J.R. Baker & S.B. Bambara, North Carolina State University, Bugwood.org

Beat Forster, Swiss Federal Institute for Forest, Snow and Landscape Research, Bugwood.org

Daniel Adam, Office National des Forêts, Bugwood.org

Daniel Adam, Office National des Forêts, Bugwood.org

Louis-Michel Nageleisen, Département de la Santé des Forêts, Bugwood.org

Maja Jurc, University of Ljubljana, Bugwood.org

Maja Jurc, University of Ljubljana, Bugwood.org

Pennsylvania Department of Conservation and Natural Resources - Forestry , Bugwood.org