Abstract. Knowledge of the evolution of arboreal forests is necessary to interpret the cause of climate formation in intracontinental regions. Paleoproxy records of sediment cores from Lake Hovsgol, Mongolia show that watershed conditions have fluctuated widely during the last 30 ka because of changing orbital parameters. Termination of glacial cooling and the subsequent prevalence of deglacial warming were consequences of solar forcing. Arboreal forests exerted an important influence on the atmospheric moisture cycle at high latitudes. Air pressure decreased because of raised humidity from water vapor penetration into inland regions that occurred along with summer monsoons. Data showing utilization of solar energy are necessary for establishing climate conditions. Atmospheric warming under increased insolation caused a shift of the monsoon limit to the north, amplifying the summer moisture supply to the watershed. That amplification engendered the appearance of the maximum vegetation in the Hovsgol drainage basin at the beginning of the Holocene. The retreat of arboreal forests that occurred along with decreased solar energy shrank the humidification-vegetation feedback loop, thereby decreasing the atmospheric humidity. The consequently lowered vapor pressure contributed to the incursion of cool air masses from the north.