The vegetation of Changbai Mountain, located in the heartland of temperate coniferous and broad-leaved mixed forest, is subject to climate change. Using the basic principles and methods of dendrochronology, and Pinus koraiensis growing on northern slopes of Changbai Mountain as objects, objectives of this work were to: (1) study the variation of tree-ring width of P. koraiensis to better understand the response of the forest ecosystem to climate change; (2) establish chronologies of P. koraiensis, correlation, and response functions with monthly climatic factors, and calculate the average biomass growth in successive years; and (3) establish regression equations for tree-ring index and the average annual biomass increment of P. koraiensis. The main conclusions are: (1) Growth of P. koraiensis was sensitive to climatic factors according to the analysis of chronology, which is suitable for dendroclimatological study. (2) Radial growth of P. koraiensis was mainly affected by the temperature of the early growing season. Radial growth was more strongly correlated to temperature than to precipitation. (3) Temperature was the main factor limiting growth, which indicated that climate warming might accelerate tree growth. (4) At present, the aboveground biomass of P. koraiensis growing on northern slopes of Changbai Mountain is 310.88 t ha^-1, with an increasing rate of 5.077 t hm^-2 a^-1 or 2.539 t carbon, indicating that the old-growth forest of P. koraiensis in the region still has a strong potential for carbon sequestration."