1. Departamento de Agronomía, División de Ciencias de la Vida (DICIVA), Campus Irapuato-Salamanca, Universidad de Guanajuato, C.P. 36824, Irapuato, Guanajuato, México
2. Instituto de Investigaciones Forestales, Universidad Veracruzana, Xalapa, Veracruz, México
3. Colegio de Postgraduados, Montecillo, Texcoco, Estado de México, México
4. US Department of Agriculture Forest Service, Rocky Mountain Research Station, 1221 S. Main Street, Moscow, Idaho 83843
5. U.S. Department of Agriculture Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, Oregon 97331