【Objective】The aim of the study was to explore the short-term responses of timberline species within western Sichuan to global warming.【Method】Short-term responses of architectures and leaf morphologies of Salix eriostachya in sub-alpine timberline ecotone, Western Sichuan to simulated warming were studied by the open-top chamber (OTC).【Results】Warming significantly increased the branch angle and leaf angle of S. eriostachya. Likewise, warmer conditions clearly changed leaf morphologies of S. eriostachya. Whereas, OTC had a significant negative effect on leaf fluctuating asymmetry (FA).【Conclusion】Taken together, our results indicate that S. eriostachya in timberline ecotone showed strong plasticity to in situ experimental warming.