1. National Center for Disciplinary Research in Conservation and Improvement of Forest Ecosystems, National Institute for Forestry, Agriculture and Livestock Research, Progreso 5, Mexico City 04010, Mexico
2. Experimental Center Valle de México, National Institute for Forestry, Agriculture and Livestock Research, Texcoco 56250, Mexico
3. Departamento Forestal, División de Agronomía, Universidad Autónoma Agraria Antonio Narro, Saltillo 25315, Mexico