جستجوی مقالات مرتبط با کلیدواژه « عناصر غذایی » در نشریات گروه « جنگلداری »

One of the concerns for the executive organizations to introduce an alternative plan of rest of the Hyrcanian forests is to make decision regarding the exit of coarse woody debris (CWD) volume from the Hyrcanian forests. The research was carried out in the permanent plot with 400 m2 based on the protocols of the comprehensive research plan enacted by Agricultural research Education and Extension organization in Iran. Within each plot beneath the CWDs over than height of 1.5 m and dimensions of 7.5 cm, the organic accumulations resulted from the decay trend were sampled. Besides, the soils mineral layer up to 10 cm depth were sampled after removing the organic accumulations, and were transported to the laboratory. The results of PCA (Principal Component Analysis) showed that beneath the CWDs including higher organic accumulations, amount of the organic carbon and the nutrients were lower in the substrate soil mineral layer. Furthermore, the results of Spearman test indicated that amounts of organic carbon and nutrients in the organic and substrate mineral layers were independent of each other (P > 0.05), and amounts of the organic carbon with Nitrogen were significantly correlated (P < 0.01). Also, the results of two-way PERMANOVA test indicated that interactions of form, species and decay of the CWDs in the study sites were not significantly effective on the organic carbon under the CWDs.

In this study, the impact of boxwood moth pest defoliation on the dynamics of leaf litter and soil nutrients in the Cheshmebolbel boxwood (Buxus hyrcana) reserve was evaluated. A random sampling technique was employed to collect litter layer samples (using a 400 cm2 frame) and soil samples (using a metal cylinder with an 8 cm diameter and a 10 cm depth) from 32 sites in unpolluted and polluted boxwood stands. The results revealed that only soil moisture percentage differed significantly among the soil physical variables, whereas all chemical soil variables showed significant differences between the two polluted and unpolluted boxwood sites. Furthermore, basal respiration (0.14, 0.12), metabolic rate, microbial ratio, and carbon availability index were significantly higher in the polluted sites compared to the unpolluted site, while no significant difference was observed based on the microbial-carbon respiration index. The principal component analysis (PCA) results demonstrated a distinct separation of the two sites, both polluted and unpolluted, along the first axis, based on both litter and soil variables. In this context, nitrogen, metabolic rate, moisture, nitrate, ammonium, and stimulated respiration (0.30, 0.39) exhibited a positive correlation with the first axis, representing the concentration of the unpolluted stand. On the other hand, C/N ratio, potassium, magnesium, calcium, and microbial biomass carbon displayed a negative correlation with the first axis, representing the concentration of unpolluted sites. In general, the findings of this research underscore the substantial influence of defoliation induced by pest outbreaks on an important aspect of forest ecosystem health, performance, and nutrient cycling.

Afforestation with oak (Quercus brantii Lindl) trees has been done for restoration of degraded areas in Zagros forests, however, few studies have been done on the dynamics of leaf and soil nutrients compared to natural trees (standard and coppice). The aim of this research is to compare the nutritional elements of leaves in natural trees (standard and coppice) and planted forms of persian oak (with an average age of about 30 years).

According to the objectives of the research, in the city of Ilam, where afforestation with persian oak species was carried out in the vicinity of its natural form, sampling were done from leaves and the soil (at a depth of 0-20 cm) in the two seasons of spring (April) and summer (September) to compare the changes in carbon, nitrogen, phosphorus, potassium, calcium and magnesium and some physical and chemical characteristics of the soil. Two-way analysis of variance (GLM) used to compare the soil and leaf properties among different regions. Principal component analysis (PCA) and Pearson's correlation test were used in order to investigate the relationships between leaf and soil nutrients and their changes in different forms.

results of GLM showed that nitrogen and phosphorus of leaves were affected by different forms of oak species and season, and their amount is higher in spring than in summer. So that the amount of nitrogen in the leaves of standard (20.2% to 1.68%) and planted trees (1.78% to 1.25%) was higher in spring compared to summer. The amount of calcium in the leaves in summer was between 1.5 and 2 times higher than in spring (planted oak; 303.66 ppm to 170.33 ppm, coppice; 282.33 ppm to 149.33 ppm, standard tress, 285.66 to 233 mg/kg. Leaf potassium was influenced by different oak forms and seasons. So that it was more in spring than in summer and in standard (201.16 mg/kg) and planted trees (161.47 mg/kg) it was 1 to 1.5 times than that of coppice trees (128.30 mg/kg). Principal component analysis and Pearson correlation showed that in two seasons, different forms of oak can be separated from each other.

