Little change in the fir tree-line position on the southeastern Tibetan Plateau after 200 years of warming

• Published in: The New phytologist Vol. 190; no. 3; pp. 760 - 769
• Main Authors: Liang, Eryuan, Wang, Yafeng, Eckstein, Dieter, Luo, Tianxiang
• Format: Journal Article
• Language: English
• Published: Oxford, UK John Wiley & Sons 01-05-2011; Blackwell Publishing Ltd; Wiley Subscription Services, Inc
• Subjects: Abies - anatomy & histology; Abies - growth & development; Abies - physiology; Abies georgei smithii; Abies georgei var. smithii; Age structure; Climate change; Dendrochronology; dendroecology; Dynamics; Ecosystem; Ecotones; Forest ecology; Geography; Global warming; Habitat selection; Plateaus; Population density; Population Dynamics; Population ecology; Recruitment; Regeneration; Regeneration (biological); Regeneration - physiology; Seasons; Seedlings; southeastern Tibetan Plateau; Temperature; Tibet; Timberlines; Time Factors; Tree age; Trees; Trees - growth & development; tree‐line dynamics; Tibet; Tibetan Plateau
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2010.03623.x

As one of the world's highest natural tree lines, the Smith fir (Abies georgei var. smithii) tree line on the southeastern Tibetan Plateau is expected to vary as a function of climate warming. However, the spatial patterns and dynamics of the Smith fir tree line are not yet well understood. Three rectangular plots (30 m × 150 m) were established in the natural alpine tree-line ecotone on two north-facing (Plot N1, 4390 m asl; Plot N2, 4380 m asl) and one east-facing (Plot E1, 4360 m asl) slope. Dendroecological methods were used to monitor the tree-line patterns and dynamics over a 50-yr interval. The three study plots showed a similar pattern of regeneration dynamics, characterized by increased recruitment after the 1950s and an abrupt increase in the 1970s. Smith fir recruitment was significantly positively correlated with both summer and winter temperatures. However, Smith fir tree lines do not show a significant upward movement, despite warming on the Tibetan Plateau. The warming in the past 200 yr is already having a significant impact on the population density of the trees, but not on the position of the Smith fir tree line.