Common Era treeline fluctuations and their implications for climate reconstructions

0565127 - ÚVGZ 2023 RIV NL eng J - Journal Article
Büntgen, Ulf - Piermattei, A. - Crivellaro, A. - Reinig, F. - Krusic, P. J. - Trnka, Miroslav - Torbenson, M. - Esper, Jan
Common Era treeline fluctuations and their implications for climate reconstructions.
Global and Planetary Change. Roč. 219, DEC (2022), č. článku 103979. ISSN 0921-8181. E-ISSN 1872-6364
R&D Projects: GA MŠMT(CZ) EF16_019/0000797
Research Infrastructure: CzeCOS III - 90123
Institutional support: RVO:86652079
Keywords : Climate reconstructions * Dendrochronology * Divergence problem * Paleoecology * Treelines
OECD category: Climatic research
Impact factor: 3.9, year: 2022
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S0921818122002466?via%3Dihub

Two hundred years after von Humboldt's pioneering work on the upper treeline, and many fundamental studies thereafter, the rate of past elevational changes in one of the most fascinating biogeographic boundaries on our planet remains poorly understood. Here, we distinguish conceptually between realised and potential treeline positions and present an ensemble model approach to simulate mean elevational treeline fluctuations for the past 2000 years. Based on dendrochronological summer temperature records, our simple, though efficient model shows that alpine treelines across the Northern Hemisphere were, on average, about 45-50 m higher after the Roman and medieval warm periods compared to their lowest mean position in the 1760s, which likely reflects the accumulated effects of repeated cold spells during the Little Ice Age. We suggest that the simulated mean differences between realised and potential treeline positions can affect the amplitude and variance of tree ring-based temperature reconstructions. Contrary to common belief, we also argue that the current offset between lower realised and much higher potential treeline positions, which appears unprecedented in the past two millennia, does not account for the yet unexplained 'Divergence Problem' in dendroclimatology, a decoupling between increasing temperature measurements and tree-ring chronologies since the 1970s.
Permanent Link: https://hdl.handle.net/11104/0336831