Platanus occidentalis |  Family: Platanaceae

Submission: Lizzy Jack and Martijn den Boon

Identification: 

Leaves – deciduous, simple, 3-5 shallow lobes, sinuses and margins are serrated, petioles are enlarged at base to enclose bud, stipules are leaflike.

Twigs – leaf scar surrounds bud, stipule scar encircles twig, buds are divergent and resinous with a single cap-like scale.

Fruit – about 1” in diameter ball of elongated achenes, borne singly on long stalks, ripen in the fall.

Bark – scaly gray-brown exfoliated outer layer with creamy white layer exposed underneath due to peeling. 

Natural History:

There are few trees more visually stunning and simple to identify than the American Sycamore (Platanus occidentalis). The American Sycamore is a commonly planted ornamental tree, with few naturally occurring stands of individuals. When growing naturally, the species prefers wet soil, and is often found in bottomland environments. Occasionally, the American Sycamore is a pioneer species in sites like floodplains and abandoned fields.

Found throughout most of the eastern United States, its tell-tale peeling bark makes it stand out. It’s hard to miss while hiking in the woods or strolling through the city. This tree can also be found growing throughout much of the eastern and southern United States, and has proven to be well-adapted to warmer climates. While these trees can grow to up to 8 feet or more in diameter, they tend to stay smaller in northern climates. Under proper conditions, mature trees can grow to staggering sizes of 150 feet tall.

Historically, American Sycamore wood has been utilized to create a range of products. It is an important lumber resource, and is used to make particle board, flooring, and furniture. Its ability to grow a thick canopy of broad leaves has helped its popularity as an ornamental tree due to its capacity to provide shade in populated areas. Another positive of using American Sycamores for landscaping is the fact that they grow extremely rapidly. However, the American Sycamore has delicate limbs that are easily disturbed by inclement weather, which could pose a threat to city residents. In addition to its lumber and landscaping uses, the sap of most Platanaceae species can be reduced to a syrup for human consumption.

The American Sycamore is affected by a number of pests and pathogens. True to its name, the Sycamore leaf beetle feeds primarily on the leaves of Sycamore trees. When combined with plane anthracnose disease, which is caused by a fungus, significant damage can occur. It is usually enough to cause visible harm to the foliage and bark of a tree, giving it a scraggly, withered appearance. 

The American Sycamore is similar to the London Planetree (Platanus x acerifolia). The London Planetree is a hybrid between the American Sycamore and Old World Sycamore (Platanus orientalis), and is commonly found in cities throughout the United States, as well as Europe. It is a resilient tree that is tolerant of disease and air pollution, making it suitable for urban areas. The appearance of the London Planetree closely resembles the American Sycamore, but it has several noticeable differences including fruit that is found in bunches of 2-3, rather than singularly. The London Planetree also has deeper lobed leaves than the American Sycamore.

References:

2022. Plant Database: Platanus occidentalis, Lady Bird Johnson Wildflower Center

Burns, Russell M., and Barbara H. Honkala, tech. coords. 1990. Silvics of North America: 2. Hardwoods. Agriculture Handbook 654. U.S. Department of Agriculture, Forest Service, Washington, DC. vol. 2, 511-517

Shane, J. 2004. Dendrology Handbook, University of Vermont, Unpublished

Nesom, G. Plant Guide: American Sycamore, United States Department of Agriculture Natural Resources Conservation Service National Plant Data Center and the Biota of North America Program