Department of Geography, McGill University, Montreal, Quebec 1-13A 2K6, Canada;
Global Environmental and Climate Change Centre ( GEC3 ), Quebec 1-13A 2K6, Canada;
McGill School of Environment, McGill University, Montreal Quebec, Canada;
College of Forestry, Northwest A & F University, Yangling 712100,China;
Department of Physical Geography & Ecosystems Analysis , Lund University, SiJlvegatan 12,223 62,Lund, Sweden;
Institut des Sciences de L'environnement, Universit~ du Quebec a Montreal, Montreal 1-13C 3P8, Canada;