Shifts in the Climate Sensitivity of Tree Ring Growth in the Mountainous Regions of Northern China Through the 20th Century.

Ongoing climate change poses a major threat to forest growth, which in turn accelerates the rate of land degradation. Given the high sensitivity of mountain forests to climate, there is an urgent need for more detailed studies on the dynamics of montane forests affected by climate change. For this study, we selected 20 tree ring width chronologies in the mountainous regions of Northern China, and investigated the responses of tree growth to climate change in the 20th century. The results indicated that the tree growth trends shifted in 1953 in the mountainous regions of Northern China. The tree growth rates exhibited an increasing trend during 1900–1953 (first stage) followed by a significant decreasing trend from 1954 to 2000 (second stage). The temperature exhibited a continuing increasing trend, while precipitation showed an increase and then decrease in two stages, in tandem with the standardized precipitation evapotranspiration index (SPEI). Initially, rising temperatures positively influenced tree radial growth. However, after 1953, continued warming inhibited tree growth, with trees being increasingly constrained by the availability of water (precipitation and SPEI), particularly during the annual growing season. Our findings emphasized that climate warming and drought have been the main causes of tree growth declines in recent decades, which underscores the susceptibility of montane forest ecosystems to warming‐induced water deficits. Our findings can facilitate the conservation of forest ecosystems, reduce land degradation, increase forest cover, as well as gradually improve the regional environment. [ABSTRACT FROM AUTHOR]