This document is the accepted manuscript version of the following article: Weber, P., Bugmann, H., & Rigling, A. (2007). Radial growth responses to drought of Pinus sylvestris and Quercus pubescens in an inner-Alpine dry valley. Journal of Vegetation Science, 18(6), 777-792. 1 https://doi.org/10.1111/j.1654-1103.2007.tb02594.x 2 3 4 Radial growth responses to drought of Pinus sylvestris and 5 Quercus pubescens in an inner-Alpine dry valley 6 7 8 9 10 Weber, Pascale1*, Bugmann, Harald2 & Rigling, Andreas1 11 12 1Swiss Federal Institute for Forest, Snow and Landscape Research, WSL, Zürcherstrasse 111, CH-8903 13 Birmensdorf, Switzerland. Email
[email protected] 14 2Forest Ecology, Department of Environmental Sciences, Swiss Federal Institute of Technology (ETH), ETH 15 Zentrum, CH-8092 Zürich, Switzerland. Email
[email protected] 16 *Corresponding author; Fax +41 (0) 44 7392 215; Email
[email protected] 17 2 Radial growth responses to drought 1 Abstract 2 Question: Lower-montane treeline ecotones such as the inner-Alpine dry valleys are regarded 3 as being sensitive to climate change. In Valais (Switzerland), one of the driest valleys of the 4 Alps, the composition of the widespread low-elevation pine forests is shifting towards a 5 mixed deciduous state. The evergreen sub-boreal Scots pine (Pinus sylvestris L.) shows high 6 mortality rates, whereas the deciduous sub-Mediterranean pubescent oak (Quercus pubescens 7 Willd.) is spreading. Here, the two species may act as early indicators of climate change. In 8 the present study, we evaluate this hypothesis by focusing on their differences in drought 9 tolerance, which are hardly known, but are likely to be crucial in the current forest shift and 10 also for future forest development.