Warming-induced unprecedented high-elevation forest growth over the monsoonal Tibetan Plateau

Abstract

Growth of high-elevation forests is generally temperature-limited and thus sensitive to warming. The Tibetan Plateau has experienced fast warming rates associated with decreased summer monsoon rainfall over the last century. However, whether such warming and monsoon-induced drought could offset a potential warming-driven enhancement of forest growth has not been examined. Here, we have compiled high-elevation forest growth data at 40 sites over the monsoonal Tibetan Plateau (MTP), and combined them in a high-elevation forest growth index (HEFGI) spanning 1567-2010. Tree growth in this region was significantly and positively correlated with July-October minimum temperatures during 1950-2010 (R2 = 0.53 P < 0.001), and insignificantly coherent with soil moisture and precipitation. The HEFGI of MTP reaches its highest values from the 2000s onwards. This result suggests that the mean HEFGI of MTP has not been negatively affected by the current drying trend and responded positively to increased temperatures.