carbon storage in the forest above-ground, litter and soil of two one-hectare sample plots in two stands with different conditions, including Darsarvin Sardasht (30% canopy cover, coppice with standard) and Piranshahr Pardanan (90% canopy cover and all of trees were of coppice), in the Zagros forests of West Azarbaijan Province was compared.

After expert investigations and forest survey, a square sample plot of one hectare (dimensions 100 x 100 meters), using 100% inventory the research was carried out. To calculate above-ground carbon stock, the variables of average crown diameter, diameter at breast height, total height, trunk height, crown height, collar diameter, crown starting diameter and crown density were measured and recorded for all the trees in the sample plot. In order to estimate the biomass and carbon storage, the allometric equations of oak were used for single-stem and coppice trees. Furthermore, five soil samples were systematically taken from a depth of 0-30 cm in each sample plot. Ten microplots of 0.5 square meters were also randomly and regularly measured in each sample plot. Then, the litter in them was separated into Coarse Woody Litters and Fine Woody Litters, and their dry weight and carbon content were measured. In order to measure the percentage of organic carbon in litter and plant samples, the method of combustion in an electric furnace was used. Soil organic carbon was measured by Black–Walkley method and soil Bulk density was determined by Clod Method.

In the Darsarvin sample plot, Sardasht, 277 trees per hectare were recorded, of which 212 trees were seed-origin  and 65 trees were coppice-origin. In the Perdanan sample plot, Piranshahr, 747 trees were recorded per hectare, and all the them in this sample plot are coppice-origin. The biomass and carbon stock of the trees in the sample plots were determined. The amount of above-ground biomass of trees in Pardanan and Darsarvin sample plots was calculated as 53.35 and 36.93 tons per hectare, respectively. Also, the amount of above-ground carbon stock was obtained in Pardanan and Darsarvin plots, 25.99 and 17.93 tons per hectare, respectively. The comparison of soil carbon stock between the Pardanan and Darsarvin sample plots showed that the average soil organic carbon stock in the Pardanan sample plot is 154.24 and in the Darsarvin sample plot is 121.96 tons per hectare. In terms of litter carbon stock, the amount of Coarse Woody Litters and Fine Woody Litters carbon stock in Pardanan sample plot is 0.66 and 3.75 tons per hectare, respectively. Coarse Woody Litters and Fine Woody Litters carbon stock in the Darsarvin sample plot was 0.23 and 2.83 tons per hectare, respectively.

The results show that the effect of stands conditions, diversity and density of vegetation canopy cover and forest management is very important in the carbon stock of the forest ecosystem, and on this basis, the difference of about 41 tons per hectare of the total carbon stock in the Pardanan sample plot (184.64 tons per hectare) compared to the Darsarvin sample plot (142.96 tons per hectare) was observed in this study. Based on the results of this research, it is suggested to prevent the cutting and collection of litter and branches, in order to increase the storage of carbon stock of above ground, soil and litter.

Zagros forests, as a second forest ecosystem in Iran. These forests have diverse ecosystem services and have a valuable position in terms of ecology, economy and society, and carbon storage. Tree species are one of the most important factors influencing soil characteristics through the production of litter and play an essential role in the carbon storage. Also, fine woody litter and coarse woody litter are very important to increace the carbon storage in forest soil. The purpose of this study is to investigate the trend of carbon storage of fine woody litter and coarse woody litter in the Marivan forests of Kurdistan province between 2019 to 2021 years.

To do this research, a two-sample plot (one-hectare) was selected in Garan (protected and protected stands) and Dolah Naw (typical forests of the Marivan county). The research was do from 2019 to the end of September 2021, and to ensure the location of the center of the microplot, the location of the microplot was recorded and marked. At the end of September of each three years of the study, by implementing 10 micro-samples of 0.5 square meters. In order to measure the dry weight and carbon stock, the samples of small scraps and wood chips were placed in an oven at 104 degrees Celsius for 24 hours according to the ASABE S358.2 (2010) standard, and then the dry weight of the samples was immediately calculated. To measure the percentage of organic carbon in the samples of scrap and wood chips, the combustion method was used in an electric furnace, and the samples were placed for 4 hours at a temperature of 550-600 degrees Celsius, and after measuring the percentage of carbon, the percentage of carbon was calculated, and then it was calculated by multiplying the percentage of carbon by weight. After the samples were dry, the weight of carbon was calculated for each microplot (separated by carrion and wood chips). in each sample, fine woody litter and coarse woody litter were sampled and samples of scraps and pieces of wood are packed in the storage space and their dry weight, percentage moisture, carbon percentage and carbon storage amount are measured in the laboratory. Two-way analysis of variance test was used to compare carbon percentage, dry weight and carbon storage of fine woody litter and coarse woody litter, and the effect of two stands (site) and sampling period (two years of research include 2019 and 2021) on research parameters was investigated. Also, Duncan's intergroup comparison test was used to check and compare the research parameters in three sampling periods. Data analysis and statistical comparisons were done using SPSS 20 software.