Therefore, it can be said that the planted Persian oak trees are similar to the standard form in terms of nitrogen, potassium, and phosphorus elements and were more than coppice trees. In addition, in planted, unlike natural forms, the amount of leaf elements were higher in summer than in spring.

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.

This study was done to investigate the effect of slope aspect and crown dieback intensity on the nutrient status of leaves of Persian oak trees influenced by dieback and site soil in the forests of Ilam province. For this purpose, the Forest area of Melah-Siah was considered and two one-hectare areas on the northern and southern aspects with almost the same altitude levels were selected. In each selected area, 10 trees were sampled in two intensities of healthy and dieback affected. Leaf samples were collected from the four main sides of tree crown and the middle part of the crown and from their terminal branches. Furthermore, from the south side of the selected trees, soil samples were prepared from two depths. Collected samples were transferred to the laboratory for analysis of OC, N, P, K, Ca and Mg.  The results showed that the slope-aspect and crown dieback intensities have significant effects on the amount of phosphorus, calcium and magnesium in Persian oak tree leaves. So that, the amount of leaf phosphorus in the northern site was higher than the southern site. Leaf calcium and magnesium concentrations were higher in the north site than the south site and in dieback-affected trees than the healthy trees. Also, the amount of soil organic carbon was significantly affected by slope aspect. The OC content in depth of 0-20 cm, in the northern site was less than the southern site. The amount of pH, CaCO3 and soil moisture in the depth of 0-20 cm and soil moisture in the depth of 20-50 cm were also changed under the slope aspect. It was concluded that leaf nutrients had more changes than soil elements under the influence of considered factors and the amount of these changes was more attributed to the slope-aspect. The studied Persian oak trees with different crown dieback degrees had a similar situation in terms of soil macro elements, but had different conditions in terms of leaf macro elements. Considering the differences between their habitats in terms of soil moisture and pH, it can be said that the dieback severity of tree crowns is related to physiological mechanisms in trees for absorbing water and nutrients.

Todays, Application of Nanotechnologies in Plant Science is one of the topics of the day. The present study was conducted to investigate the effect of carbon nanotube treatments, calcium chloride 1% and potassium nitrate 1% on leaf nutrients and height growth of Iranian oak seedlings. This experiment was performed in a completely randomized block with three replications in the research greenhouse of Malayer University. For this purpose, the seeds were primed in the first treatment included five levels of concentration of carbon nanotubes (10, 25, 50, 75, 100 mg / l) for six hours, the second treatment of calcium chloride 1% for 48 hours and the third treatment Potassium nitrate for 24 hours and control treatment (non-priming). At the end of a six-month period, the growth rate and nutrient levels of nutrients in the leaves and soil under the seedlings were measured. According to the results, the highest concentration of soil nutrients was observed in low concentrations of nanoparticles. Findings showed that in compared to the other treatments, the greatest effect of potassium nitrate 1% was in increasing soil carbon. Also the Findings showed that the amount of nutrients in the leaves decreased with increasing concentration of carbon nanotubes. According to the results, the use of carbon nanotubes with a concentration of 50 mg / l has good conditions in increasing the concentration of nutrients in the leaves. Also, the use of concentrations of 50 and 75 mg / l of carbon nanotubes increases the height growth of oak seedlings.

