The past 200 years witness obvious warming on the Tibetan Plateau. Recent research by ITP Prof. LIANG Eryuan and his colleagues, however, finds little change in the fir tree ring position on Mt Sygera, southeast Tibetan plateau, despite the warming.

Their research tends to unravel the spatial patterns and dynamics of the Smith fir (Abies georgei var. smithii) tree line, one of the world’s highest natural tree lines. Thus the Plateau is chosen for field experiment, as human impacts far yield to natural forces in such high-elevated mountainous environment.

The research has been conducted on Mt Sygera (29°10′-30°15′, 93°12′-95°35′) on the northwestern side of the Great Canyon of the Yarlung Zangbo River in southeast Tibetan Plateau since 2007. In field research, three rectangular plots (30 m × 150 m) have been 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) slopes. Researchers also use dendroecological methods to monitor the tree-line patterns and dynamics over a 50-yr interval.

According to their research, there is a similar pattern of regeneration dynamics, characterized by increased recruitment after the 1950s and an abrupt increase in the 1970s. Correlation of Smith fir recruitment with meteorological parameters acquired at the SETORS shows a significantly positive correlation with both summer and winter temperatures. But their research fails to find a significant upward shift in Smith fir tree lines against obvious warming on the Tibetan Plateau.

See “Liang EY, Wang YF, Eckstein D, Luo TX. 2011. Little change of the fir tree-line position on the southeastern Tibetan Plateau after 200 years of warming. New Phytologist, 190: 760-769” for more.