babak pilehvar

Drought significantly impacts plant growth and has become a critical global concern. Understanding how plants respond to drought is essential. Under arid conditions, forests are prone to experiencing various types of stress. Trees protect themselves from drought stress through both physical and chemical defenses. Physical defenses include increasing the density of structures like leaves, thorns, and hairs, while chemical defenses involve producing physiological responses that serve as protective barriers against environmental factors. Oaks are known for their resistance to drought and heat, which is attributed to their physiological responses during dry conditions. The reaction of the dominant species of Persian oak (Quercus brantii) in the Zagros forests to recent droughts suggests that this species is highly sensitive to these conditions. The response to drought stress in mature, multi-year-old trees differs from that of seedlings of the same species. Certain physiological mechanisms influence the internal changes in trees as they react to stress. Therefore, the objective of this study is to examine the effects of drought stress on the physiological traits of mature oak trees under both optimal and stressful natural conditions.

This research was conducted on multi-year-old Persian oak trees over two years (2020-2022) in the natural forest environment of the Fajr Safa agro-industrial complex, located 10 kilometers from Khorramabad city. The experiment followed a completely randomized block design with three levels of drought stress. Drought treatments included a severe drought treatment (where the soil was completely covered with white plastic to prevent any moisture from reaching it for two years), moderate soil moisture treatment (with irrigation every 10 days), and a control group. The statistical sample included 120 trees, divided into 30 trees for each treatment group. On September 10, 2022, at the end of the experiment, leaves were collected from each tree at a fixed height of two meters around the trunk, from all four cardinal directions, and were taken to the laboratory. By measuring fresh weight, turgid weight, and dry weight, the relative water content of the leaves was calculated. To further analyze physiological traits, the leaves were dried in an oven at 70°C for 72 hours and ground into a powder. The following were measured in trees across all three treatment groups: proline levels, soluble and insoluble sugars, enzyme activity (peroxidase, superoxide dismutase, and ascorbate oxidase), as well as the amounts of carotenoids, chlorophyll a, chlorophyll b, and total chlorophyll.

The analysis of variance results indicated that different treatment levels had a significant effect at the 0.05 level on the amounts of proline, relative water content of the leaves, and the activities of enzymes (peroxidase, superoxide dismutase, and ascorbate oxidase). However, no significant difference at the 0.05 level was observed between treatments regarding soluble sugars, insoluble sugars, and photosynthetic pigments (carotenoids, chlorophyll a, chlorophyll b, and total chlorophyll). Among the treatment levels, the relative water content of the leaves showed the most variation. As drought stress increased, the relative water content of the leaves decreased, while proline, soluble sugars, insoluble sugars, enzymes (superoxide dismutase, peroxidase, and ascorbate oxidase), and photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids) showed an increasing trend. The highest proline levels were found in the control group, with the lowest observed in the irrigated group. Relative water content, peroxidase, and superoxide dismutase activity were highest in the irrigated group. Under severe drought stress, levels of proline, soluble sugars, and insoluble sugars increased compared to the control group.

Based on the results of this study, mature oak trees tend to preserve carbohydrates and sugars under stress. This research highlights the adaptability of mature oak trees to both optimal conditions (comparing control with irrigated trees) and their resilience during dry periods (comparing control with stressed trees). The findings indicate that mature Persian oak trees can resist drought stress to some extent by increasing proline and antioxidant enzyme activity. Compared to previous studies, where seedlings showed greater vulnerability to changes in carbohydrates and soluble sugars under stress, mature trees seem to conserve their carbohydrates and sugars. These findings are highly relevant for forest management strategies and can inform forest specialists and stakeholders. Overall, the results suggest a strong relationship between drought stress responses and plant physiology. It can be concluded that the climatic conditions affecting Persian oak stands are critical and should be a major consideration for forest managers responsible for developing management programs for the western forests of the country.

The spatial patterns of trees, as the main components of a forest ecosystem, depend on their internal characteristics, interspecific relationships, and external environmental and habitat characteristics. The tree species that make up the forest types are among the major factors influencing soil characteristics through the production of litterfall, and they play an essential role in the quantity and quality of soil organic matter and the release of soil nutrients. Organic matter is one of the important parts of the soil, which includes tissue remains of plants and animals, their undecomposed to partially decomposed components, and dead microorganisms. The presence of organic matter, in addition to indicating the soil fertility and quality, is considered a suitable indicator for soil fertility, resulting from the interaction of physical, chemical, and biological processes. By improving soil granulation conditions, organic matter improves soil porosity and permeability; therefore, it has an important role in the stability of the ecosystem. For this reason, examining its various aspects is one of the main needs and the basis of studies on soil quality, carbon cycles, and climate change. Since there is very little information about the organic matter that can be extracted with hot water as a qualitative indicator of soil organic matter in forests, the need to pay attention to better understand the effect of different vegetation types on the soil leads to a more accurate prediction of the effect of species on ecosystems and their optimal management for managers and foresters. The present study investigates soil organic carbon and nitrogen with hot and cold water extraction methods as an indicator of soil material changes in two pure (Quercus infectoria) and mixed (Quercus libani- Quercus infectoria) types of North Zagros forests (Armardeh Baneh).

