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Scattered Greek juniper (Juniperus excelsa M. Bieb.) trees have ecological values, such as soil protection and soil erosion reduction in the Irano-Turanian region; however, intensive exploitation puts their habitats at risk. Therefore, knowing the soil characteristics of these habitats plays an important role in their management. The aim of this study was to investigate the soil quality of semi-arid woodlands dominated by a pure Juniperus excelsa community. At three sites in the Irano-Turanian region, soil samples were randomly taken from a depth of 0-20 cm in the eastern direction under the crowns of Greek juniper trees and from bare soil. The evaluated physical properties included bulk density (Bd), moisture, sand percentage, silt percentage and clay. Chemical properties included pH, electrical conductivity (EC), organic carbon (SOC), total nitrogen (TN), and nutrient concentrations of bare soil compared to the below-crown soil. Additionally, we investigated basal respiration (BR) and microbial biomass carbon (MBC) to evaluate the influence of Greek juniper trees on soil microbial activity. The bulk density value in samples taken under crowns was significantly lower by 42% compared to bare soil; however, significantly higher soil moisture (+39.8%) was obtained under tree crowns. Although clay and sand content under tree crowns was significantly higher than that of bare soil, sand content under tree crowns was significantly lower than in bare soil. According to our findings, soil pH under tree crowns and in bare soil was 7.13, which increased to 7.67 in bare soil. Soil EC (+15%), SOC (+76%), and TN (+29%) were significantly higher under tree crowns. The concentrations of magnesium and sodium were similar between bare and below-crown soils, but significantly higher phosphorus (+46%), potassium (+41%), calcium (+31.1%), iron (43.3), and zinc (+56.6%) were observed under Greek juniper crowns. Soil microbial activity was higher under tree crowns compared to bare soil, as evidenced by significantly increased BR (+49.1%) and MBC (+43.5%). Our findings indicate that scattered Greek juniper trees can improve soil properties, and their destruction leads to a significant decrease in soil quality. Generally, planting Greek juniper seedlings in degraded areas can help restore the soil quality.

A quantitative method is presented to evaluate the ability of plants for rill and gully erosion control in the Moghan region in the province of Ardabil. This research was carried out during a five-year period (2016-2020). Five indicators, namely, stem density (SD), topsoil erosion-reducing potential of plant roots during the concentrated flow erosion (RSD), sediment obstruction potential (SOP), index of plant stiffness (MEI), and root cohesion (Cr) were calculated for 20 native plants of the region (SD=1.411×10-4 – 0.28, RSD=6.68×10-24 – 10.1076, SOP=8.275×10-5 – 0.696, MEI=1.69×10-6 – 27.134 N, Cr=5.432×10-4 – 34.626 Pa). Tamarix ramosissima Ledeb., Salsola dendroides Pall.,Artemisia fragrans Willd., Stipa arabica Trin. & Rupr. var. arabica, Alhagi camelorum Fisch., Verbascum stachydifome Boiss. & Buhse., Festuca ovina L., and Melica altissima L. are very appropriate species for controlling rill and gully erosion. Festuca ovina L., Stipa arabica Trin. & Rupr. var. arabica and Melica altissima L.have a distinct potential to obstruct sediment inflow into channels at the gully outlets. As each species has a particular ability in one or more of the indices, combined planting of selected plant species may be more effective in erosion control. The results of this study may be used in adjacent regions and under similar cold-semiarid and cold-arid environments.

Caucasian whortleberry (Vaccinium arctostaphylos) is one of the most valuable medicinal shrubs in beech Forests. This study aimed at determining the relationship between vegetation properties of whortleberry with soil and landform index in Soha forest. Sample plots, each 500 m2, were selectively established in three land forms (ridge, valley and hillside) and in four geographical directions (north, south, east and west) from lower to higher distribution areas. Overall, 24 sample plots were used to measure the vegetative characteristics. Soil characteristics including soil texture (clay, silt and sand), pH, Ec, total nitrogen, soil organic carbon and calcium carbonate were also studied in 12 sample plots. The results showed that Caucasian whortleberry distribution varies from 1570 to 1940 meter above sea level. In general, hillsides and ridge forms with south and west-facing hillsides are suitable sites for this species. The highest mean of height (2.19 m), collar diameter (8.7 cm) and crown diameter (1.92 m) were observed on slope land form. The soil of whortleberry habitats is deep to semi-shallow with pH (5.32 to 6.01), electrical conductivity (0.481 to 0.809 ds/m) and with soil texture loam to sandy- loam. The PCA analysis showed that the physical properties of soil (sand, clay and silt), pH, and soil organic carbon content have important impacts on the presence of this species. From the results of this study, it can be concluded that habitats of Caucasian whortleberry in land forms valley and hillside, and aspects of north and east with light soil texture have created favorable conditions for the growth of this species in the study area.

