Oak trees have been giving us shade and beautifying our California landscape for a very long time. They can be found on rolling hills, along rivers, creeks and in valleys of 52 of the state’s 58 counties. With a life span of up to 400 years, some oaks can grow to be enormous! They provide shelter and food for thousands of insects, birds and animals.
Oak trees do very well with the hot, dry summers and cool, wet winters characteristic of the Sacramento Valley. There are 20 species of oak trees native to California and more than 20 hybrids, but most of Sacramento County’s oaks are one of three species: valley oak, interior live oak, or blue oak.
The valley oak is the largest oak tree found in California. It can grow to be over 100 feet tall and can live for almost 300 years. The valley oak is found growing by creeks and rivers in valleys near the California coast and in the Central Valley. It is a deciduous tree with pale green-yellow leaves. The acorns are long and narrow.
The interior live oak grows in hilly or mountainous areas as well as near creeks and streams. It grows between 25 and 80 feet tall and forms a round crown of branches at the top. It has “evergreen” leaves, which means they stay on the tree all year. They are dark green, nearly flat and leathery looking. The interior live oak’s acorns are small and thin.
The blue oak grows in the hot, dry foothills. It grows to be 20 to 60 feet tall. The blue oak is deciduous. Its leaves are blue-green and they vary in size and shape. Some of the leaves have smooth edges and some are uneven. The blue oak’s acorns are fat and stubby.
Today, oak trees face many dangers. Many young oak trees are stepped on by pasture animals, run over by lawn mowers or crushed by bulldozers. Full-grown trees are often damaged or killed when new homes, roads or shopping malls are built. In order to keep native oaks in California, we all need to help by planting new oak trees.
To maintain a forest or woodland, each oak tree needs to produce just one replacement tree in its lifetime, but disease, drought, fire, and grazing wildlife can all destroy oak seedlings. Fortunately, each oak tree produces thousands of acorns during its life span. You can help regenerate California oak habitat by caring for a seedling and protecting it from harm.