The paper deals with the results of the palinological study of cultural stratifications of the multilayer Birsk settlement. 13 samples for pollen-spore analysis were taken from the reopened wall of the 1978 excavation. As a result of the analysis, a column of data characterizing the change in vegetation during the existing of the settlement is obtained. Three climatic periods for the Belaya region during the transition from the bronze age to the early iron age are distinguished by the authors – two periods of humidification and two periods of drying climate. By analyzing materials of the settlement the authors managed to date the first stage of humidity of the XII–IX centuries BC. The second period of humidification is dated within the VII–V centuries BC. Brief period of climate aridization is referred to the time from the turn of IX–VIII centuries BC to the turn of VIII–VII centuries BC.