The finding showed that the dry weight of fine woody litter was 4.46, 2.89, and 4.94 tons per hectare in the years 2019, 2020 and 2021, respectively, and the average fine woody litter in Garan site was higher than that of Dolah Naw. Garan site fine woody litter carbon was estimated as 1.878, 1.21, and 2.009 tons per hectare in the three years of study, and these values were higher than Doleh Naw site. The results of two-way analysis of variance showed that the difference in dry weight and carbon storage in two stands (site) was statistically significant. Also, the average dry weight of coarse woody litter in the sample plot of Garan in the years 2019, 2020 and 2021 was 0.456, 0.327 and 0.599 tons per hectare, respectively. 0.214, 0.178 and 0.322 tons per hectare were confirmed, and in total, the carbon storage of coarse woody litter in Garan habitat was more than that of Doleh Naw, and this difference was statistically significant. On the other hand, the average carbon percentage of fine woody litter in Garan sample plot in 2019, 2020 and 2021 was 42.07, 42.22 and 41.03%, respectively, and the carbon percentage of fine woody litter in Garan sample plot was more than Doleh Naw. Based on the two-way analysis of variance test for coarse woody litter, a significant difference was observed for the parameters of dry weight, carbon storage and carbon percentage of the samples in the years of statistical collection, but no significant effect was observed in the context of the site and the interaction effect of year × stands (site). In general, in the Garan site, the carbon storage of fine woody litter and coarse woody litter was estimated as 4.09 and 0.46 tons per hectare, respectively, which was more than Dolah Naw (with values of 3.55 and 0.39 tons per hectare). The highest carbon storage in fine woody litter and coarse woody litter occurred in the years 2021, 2019 and 2020, respectively. The general results showed that the amount of carcass dry weight and carbon storage in Garan site was 0.14 more than Dolah Naw site.

The general findings of the research showed that the average dry weight and carbon storage for fine woody litter and coarse woody litter in Garan stands (site) was higher than Doleh Naw stands and according to the positive effect of protection on the amount of carbon storage a fine woody litter and coarse woody litter; in order to optimally manage the study forests and other similar forests, it is suggested to manage and use protection in degraded areas. Forest restoration and development increased the amount of fine woody litter and coarse woody litter.

This study was conducted in the Zagros forests to investigate and monitor the status of elements in the soil and their absorption in areas with and without oak decline. Two plots, each with 100 trees, were randomly established in the south direction in the areas of "Sama Castle" and "White Mud," representing the decline and control (without decline) sites. In the oak decline plot, five healthy and five declining trees were selected, while only five healthy trees were chosen in the control plot. Selection of healthy and declining trees in the first year was done selectively and with proper distribution throughout the sample. In the following years, soil and leaf samples were collected from the selected trees. Soil samples were collected under the tree crowns at two depths (0-30 cm and 30-60 cm). Additionally, 20 leaves per tree were sampled in late July and early August. The results showed that the amount of phosphorus in the leaves of trees in the both decline and control sites was significantly different at a 99% confidence level. As the intensity of drought increased, the amount of phosphorus in the leaves also increased. Soil moisture was estimated at 5.74% in the decline site and 7.14% in the control site, with this difference being statistically significant. The amount of calcium in the soil of the control area was approximately 1.5 times greater than in the area experiencing decline. The results of this research, focusing on soil characteristics related to oak decline, can provide important data for the oak decline information system in the Zagros forests of Iran.

This research measured and analyzed forest ground vegetation in permanent plots of typical and exclosure areas in the Zagros provinces, providing the possibility for long-term monitoring of quantitative and qualitative changes in vegetation. In total, 30 one-hectare square sample plots and 600 one-meter square microplots were studied along the Zagros, with floristic and environmental data related to tree and forest floor measured and recorded. According to the results, 370 species were identified in the ground vegetation and 20 species of phanerophytes. The most abundant families in exclosure and typical sites were Asteraceae and Poaceae, respectively. Sixty-six percent of the ground vegetation population belonged to the Poaceae family, with the most populated genus being Bromus, comprising 25% of all plant individuals. The largest genus was Astragalus (with 18 species), and its population was about 2.5 times higher in exclosure sites than in typical sites. The average percentage of ground cover (51.2%) and litter cover (34.3%) in exclosure plots was significantly higher than in typical plots (37.6% for ground cover and 25.2% for litter cover). The number of phanerophyte species in the exclosure area was significantly greater than in the typical area, while the difference for other life forms was insignificant. The comparison of diversity indices for ground species in the exclosure and typical plots showed no significant difference between these two groups. In general, the relative protection implemented in some parts of the Zagros, although it did not affect ground species diversity indices, did affect ground vegetation cover, litter cover, species composition, and phanerophyte species.

The Zagros forests, being the largest and most important forest ecosystems in the country, provide valuable ecosystem services. The percentage of forest canopy cover, a crucial component of forest statistics, has a strong relationship with ecohydrological processes and plays a vital role in forest inventory programs. In this study, changes in canopy cover percentage were examined in sample plots located in the provinces of Kurdistan (Dulehnaw, Gharan, Belveh, and Saraki) and Chaharmahal and Bakhtiari (Gelsefid, Rahimabad, Gardaneh Cheri, and Mavarz), representing the northern and southern Zagros forests, respectively. Each plot underwent a comprehensive measurement process, including the assessment of species composition, growth form, and average crown diameter. Static images of tree canopies were captured in 2021 and 2022 to analyze changes in canopy cover. The analysis revealed statistically significant differences in canopy cover between provinces. Significant differences in canopy cover changes were observed in the Dulehnaw, Gharan, and Rahimabad forest stands over the two years, but no significant statistical differences were found in the Saraki, Belveh, Gardaneh Cheri, Mavarz, and Gelsefid stands. Furthermore, in both provinces, the highest increase in canopy cover percentage was recorded in the southern direction, with values of 7.46% and 3.97%, respectively. Detailed and comprehensive analyses of the canopy cover index, particularly in the Zagros region, are crucial for effective management planning in forest ecosystems. The two-year variations in this index provide valuable insights into the influence of vegetation type, structure, and ecological conditions on canopy dynamics, serving as a gateway for energy to plants.

