Anomalies of Birch (Betula) Branching in Protective Forest Belts of Highways

Abstract

A wide range of pollutants can reflect adversely on species of wild flora. Woody species actively accumulate pollutants formed as a result of anthropogenic activities. Birch as a widespread species in protection plantations of highways undergoes a high load. The research purpose is a comparative analysis of morphology of silver birch and its hybrid forms, which suffer from environmental pollution from vehicle emissions; as well as classification of parameters that are not usual for the accepted taxonomic description of the species. Modifications of vegetative organs of silver birch were found along the Nizhny Novgorod - Moscow highway during the research. Morphology of parts and organs of the birch has changed due to the environmental conditions unusual for this species; various morphoses and modifications have appeared. Marked changes in the form of increased whorled shoots, variations in the shape and morphology of leaf laminas, and an increase in thickness and structure of cover tissues were noted. It was found that modified parameters occur according to patterns that depend on the remoteness of plants from the pollution source and the spatial location of their vegetative parts and organs. The revealed regularities can be used in selection of birch resistant to chemical pollution, as well as in improvement of dendroindication methods.