Changes in flooding regime have resulted in widespread declines in ecosystem functioning Flooding affects soils by altering soil structure, depleting O2, accumulating CO2, inducing anaerobic condition in soil, development of root rot, loss of mycorrhizae, and reductions in root metabolism, leads anaerobic decomposition of organic matter, and changing macro and micro elements of soil and leaf. In this experiment, the variations of macro and micro nutrient concentration in soil and leaf of Alnus subcordata (L.) seedlings under soil flooding stress were investigated during a 120-day outdoor experiment. Seedlings were subjected to three fixed treatments: 1) unflooded; 2) flooded to 3 cm depth and 3) flooded to 15 cm depth and their macro and micro nutrient concentration in leaf and soil were measured at the end of the experiment. Results indicated flooding had no effect on the concentration of Mg, Ca, Zn and organic C soil, while the concentration of P, N and K decreased and the concentration of Fe and Mn increased in the soil by flooding, although did not result in toxicity of elements of soil. In leaves of flooded seedlings, the concentrations of N, P, K, Zn, Ca, Mg and organic C decreased, but the concentrations of Mn and Fe increased to a detrimental level. In addition, there was a significant positive correlation between most of elements in soil and leaf. Generally, the results indicated that flooding changed the concentration of much elements in leaf and soil seedlings of A. subcordata that it is a current phenomenon in anaerobic condition of soil caused by flooding.

In this study, the effect of soil and water affected by municipal effluent on the performance of three poplar clones of Populus nigra L. after one year was investigated in a factorial experiment with two factors (1- soil and water in two levels and 2- poplar clones in three levels) based on the completely randomized design with five replications. After one year, in three poplar clones, significant increase in growth and biomass parameters of plants treated by soil and water affected by municipal effluent was observed. In three poplar clones, the significant increase of nutrients and heavy metals in organs of plants treated by soil and water affected by municipal effluent was observed. In three clones, Fe, Cu, Ni, Cr and Pb were mainly accumulated in roots, whereas Zn and Mn showed the highest concentrations in leaves. The three poplar clones did not show statistically significant differences in terms of uptake and accumulation of nutrients and heavy metals in plant organs. The effect of clone on most growth and biomass parameters was significant (p ≤ 0.01). The highest growth and biomass rates were seen in plants of P. nigra 62/154 treated by soil and water affected by municipal effluent. The results of the present study showed that for wood farming in lands affected by municipal effluent, all three poplar clones can be used by prioritizing the P. nigra 62/154 clone.

To investigate the relationship between some physical and chemical properties of soil and tree ecophysiological properties on dieback of Oak trees, 30 square sample plots with 2500 m2 area, in a random systematic grid (200×200) were selected. The percentage of dieback were measured in each sample plot and soil and leaves of trees were sampled. Some soil properties such as texture, electrical conductivity, acidity, bulk density, porosity, Carbon and organic matter and concentrations of Ca, Mg, N, P, K, Na were measured. Also, Peroxidase, Catalase and Ascorbate peroxidase enzymes, MDA, Proline, Chlorophyll a, b, total Chlorophyll, Carotenoid pigment and concentrations of Ca, Na, K, Mg, P and N in leaves were measured. Comparison of variable means showed that there is just significant difference in leaf nitrogen between different dieback classes. In general, the results of this study showed that the soil properties in our study area were not significantly affect on oak decline. On the other hand, the physiological capabilities of trees solely, cannot be the cause of their different dieback.

Salinity stress is one of the most important factors limiting the growth and expansion of plants on the planet. In the world, an area of about 800 million hectares, in Iran about 44 million hectares and in Golestan province more than 75000 hectares of its lands are affected by salinity and has poor vegetation, sparse and exclusively salinity-resistant species. The use of salinity stress-resistant tree species and increasing their yield by adding the required nutrients from different sources to the soil can be effective in establishing vegetation and optimal use of saline soils.

For this purpose, the present study was performed on one-year-old bitter olive seedlings (Melia azedarach) in a factorial experiment with two-factor as a completely randomized design. Salinity stress with irrigation water once every five days in five levels including 0, 5, 10, 15 and 20ds/m and fertilization in four levels including 0, 50, 75 and 100 g of Herbban mineral fertilizer it was applied for each seedling with five replications for 120 days. In order to reduce the adverse effects of displacement and repair of damaged roots, fertilization was performed 50 days before salinity stress. During the period of salinity stress, the rate of vitality quality and survival percentage were measured every five days and at the end of the period, 15 vegetative traits were measured. Data analysis of variance was performed using SPSS software and Duncan test was used to compare the means. Rank data were also analyzed by Kruskal and Ellis tests.