Different forest types were determined using the opinions of forestry experts and statistics in the study area. The forestry characteristics were measured with five random 400 m2 sample plots in each type. The topsoil of the studied types was collected using 10 mixed samples from a depth of 0-10 cm (after removing the litterfall layer). After transporting the soil samples to the laboratory with plastic bags, the soil samples were passed through a 2 mm sieve and divided into two parts. A part of the sample was immediately exposed to 4 °C to measure the microbial mass of carbon and nitrogen, and a part of the sample was placed in the open air to measure organic carbon and total nitrogen. After measuring the studied variables, the statistical comparison of the average variables in forest types was evaluated using the independent samples t-test, analysis of variance, and their correlations with Pearson's correlation coefficient. 

The contents of soil organic carbon and total nitrogen in the pure Q. infectoria and Q. libani-Q. infectoria types did not show significant differences. Although the amounts of hot and cold water extractable carbon and nitrogen, the microbial carbon, and nitrogen biomass were higher in Q. libani-Q. infectoria types, this difference was not significant, except for hot-water extractable carbon. There was a significant correlation between hot-water extractable carbon, microbial biomass of carbon, and cold-water extractable carbon. A significant correlation was also observed between hot-water extractable nitrogen and microbial nitrogen and carbon. Finally, there was a significant correlation between soil nitrogen with microbial biomass carbon and cold-water extractable nitrogen, but the correlation coefficient was lower than that of soil organic carbon with microbial biomass carbon and cold-water extractable carbon.

There is an interaction between trees and soil. The growth and production of trees are related to the soil characteristics; on the other hand, the trees with their leaves and unique characteristics affect the understory soil. Based on the study outcomes, it can be concluded that extractable organic matter with hot water can be used as a sensitive indicator of changes in organic matter quality in forest soils.

Soil is one of the important components of the forest ecosystem and can be affected by vegetation. Knowing the quality of the soil can be used as a guide to analyze the health of the forest ecosystem. Since soil characteristics are influenced by different forest types. The purpose of this study was to investigate the soil quality in four types of (Pure Quercus infectoria), (Quercus brantii-Quercus libani and other species) (Pure Quercus libani), and (Quercus infectoria-Quercus libani) in the forests of north Zagros. For this purpose, 15 physical, chemical and biological characteristics of soil from a horizon were selected as the Total Data Set. Then, using principal components analysis, 4 characteristics including nitrogen, phosphorus, soil absorbable potassium and the metabolic quotient were selected as the minimum data set. Soil Quality Index was evaluated in these two datasets. The results showed that the average soil quality index of four forest types was calculated from 0.23 (Pure Quercus infectoria) to 0.44 (Quercus brantii-Quercus libani and other species). The soil quality index was 0.25 and 0.24 for the pure Quercuslibani and Quercus libani- Quercus infectoria types, respectively. The coefficient of explanation between the Minimum Data Set and the Total Data Set is equal to 0.80, which indicates the reliability of using the Minimum Data Set instead of the Total Data Set Therefore, the use of the most effective soil characteristics in soil quality assessment studies, while reducing the time of soil science studies, provides the basis for economic savings in the discussion of forestry studies.

Non-native plant species have been introduced to provide various goods and services. Some species have not shown negative effects on the ecosystem, while others cause habitat disturbances. Considering this issue, it is necessary to know these species' positive and negative effects. Paulownia is an exotic industrial tree species, and there are debates on the positive and negative effects of its plantation in forests and non-forest areas among experts and scientists. There are few studies on paulownia invasion behaviour based on the literature review in Iran. This study tries to investigate the competitive behaviour of Paulownia using scientific methods in reforested mixed stands in the educational and research forest of Shast-Kalate. Data were collected in the educational and research forest of Dr. BahramNia (Shast Kalateh) in the two areas. An area of 2.5 hectares of native species mixed with non-native species of Paulownia and another area of 2.5 hectares that only had native species (control). All trees in the study area were recorded. The measured variables for each tree include tree species, diameter at the breast height (DBH), tree height, and crown diameter. All trees with a diameter at the breast height above 5 cm are included in the surveying. The spatial coordinates of all trees were also recorded. The trees included the non-native species of Paulownia fortunei, and the native trees included Acer velutinum bioss, Acer cappadocicum Gled, and Carpinus betulus L. In order to investigate the interaction between species, bivariate O-Ring statistics and bivariate mark correlation functions were used based on distance. The independent T-statistic was used to compare the biometric variables of native species. The graphs obtained from the O-Ring statistic between Paulownia species and native species indicate that the relationships are generally of the attraction or independent type. Also, the mark correlation function results indicate negative and independent interactions based on the DBH and crown diameter and negative for tree height between Paulownia and Acer cappadocicum. Interactions between Paulownia species and Carpinus betulus in all distances were independent based on DBH and negative and independent regarding crown diameter and tree height. Also, positive, negative and independent interactions were seen regarding tree height and crown diameter between Paulownia species and Acer velutinum and attraction and independent interactions were seen in terms of DBH. The independent t-statistics indicate that the average DBH and crown diameter of the Acer cappadocicum Gled in Paulownia mixed plantation is more than the control area, there is no significant difference in tree height. The average DBH and crown diameter of Acer velutinum bioss were higher, and tree height was less in Paulownia mixed plantation compared to the control area. The tree height of the Carpinus betulus L. was higher, and the crown diameter was less in the control than the Paulownia mixed plantation. No significant differences were seen in DBH between the two study areas. Considering Paulownia's growth nature, a higher tree height, DBH, and crown diameter can be expected, and the results confirmed this. In contrast, this growth rate does not exist in native species. On the other hand, the marks used in the mark correlation function include the variables of tree height, DBH and crown diameter, so the negative marked correlation function results can be attributed to this property. In order to introduce a species as invasive, comprehensive research is needed for its effects on the regeneration of native species, composition of vegetation, and soil properties.

