Also known as Mount Graham, this is the tallest of the Madrean Sky Islands reaching 10,720 feet. It is the only Sky Island with a true spruce/fir forest community. The Pinaleños have many species including the Mt. Graham red squirrel and Alnus incana ssp. tenuifolia, which reveal its affinity to the high country of the Rocky Mountains. It is still well within the realm of Madrean influence as well, with well-formed Madrean oak woodland on much of its lower slopes.