All of Mexico except for the most isolated desert regions has been profoundly altered by ranching, grazing, farming, firewood gathering, deforestation, rare plant robbery (especially cacti, palms, orchids & bromeliads) etc. Most affected have been the Oak-Pine and Tropical Evergreen and Deciduous Forest zones. This map shows what used to be, or what exists in small patches only, except for the most arid, not irrigated places.

Vegetation map of Mexico