To investigate the effect of drought stress on the vegetative, physiological, and biochemical characteristics of purple seedlings, an experiment was conducted in the form of a completely randomized design with four levels of irrigation including 75% (mild stress), 50% (medium stress) and 25% (severe stress) of the field capacity (FC) and the control (100% FC) in greenhouse conditions. The results showed that severe drought stress significantly reduced vegetative traits such as seedling height growth (86.8%), the number of leaves, and total fresh and dry biomass by 93%, 46.2%, and 44.8%, respectively, but increased root volumetric growth (1034%). Also, drought stress affected all parameters of gas exchange and photosynthetic pigments. So that at the level of 25% FC, it caused a significant decrease in the rate of photosynthesis (1/20 µmolCo2m-2s-1), transpiration (0/65 mmolm-2s-1), stomatal conductance (106/2 mmolm-2s-1) and mesophilic (0/0088 mmolm-2s-1), intracellular carbon dioxide concentration (134/2 mmolCO2 m-2s-1) and carboxylation efficiency (0/00112 µmolCO2 mol-1H2O). The amount of photosynthetic pigments (chlorophyll a, b, total chlorophyll, and carotenoids) also showed a significant decrease at 25% FC (4.07, 1.96, 6.03 and 1.23 mg g-1 FW, respectively.). Also, drought stress increased the amount of proline and soluble sugar and showed the highest values at the level of 25% FC (respectively, 1.348 µmol g-1 FW of proline and 41.51 mg g-1 FW of soluble sugar). According to the above evaluations, it seems that the purple variety can tolerate drought stress up to 75% FC without causing damage to the plant tissue, but if the amount of water is reduced to the threshold of 25% FC, its growth and performance will be severely affected.

Considering the importance of the forests of North Zagros in terms of conservation, economic-social and regeneration, this research aims to identify the composition and diversity of herbaceous species in different oak types located in Armardeh forests in Baneh city and the relationship between the herbaceous cover with edaphic conditions. Forest types were identified with field inspection. In each type, 5 samples of 500 square meters were randomly collected to collect trees and 5 soil samples were taken from each types to a depth of 10 cm. Also, a small sample of one square meter was randomly used for herbaceous species. The biological form of the species was obtained using the Raunkiaer method, the chorotypes according to were obtained to Zohary method, and the biological diversity was obtained using plant diversity indices, then the relationship and ordination of the vegetation with edaphic variables were investigated with detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA). The results showed that Asteraceae, Fabaceae and Poaceae families have the highest number of plant species respectively. Trophies and hemicryptophytes had the highest percentages, respectively, and the most important chorotypes of the region were the vegetative elements of (Iranian-Turan). The results of variance analysis, Pearson's correlation and vegetation ordination showed that the separation of vegetation types, species distribution in North Zagros was mainly influenced by soil texture, sodium, organic matter, potassium and phosphorus. According to the findings of this research, it can be acknowledged that due to the widespread of Zagros forests, attention to forest types and soil can represent the changes in the vegetation cover and be considered in the management of these forests.

Soil microbial respiration in forests constitutes a significant share of carbon dioxide emissions in terrestrial ecosystems and is very sensitive to environmental changes such as soil temperature and moisture and the type of vegetation. In this study, soil microbial respiration and two environmental factors including temperature and soil moisture were conducted in five forest types in four seasons. Soil microbial respiration was measured by the closed bottle method, soil moisture in the laboratory and soil temperature with a thermometer simultaneously with soil sampling in areas of surface soil (0 to 10 cm depth), and the relationships between soil microbial respiration and environmental variables were analyzed. The results showed that the soil microbial respiration rate is significantly higher in the wet period (spring). The pure Quercus libani types with an average of 0.090 throughout the year had the highest amount and the pure Q. infectoria types with an amount of 0.078 mg/g of soil per day had the lowest amount of microbial respiration. Also, no significant difference was observed in soil microbial respiration between forest types.