The results showed that salinity stress caused a significant decrease in vitality quality, survival, longitudinal growth, leaf area, number of leaves, average individual leaf area, specific leaf area, leaf fresh weight, leaf dry weight, fresh weight Root and leaf specific gravity increased at 5% probability level. The effect of fertilization caused a significant increase in longitudinal growth and a significant decrease in leaf specific gravity. The highest vitality quality and survival were observed in conditions without salinity stress and fertilizer application. The lowest vitality quality and survival were obtained at 20ds/m and 100 g of fertilizer. Significant increase in longitudinal growth and significant decrease in leaf specific gravity were the only significant effects of fertilization. Comparison of means did not show any difference between the mentioned traits at the control level and 5ds/m. The highest survival percentage at the end of the period at the levels of 10 and 15 ds/m were equal to 100 and 75%, respectively.

Therefore, according to the results, bitter olive easily tolerates salinity of 5ds/m and if suitable fertilizers are used with short stabilization time and high absorption percentage, it can be grown in areas with salinity of 10-15ds/m acted with different goals.

Nowadays, the oak decline is the most important challenge in the Zagros forests for the last decade. Concerning the importance of soil physical, chemical, and biological properties in the forest ecosystems performance, the impacts of oak decline on soil characteristics were studied. In spring, two declined stands and two healthy stands of Brant`s oak (Quercus brantii Lindl.) with one ha area (100×100 m) in the north and south aspects were selected and then soil samples were collected systematically from 0-10 cm depth. Next, soil texture, reaction, EC, moisture content, organic carbon, nitrogen, potassium, and phosphorus content of collected soils were analyzed. Furthermore, basal soil microbial respiration, induced soil microbial respiration, and nitrification potential were measured. The results showed that pH, organic material and carbon, and nitrogen did not have any significant difference between the declined and healthy stands. On the other hand, EC (around 28-29 %), moisture (around 3-4 times), potassium (around two times), and phosphorus (around 4-5 times) content were considerably higher in the healthy stands. Furthermore, the highest induced microbial respiration were recorded in southern (2.06) and northern healthy stands (1.67) and southern decline stand (1.38 mg CO2.100g-1.dm.h-1), respectively while we did not find any reasonable trend for basal respiration. Nitrification potential did not response to oak decline occurrence. Although soil nutrient significantly declined in response to oak decline, it can be supposed that dried leaves and branches can repair deficiency of soil organic material to some extent in the declined stands but over time, as trees weaken, soil quality will decline. Finally, monitoring of soil fauna and soil enzymes can be suggested for future research.

Fire is a big threat to natural resources in the world and is an important factor in changing the physical and chemical characteristics of the soil. The purpose of this study was to investigate the effect of fire on the physical and chemical properties of the soil in oak forest of Badreh located in 70 km of Ilam province and to compare it with unburnt (control) areas. Soil sampling carried out in two topsoil (0-5cm) and subsoil (5-20cm) depths. Five plots in 50×50m dimension designed in burnt and unburnt forests and in each plot 5 soil samples were collected randomly from topsoil and subsoil and were transferred to the laboratory to soil physical and chemical analyses. According to the results fire increased the amount of sand and silt by 15.56%, 15.18% respectively, compared with unburnt forest. But, the percentage of clay decreased under burn condition. Fire declined aggregate stability in soil 0-5 and 5-20cm depths by 10.61 and 17.81 respectively. The most CEC content (20.98 cmol/kg) and the least one (16.56 cmol/kg) was observed in unburnt forest comparison with burnt forest respectively. Burned increased soil organic carbon but by increasing soil depth decreased it. In the study area, fire affected significantly K and P available in forest soil. To sum up, fire changed soil physical and chemical properties of oak forest in Badreh region in Ilam Province as well as this phenomenon increased essential nutrient elements resulting from soil fertility improvement in the study area.

