The Davis Mountains, originally known as Limpia Mountains, are a range of mountains in West Texas, located near Fort Davis, after which they are named. The fort was named for then United States Secretary of War and later Confederate President Jefferson Davis. They are a popular site for camping and hiking and the region includes Fort Davis National Historic Site and Davis Mountains State Park. The historical and architectural value of the fort, alongside the rugged natural environment of the park are a significant destination for tourism in Texas. Most of the land in the Davis Mountains is under private ownership as ranch land, but The Nature Conservancy owns or has conservation easements on more than . Description Rather than being a single coherent range, the Davis Mountains are an irregular jumble of isolated peaks and ridges separated by flatter areas. The mountains occupy a rough square about on each side. The mountains are of volcanic origin composed of strata associated with eruptions of the Trans-Pecos Volcanic Field 35 million years ago. The highest peak in the Davis Mountains is Mount Livermore at the fifth-highest peak in Texas. Vegetation The Davis Mountains are a sky island, an isolated mountain range surrounded by desert. The town of Fort Davis at the foot of the Davis Mountains has an elevation of . From that elevation, the sky island rises to . As the elevation increases, average temperatures decline and precipitation increases, permitting an "island" of forest and other mesic habitat at higher elevations. The most common vegetation of the Davis Mountains is montane grassland, often mixed with scattered bushes and trees. As is common in most Northern Hemisphere semiarid climates, the vegetation on the southern slopes of the mountains is noticeably sparser than on the northern slopes. This is due to the greater exposure to the sun on southern slopes, thus warmer temperatures and drier soils. Mixed in with the grassland, and usually at higher elevations, are four woodland and forest zones. First, at elevations below and at higher, drier elevations, the dominant tree species is the alligator juniper mixed with oak species and pinyon pine. Secondly, woodlands with pinyon pine as the most common species are found on steep slopes at elevations of . Third, woodlands in which the gray oak is the most common tree and mixed with other oak species are also found on steep slopes at elevations of