Our lovely Chestnut Oak, Quercucs prinus, offers dense shade and can be found in Bayne Park between Bayne Library and the Skate Park.

This tree’s common name ‘Chestnut Oak’ is due to the form of its leaves, which closely resemble those of the American Chestnut tree. Both trees are members of the Beech family. The football shaped leaves range from between four to eight inches in length. The upper leaf surface is deep-green in color and glossy, while the underside is pale-green in color and matte.

Follow the parallel veins from the center of the leaf in the image above noting that each vein terminates at a rounded tooth at the scalloped leaf edge.

The Chestnut Oak is easily distinguished by its deeply-furrowed craggy bark with blocky ridges. This tree is noted as having the thickest bark of any eastern North American Oak.

In the Spring, male and female flowers appear separately but on the same branch.​ Male flowers occur in drooping catkins, and the tiny female flowers are fertilized when pollen from the male catkins is transported by the wind. Afterwards the catkins become dry as shown in the above image. They drop from the tree and occasionally get caught on the lower branches and leaves.

As the Chestnut Oak is a member of the white oak group, its acorns mature in one growing season. They ripen in Autumn and drop to the ground where they can immediately sprout. The Pin Oak and Northern Red Oak are members of the red oak group which have acorns that take two seasons to fully develop.

Although it can produce some acorns every year, the Chestnut Oak is not known as a prodigious yearly acorn producer. Bountiful acorn crops are infrequent, occurring approximately every four to five years. The large acorns are eaten by many species including squirrels, chipmunks, turkeys, deer, and mice. 

In addition to producing a food source, the tree gives cover and provides nesting cavities for small birds, mammals, and bees. Leaves and twigs of the Chestnut Oak are used by birds to build nests, and squirrels use them to construct their dreys.

In the Autumn the leaves change to orange-yellow or orange-red. In the far left of the image above you can see branches showing the orange-red leaves of our Chestnut Oak during early Autumn in 2019.

Gypsy moth caterpillars are a known pest of Oak trees. The flightless female Gypsy moth shown in the above photograph by Ilia Ustyantsev lays egg masses containing up to a thousand eggs. In the spring the tiny caterpillars hatch and voraciously feed on the tree’s leaves, and as they grow they can strip the tree of its leaves. A defoliated tree isn’t able to effectively photosynthesize and has to spend its reserve energy generating replacement leaves. This causes immense stress to the tree which can make it susceptible to other pests and diseases, ultimately leading to its decline.

The Gypsy moths were brought to the United States in the late 1860’s with the intention of starting a silkworm industry and some escaped. The caterpillars of Gypsy moths have caused peril to many trees across the northeastern United States and are especially destructive to oak trees. They are difficult to control and contain once they have hatched as they have an effective method of dispersal. Young caterpillars climb upwards toward the light which brings them high into the canopy of the tree. The lightweight caterpillars spin a thin support of silk thread and dangle until a strong breeze carries them into the sky. Wind currents spread the caterpillars out over great distances, and their silken parasails slow their descent as they land upon trees to feed upon the leaves.

The wood of the Chestnut Oak is known for having good resistance to decay. Durable and heavy with a tight grain, it is frequently used for fence posts and railroad ties. The inner bark is rich in tannic acid, which was used in the process of tanning animal hides.

Book Recommendations:

Seeing Trees: Discover the Extraordinary Secrets of Everyday Trees by Nancy R. Hugo featuring photography by Robert Llewellyn will indulge you in the magnificent details of trees through the seasons.

How to Paint Trees, Flowers, & Foliage by Patricia Seligman is full of painting tips and techniques. You might be inspired to create a plein air painting of the trees in Bellevue’s own Bayne Park!  

Learn more about all the Trees of Bayne Park and explore our Interactive Bayne Park Tree Map to see the locations, photographs, and names of over a dozen different species of trees. Be sure to also visit our Treesources page to lean about local trees, caring for trees, and more.

Written by Linda, Spring 2020