This research was conducted on two square plots (each 1 ha) located in Vezge Mansurabad (a protected area in Boyer-Ahmad County) and TuteNadeh (in Dena County) in Kohgiluyeh and Boyer-Ahmad province. Five soil samples, taken regularly over three years from a depth of 0-30 cm from each plot, were analyzed for carbon, nitrogen, phosphorus, water content, microbial respiration, soil bulk density, and gravel percentage. The mean carbon storage of soil was estimated at 84.80 t/ha and 67.60 t/ha in the TuteNadeh and Vezge Mansurabad plots, respectively. Three years of monitoring revealed a significant difference between the two plots in terms of soil parameters. In TuteNadeh, the three-year changes in organic carbon and total nitrogen content followed a parallel trend, with a reduction in the former directly leading to a similar drop in the latter's content. At this site, the content of absorbable phosphorus was found to be irregularly altered. Variations in organic carbon content were directly correlated with variations in soil microbial respiration. In Vezge Mansurabad, variations in organic carbon, nitrogen, phosphorus, water content, and microbial respiration were similar to those in TuteNadeh, but variations in soil phosphorus were sinusoidal and followed an irregular pattern. The mean quantities of absorbable phosphorus, water content, and microbial respiration in the TuteNadeh plot were 15.44 mg/kg, 12.59%, and 434 mg/kg, respectively, which are significantly different from the corresponding values of 10.05 mg/kg, 13.94%, and 547 mg/kg in Vezge Mansurabad. In conclusion, the results show that soils with higher organic carbon content are relatively richer in other influencing variables.

The Zagros forests vegetation area, with an area of more than 5 million hectares and providing more than 40% of the country's water, is ecologically very important. The forest covers 256,000 hectares of Kurdistan province (8.8% of the province) and makes a significant contribution to carbon sequestration. Atmospheric carbon dioxide has increased significantly in recent decades. In reducing atmospheric carbon dioxide, vegetation and the soil beneath it play a very important role. The aerial parts of trees (the ground layer) contribute greatly to biomass production and carbon sequestration. The purpose of this research was to investigate the carbon sequestration of the tree layer in two sample plots: Garan (Gargh and protected stands) and Dolah Naw (typical forests of the province).

 In order to carry out this research, two samples from Garan and Dolah Naw in Marivan County were selected. In each region, a square sample plot of one hectare was established, and with 100% statistical inventory, quantitative characteristics, including tree species, breast diameter, tree height, crown height, and crown area, were recorded. In both sample plots, the trunks and top branches of the trees were sampled, and for this purpose, three trees were selected for each species in each plot. Samples were taken from the trunk, main branches, and secondary branches of the trees. In the laboratory, the wet weight, dry weight, and carbon percentage of wood samples were calculated by burning the dried samples in an electric furnace. Then, the above-ground biomass of trees was calculated using allometric equations, and finally, the carbon stock of all trees was estimated. The quantitative parameters and the average of the above-ground biomass and carbon stock were compared. An independent t-test was used to compare quantitative parameters and carbon storage in the two sample plots of Garan and Dolah Naw.

 The findings of the research showed that the amount of biomass on the ground in Dolah Naw and Garan sample plots was 45.3 and 41.4 tons per hectare, respectively. In the Dolah Naw sample plot, two species, Quercus brantii and Q. infectoria, with a total of 24.68 tons per hectare, accounted for 54.5% of the biomass of the tree layer. The carbon stock of the tree layer in Dolah Naw and Garan samples was calculated as 22.4 and 20.3 tons per hectare, respectively, and the results of the independent t-test showed a significant difference between the quantitative characteristics of diameter at breast height, total height, tree crown area, biomass, and carbon storage in the two sample plots. The contribution of the Q. infectoria species to carbon sequestration in Dolah Naw and Garan samples was 6.48 and 9.13 tons per hectare, respectively. On the other hand, the averages of quantitative characteristics, including tree height (3.7 meters), diameter at breast height (15.79 cm), and crown area (6.77 square meters), in the Dolah Naw sample plot were greater than those in the Garan sample plot.

 The general results showed that the carbon storage of Dolah Naw stands (wood biomass with slightly higher forest characteristics) was greater than that of Garan forest. To optimally manage these forests and increase carbon dioxide storage, it is essential to manage and control the factors of forest destruction (such as the development of agriculture under the forest canopy, intensive grazing, excess livestock capacity, fire management and control, coal mining, and other factors) and take action in degraded areas to promote reforestation and afforestation using native species (Quercus brantii, Quercus infectoria, Quercus libani, and Pistacia atlantica) in the destroyed stands.