Soil respiration is carbon dioxide emission from soil surface which controls the primary carbon cycle in ecosystems. Recently, soil respiration has become an important ecological process in the global carbon balance and has an important impact on global climate change. Measuring soil respiration is important for quantifying the CO2 flux from soils to the atmosphere. The aim of this study is to compare the soil respiration rate at different hours of the day between five forest types (Pure Quercus infectoria) (Quercus infectoria-Quercus libani) (Pure Quercus libani) (Quercus libani- Quercus brantii- Quercus infectoria) (Quercus libani- Quercus infectoria) in the four seasons of the year (spring, summer, autumn, and winter) and to identify the effect of environmental factors (temperature and moisture) that cause changes in soil respiration rate were analyzed by using different models. Also, the correlation between respiration and soil chemical properties was evaluated.

The five dominant forest types of the region were selected after forest walking and review of resources, and samples of 20 x 20 square meters were selected in each types of plot (so that it is representative of the desired types). In order to measure soil respiration, 8 PVC pipes with specific size and diameter were installed at a depth of 5 cm in the selected sample piece and measured using Anderson's method at different hours of the day. Soil temperature and moisture were recorded with a thermometer and a TDR device, respectively, simultaneously with the measurement of soil respiration. In order to conduct chemical tests, 5 soil samples from each type were taken in the growing season and transferred to the laboratory.

The highest amount of soil respiration during the day was observed at 14:00 in the afternoon, also the Pure Libani type showed the highest rate of soil respiration with an average

Medicinal plants are rich in secondary metabolites that constitute the composition of many drugs. The quantity and quality of these valuable materials are affected by environmental factors. The present study evaluated biochemical properties in leaves and fruits for three populations of Prunus scoparia (Spach) C.K. Schneid. Analysis of essential oil (EO) samples was performed by using GC and GC–MS. The results showed that total phenolic content (TPC) and total flavonoid content (TFC) of leaves in population 2 (Markazi) were 39.01 and 11.32 mg/g DW respectively. DPPH radical scavenging activity in population 2 was 45.5 % in leaves. Fruit EO content was 33% in population 1 (Lorestan). Heat map analysis distinguished two different clusters as one cluster for population 2 and another cluster for populations 1 and 3. The GC/MS analysis showed the main EO composition of fruits were Benzaldehyde (15.19-18.65%) followed by n-Hexadecanoic acid (14.67-18.3%), Benzyl Alcohol (4.12-6.42%), and 9-Octadecenoic acid (Z)-, ethyl ester (4.9-6.28%). In addition, the major EO profile for leaves were Neophytadiene (3.2-15%), dehydroaromadendrene (7.4-13.9%), Borneol (7.12-10.4%), cis-3-Hexenyl benzoate (6.4-9.5), trans-beta-Ionone (4.3-7.8%), Eugenol (2.3-7.3%), Benzyl benzoate (2.7-4.12%), and Di-epi-alpha-cedrene-(I) (2-5.5%).

The current research is based on the existing ecological conditions in the Zagros forests and knowledge of the response of forest trees to these conditions and the purpose of this study is to investigate the effect of topographic factors, tree characteristics on of fine roots biomass of gal oak (Quercus infectoria Oliv.) and also to compare the amount of nitrogen, phosphorus and potassium in the fine roots of trees in the Shineh region, Lorestan province. Initially, random and regular sampling method used with 100×100 meters of statistical network. Tree characteristics, including diameter at breast height, crown diameter, height/DBH ratio, also the concentration of the NPK on two altitude classes and also the fine root biomass in three directions, at a depth of 0 - 30, slope 15 - 60% and altitude of 1300 - 1500 meter above sea level were measured. The results showed that depth and geographical directions had significant effect on the fine roots biomass. This biomass is greater at a depth of 15-30 cm and in the east direction. Above mean sea level had no significant effect on root biomass. The biomass was greater at a slope of 46-60 percent. Also, crown diameter, height coefficient and amount of NPK have significant effect on root biomass of gal oak. But the DBH and the height of the tree have no significant effect on root biomass. Nitrogen had the highest positive correlation and potassium had the least negative correlation with the amount of fine root biomass. Knowing more about the characteristics of trees according to the state of forest stands can be effective in protection and restoration, especially in their treatment operations.

This study investigated the variation in plant diversity, floristic quality indices, and the forest integrity of various broadleaf forest types.