In this study, the effect of irrigation with landfill leachate on the chemicals concept of the tree branches of Populous and Fraxinus was investigated. The treatments included different concentrations of landfill leachate (0, 25, 50, 75 and 100%). The results of the interaction effect of kind of species and concentration of landfill leachate on the chemicals concept of tree branches showed that increased concentration of landfill leachate leads to increasing of the micro nutrient amounts except zinc, the amount of macro nutrients and also heavy metal of plumbum. On the other hand, the amount of iron, zinc and calcium in shoot of Populous was significantly higher than that of Fraxinus trees which was resulted from being fasting growth and high level of absorbance of populous as compared to Fraxinus. According to the results of soil analysis, it can be said that increased concentration of landfill leachate resulted in the significant increasing of the amount of phosphorus, zinc, nitrogen, ferrus and manganese in the soil. Overall, the results confirmed that utilization of landfill leachate for irrigation of trees leads to increased amount of some nutrients in the soil and shoot trees but there have been no sign of toxicity in trees until concentration of 75% of landfill leachate. So, it can be concluded that landfill leachate has potential to be used as liquid fertilizer and its heavy metal concept is tolerable for populous and fraxinus trees. With proper management it can be utilized as fertilizer for reinforcement of soil and some of tree species.

Changes in the quality of water reaching forest floor are of the most important consequences of native and exotic tree species plantations for rehabilitating the derelict areas of the Caspian forests. The aim of this study was to compare the chemical composition of throughfall in plantations of Persian maple (Acer velutinim Bioss) and Turkish Pine (Pinus brutia Ten) in Darabkola Forest, Sari. The amount of gross rainfall and throughfall were measured using six and twenty plastic collectors, respectively, from May 15, 2012 to 15 March, 2013. To compare the concentration of Potassium, Calcium, and Magnesium of the throughfall, four throughfall and rainfall samples were monthly taken from each stand. The results showed that the average of EC in growing season in Persian maple stand (170 µs/cm) was significantly higher than in Turkish pine stand (135 µs/cm) and in rainfall (55 µs/cm). Mean concentration of Potassium (Acer: 6.15, Pine 5.63 mg.l-1), Calcium (Acer: 0.53, Pine: 0.83 mg.l-1) and Magnesium (Acer: 0.59, Pine: 0.55 mg.l-1) were not significantly different between Acer and Pine stands. Mean concentration of potassium and magnesium in Persian maple stand (K: 6.15, Mg: 0.59 mg.l-1) and Turkish pine (K: 5.63, Mg: 0.55 mg.l-1) was significantly higher than the rainfall (K: 0.24, Mg: 0.32 mg.l-1). We concluded that the plantations change the water quality reaching the forest floor. It is needed to examine the effects of all endemic and exotic tree species on chemical composition of throughfall in future studies.

The aim of this study was to investigate the effect of pure and mixed stands of beech and hornbeam on soil properties, soil respiration andlitterfall rate in Sari educational-research forest of Darabkola. Ten circular plots were randomly considered in each of the three stands. Soil samples were taken at a depth of 0 - 10 cm and soil chemical and physical properties were measured. To collect litter, 10 litter traps (50 × 50 cm) were placed in the stands and the litter was collected every two months. Results showed that soil acidity, total nitrogen, sand and silt percentage and soil microbial respiration were significantly different in different stands. The studied stands showed a significant difference between the amounts of litter. According to the results, the highest and lowest amount of litter was observed in October and April, respectively.

Forest fire and leaf litter is one of the effective factors influencing soil nutrient. Fire intensity and duration can affect the properties of ash and surface soil. The aim of this study was to investigate the physio- chemical properties of ash after the heating of Aleppo oak (Quercus infectoria Oliv.) litter at various temperatures under laboratory conditions. In order to collect litter, Khavmire Abad district in Marivan forest was selected such that litter samples were taken under the crown of the 8 Aleppo oak trees. Trees were selected on a transect parallel to the contour lines, 30 m interval. Leaf litter has milled first and then the samples were prepared in four treatments (milled litter and three treatments heated at 200, 400 and 600 °C). The results showed that the color of ash was dark brown, gray and light gray in temperatures of 200, 400 and 600 °C, respectively. The amount of pH, EC, P, Ca, K and Mg increased significantly with increasing temperature, while OC and TN first increased until 200°C and then decreased significantly. The reduction of nutrient concentrations in the ash of Aleppo oak was: N> C> P> K> Mg> Ca. In sum, temperature can significantly affect the availability of nutrients in ash of Aleppo oak after heating. In addition, different temperatures had significant effects on the amount of nutrients and ash color.

