1. University of Göttingen, Wood Biology and Wood Products , Büsgenweg 4, D-37077 Göttingen , Germany
2. Thünen Institute of Wood Research , Leuschnerstrasse 91c, D-21031 Hamburg , Germany
3. Institute for Building Materials, ETH Zürich , Steffano-Franscini-Platz 3, CH 8093 Zürich , Switzerland
4. Wood Science and Engineering, Luleå University of Technology , Forskargatan 1, SE-931 87 Skelleteå , Sweden