Study of Nutrient Uptake Status of Tree Species in a number of parks in Tehran

The decline of natural forests has been caused urban afforestation to acquire a particular importance with the purpose of green space development level, therefore, the selection of appropriate plant species plays a substantial role in the development and stability of urban green space. The nutrients evaluation is significant in in selection of appropriate species for planting and in a way that species can be selected and supplemented by either consumption of the whole available nutrients in habitat or with their accompanying species.

The present study was conducted to evaluate the high consumption nutrients (Nitrogen, Phosphorus, Calcium, Carbon, Magnesium and Potassium) in the leaves of Mulberry, Ash, Tehran Eldarica Pine and Arizona Cypress in two summer and autumn seasons in four geographical areas (Jamshidieh Park, Sorkheh Hesar Park, Vard Avard Park and Shaghayegh Park) in Tehran. Also, retranslocation of nutrients was measured in four parks and three species (Mulberry, Ash and Tehran Eldarica Pine). At the end of the growing season, the mature green leaves (80 samples) and at the end of the autumn season, the fallen leaves (60 samples) were collected at the base of the tree and packed in zippered bags with the desired specifications on them and transferred to the laboratory. The leaves were washed with sterile distilled water to remove contaminants, then dried in an oven at 70 ° C for 24 hours and then ground. Chemical analyzes were performed using standard instructions. Statistical analyzes such as general comparison of means (one-way analysis of variance) and group means (Duncan test) were performed.

The results of this study showed that the average nutrients in summer leaves are higher than autumn leaves. In Sorkheh Hesar, Shaghayegh and Jamshidieh parks, in summer leaves, the highest amounts of nutrients related to calcium (62.66 mg/g in Shaghayegh Park) and in Alder was recorded. While in Vard Avard Park, the highest amount of this element was observed in mulberry (68.32 mg/g). In autumn leaves, in three parks of Shaghayegh, Jamshidieh and Vard Avard, the highest concentration of nutrients related to calcium (42.66 mg/g in Shaghayegh Park) and was recorded in mulberry. While in Sorkheh Hesar Park, calcium concentration was recorded in Alder (50.66 mg/g). Regarding the percentage of nutrient retranslocation in the studied species in Sorkheh Hesar Park Magnesium (63.04%) in Alder, in Shaghayegh Park Potassium (52.58%) in Mulberry, in Jamshidieh Park Potassium (63.79%) in Tehran Eldarica pine and in Vard Avard Park calcium (41.45%) in mulberry had the highest nutrient retranslocation.

The species studied in this study had different nutrients in their summer and autumn leaves. These species also retranslocation a different amount of each element. It is suggested that this issue be taken into consideration in the management and planning of urban forestry, and the tree species used, which are mainly the main tree species in urban forestry, should be classified based on the status of nutrients.