In order to assess the effect of mistletoe (Loranthus europaeus) on macro (Potassium, Sodium, Phosphor) and micro (Iron and Zinc) nutrients and leaf morphological traits including leaf area, especial area, dry weight and special weight of leaves, the Acer monspessulanum species as the prevalent host of mistletoe in some parts of Vezg forests of Yasouj in Kohgilooyeh and Boyerahmad province was selected. For this purpose, seven trees infected to mistletoe, and a healthy tree near each with similar situation were selected. The leaf sampling was prepared to compare the amount of elements, from mistletoe branches, infected and healthy branches of infected trees and also perfectly healthy trees with similar sampling direction. Results showed higher amount one, Na, K, Fe and Zn nutrients in mistletoe leaves as compared with healthy and infected leaves of infected trees and healthy trees. However content of P in mistletoe leaves was less in healthy and infected leaves of infected trees and healthy trees. The Na content in infected branches of infected trees was higher in healthy branches of infected and healthy trees. The findings revealed that there were not significant differences between morphological traits of healthy and infected leaves of infected trees and healthy trees. The second major finding was that L. europaeus species disturbed the nutrients balance in the host, but could not affect the leaf morphological traits including leaf area, leaf area index, leaf dry weight, and leaf specific weight of the host trees.

Appropriate knowledge of the species ecological requirements will have an important role in the conservation and protection of the reforestation. Mobarakeh steel company created 1,500 hectares of artificial forest by non native tree species. Cupressus arizonica is one of this species. Tree species decline causing serious problems in this area. Plantation areas of this species were identified toinvestigate the causes of cypress dieback. A plot of 2000 m2 was considered in each area that planted by this species. In addition, quality and quantity characters of all trees in each plot such asdiameter, height and crown diameter and trees health were measured. The leaf samples offive healthy and unhealthy trees were collected separately for analytical measurements. The soil sampling and profiling was performed from the areas under healthy and unhealthy tree canopy in each plot. The results of this investigation showed that there are many limiting factors such as poor soil and water salinity as the main factors in reducing the absorption of micro and macro nutrients in unhealthy trees.

Decline in natural forests area due to various factors has caused the importance of plantation which is carried out with the aim of developing forest surface and wood production. Therefore, assessing the nature of plantations can play an important role in creating forests with better quality and quantity in the future. Nutritional status of habitat is an important qualitative factor in forest stand. The primary sources of nutrient elements in soil and leaf are nutrient retranslocation of old leaves. Retranslocation, movement and transfer of nutrient elements from aging leaves to tissue reservoirs occur each year, which is a key process in most ecosystems. In this study, the amount of nutrient elements (Ca, K, P, N, Mg) in summer and autumn leaves and amount of retranslocation of these elements in three plantation species (Acer, Zelkova and Pinus) of Darabkla-Mazindaran were measured. Sampling was conducted in two stages, one in mid-summer during ascending period of nutritional dynamism of trees, and the second stage in mid-autumn simultaneously with the beginning time of leaf fall in the same trees previously sampled. Results showed that there is difference between nutrient elements in summer and autumn leaves in the studied species. The magnitude of nutrient retranslocation was obtained in order of: P>Ca>N>Mg>K. Among the studied species, the highest retranslocation of Ca and Mg were determined in Acer, N and K in Zelkova and P in Pinus. The results of this study showed that the studied species had different nutritional elements and also different amounts of element retranslocation. Since the studied species had been raised under similar conditions, therefore it could be concluded that these differences are due to genetic variation of species.

Arbuscular mycorrhizas fungi (AM) are the most important microorganisms of soil having an important role in soil fertility. The symbiosis rate between AM and plants are different based on specific physiological characteristics and morphological root characteristics. Thirty individuals of Acer cinerascens grown in natural habitats located at Bazoft, Chaharmahal-o-Bakhtiari, the western forests of Iran, were chosen. Roots were sampled during spring and autumn to find out the interactions between arbuscular mycorrhizal and soil elements. Arbuscular mycorrhizal fungi were isolated and characterized by wet sieve. Then roots were stained and colonization percentage was measured. Four species of Glomus and one species of Acaulospora were identified. Significant difference was found between arbuscular mycorrhizal colonization percentage and spore frequency in spring and autumn. Significant correlation was observed between colonization percentage and availability of potassium in spring.