The extreme drought in the 1920s and its effect on tree growth deduced from tree ring analysis: a case study in North China

Using tree-ring analysis coupled with historical records, we investigated the possibility of developing a tree-ring network in North China, and the possible disturbance for the dieback of Meyer spruce (Picea meyeri) forest in typical steppe. Four tree-ring chronologies were employed: one for Meyer spruce and Korean spruce (Picea koraiensis) in eastern Inner Mongolia, and two for Chinese pine (Pinus tabulaeformis) in central Inner Mongolia. Significant parallel behaviour between the chronologies revealed the possibility of developing a large-scale tree-ring network in North China. In addition, the coincident growth decline in the 1920s in Chinese pine and Korean spruce chronologies revealed the most severe drought period for more than 200 years in North China, which was confirmed by converging lines of historical events. A clear correspondence between a peak in the age distribution (1933-1935) and a persistent drought event from 1922 to 1932 implied that the extreme drought in the 1920s was probably the underlying cause of Meyer spruce mortality