Soil and vegetation are mutually influencing because of strong bilateral relations. Soil characteristics can be different depending on the density of vegetation and the type of land use. Since the long-term stability of forest ecosystems is dependent on maintaining the quality of the soil, knowing the condition of the soil in forest areas and investigating the effects of various activities on the soil properties is very important and effective in forest management. Therefore, in this research, we investigated and studied the effects of intensive Thinning operations on some soil components in a Coppice stand and young Sprout-Clumps of Quercus brantii Lindl. species in Rikhlan forest (a forest site in Marivan). This area is an indicator of the degraded forests of North Zagros. this research was conducted in the form of complete randomized blocks in three treatments and three repetitions. The duration of the research was 8 years in two phases of 4 years. In addition to thinning treatments, soil samples were also prepared and analyzed from a depth of 0-15 cm of each treatment. The general conclusion is that thinning operations have long-term effects on some soil indices, and thinning with increasing intensity (18% of all Sprouts removed in the first 4 years and 22% of remaining Sprouts in the next 4 years) compared to thinning with The reducing intensity (32% of all Sprouts removed in the first 4 years and 28% of remaining Sprouts in the next 4 years) has caused the least stress on soil fertility indicators.

Reproduction (regeneration) is a fundamental process that drives the dynamics of a forest, occurring continuously in a healthy and natural forest with a specific spatial and temporal pattern. Natural regeneration poses significant challenges in Zagros forests, Iran. This research was undertaken to examine and analyze the current state of reproduction of tree and shrub species in the monitoring sample plots of Zagros forests. This study, while scrutinizing the species composition, origin, distribution curves, and health of seedlings and saplings, explores the interrelationship between reproduction and nurse species. It will serve as the foundation for long-term studies that determine the temporal changes in reproduction and its characteristics in the Zagros forests.

This research was conducted in the permanent monitoring plots of Zagros, spanning from West Azerbaijan to Fars province. A total of 120 sample plots of 100 square meters were studied within these plots. Each province had 30 studied sites in the typical forests, with 10 of them located in the protected forests. The variables studied included reproduction density by species, origin and type of reproduction, nurse species, height of seedling, terminal bud, and health status of reproduction. A height of 0.5 meters was set as the criterion to distinguish reproduction. The t-test was used to compare parametric data in two groups, while the Kruskal Wallis and Mann-Whitney U tests were employed for non-parametric data.

In the studied area, the reproduction of 20 forest tree and shrub species was recorded, and the density of seedlings and saplings was calculated to be 366 plants per hectare. However, the reproduction was not uniformly distributed, with 37% of the sample plots lacking reproduction. The abundance distribution diagram in the height classes revealed a decrease in the number of oak (Quercus spp.) and hawthorn (Crataegus spp.) reproduction with a height of less than 5 cm. Of the total number of recorded reproduction, 72.5% originated from seeds and 25% were shoots. Overall, 66% of reproduction was dependent on nurses, with oak, hawthorn, stone, and rock playing the greatest roles as nurses. Stones and rocks played a more significant role in the revival of seedlings. Cerasus microcarpa (C.A.Mey.) Boiss., Q. infectoria Oliv., and Q. libani Oliv. had the highest dependence on the nurse, while Pyrus spp., Daphne mucronata Royle, and Crataegus spp. had the least dependence on nurse species. Reproduction sheltered by nurses was significantly healthier than those without nurses. Also, reproduction sheltered by stones and rocks had a higher health rate than reproduction sheltered by trees, although this difference was not significant. Lonicera nummulariifolia Jaub. & Spach, Fraxinus angustifolia Vahl, and Acer monspessulanum L. had the worst condition in terms of reproduction. Despite the presence of mature trees, they had no reproduction (L. nummulariifolia and F. angustifolia) or had very low reproduction (A. monspessulanum). The results showed that the number of reproduction in protected sites was higher than non-protected sites. Although this difference was not significant, the reproduction in the protected sites was significantly healthier.

The results indicated that the reproduction in the Zagros forests is not in a normal situation. However, given suitable spatial and temporal conditions, reproduction occurs and establishes. Although in conditions of disturbance and overgrazing, reproduction attempts to survive by taking shelter near stones, pits, or under thorny shrubs, the conservation of the forest stand by maintaining the tree canopy (oak, hawthorn, and other species) and the forest’s natural structure provides the best conditions for the establishment and survival of reproduction, thereby ensuring the sustainability of the ecosystem.

The Zagros forests vegetation area with an area of more than 5 million hectares and providing more than 40% of the country's water are ecologically very important and the forest covers 256000 hectares of Kurdistan province (8.8% of the province) and in recent years, Oak decline and decay have increase in these forests. Oak decline in the Zagros forests has started in the last two decades and has caused serious damage to the forests of this vegetation area and study of the effective and aggravating factors of Oak decline provides valuable information to natural resource managers. The factors of slope aspect and physical and chemical soil parameters can has an effect on the aggravation oak decline in this forest. The aim of this study was to investigate and compare the physical and chemical soil parameters in around healthy and dieback trees under the influence of slope and dieback in Marivan forests (in Kurdistan province).

Deteriorated (Garan) and control (Dolah Naw) stands were selected in the northern and southern slopes aspect. In the Garan habitat (Oak decline) on the northern slope, five healthy trees and five dieback trees were selected (10 trees in total), on the other hand, in this habitat on the southern slope, 10 more trees were selected (five healthy trees and five trees with dieback). In Dolah Naw habitat (control habitat), five healthy trees were selected in each aspect (in total, 10 trees in the control habitat). In total, 30 healthy and dieback trees were selected and numbered (20 healthy trees in the control and dieback trees and 10 trees in the dieback stands). Then, in the vicinity of the trunk of each tree (in the shaded part of the crown), a soil sample was taken at a depth of 0-20 cm (Horizon A) and the samples were transported to the laboratory in plastic bags. Physical and chemical characteristics (moisture percentage, acidity, soil electrical conductivity, absorbable phosphorus, absorbable potassium, nitrogen percentage, organic carbon percentage, lime, calcium and magnesium percentage) were measured for each soil sample. The two-way analysis of variance test was used to compare the effect of each factor and the interaction effect of the investigated factors on the physical and chemical parameters of the soil and data analysis was done in SPSS 20 software.

