Variability and rapid response of subalpine fir (Abies fargesii) to climate warming at upper altitudinal limits in north-central China

Abstract

In the Qinling Mountains of north-central China, subalpine fir treelines exhibited a significant upward movement on the northern slope, but only a slight change on the southern slope over the past 200 years, supporting the idea that pattern and timing of treeline change are contingent on local environmental conditions. Variability in the response of altitudinal treelines to climate change might be contingent on species-specific characteristics and on different climate. The objective of this study was to examine the pattern, timing and variability in response of Abies fargesii treeline to climate warming among topographically similar, but climatically different sites. Rectangular plots were established across subalpine fir treeline ecotones on the northern and southern slopes of the Qinling Mountains. Dendroecological techniques were used to examine treeline patterns and dynamics at 50-year intervals. The results showed that despite the differences in regional climate, all the plots studied displayed a recent rapid recruitment trend. Tree recruitment was favored by high spring–summer temperatures on the northern slope and by high summer temperatures on the southern slope. Subalpine fir treelines exhibited a significant upward movement on the northern slope, but only a slight change on the southern slope over the past 200 years. The variability in changes of treeline position on the northern and southern slope can be attributed to the differences in regional climate conditions, supporting the idea that pattern and timing of treeline change is contingent on local environmental conditions.