Originally printed in the June 23, 2004 edition of the Illinois Valley News
This morning I had the opportunity to take an early morning walk through the Forks State Park. It was cool and quiet, that is if you ignore the constant rumbling coming from the highway. I could hear several different kinds of birds and I saw many wildflowers, even though the peak of the spring flowers is past. The dominant plants were oaks. Most of the trees were either Oregon white oak or California black oak, and of course poison oak was abundant on the ground or as climbers on trees. Poison oak is not considered a “true oak” since it is in the Sumac Family, but is called oak because of the shape of its leaves.
California black oak, as the name implies, is mostly native to northern California, and is abundant in the coastal mountains and in the Sierra Nevada Range. Lane County, near Eugene is as far north as the tree has been found. There are a few isolated stands as far south as the mountains of southern California. The trunks of the trees are very dark brown, almost black, and this is the reason for its name. The scientific name is Quercus kelloggii. All of the “true oaks” have Quercus, which is the Latin word for oak, as their genus name. The species name was given to honor Albert Kellogg who was a botanist in California and did much to get botany established in California. He came to California in 1849 with a gold rush party and did work in the gold fields for awhile until deciding that botany was his preferred field.
Oregon white oak is more abundant in Oregon than California and is found as far north as British Columbia. It is very common in the Cascade Mountains of Oregon and Washington. The southern limit is in the mountains just north of San Francisco. It has a very light colored trunk but it often has furrows that hold moss and lichens and will sometimes appear darker than it really is. This tree was first described by David Douglas in the 1820s and he named it Quercus garryana to honor Nicholas Garry who was the deputy governor of the Hudson Bay Company and aided Douglas in his collecting and traveling.
Black oak and white oak both have loose, hanging catkins for flowers. Catkins are dense clusters of small flowers with no petals, hanging on a single strand. These appear in the spring before the leaves and have no colorful petals to attract insects or moths. They are dependent on wind to carry the pollen from one flower to another. Once pollinated, black oak requires two summers for the acorns to mature, whereas white oak acorns will mature in one year. White oak acorns will also germinate in the fall and then go dormant in the winter. This requires squirrels to bite into the acorn to stop germination if it is going to bury the acorn for future consumption. Acorn woodpeckers prefer black oak acorns to force into the holes which they drill into barns, fence posts, roofs, telephone poles, and trees. Black oak acorns do not start to germinate until spring and thus they can be stored all winter.
The leaves of both black and white oak are deeply lobed. The black oak has points on the end of each lobe and the white oak lobes are rounded. Even though the bark color is sometimes confusing, the leaves make it easy to differentiate between these two large beautiful trees. The oaks are very important to the ecology of the area, providing both food and shelter to many different animals. They also provide an important back drop for early mornings walks in the park.