The one-way analysis of variance test showed that there was a significant difference between the parameters of pH, electrical conductivity, percentage of organic carbon, potassium, nitrogen, moisture, lime, magnesium and calcium among the soil samples of healthy and dieback trees in the northern and southern slopes. The results of the analysis of variance test confirmed the interaction effect of kind of stands × slope aspect for electrical conductivity and calcium and for slope aspect × tree health in the parameter was lime percentage. Other findings showed that the highest average parameters of electrical conductivity, available phosphorus, potassium, organic carbon, nitrogen, and moisture were respectively 2.654 (d s m-1), 1.10 (mg/kg), and 869.5 (mg/kg). ), 4.03%, 0.35% and 12.4% were observed in the soil adjacent to the control trees in the northern slope and for magnesium, calcium and CaCO3 parameters of healthy trees in the southern slope with the values ​​of 21 (meq/100), 42.2 (meq/100) and 13.60% was significantly more than other treatments. On the other hand, in the soil sample adjacent to the trees located in the stands affected by dieback, the average physical-chemical parameters were lower than the control stand (Doleh Naw) and this shows the importance of the physical-chemical parameters of the soil in reducing or increasing the resistance of trees to tree dieback. The findings of the research showed that the highest average macro elements (available phosphorus, potassium and nitrogen) in the soil adjacent to healthy trees in the northern slope and for calcium and magnesium, the highest amount of these elements were observed and confirmed in the soil adjacent to the trees in the southern slope and in the total amount Macro elements were more in the soil of the trees of control (north and south domain); Therefore, the physical and chemical characteristics of the soil (especially macro elements) have an effect on the resistance of oak trees to dieback and other environmental stresses, and the lack of macro elements causes the trees to be weak against the phenomenon of oak dieback.

In general, in the soil adjacent to the dieback trees, the poverty of nutrients and macro elements and lower values ​​of the studied parameters were observed. In general, in the trees affected by Oak decline, the poverty of nutrients and macro elements was observed, and the lower values ​​of the parameters were observed in the soil adjacent to the trees affected by Oak decline. Based on the results, for the optimal management of dieback stands and trees, increase protection measures (control of livestock grazing through grazing and reduction of traditional exploitations), increase restoration programs and forest development in the stands affected by dieback (increase seeding and enrichment operations). In degraded stands and planting with native species in dieback stands) and implementation of health cuts (withered and dieback branches and stems) were suggested.

Measurement and monitoring of structural characteristics of forest stands are essential for studying the dynamics of vegetation, as well as planning forestry interventions such as silvicultural operations and restoration activities. This research, conducted within the framework of the comprehensive Zagros Forest Monitoring and Assessment Program, aimed to evaluate the structure of forest stands in the growth area of Zagros, using a total of 34 one-hectare sample plots designed through a location-based monitoring approach. In each location, a randomly selected square-shaped one-hectare sample plot was established. The results demonstrated that the total number of tree and shrub species ranged from a minimum of 1 to a maximum of 6 species, with a density ranging from 18 to 924 stems ha-1. Regarding the tree species composition, the maximum number of branch base stems was 826, and branch base stems were dominant in most sites. The average diameter of branch shoots ranged from 3 to 69 cm, while tree heights ranged from 3 to 10.8 m. Furthermore, the study revealed that the uniform angle index value ranged from 0.469 to 0.086 across different sample plots, indicating a scattered pattern in all stands. The composite index value ranged from 0.2 to 0.5, suggesting that most stands are in a fair to moderate condition in terms of stability. Monitoring the temporal changes in structural characteristics of the studied stands through repeated measurements in the future phases will provide valuable insights into Zagros Forest stands.

Crown canopy is a major structural characteristic of forest trees and is vital to their ecological function. The present study investigated tree crown changes in Marivan County coppice forests. This research was conducted in two forest areas, Garan and Doleh Naw. First, five trees were selected for each habitat. The crown of each tree was photographed in the four main geographical directions one meter from the tree trunk. It was done in September 2021 and 2022. Tree canopy measurement in each image was done using MIP Cloud4 student software. Paired t-test was used to compare tree canopy percentages in two imaging periods. According to the results, the canopy of trees in Garan and Dolah Naw habitats in 2022, compared to 2021, increased by 9.02% and 11.51%, respectively. Meanwhile, in the habitats of Garan and Dolah Naw, the highest increase and change in the tree crown was observed on the southern and eastern sides of the tree crown. Also, from 2021 to 2022, the weather conditions improved. Dolah-Naw habitat trees had slightly larger average parameters than the Garan habitat. Irrigation of degraded areas (with increasing tree crowning) is crucial for sustainable management due to the importance of tree crown canopy in forest stand functions.

