Pinyon and juniper, such as this stand near Guadalupe Mountains State Park, grew in the Hueco Bolson in the distant past. Between 12,000 and 10,800 years ago, a shift in vegetation occurred; pinyon began to disappear and grassland communities emerged. The conifers made a brief reappearance around 3,000 B.P., during a more mesic period. Photo by Susan Dial. |