A STAND GROWTH AND YIELD MODEL FOR NORTHERNREFORESTED STANDS OF MEXICO

The aim of this research was to develop a growth and yield model for predictions of the basal area and timber volume of reforested stands in degraded, arid, semi-arid and dry-temperate lands of northern Mexico. In total, 124 forest stands (chronosequences) were sampled for allometric features (basal and breast height diameter, canopy height and canopy cover); data from 75% of the stands were used for model fitting and data from the remaining 25% of the stands were used for the model validation. Thepotential timber volume and basal area growth were determined for each reforested species. The growthrates of reforested native coniferous species in the states of Durango (P. durangensis Martinez, P. cooperiC.E. Blanco, and P. engelmannii Carri`ere) and Nuevo Leon (P. pseudostrobus Lindl.) were higher thanthose of pine species not native to south Central Durango (P. arizonica Engelmann), eastern Nuevo Leon(P. cembroides Zucc., P. pinceana Gordon, and P. nelsonii Shaw) and Coahuila (P. halepensis Mill.).Because forest stands are often reforested at high seedling densities, the productivity is higher than thatof pre-existing native forests communities. Therefore, this practice is recommended in order to increasetimber stocks and the productivity of Mexico?s degraded temperate and semi-arid forests