The Madrean sky islands are a complex of small mountain ranges in southern Arizona and New Mexico which are home to enclaves of Madrean pine-oak woodlands. The enclaves are surrounded at lower elevations by the Sonoran and Chihuahuan deserts.

The sky islands are the northernmost of the Madrean pine-oak woodlands, and are classified as part of the Sierra Madre Occidental pine-oak forests ecoregion. The sky islands were isolated from one another and from the pine-oak woodlands of the Sierra Madre Occidental to the south by the warming and drying of the climate since the ice ages.

There are approximately 27 Madrean sky islands in the United States, and 15 in northern Mexico.

External link

• Sky Island Alliance homepage
• Southwestern Sky Island Ecosystems (US Geologic Survey)
• Madrean Sky Islands Montane Forests (Vanderbilt University)
• Sierra Madre Occidental pine-oak woodlands (World Wildlife Fund)