An analysis is made of the geobotanical forecasting technique. Mapping is known to be recognized as the most powerful method of forecasting-geobotanical investigations. A close interrelation between geobotanical forecasting and vegetation mapping is demonstrated. To improve objectivity of the findings used cartographic models of modern and predicted vegetation which most fully represent the entire structural-cenotic diversity of plant communities in Prebaikalia, the central region of Baikalian Siberia. The predictive constructions are based on analyzing modern vegetation which always includes structural features of its future that manifest themselves in primary and stable secondary communities. We developed the legend and compiled the map (sc 1:200 000) of the region’s modern vegetation. The state of the natural environment of the Lena-Angara interfluve is assessed having regard to the various functions of plant communities in geosystems. The 1:200 000 map of probability-predictive (within 200 years) vegetation is presented for Lena-Angara interfluve. It is shown that complete recovery of the primary structure will not occur within 200 years. It is found that it is necessary to carry out predictive-cartographic investigations for the whole of Baikalian Siberia as vegetation of this region is characterized by a decreased activity of recovery processes occurring under the influence of anthropogenic factors. The reason has to do with the harsh natural conditions where it is not worthwhile to pursue extensive nature management, such as is universally the case to date, leading to undesirable economic consequences, because the degree of disturbance to vegetation in a number of areas of Prebaikalia has now reached as critical level. It is concluded that a further policy of nature management on this territory must be built upon the new principles to be approved by government documents.Keywords: vegetation mapping, ecology, natural environment of Prebaikalia, functional organization of vegetation, predictive map.