In order to properly manage the forest, we need tools that can be used to study the changes in the forest structure. In this research, the structure of degraded oak forests of Piranshahr and Sardasht in West Azerbaijan province were investigated. Characteristics of the stand were investigated in two one-hectare sample plot with dimensions of 100 x 100 meters in two different forest types, including Darsarvin Sardasht (30% canopy cover, coppice with standard) and Piranshahr Pardanan (90% canopy cover and all of trees were of coppice). Using 100% inventory and a set of indices based on the nearest neighbor, three characteristics of location, mixture and dimensions of trees were investigated.

The investigation of the structure was done by using the indices of density, diameter, height, basal area and trees location. As well as the indices based on the nearest neighbor in two sample plots were used. The structural variables of all the trees in the sample plot were measured separately for coppice and standard trees. The characteristics of the species, spatial coordinates, diameter at the height of 0.5 meters of the trunk, and height of all trees were measured. Three criteria of species density, basal area and canopy cover were also used for forest typology. To describe and quantify the structural features of forest stands in this research, indices based on the nearest neighbor were used. For this purpose, distance to neighbors, uniform angle, Clark and Evans, Mingling, DBH differentiation and CC differentiation were used. The calculations related to the structural characteristics of the examined stands were done using SPSS version 20 software and the calculations related to the structural indices were done using the Crancod software set (ver 1.3).

The Clarke and Evans index with values of 0.82 and 0.94 for Darsarvin and Pardanan, and uniform angle with values of 0.56 and 0.52, respectively, showed a cluster distribution pattern and random species distribution pattern in both stands. Mingling index shows that there is more mixture of neighboring trees in Pardanan (0.65) than in Darsarvin (0.38). The diameter difference index shows a greater difference in the half-meter trunk diameter of Pardanan (0.55) compared to Darsarvin (0.46). But the canopy differentiation index shows a greater difference in the canopy cover of Darsarvin (0.58) than in Pardanan stand (0.53). The results of the combined diversity index showed that the structural diversity in Pardanan (0.41) is higher than Darsarvin (0.36). This index shows that there is a low level of combined spatial, species and dimensional diversity in the two stands. Results are consistent with the situation of the two regions that are affected by destructive factors and limited regeneration. These results can be used for comparing structural characteristics of forests and determining the impact of human intervention.

The results of the composite diversity index showed that there is a low level of spatial, species and dimensional composite diversity in the two forest stands, and these results are consistent with the influence of destructive factors as well as the limitation of regeneration. Considering the difference in the stands in the two sample plots in this investigation, the results of these indices can be used as a basis for comparison with other similar forests and determining the amount of deviations caused by natural processes and human interventions. Also, it seems necessary to achieve a suitable management model and Silviculture practices in the forests of this region and determine the structure and planning based on the current situation using these indicators.

This research was designed to investigate the dieback of oak (Quercus infectoria; Q. libani) trees in the northern Zagros forests in West Azerbaijan Province. Characteristics of the stand were investigated in a one-hectare sample plot with dimensions of 100 × 100 meters. To monitor dieback, inside the sample, a sub-plot with a floating surface was determined where 100 oak trees could be placed. The dieback was monitored over four years (2019-2022) using a five-level scale: 1) healthy, 2) dieback, 3) crown dieback up to 50%, 4) crown dieback exceeding 50%, and 5) tree cut down. The results showed a decrease in the number of healthy trees from 94% to 71% between 2019 and 2022, with 9% of trees ultimately being cut down. To investigate the relationship between leaf surface and the dimensions and weight of seeds of trees, 20 leaves were selected from five permanent trees, and their surface was calculated annually for three years (2019-2021). Additionally, 25 seeds were harvested, and the dimensions and weight of the seeds were determined annually. The results of calculating the average leaf area over three years showed a significant decreasing trend. Except for seed weight, other dimensions in the seed showed a significant decreasing trend during the monitoring years. Overall, the results showed that despite the absence of oak charcoal disease in the province, the trend of decreasing healthy trees and increasing trees with different levels of dieback is very worrying.

The Zagros forests are known as the second-largest forest ecosystems in the country in terms of surface area, and they provide many ecosystem services such as carbon storage. Soils are the largest reservoir of carbon storage in dry ecosystems. The purpose of this study was to investigate the carbon storage status of coppice oak stands (exclosure and non-protected stands). In this regard, two forest stands, Garan (an exclosure area) and Dolah Naw (a typical forest of Kurdistan province), were selected in Marivan county, Kurdistan province. A square sample plot of one hectare was considered randomly in each stand. In each plot, five soil samples were taken from a depth of 0-30 cm, and physico-chemical characteristics of the soil, microbial respiration, and organic carbon percentage were measured in the laboratory. Considering the normality of the data, the independent t-test was used to compare the averages of the study parameters in the two plots. The results showed that the percentage of organic carbon and carbon storage in the Garan, with values of 3.63% and 104.3 tons per hectare, respectively, was significantly higher than that of the Dolah Naw (with 2.63% and 86.7 tons per hectare). Additionally, the parameter values of gravel percentage, microbial respiration, and C/N ratio in the Garan (37.3%, 472.9 mg CO2/kg, and 13.1, respectively) were higher than those in the Dolah Naw. The general results of the research showed that carbon storage in the Garan stand (under protection management) exceeded that of the Dolah Naw. As a result, exclosure and forest protection increases the percentage of carbon storage and the amount of soil carbon storage.

