1. Plant Sciences (IBG2), Forschungszentrum Jülich, D‐52425 Jülich, Germany
2. Cornell University, Ithaca, NY 14853, USA
3. University of Minnesota, 1530 Cleveland Avenue North, St. Paul, MN 55108 USA
4. Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
5. Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, 62‐035 Kornik, Poland
6. School of Plant Biology, University of Western Australia & Science Division, Department of Environment and Conservation, Perth, Crawley WA 6009, Australia
7. Nature Conservation and Plant Ecology Group, Wageningen University, PO Box 47, 6700 AA Wageningen, the Netherlands
8. Department of Experimental Plant Ecology, Radboud University, PO Box 9010, 6500 GL Nijmegen, the Netherlands