CALIFORNIA NATIVE PLANT SOCIETY TREE STUDY KIT

VALLEY OAK aka VALLEY WHITE

• Valley oaks are unique to California.
• The oak galls (that kids call oak balls) on valley oaks are made by wasps. They start out green (that's why they're sometimes called oak apples), become tan, and later may be found covered with a black mold. Look for the holes where the wasps chewed their way out when they hatched.
• Acorns were an important staple in the Miwok diet.
• Many native animals rely on acorns. Approximately 170 species of birds use oaks as some point in their life cycle. A scrub jay may cache 5000 acorns in a season! 58 species of lizards, snakes and amphibians are associated with oak habitats. 105 mammals use the oak resource. For example, 35% of the fall diet of deer is acorns. 5000 species of insects use oaks and 1000 are dependent on them.
• Fossil records indicate there have been oaks in California for at least ten million years.
• Oaks woodlands are in trouble in California due to development, dams preventing the floods which reduced the numbers of gophers and other predators of acorns and seedlings, invasion of weeds like French broom which out-compete oak seedlings, and ranching (A cow can eat 1800 acorns a day, not to mention trampling on oak seedlings.)