In this study, we used 288 plots of 1m2 in the middle Zagros forest to investigate the role of three forest types including Quercus infectoria, Quercus brantii, and Pyrus glabra on forest diversity indices and floristic quality

results revealed significant differences in Shannon wiener, Margalef, and Menhinic indices, as well as some soil properties, between forest types, but no significant differences in evenness and Simpson indices. Diversity indices mean coefficient of conservatism and floristic quality index (FQI) were significantly greater in the protected forest dominated by Quercus infectoria than in other protected forests.

This study demonstrates that tree species and certain topographical and edaphic factors have distinct effects on the distribution of understory plants, plant diversity, and floristic quality in different forest types. The results of this research, while confirming the use of plant diversity indices, also introduce the conservatism coefficient and species fidelity as additional tools in evaluating forest integrity, because by using them, more and better information can be obtained about the conditions of the forest.

A comprehensive study of vegetation changes requires consideration of all influential factors in the ecosystem. The Zagros forests, as one of Iran's most important forest ecosystems, contain diversified vegetation including trees, shrubs, and herbaceous species. Therefore, accurate identification of vegetation and knowledge of their ecological role can help in protecting natural resources and sustainable development. The aim of this study was to investigate the changes in herbaceous vegetation in the Hashtadpahloo forests of Lorestan province.

For this purpose, after physiognomic typing of the region, 21 multi-scales, modified Whittaker plots were randomly selected in pure oak type (Quercus brantii Lindl.), Mixed oak and Acer type (Quercus brantii Lindl., Acer monspessulanum L.), Shrubs and cushion plants type (Daphne mucronata Royle, Cotoneaster morulus Pojark), and rangeland type (grassland and rangeland species). Species richness, canopy cover of tree species, Physiographic factors such as slope, aspect and altitude were measured at 250 m2 (25×10) plots, and presence and cover percentage of each herbaceous plant was recorded at o.25 m2 plots. (0.25 × 1. Furthermore a combined soil samples were taken at 0–30 cm depths to determine soil properties. After measuring plant diversity indices such as Margalf, Mannick and Shannon Wiener indices and some physical and chemical characteristics of soil in laboratory, principle component analysis (PCA) was used to indicate the most important environmental factors affecting diversity indices in different types.

The results showed that there were significant differences among different vegetation types with respect to Menhinick and Margalef richness indices, aspect, slope, altitude, and canopy cover (p<0.05). While Simpson's and Pylo's indicators of diversity, dominance, and evenness had no significant differences among different types. The highest Menhinick and Margalef richness indices were observed in pure oak type, whereas rangeland type had the lowest richness indices and canopy cover and the highest slope and altitude. In addition, the soil variables absorbable potassium and magnesium had a significant correlation with the values of Manchinic, Margalf, Simpson, and Shannon-Weiner indices. Based on the PCA results, dominance, diversity, and species richness indices (constituent variables of the first component), edaphic factors (constituent variables of the second component), and eventually Physiographic factors such as slope, aspect, and altitude with canopy cover (constituent variables of the third component), describe the highest percentage of changes in the herbaceous community of the region respectively.

As a result, it can be acknowledged that due to the wide spread of Zagros forests, simultaneous attention to the three components of forest types, physiography and soil can favorably reflect the changes in the vegetation of the herbaceous vegetation of the Zagros, and they can be used in the management of these forests.

Tree species have different effects on soil properties and nutrients. Plantation as a management strategy for soil productivity retention and the prevention of destruction can be effective in the continuity of forest productivity. One of the most important goals of planting coniferous species is to increase wood production, create forest parks and conservation forests. The objective of this study was to investigate the seasonal variations in nutrient concentrations in plant organs and soil of pinus brutia Ten.  stands.

For this purpose, the ​​Makhmalkuh forest park in Lorestan province was selected and in 1396, random sampling was performed using 5 (400 m2) sample plots. In each sample plot, an indicator tree pinus brutia Ten. was selected and its young and perennial leaves and twigs were sampled in the upper third of the crown in four seasons, as well as from two depths of 0-5 and 5-15 cm a mixed soil sample was taken in each sample plot. Soil texture, pH, organic carbon (C), total nitrogen (N), available phosphorus (P), and potassium (K), for all samples were measured in the laboratory. The soil parameters, nutrients of soil and plants organs were analyzed by using one-way analysis (ANOVA) and Duncan test procedures among different seasons.

According to the results, the lowest amount of dry weight and percentage of moisture in all four organs was observed in summer and the highest amount was observed in winter. Based on the results, there was a significant difference between the nutrient concentrations of plant organs in different seasons (sig<0.01). In all four organs, the highest amount of nitrogen was recorded in spring, potassium in winter and phosphorus in summer. The results of correlation studies also showed a significant relationship between nutrient concentrations of different organs and different soil characteristics.

High amounts of nitrogen and phosphorus in the spring can be argued that increasing the temperature in most cases increases the metabolic activity in the soil, evaporation and transpiration and absorption of nutrients. Different climatic conditions in different seasons, lack of soil moisture, retranslocation of nutrients from perennial needles and branches to young parts and seasonal and monthly changes in the chemical composition of the throughfall can be the most important reasons for these changes.

