A small tributary of the Tsegi Canyon watershed shelters an unexpected deciduous forest in the desert wilderness, where a quaking aspen grove grows on the canyon floor and north-facing cliffs provide shady habitat for Douglas-fir trees. Steep canyon walls seep moisture into the basin at the canyon head, preserving a shaded, humid environment where water-loving plants and trees more typical of mountain slopes find refuge. These isolated landscapes are relict forests, survivors of an ice age environment that dominated here some 10,000 to 20,000 years ago. Among the life supported here are turkey vultures, redosier dogwood with white blossoms and berries, water birch thickets, Douglas-fir used by the early Anasazi (Hisatsinom) for roof building, quaking aspen that reflects an earlier cooler and wetter Southwest climate, canyon tree frogs along the canyon floor, and rare spotted owls that depend on the moist, cool old growth.