Madrean pine–oak woodlands

Conservation International estimates the woodlands' original area at 461,265 km2.

The woodlands are surrounded at lower elevations by other ecoregions, mostly tropical and subtropical deserts and xeric shrublands, forests, and grasslands.

There are also approximately 27 enclaves in southern Arizona and New Mexico and in western Texas, where they are known as the "Madrean sky islands".

The pine–oak woodlands are composed of stands of oak (Quercus), pine (Pinus), douglas-fir (Pseudotsuga) and fir (Abies).

The World Wildlife Fund recognizes several distinct Madrean pine–oak woodlands ecoregions, based on geographic distribution and species mix.