There are various vegetation sampling methods regarding objectives of Management at forests. To aim of this study, we undertook a comparative study at Shineh Ghelaee protected forest at middle Zagros using single-scale sampling, single-scale sampling based on transects, and multi-scale sampling methods to investigate the herbaceous layer diversity. In order to know the situation of the region and compare the performance of different sampling methods, richness and diversity indices, the mean of conservatism coefficient and floristic quality index, and the conservation status of plant species in the region were calculated and compared with three sampling methods. The results indicated that Poaceae, Asteraceae, and Fabaceae were the most important families based on the number of species and chorological studies revealed that the most species belonged to the Irano-Turanian zone, The results also showed the life-form of plants dominated by therophytes in this region. Also, the results revealed that the greatest abundance of conservative species (Coefficient of conservatism:1-3 and belonging to the first category of coefficients conservatism), observed by three sampling methods, whereas the total number of plant species,  endemic vascular plant species, diversity indices, evenness index, mean CC and FQI were higher at single -scale sampling method results. In the percent study, it seems that different sampling methods can influence the identification of endemic species, mean CC and FQI, and diversity indices, As a result to study vegetation in areas we suggest that single-scale sampling, single-scale sampling based on transect, and multi-scale sampling methods have the same efficiency in small and homogenous areas with floristic surveying goals, whereas single-scale sampling methods are more appropriate to measure mean CC, diversity indices and FQI.

To manage and conserve biodiversity, comprehensive knowledge of spatial patterns of species richness and diversity and effective factors on them is necessary. The changes of diversity and richness indices at an altitudinal gradient (700 meters) in Persian oak (Quercus brantii Lindl.) forests “Taf catchment in Khoram Abad” was investigated in this study. The physiographic and soil properties, and tree canopy cover were measured by the two 500 m2 sampling plots in each 100 m altitudinal classes. The three randomly located subplots (4m2), was used to investigate the ground herbal layer in each sampling plot. Based on the results there is not any significant correlation between richness, evenness, and diversity indices with altitude and slope, while a negative significant correlation was seen between evenness and diversity indices with tree canopy cover. Contrary to the absence of correlation between evenness and diversity indices with soil properties, there is a positive correlation between the amount of soil clay and silt and negative correlation between soil OC, K, N, and sand with richness indices. The results of PCA analysis showed that the amount of K, P, OC, saturated water content, pH, altitude, and tree canopy cover are the most important environmental factor in the study area. Despite the absence of specific patterns in richness, and diversity indices along the altitude gradient, the findings show that tree canopy cover affects evenness and diversity indices, and the soil properties affect richness indices.

Tree species through litter fall have the most important effect on soil properties and play a fundamental role in the carbon cycle and nutrient release. This study aimed to investigate the corelation between tree species and changes in carbon sequestration and some soil properties in the forest types of central Zagros The tree species features in the Persian oak, Aleppo oak, and Wild pear forest types were measured by 24 plots of 500 m2 (20×25 m) and soil properties were determined (at two depths of 0-10 & 10-30 cm) by 48 combined sample. Data on tree features, soil properties, and carbon sequestration variables were analyzed and compared by one-way ANOVA. Based on the results, unlike crown height and tree density, canopy area showed no significant difference. Significant differences among forest types were also observed in carbon sequestration, soil texture, N, OC, K, pH, and saturated humidity in the 1st sampling depth but the T.N.V, C/N ratio, EC, Ca, bulk density, and saturated humidity showed no significant differences in the 2nd sampling depth. The most values of clay, silt, and pH, were seen in both Wild Pear and Aleppo oak forest types while Persian oak forest type had the most values of carbon sequestration, sand, K, N, OC, and saturated humidity in the 1st sampling depth. The crown height was the most important variable that showed significant correlation with the changes of carbon sequestration, K, pH, and saturated humidity. It is concluded that the changes in carbon sequestration and soil nutrients in Zagros forest types is mostly affected by forest types and crown height. It is suggested that to estimate carbon sequestration by remote sensing in Zagros forest, the Lidar data that able to measure crown height be applied.

Retranslocation of nutrients from senescing leaves to young and permanent parts of tree bodies is one of the main strategies to confront with nutrient loss from the soil especially in sites with nutrient poor soils. The aim of this study is to investigate retranslocation of nitrogen, phosphorous and potassium in pinus brutia. For this purpose we selected Makhmalkooh afforested forest at Lorestan province and sampling was carried out at 5 times. In each plot, young and senescent needles and twigs were sampled and nutrient retranslocation were measured. Within each plot, we also collected a composed sample of soil and soil physico-chemical properties were measured. Our results showed that net retranslocation was done at two growing seasons (spring and fall) and September to November. Results also highlighted correlations between nutrients concentration in plant tissues and some of the soil properties like electrical conductivity, organic carbon and pH. This emphasis on close relationship between nutrient's soils concentration and plant retranslocation. In conclusion, based on the results of this study, soil properties such as soil fertility, nutrient concentration in the senescent needles, annual precipitation and drought periods at summer are key factors that influence on nutrients retranslocation. The retranslocation results in Makhmalkooh forest reinforced the hypothesis that forest adapted to climate and edaphic condition and can be used as a guide for management plans to assist in nutritional decisions making of forest trees.

