Increased sensitivity of Dahurian larch radial growth to summer temperature with the rapid warming in Northeast China

Abstract

Temperature increase would benefit tree radial growth in the high latitude permafrost zone due to the increment of the thaw depth of permafrost. Tree rings from temperature-limited regions are highly sensitive to temperature variations. Seven Dahurian larch (Larix gmelinii Rupr.) tree-ring width chronologies sampled at the permafrost zone in western Great Xing’an Mountain, Northeast China, were developed to investigate regional larch growth. A regional larch growth record was produced using the first principal component (PC1) of a principal components analysis. PC1 accounted for 65.6 % of the total variance. Regional larch growth was mainly limited by summer temperatures in this region. The temporal variations in the linear trend of average summer temperature were calculated at 30-year intervals. A significant increase trend (P < 0.05) was found in average summer temperature after the 1971–2000 period, indicating that temperature started to increase rapidly after the 1971–2000 period; there was no obvious trend before that period. Moreover, the relationship between tree radial growth and temperature intensified since the 1969–1998 period. Thaw depth also started to show significant influences on the tree radial growth after the 1969–1998 period where rapid warming accelerated the thaw of permafrost and benefited tree radial growth. Tree radial growth was more sensitive to temperature after the rapid warming because of changes in the moisture availability caused by the permafrost thaw. From these results, it appears that an increase in temperature would benefit tree radial growth in the high latitude permafrost zone by increasing the thaw depth of permafrost.