Pollution from the Automobile Transport Influencing Biochemical and Morphological Condition Indicators of Oak Trees

The automobile transport affects the biochemical and morphological indicators of the trees state in urban stands. On the example of 28 oak trees growing in places with different levels of traffic pollution (10–30 m from the Moscow Ring Road and Uzkoye forest park, Moscow), a comprehensive analysis of their morphological parameters was carried out and the content of proline, macroelements and heavy metals in leaves and branches of trees of different age groups (old age >100 years old, young 15–20 years old) was determined. Soil samples have been taken layer by layer up to a depth of 1 m within a radius of no more than 2 m from the tree, and the total content of Mg, P, K, Ca, Fe, Cu, Zn, Pb, as well as the the content of mobile forms of Zn, Cu, Pb, Fe (acetate-ammonium extract) and the concentration of Ca2+, Mg2+, Cl–, Na+, ions in the aqueous extract has been measured. In accordance with the forestry scale of the trees’ sanitary state categories and the growth and development classification of the Q. robur crowns, the trees under study were assigned to three life state groups: The worst (group 1), average (group 2), and the best (group 3). Close values of the heavy metals concentration were found in the branches of 100-year-old and 10–15-year-old trees belonging to the group of the worst life state. Concentrations of Zn, Fe, Ca, and S in tree branches had close negative correlations with the state of tree vitality (the group number); for leaves, these correlations were less obvious or completely absent. Concentrations of K and P in tree branches positively correlated with indicators of their vital state, while in leaves this type of connection was not revealed. A close negative correlation was found between the concentration of Zn, Fe, Ca, and S and the concentration of P and K in tree branches, and positive in leaves. An increase in the concentration of K and P in leaves in response to an increase in the concentration of pollutants in them is one of the mechanisms of the assimilation apparatus protection from the automobile transport impact. © 2021, Izdatel'stvo Nauka. All rights reserved