1. Max Planck Institute for Chemical Ecology, Department of Biochemistry, Beutenberg Campus, D–07745 Jena, Germany (A. Schmidt, B.W., U.T., J.G); Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, N–1432 Aݸs, Norway (T.K.); and Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Quebec, Quebec, Canada G1V 4C7 (A. Seݩguin)