Climate sensitivity of purple cone spruce (Picea purpurea) across an altitudinal gradient on the eastern Tibetan Plateau

• Published in: Dendrochronologia (Verona) Vol. 56; p. 125586
• Main Authors: Zhao, Zhijiang, Kang, Dongwei, Guo, Wenxia, Zhao, Lianjun, Cui, Li, Li, Junqing
• Format: Journal Article
• Language: English
• Published: Elsevier GmbH 01.08.2019
• Subjects: Altitude gradient; Picea purpurea; Radial growth; Tree-ring chronology; Wanglang Nature Reserve; Tree-ring chronology; Picea purpurea; Altitude gradient; Wanglang Nature Reserve; Radial growth
• ISSN: 1125-7865; 1612-0051
• DOI: 10.1016/j.dendro.2019.03.006

Picea purpurea (Purple cone spruce) is a dominant and widely distributed tree species in the subalpine area of the Wanglang Nature Reserve. We investigated variations in radial growth and its response to climate in P. purpurea along an altitudinal gradient. In this study, P. purpurea chronologies were developed from three altitudinal sites ranging from 2850 to 3250 m above sea level. Correlation analysis and principal component analysis were used for all the chronologies to detect the growth patterns at different altitudes. Correlation analysis was used to assess the relationships between chronologies and climatic factors. Tree-ring widths among the three elevations were all positively correlated with June maximum temperature in the current year. Radial growth at the higher altitude was more sensitive to temperature than those of the two lower altitudes. Ring-widths at the low and middle sites were mainly negatively affected by temperatures in the previous growing season (June and August). Spruce growth at the upper site was strongly positively affected by temperatures in the previous winter, the current spring and current growing season. Climatological analysis revealed that elevation-dependent and elevation-independent signals were present in this semi-humid subalpine area. Precipitation was not the main factor affecting the tree growth in the growing season throughout the study area. The noteworthy findings were that the lag effects of temperatures to spruce growth was more significant at the low and middle altitude sites, and spruce growth at the high altitude site clearly benefited from the warmer climate before and during the growing season. This study will provide a basis for better predicting forest dynamics and carrying out vegetation restoration in the future.