Abstract
The effects of temperature and precipitation on the formation of annual rings in stem wood of Siberian larch in ecotopes with optimal, insufficient, and excessive soil moistening are discussed. It is shown that precipitation fallen in the period from April to June, when the needles are formed, has a favorable effect on xylem increment. This relationship is better manifested in trees growing under conditions of insufficient soil moistening. In all types of ecotopes, a positive correlation between the annual ring width and warm and dry weather in July has been observed.