This research carried out to quantification of juniper stands structure in Kandragak region. For this purpose, three one-hectare study area were selected and the full calipering and the nearest neighbor’s methods were used to quantification of stand structure. Some indices including mingling index, distance to nearest neighbors, Clarke and Evans, and uniform angle and dimensional differences were employed to quantification of the stand structure. Results indicated the mean of DBH and crown coverage were 13.2 cm and 8.7 m2, respectively. Results showed mean value of Clarke and Evans and uniform angle indices was 1.05 and 0.45, respectively that revealed clumped or random distribution of juniper trees. The mean of mingling index calculated 0.14 among three study area showed low tendency of juniper to mix with other tree species. The mean value of distance to the neighbors was 3.70 meter and the height and diameter differentiation were 0.16 and 0.23, respectively. According to findings juniper in the natural habitats tends to be fairly pure in species composition and have slightly heterogeneous diameter distributions and uniform tree height. Accordingly, in the decision making and planning strategies, maintaining the natural structure and spatial pattern of trees have to be sufficiently considered.

Mycorrhizal fungi form mutualistic symbioses with the roots of 80% of plants which increase growth and nutrient uptake for the host plants. This research was conducted to determine the effect of individual Glomus intraradices Schenck & Smith and Trichoderma harzianum Rifai species on the root colonization, biomass allocation, physiological characteristics and nutrient uptake of hazelnut (Corylus avellana Linnaeus) seedlings in the nursery. The results showed that both G. intraradices and T. harzianum improved biomass, physiological characteristics and nutrient uptake of hazelnut seedlings as well as simultaneous root colonization. However, the growth rate for G. intraradices treatment was significantly higher than that for T. harzianum treatment. The highest leaf dry mass (2.66 g), root dry mass (3.39 g), root volume (11.31 cm3), total plant dry weight (11.20 g) were detected in seedlings inoculated with G. intraradices. Inoculation with G. intraradices and T. harzianum increased net photosynthesis (64 and 26%), stomatal conductance (66.1 and 31.4%) and water use efficiency (50 and 22%). Both G. intraradices and T. harzianum showed increased nutrient accumulation. The G. intraradices treatment resulted in the most efficient nutrient absorption with increases of 58.4% (N), 85.2% (P) and 83.2% (K) in plants. It can be deduced that although G. intraradices in comparison with T. harzianum more favourably affected the growth and leaf gas exchange as well as nutrient uptake of hazelnut seedlings, it can be suggested that the inoculation of hazelnut roots with both arbuscular mycorrhizal fungi is a proper measure to produce the healthy and strong seedlings of this species in the nursery.

Wild pistachio (Pistacia atlantica F&M.) trees grow in many arid and semi- arid areas of Iran including Khalkhal rigion in Ardabil province. In order to recognize the site demands of this species in Khalkhal forests, six sites (Bane Khalkhal, Kandarag, Mazrae, Nodeh, Jafarabad and Nimehil) were selected and soil properties, climatic data, topoghaphy and growth of wild pistachio were surveyed. Totally, 109 sample plots, each 400m2 with selective sampling method were established. In each sample plot qualitatives and quntitatives characteristics including number of tree, total height, diameter at breast height, basal area, trunk height and crown diameter were recorded. Results showed that wild pistachio is distributed on sites between 760m and 1880 m.a.s.l. with 320mm to 440mm annual precipitation and mean annul temperature between 10.2 ˚C and 17.1 ˚C. The soil of pistachio habitats is shallow, with pH between 7.4 and 8.1, and EC between 0.21 d.s/m and 0.39 d.s/m . Six vegatation types of pure Pistacia, Juniperus-Acer with Pistacia, Rhamnus-Juniperus with Pistacia, Rhamnus-Pistacia, Pistacia-Amygdalus with Paliurus and Juniperus-Pistacia with Amygdalus were recognized. The results of inventory showed that mean dbh of wild pistachio trees varies between 14.6cm in Mazrae and 4.6cm in Nimehil. The mean crown diameter and mean height of trees were calculated of 2.48m and 2.9m, respectively.

Phenological characteristics of Pistacia atlantica Desf subsp. Mutica (F. & M.) Rech were investigated at two different sites of Khalkhal Forests (Mazrae and Kandiragh) at two altitudes (1450 and 1650 m.a.s.l) and one aspect (south), during the years of 2001 to 2003. For this study, 30 trees at each site were selected and registered. The study started at March (beginning of the growing season) and ended at full leaf fall of each year. Every 7-10 days, the phenological characteristics were measured as date of budding, date of leaf formation, flowering, fruiting, fruit ripening and leaf fall. Statistical analaysis was done by compound analysis of variance method. Results showed that date of budding is between 3rd and 4th week of April, flowering between 4th week of April and 1st week of May, fruit set between 2nd and 3rd week of May, fruit ripening between 4th week of October and 1st week of November and leaf fall between 1st and 2nd week of December. The statistical analysis showed that there were significant differences beween the phenological characteristics and two altitudes. There was significant negative correlations between average rainfall and date of budding and flowering.