The Conceptual Model of Dendroflora Introduction in the Northern Latitudes of the Russian Plain

The increasing of the socio-aesthetic significance of urban green spaces, especially in the formation of a rigid urbanized human habitat, initiates the development of the theoretical foundations of stepwise introduction in the northern direction. The aim of the research has been to generalize the regional features of the introduction of dendroflora species in the conditions of the European North of Russia. The methodological basis has been the works of specialists in the field of forest introduction, including Northern introducers F.B. Orlov, P.M. Malakhovets, V.N. Nilov, N.A. Demidova, O.S. Zalyvskaya, E.B. Karbasnikova et al. The results of the research have both theoretical and practical significance and are an integral part of the general theory of step-by-step introduction in the northern direction. In the process of many years of research and generalization of the experience of spontaneous introduction, an original working hypothesis of the stepwise introduction of woody plants in northern natural and climatic conditions has been formed and developed: for the urban environment, the presence of a special microclimate (heat island) is generally recognized and this microclimatic resource is sufficient for the successful naturalization of some species of dendroflora despite the introduction stress. The results of the work of the oldest introduction centres in the European North are briefly described. An algorithm and a regional strategy for the development of research of the introduction process of dendroflora species in the conditions of the North are presented. A conceptual scheme for the introduction testing of dendroflora species in the conditions of the northern latitudes of the Russian Plain has been proposed. There are 4 stages of acclimatization and 3 stages of naturalization. A number of scales have been developed that contribute to the improvement and optimization of introduction tests, and the assessment of sanitary, hygienic and social functions performed by introduced species of dendroflora. The richness of species diversity of urban dendroflora, new to northern conditions, is a good breeding base for further introduction tests and a scientific basis for predicting the success of the stepwise introduction of many valuable woody and shrub species to northern latitudes.