The article proposes a methodology for carrying out works aimed at developing a unified forest–seed zoning of the territory of Ukraine, which should ensure the genetic conservation of tree species, effective protection of the most valuable populations from the penetration of alien genetic material, enrichment of the gene pool of less valuable populations due to artificially regulated influx of genes from the most valuable populations. The theoretical basis for the development of forest–seed zoning is the natural intraspecific variability of tree species, formed in the process of evolution as a result of adaptation of local populations to the conditions of their habitat under the influence of natural selection. The differentiation of individual units of forest–seed zoning is based on the scheme of previously developed physico–geographical zoning of the territory of Ukraine.