Oaks in Zion Park

The two dominant oaks in Zion Park are the Gambel Oak (or Rocky Mountain White Oak) and the Turbinella Live Oak. I enjoy learning about oak trees and their regional differences when I travel.

Gambel Oak (Quercus Gambelii) is in the Fagaceae family, and native to dry foothills and river canyons in the southwest United States. It is deciduous and grows in clumps, either as low shrubs or moderate sized trees (typically 15 – 30 feet high). The leaves have rounded lobes, which is characteristic of white oaks. Although many acorns are produced, most propagation is by underground spreading stems. Native populations used the acorns as a food source, and the tough wood as a building material.

Lobed Gambel Oak leaves. The oaks growing in the warmer climate
near the Virgin River still had their leaves in October. At higher
elevations, the leaves had dropped.

Turbinella Live Oak (Q. turbinella) is also in the Fagaceae family and native to dry foothills and mountain slopes in the southwest. It is evergreen, slow growing, and grows in shrublike form (typically 10 feet high and wide). The leaves are leathery with prickly lobes, and can form impenetrable thickets. The acorns are long and slender, and fall from the tree soon after reaching maturity, leaving their caps persisting in the tree. The acorns can be eaten once the tannin is leached out, and the wood is very tough.

Prickly Turbinella Live Oak leaves can create a
formidable thicket.

The Gambel Oak (deciduous) forms hybrid trees with the Turbinella Live Oak (evergreen). According to a description by Dr. Stanley L. Welsh, in Wildflowers of Zion National Park, “the hybrids are only partially evergreen and most easily detectable in winter when Gambel Oak is without leaves.” I don’t have a photo, but I believe I saw this – a leafless oak with several green branches. I initially thought this was some kind of parasite, like mistletoe, but was too far away to investigate. I have read about hybridized California oaks in Oaks of California, by Bruce M. Pavlik, Pamela C. Muick, Sharon G. Johnson, and Marjorie Popper (Cachuma Press and the California Oak Foundation, 1992). It was interesting to see hybridization in action.