This study aimed to evaluate the structural characteristics of natural forests and providing the possibility of studying the changes in the structural characteristics of these stands over time, in order to plan and manage the forest in the Tang Dalab To achieve this, all trees were calipered in two one-hectare plots. Additionally, the structural characteristics were measured using the nearest neighbor’s method. To measure several indices like nearest neighbor distance index (density of trees), uniform angle index Clark and Evans index (variety of location), Mingling index (species mixture), diameter and canopy differentiation indices (dimensional differences of trees), and complex structural diversity index (tree diversity) were used. The results of uniform angle (south site 0.44 and north site 0.48) and Clark and Evans indices (Southern aspect 1/07 and Northern aspect 1/09)indicated a random spatial pattern of trees. According to the Mingling index, the northern aspect has relatively moderate mixing (0.31) and no mixing (0) in the pure southern aspect). The mean distance to the neighbors was 8.12 m in the northern stand and 5.81 in the southern aspect. The results of the diameter and canopy differentiation index indicated a low difference in diameter (0.24) and canopy (0.24) in the southern aspect an average difference in diameter differentiation (0.41) and a high difference in canopy differentiation (0.51) in the northern aspect complex structural diversity index, indicated more diversity in the northern aspect (0.38) compared to the southern aspect (0.18). The indicators used in this research can be used to describe the structure and ecological characteristics of different tree species in order to increase ecosystem stability and planning to create heterogeneity in the structure of the stand and help forest managers in planning and making appropriate decisions. However, the effectiveness of these indicators in some situations is doubted by some researchers.

In light of projections indicating a growing demand for wood in the forthcoming years and the initiation of a plan to cease the exploitation of the Hyrcanian forests from 2019, the inadequacy of wood essential for the country's wood industry has emerged as a paramount challenge. The escalation in the exchange rate has rendered wood imports insufficient to cater to the nation's entire needs, underscoring the imperative to elevate wood cultivation levels as a primary solution. Despite the relatively modest expanse of poplar plantations and wood cultivation in Kurdistan province, the conducive conditions of ample rainfall and the presence of numerous seasonal and permanent rivers render it a viable area for expansion. Consequently, it becomes crucial to identify and effectively manage the obstacles and challenges impeding the development of wood cultivation in Kurdistan province.

This study focused on wood plantations and management strategies in Kurdistan province. A comprehensive questionnaire, encompassing the strengths, weaknesses, opportunities, and threats related to the development of wood farming in Kurdistan province, was meticulously prepared and finalized. The geographical boundaries of Kurdistan province served as the system's perimeter for the identification and categorization of these four key components. Employing purposeful sampling, experts well-versed in the research topic were deliberately chosen for their valuable insights. A total of 60 informed experts and local stakeholders, determined in accordance with Cochran's formula with a 10% error rate, actively participated in the review and scoring of the SWOT analysis questionnaire for wood farming in Kurdistan province, utilizing a Likert scale ranging from 1 to 5 points. The collected data, including the questionnaire results and SWAT analysis scores, were meticulously entered into an Excel program. Subsequently, total points for each item were calculated, followed by the determination of averages and relative weights for each of the four subsections of the SWAT analysis. Building on the average scores for strengths and weaknesses (internal organization) as well as opportunities and threats (external organization), the management strategy was discerned through the utilization of the Space Matrix and Strategic Action tools for wood farming in the province. This determined management strategy served as the foundation for the development of strategic plans spanning a period of 10 to 15 years, meticulously crafted to optimize wood farming in Kurdistan province.

According to the research findings, there are 16 strengths, 22 weaknesses, 15 opportunities, and 8 threats identified for the development of wood farming in Kurdistan province. The results highlight the most significant strength and opportunity for wood farming development in Kurdistan: "3000 kilometers of seasonal and permanent rivers in the province" and "the increasing demand from wood and paper industries for wood raw materials," respectively. Conversely, the most critical weakness and threat for wood farming in the province are identified as the "long harvest period of wood (economic age over 8 years) and the lack of income during this period" and "climate change leading to a reduction in annual rainfall and surface water." Local stakeholders emphasized that "the increase in demand for wood in other Iranian provinces (due to the lack of conversion industries in Kurdistan province)" stands out as a pivotal opportunity for the development of wood farming. Based on these findings, the conservative strategy (with a position of -19.67; 25.14) was endorsed in the second quarter of the coordinate system. Consequently, four long-term programs were formulated to optimize wood farming development in Kurdistan province: 1) Ensuring the annual pre-purchase of wood from farmers, 2) providing support and allocating facilities for the development of wood cultivation in the province, 3) promoting wood farming and increasing community participation, and 4) enhancing the province's infrastructure and fostering the growth of wood-related industries.

Recognizing the crucial significance of advancing wood farming in Kurdistan province, it is imperative to underscore and strategically plan the following short-term initiatives: 1- Construction of a Wood Industry Factory, 2- Cooperative and Local Organization Engagement, 3- Technical Involvement of Natural Resources Experts, 4- Formation of Trade Union Cooperatives, 5- Guaranteed Wood Purchase Opportunities, 6- Wood Farming Festival, and 7- Infrastructure Enhancement and Industry Development.

