irano-turanian

Aiming to understand the habitat conditions of Prunus chorassanica (Pojark.) A.E.Murray as an endemic shrub species of Iran, this study was conducted in Khorasan Razavi Province. To measure the canopy coverage percentage and density of plant species in the three studied sites located in Dargaz County, three transects of 100 meters were established. Along each transect, a 5 m2 plot was established every ten meters and sampling was done by systematic random method. Also, the ecological conditions of the species growth and distribution; including climate, topography and edaphic characteristics of the sites were investigated. The canopy cover of P. chorassanica in the three studied sites were 7.87 to 11.7% and the density were between 50 to 75 tree per ha. In the shrub's sites, 34, 38.5 and 27.5% of the soil was sand, silt and clay and the desired soil texture was loam. The average pH and electrical conductivity of the soil are equal to 7.73 and 0.8 dS/m, respectively. This species grows and spreads in altitudes above 2000 meters and on slopes between 30 and 55%, generally in the northern direction. Considering the value of this species, in the form of action for protection outside the main site, it is necessary to collect the seeds of this species and store them in the Iran's Natural Resources Gene Bank. Also, it should be planted in the National Botanical Garden of Iran so that, if necessary, it is possible to revive its population in nature.

Species selection and suitable planting methods are essential for creating plantation and green space. This is important specially in arid and semi-arid regions. The object of the present study was to investigate the growth and primary establishment of four tree species using four different soil remediation treatments in Semnan City. These treatments were applied to two-years-old saplings in three replications and five observations in each replication and the quantitative and qualitative characteristics of saplings were measured and recorded during the experimental period. The results showed that straw mulch (together with stone cover) caused the highest collar growth in all investigated species, while the usage of hydrogels and zeolites did not have a significant positive effect on the sapling growth and decreased the growth in some cases. Compared to control soil (sandy-loam), the modified soil texture treatment (loam soil) did not change the collar diameter, height and total length of lateral branches of Melia and Cupressus saplings, but it reduced the diameter growth in Pistacia and Quercus saplings. The highest rate of survival in all investigated species was observed in control and straw treatments. The results of this study showed that Pistacia and Melia had the highest and lowest survival rate, respectively. However, Melia had the highest height and collar diameter growth amongst investigated species with maximum growth under straw treatment. Contrasting other species, Quercus has experienced a significant decrease in collar diameter and height (in all treatments specially hydrogels and zeolites) after June and has progressed to shrub form.