California Sycamore - Platanus racemosa
Sycamore trees, also called plane trees, are among the most common shade trees planted in the United States and Europe. Our native plane tree, Platanus racemosa, is a unique individual in the sycamore family. Found only in this region of the country, it is a historic component of the California landscape of streamsides, rocky canyons, moist valleys, and arid foothills.
The tree reflects California’s wild nature with its unpredictable growth, contorted and low spreading branches or leaning trunk (s). Always graceful, the tree grows very fast with a height reaching 30 – 80 feet tall. The canopy spread can be 20-50 feet wide, and a massive trunk is built in the process. These trees can have a very long life span, with horticulturalists documenting some specimens living up to 400 years.
Native Americans utilized the California sycamore for more than just shade and aesthetics. Records show that the inner bark was used for food and medicinal tonic, leaves were used to wrap bread during baking, and limbs and branches were used in house construction. Today, we use sycamore tree wood, classified as a hardwood, most frequently for veneer (e.g. lacewood), butcher’s blocks, furniture and pulpwood.
Despite its geographic isolation, Platanus racemosa remains strong in its ability to survive and thrive regardless of various pressures from human management, environmental shifts and ecological changes taking place around it.
Sycamores have the largest leaves of any native tree in North America with 5 long, distinct lobes extending more than half the length of the blade. Occasionally a leaf can be 10 inches wide, but most are 7-8 inches wide. The base of the short leaf stalk is held by a distinct two-pointed green structure called a stipule that can be used to help identify our indigenous species against its smaller cousin, the London Plane tree.
In spring, when the first flush of leaves begin to unfurl, they may be subject to anthracnose, a fungal disease that causes some of the leaves to curl up. While it looks disfiguring, it is not fatal, and the tree will recover without intervention. In autumn, leaves turn a subtle yellowish brown before falling off.
The most noticeable feature of this tree is the patchy brown, gray and white bark that peels off to reveal a smooth, almost pure white inner bark. Older bark is thicker (1-3 inches), furrowed and dark brown. A common pest found inside the bark is the Sycamore borer (Synanthedon resplendens) that creates exit holes in the rough bark from May through July after overwintering as larvae in tunnels within the bark. The tell-tale sign is the sawdust like frass in crevices and around the tree base. Sycamore trees can tolerate very high populations of these insects without threat to tree health. The bark also serves as a food source for beavers and fox squirrels.
Flowers & Fruit
Tiny male and female flowers are borne in dense, round heads and look like fuzzy marbles on a string. These flowers produce fruit in the form of seed balls, three to seven along a single stem, designed to fracture when the seed reaches maturity.
These seeds have short, cinnamon-colored hairs that act as parachutes helping with wind dispersion of tiny seeds. The seed balls are then utilized by squirrels and small rodents, while the seeds provide food for purple finch, goldfinch, and other species of birds.
Mistletoe is often found in the California sycamore, and is commonly brought to the trees by the birds that find shelter there. This parasitic plant provides food for many species of animals in our urban community including bluebirds, Lawrence’s goldfinch, and the great purple hairstreak butterfly.
The larvae of the Western tiger swallowtail butterfly (Papilio rutulus) also depends on the sycamore for its home-offering protection from summer sun and nutrients to the developing larva as the caterpillar becomes an adult.
Tell your family and friends about the significance of this beautiful tree and its invaluable role in a sustainable environment that we all need to protect.
Protect & Enjoy
Protecting our native trees requires our active partnership and contribution to the common goal of resource management. Oak, sycamore, and bay trees hold a unique place in our local ecosystem and provide habitat for 81 species of resident and migratory birds.
Urbanization continues to present a challenge within the sustainable capability of the ecosystem. Open spaces, clean air and homes for wildlife are worth protecting, but will demand support for the native trees existence in the local landscape.
Trees are living resources and assure healthy living habitats for interconnected flora and fauna, and the people that live within these habitats. To ensure that our trees will survive and thrive, please protect them by following these suggestions:
- Do not injure the trunk with objects.
- Keep all machines and weed whips away from tree trunks.
- Practice conservative pruning.
- Do not over water.