This study aims to determine the floristic composition and investigate the distribution of communities along an altitude gradient in oak forests of Taf in Khoramabad. The study area was classified into 100m elevation classes, and in each class two 500m2 plots were chosen randomly for measuring trees and shrubs layer. Also in each 500 m2 plot three 4m2 plots were distributed for measuring herbaceous layer composition. Changes in vegetation along an altitudinal gradient were studied using slope, altitude and some edaphic data by CCA, DCA and TWINSPAN ordination and classification methods. Based on the results, 116 species from 35 genera were observed along the altitude gradient. Asteraceae, Poaceae and Fabaceae families had the most species respectively. Therophytes, Hemicryptophytes and Cryptophytes were the most dominant life forms and Iran-Toranian and Iran-Torani-Mediterranean were the most chorotypes in this area.

The milkweed shrub, in addition to ecological functions, has special industrial and medicinal values. This plant is widely planted for afforestation in arid lands in the south of Iran. Regard to scarcity of fresh water, using of seawater as a vital and alternative source of water for irrigating of halophyte plants was suggested. Thus, the current research was carried out to investigate the efficiency of diluted seawater on seed germination, growth and physiology parameters of milkweed seedling. For this purpose, an experiment was conducted in completely randomized design with three replications in two separate experiments; in vitro and nursery, with different levels of diluted seawater i.e. 0, 12.5, 25 and 50% using saline meter. The results of seed germination test showed that germination parameters and seed vigor index significantly decreased by increasing seawater concentration to more than 12.5%. The results of nursery experiment revealed that concentrations of more than 25% of seawater significantly reduced growth performance and gas exchange of seedling. The survival rate 55%, height 19.9 cm, specific leaf area 190.7 g/cm2 and root length 22.54 cm as well as photosynthesis rate 2.83 µmol, transpiration rate 0.42 mmol, chlorophyll 20.45% and relative water content 43.95% were observed in 25% seawater treatments. It is recommended that researchers conduct a broader study of the salinity-tolerant physiology of this valuable medicinal plant to obtain more comprehensive information for afforestation programs.

Functional groups are defined as groups of species exhibiting similar responses to an environmental variables. The aim of this study was to investigate the response of plant functional groups to some environmental variables in Mountain forests of southern Zagros (Khuzsetan province- county baghmalek). Vegetation and environmental factors were sampled by 50 circular plots of 1000 m2 selective-randomly along an elevational gradient from 646 to 3172 m a.s.l. sampled vegetation were identified in terms of different growth Forms to woody (tree and shrub), herb and woody seedling (tree and shrub seedling) functional groups and the changes of these functional groups in relation to environmental variables were analyzed using Canonical Correspondence analysis. The results showed that all the functional groups of forest vegetation showed a statistically strong significant correlation with elevation, soil Electrical conductivity, soil available k and soil pH. Also woody functional group showed a correlation with Microbial biomass carbon, clay percentage, Aspect, Organic matter content, sand percentage, slope and Total of nitrogen, herbs showed a correlation with Soil organic matter, soil available p, Total of nitrogen, sand percentage, clay percentage, basal respiration, Bulk density and slope, while woody seedlings showed a correlation with aspect, Total of nitrogen, sand percentage, slope, Microbial biomass carbon and clay percentage. species diversity of woody functional group to 2350 m a.s.l were hight and then above 2350 m a.s.l were low. while herbs were lower diversity at intermediate elevations (1300-1600 m a.s.l) and above 2350 m a.s.l and seedlings had maximum diversity at intermediate elevations.

In this study different concentrations of SiO2 nanoparticles (o, 75, 150, 250, 350, 500 milligram per liter) have been used as a pre-treatment before cold stratification on Sorbus luristanica’s seeds in order to assessment of the nanoparticle potential for simulation of seed germination and growth of the species. For this purpose, the seeds were primed with the nanoparticles for 24 hours and then stratified in sand for 3 months. The experiment was performed as a completely randomized design with 4 replications with 25 seeds in each replication. After 3 month, stratified seeds were transported to germinator and after starting of germination symptoms, germination data were recorded daily for 22 days. The results showed that seed germination under 250 and 350 m/L NSiO2 treatments improved around 100% while seed germination in control seeds was 26%.

Production of nanoparticles and their use are on the rise in different areas of plant science. However, in spite of their increasing production, there is limited information about their effects on plant biology. In the current study, the potential of TiO2 nanoparticles was investigated for the purpose of improving seed germination of Sorbus luristanica and then subsequent effects of nanoparticles on the growth and biomass of the plants were determined.

