Features of Growth and Design of Protective Forests Plantings Along Highways of the South of Russia

Protective forest plantations along highways are an integral element and one of the important factors of road safety. The main units of such plantings are tree and shrub species, which in turn form a stand capable of performing useful protective functions. The protective forest stands along highways in Southern Russia were studied on the example of the objects that grow along the M-4 Don highway 30 km from Rostov-on-Don. The forest taxation indices of 18 species of tree and shrub species that form linear plantings were studied. The main tree species in the plantings are: Robinia false acacia, lanceolate ash, small-leaved elm, holly maple, three-pronged gledichia. The main shrubs are: svidina blood red and sumac leather. When designing roadside forest stands, great importance should be given to the initial variant of mixing tree and shrub species. It is not allowed to mix the tree species with different life periods in plantings, as this leads to difficulties in carrying out subsequent forestry care. Thus, the participation of black poplar or pyramidal poplar in plantings with the participation of sharp-leaved maple is unacceptable. The life span of woody plants should be in the same period. The conducted research allowed recommending the optimal mixing schemes for the creation of new protective forest plantations along the highways of Southern Russia.