Seed-caching animals which bury acorns, such as scrub jay and California ground squirrel, are important to species survival. Some acorns, however, remained until spring when black-tailed deer and cattle were excluded from the area. Germination is hypogeal. Pocket gopher populations in the Central Valley, once controlled by drownings during seasonal innundations, have greatly increased following the building of flood-control dams. Aboveground herbivory by pocket gopher and other animals causes much mortality as well.
Seedlings are sensitive to competition from grasses and forbs, particularly annual grasses.
Soil textures include silty loam, clayey loam, and sandy clay loam. Valley oaks in riparian forests receive subsurface irrigation. The oaks grow in a Mediterranean climate, characterized by wet, mild winters and hot, dry summers. On swales denuded by gold dredging on the Merced River, valley oak seedlings established under the shade of young willows.