Seeds of S. luristanica were collected from its natural stands. The seeds were primed with different concentrations of 0, 75, 150, 250, 350 and 500 TiO2 nanoparticles miligeram per liter for 24 h. The treated seeds were placed in wet sand at room temperature for 2 weeks and then in cold for 3 months. The expriment was set as a completely randimized design with 4 replications. Aftre 3 months of stratification in moistened sand, the stratified seeds were put in the germinator and with the appearance of seed germination signs, germination data were recorded daily during 22 days. At the end of the seed germination experiment, some germination parameters such as seed germination percentage, seed vigority and mean time to germination were calculated. Moreover, some growth and biomass parameters including leaf number, plant height and dry and fresh biomass of leaf, stem as well as roots were measured. In addition, scaning electron microscopic (SEM) was used for observation of presence and adhesiveness of TiO2 nanoparticles on the seed coat.

Based on the results, all the germination parametres including seed germination percentage, seed vigoroty and mean germination time were improved by the TiO2 nanoparticles treatments. In addition, 500 mg.L-1 treatment considerably improved seed germination characteristics. The peresence of TiO2 nanoparticles on the treated seeds and lack of the nanomatreials on the conrtol seeds were obsereved by scaning electron microscopic pictures. The One-way ANOVA showed that 75 mg.L-1 treatment was more succesful for improving the grwoth (such as shoot length) and biomass production (fresh and dry biomass of leaf, stem and root and total biomass as well).  

It can be concluded that priming of the seeds of this species with different concentrations of TiO2 nanoparticles leads to improvement of seed germination and growth and biomass parameters. However, the patterns of effects were different in each phase. Therefore, the objectives should be formulated first and then the best concentration should be chosen. It seems that with appropriate concentrations, nanoparticles can be useful for breaking seed dormancy and production of the species. Given the promising resutls of 150 mg.L-1 treatment, it can represent a successful treatment for breaking seed dormancy and seedling production of S. luristanica.
Highlights

1- Study of seed germination of Sorbus luristanica for the first time 2- Using Nano-materials and their potentials in breaking seed dormancy and improving the species germination 3- Using SEM in order to study presence and adhesiveness of nanoparticles on the seed coat

This study investigates floristic quality of central Zagros forest in relation to environmental disturbances using conservatism coefficient. Tree layer of the most important forest types in central Zagros was surveyed using 24 plots (500 m2 area) and herb layer was measure by 72 plots (4 m2 area). Then the list of collected flora send to an expert group of botanist and ecologist to assign conservatism coefficient to them based on the amount of each species sensitivity to disturbances and fidelity to the ecological site condition. Based on the results only a few species take high rank score which means the most collected plant species were sensitive to the disturbances and have low fidelity to the site. In fact more than half of the collected species belong to the lowest class of conservatism coefficient (1-3), which pyrus glabra forest type involves the most plant species of this class.

This study aimed to detect the effects of anthropogenic disturbance on vegetation changes based on conservatism species concept and its relation to environmental factors in two protected vs disturbed area. The study area, Shine Qelaii gall oak forests, located in 88 Km from the north west of Khoramababd. Multiscale sampling plots were used randomly to collect data on forest floor vegetation, trees, soils, and other environmental factors. Among collected plant specimens, conservatism species were identified and DCA and CCA ordination methods were applied to determine correlation between plant species and environmental factors, plant diversity also were investigate by nonparametric numerical diversity indices. The most effective environmental factors on distinction among vegetation communities were determined by PCA ordination method. Based on the results, more invasive species and less richness and diversity indices were seen on the disturbed forest type compare to the protected one. A positive correlation was seen in ground flora vegetation and soil nutrients. Altitude, canopy cover, exposure, OC, K, N, P, clay, sand, and bulk density were the most effective environmental factors on vegetation types. This study showed that conservatism species concept together choosing two close and same watershed can eliminate confused factors and resulted to more accurate determination of conservation management effects on vegetation composition

Robinia pseudoacacia L. and Cercis siliquastrum L. are appropriate species for plantation and development programs in urban green spaces. This study was done to investigate the physiological response of potted seedling belongs to these species under salinity stress. The experiment was as completely randomized design with four replications (Per repetition 4 pots). For this purpose, in a research greenhouse, seedlings of both species (Black locust and Judas tree) were irrigated with sodium chloride solution in four levels of salinity (0, 5, 10 and 20 dsm) for a period of 90 days. The results indicated that all physiological factors of both species have been reduced with increasing salinity stress, respectively. The lowest values of stomatal conductance, photosynthesis, transpiration and stem water potential were belonged to seedlings irrigated in high levels of salinity. Also, suitable responses of studied parameters up to 10 dsm of salinity were obtained by both species. According to results, It is recommended to use these two species in plantation, afforestation and urban green space development programs, where the density of salinity is lower than10 dsm in soil and water resources (arid and semi- arid regions).