California woodlands are dominated by hardwood trees, especially oaks. Woodland canopies can extend from10 percent of the cover to nearly 100 percent in places. In the Sierra foothills, interior live oak and blue oak are the common trees. California black oaks occur in the upper foothill zones and are part of the transition to montane hardwood-conifer forest. In the Coast Ranges, the coast live oak is the most common tree. One pine, the gray or foothill pine, occurs in oak woodlands, and it had great value to Native American in the region. Woodlands may have an understory of herbs, shrubs, or small trees. Because of this structural and species complexity, oak woodlands are one of the most diverse habitats in California, providing food, shelter, and breeding places to a great variety of wildlife.