1. Institute of Plant Sciences and Oeschger Centre for Climate Change Research University of Bern Bern 3013 Switzerland
2. EPHE Department of Palaeoclimatology and Marine Palaeoenvironments PSL Research University UMR CNRS 5805 EPOC Université de Bordeaux Pessac 33615 France
3. Swiss Federal Institute for Forest, Snow and Landscape Research WSL Cadenazzo 6953 Switzerland
4. Departamento de Sistemas y Recursos Naturales ETSI de Montes Forestal y del Medio Natural Universidad Politécnica de Madrid Madrid 28040 Spain
5. Departamento de Biología Vegetal Universidad de Murcia Murcia 30100 Spain
6. Centre for Quaternary Research Royal Holloway University London Egham TW20 0EX United Kingdom