One of the environmental problems of Zagros forests is oak decline, which is less intense in northern Zagros than in middle and southern Zagros. The purpose of this study was to investigate the oak decline in Baneh County (Kurdistan Province) in 2019, 2020, 2021, and 2022. In order to carry out this research, two plots (with 100 trees) were considered in Belveh (tree dieback–southern slope) and Saraki (tree dieback–northern slope) sites in Baneh County in the northwest of Kurdistan Province. In 2019, oak trees were numbered at the desired sites, and in October 2019, 2020, 2021, and 2022, oak decline classes (five classes) were recorded for each tree. The results showed that the number of healthy trees in the Saraki and Belveh sites decreased by 25 and 28 trees, respectively, from 2019 to 2022; in contrast, the number of dieback trees increased by 14 and 19 trees, respectively, and the intensity of oak decline was greater in the Belveh site (southern dieback stands) than in Saraki (northern dieback stands). In general, the decline rate in the southern stands was higher than that in the northern stands, and the highest oak decline was observed in the southern slope. To optimally manage these forests, it is necessary to manage the factors that exacerbate oak decline and to control human interference and forest destruction so that the current situation is fixed and the seeds of healthy stands on the northern slopes are used for the regeneration and development of the forest.

Forest management achieves its management goals by considering the natural state of the forest and having enough knowledge in relation to ecological characteristics of forest species and the current state of the forest structure and monitoring changes resulting from management activities. This research was carried out with the aim of knowing the existing structural situation in Tang Dalab forest area, in two Aspect direction, northern and southern.

In the center of two northern and southern sites, a square sample plot of one hectare (dimensions 100 x 100 meters) was permanently selected and planted. All trees and Coppice shoots located in this area were numbered and specified and the structural variables of all the trees in the sample plot were measured. To compare the average of the investigated variables in both sites, after testing the homogeneity of variances and the normality of the distribution of variables, t-student test was used

The results showed that the southern stand with a density of 72 Persian oak species (Quercus brantii Lindl) per hectare was completely seedling and its forest type is Quercus brantii Lindl while the northern stand with a density of 57 trees per hectare, 82% of its seedling and its forest type was Q. brantii - C. azarolus. The results of the T-test showed that all the studied variables have a significant difference between the southern stand and the northern stand at the probability level of 1% The average diameter at root collar (DRC), diameter at 0.5m height, and diameter breast height (DBH) of trees in the southern stand were more than the northern stand. The distribution of trees in the diameter classes of the southern stand, showed that this stand has an irregularly even-aged structure. The chart of diameter distribution of this stand states that there was no regeneration in the past years in the northern stand, in addition to coppice and young Persian oak trees, in the lower diameter classes, a number of young trees of other species with small diameters were seen. The height distribution diagram of trees in the southern stand showed that the largest number of trees are in the middle of the diagram and in the height classes of 5 to 11 meters. In the northern stand, coppice trees were present in the lower height classes (less than 3 meters). While more than 80% of seedling trees have a height between 6 and 11 meters. The results of the investigation of the basal area diameter at 0.5m of the trees in both stands showed that This variable in the southern stand (26.41 square meters) due to the presence of seedling trees and higher density, it was about More than three times the northern stand (7.48 square meters).

The superiority of the southern group over the northern group showed that the aspect has a major influence on the vegetation and forest structure. in sustainable forest management planning, while monitoring the structure of forest stands during periods of time, at least ten years, it is necessary to pay special attention to the different conditions of aspect in order to preserve, revive and develop these forests.

Forest destruction causes soil destruction as the basis of terrestrial ecosystem life. Therefore, monitoring the soil and evaluating the process of changes over time can prevent the destruction of the soil and consequently the ecosystems with scientific data. In this study, the chemical and biological properties of soil were investigated in two Brant's oak (Quercus brantii Lindl.) sites, Chari and Mavarz, as a part of Zagros Forests in Chaharmahal and Bakhtiari province, Iran. Soil samples were collected from a depth of 0-10 cm and chemical and biological characteristics were measured in two years 2019 and 2021. The results in Chari site showed that the values of organic carbon, organic matter, substrate induced respiration, and nitrification potential increased significantly in the second year compared to the first year. This finding can be attributed to the more species diversity, higher canopy percentage, and relative protection of the Chari site. While in Mavarz site, only electrical conductivity and dry weight of soil showed significant changes in the second year compared to the first year which could be caused by livestock grazing and decrease in rainfall. The trend of changes in the Chari site has been positive which made improvement of some soil characteristics. Generally, management based on protecting the Zagros habitats as well as its positive effect on the biological and chemical characteristics of the soil can have a significant role in the health of oak trees which are encountering the oak decline.

One of the environmental problems of the Zagros forests, is the occurrence of oak decline phenomenon in Zagros Forest. The intensity of oak decline in the North Zagros is slower than in the Middle and South Zagros. The purpose of this study was to investigate the trends of oak decline in forests of Baneh city from 2019 to 2020.Four sites including Belveh and Gandman (southern aspect) and Saraki and Mirhesam (northern aspect) were selected and 100 trees were evaluated in each site. Oak decline status was recorded during two years of research in five classes: healthy trees, dieback in crwon, dieback up to 50%, dieback more than 50% and standing dead tree. Wilcoxon and Friedman (non-parametric tests) were used to compare the decline codes at each site for two consecutive years and to compare the decline codes at four sites per year (separately). The results showed that the greatest change of oak decline class was in Saraki site (with 0.27 change). At all four sites, the trees were shifting to oak decline classes in the second year of the research, and the change in oak decline classes at each site for two consecutive years (Wilcoxon test) was statistically significant. Besides, the change of dieback trees (dieback and dieback up to 50%) from 24% of trees in 2019 to 44% of trees in 2020 had changed. Most oak decline was observed on the southern aspect. Overall, it is suggested that human intervention be controlled.