Different responses of radial growth to climate warming in <I>Pinus koraiensis</I> and <I>Picea jezoensis</I> var. <I>komarovii</I> at their upper elevational limits in Changbai Mountain, China

Abstract

Aims Temperature is generally considered the limiting factor for tree growth at species' upper elevational limits. Our objectives were to determine the upper elevational limit response of radial growth in Pinus koraiensis and Picea jezoensis var. komarovii to climate warming in Changbai Mountain Nature Reserve of China and to eluci- date temperature sensitivity of radial growth. Methods We selected typical trees at each species' upper limit for increment coring and established ring-width chronologies for both species. We compared the general trend of the chronologies with temperatures during 1958-2006. To determine species' response to rising temperature, we analyzed the relationship between chronol- ogy and important meteorological factors (temperature, precipitation, growing season length, effective accumula- tive temperature, etc.) using correlation, response function, moving correlation and pointing year analyses. Important findings As temperature rose, ring widths in Pinus koraiensis exhibited the same increasing trend as temperature, while ring widths in Picea jezoensis var. komarovii exhibited decreasing sensitivity to temperature. The increase of temperature and precipitation in the growing season mutually enhance Pinus koraiensis growth. Prolongation of the growing season and rising temperature during the growing season also can accelerate the growth of Pinus koraiensis. For Picea jezoensis var. komarovii, water stress caused by increasing temperature is the main reason for its relationship between ring width and temperature. Correlations between Picea jezoensis var. komarovii ring width and almost all temperature indices are significantly negative. As temperature rose, correla- tions between ring width and precipitation, especially spring precipitation, changed from negative to positive. High temperature in each month and inadequate precipitation in the middle and late growing season are the im- portant meteorology conditions for narrow rings. Also, the insignificant extension of the growing season may