The bark of Live Oak Trees is usually gray and smooth when young, and as the tree ages the bark can remain gray or turn even black in shade venues. Some Live Oak Trees exhibit crusty and furrowed bark at aging. The coloring of the Live Oak Tree bark can depend on a number of other factors such as saphrophitic organisms growing atop the bark: algae, fungi, lichens, and even ferns like the Resurrection Ferns that appear gray when dry but bright green after rains. The Resurrection Ferns can sometimes completely encircle the Live Oak Tree trunk. The color of the Live Oak Tree bark can vary with the season, the side of the tree where the tree is views and the influence of shading and humidity factors caused by associated tree and shrub species growing nearby.