These pinyon-juniper-oak woodlands are pretty typical of the dry Southwest. Chisos woodlands include only one pine, three junipers, and many varieties of oak. You can easily identify pinyon and juniper trees, but the oaks are often hard to tell apart because they tend to hybridize. The different tree species have different soil and water requirements and where moisture is harder to come by they grow smaller and more widely spaced. You’ll find redberry juniper at drier, lower elevations, such as Green Gulch. This is a rather scraggly shrub or small tree whose lower branches often touch the ground. It has scale-like yellow-green leaves, and red berry-like cones. It will often invade abused grasslands. The gray oak, an evergreen with small olive-green leaves and dark gray bark, also prefers drier soils. On exposed slopes it too takes on shrub-like proportions but grows to 20 meters (65 feet) in protected canyons. Birds, peccaries, and deer feed on gray oak acorns. The Indians preferred the acorns of the Emory oak. [Illustration: Startling plant combinations comprise this forest floor on the South Rim of the Chisos. Such biotic richness and surprise led to the park’s designation as an International Biosphere Reserve.] [Illustration: Volcanic spires remind us that change has not always come slowly in the Big Bend. Molten rock under intense pressure created these spires as plugs inside softer rock, which has long since eroded away.] The other narrowleaf evergreens prefer intermediate to moister soils and the Chisos Basin is a good place to see both drooping and alligator junipers, the latter named for the square scales that make its bark look like alligator hide. This slow-growing, long-lived tree has bluish-green needles, and gray fox and rock squirrel relish its berry-like cones. Drooping juniper all but cries out for recognition. Its wilted leaves and drooping branches seem to be dying of thirst, but in fact are perfectly healthy, as is the bark that shreds in long, fibrous strips. You’ll find plenty of drooping juniper in Mexico, but the only place you can see it in the United States is right here in the Chisos Mountains.