An Uncommon Oak with Telltale Leaves
As its name implies, the swamp white oak is a lowland tree, often found in areas subject to periodic flooding, and on the edges of swamps and poorly drained meadows. Unlike white oaks (Q. alba) and burr oaks (Q. macrocarpa), which occur in large stands in the forests and oak savannahs of the Midwest, swamp white oaks are usually found growing singly amongst forests dominated by other species. They are thus relatively rare, encountered much less often than their oaken brethren. Although less common, swamp white oaks are easy to spot, even for novices. The Latin name bicolor refers to the how the leaves display two colors: a shiny green upper side and a paler, silvery-white underside. As the wind blows and the swamp white oak leaves flutter, these two contrasting colors are easily spotted twinkling.
North American distribution of Swamp White Oak
Human Uses for Swamp White Oak
Although swamp white oaks and white oaks are botanically distinct, both trees are used in similar ways. The Iroquois of upstate New York and southern Quebec ate the fat acorns of the swamp white oak just as they ate the white oak acorns. Medicinally, they used the bark of the swamp white oak to treat cholera, tuberculosis, broken bones, and the lonesomeness a man feels when his wife runs away.
As lumber, swamp white oak is often a little knottier than white oak, but the two are not usually differentiated, as we value both for their hardness, durability, and moderate price, making them excellent candidates for flooring, cabinetry, furniture, and trim. Like white oak, swamp white oak is used by coopers in the construction of water-tight barrels. However, since it seldom occurs in large stands, swamp white oak is rare in the lumber market; less than 1% of white oak on the market is swamp white oak.
Form & Structure
Both young and mature swamp white oaks take on lovely forms. When young, they are pyramidal (like a Christmas tree), giving them a very proper, formal appearance. But as these trees age, the lower branches sweep downward gracefully, the middle branches grow horizontally, and the upper branches remain erect, giving the tree a strong columnar appearance. In Madison, an excellent example of a mature specimen can be found at the northeast corner of Linden and Babcock. The plump acorns of the swamp white attract woodpeckers, blue jays, squirrels, and wild turkeys, and the tree hosts many native butterfly species.
Mature Swamp White Oak on UW-Madison campus. Photo credit: Hynsoo Leo Kim
Oak Galls & Parasitic Wasps
When certain wasps lay their eggs on swamp white oaks (as well as on other oaks), the larva produce hormones that cause the tree to produce a gall, an irregular growth that encapsulates the larva, protecting it from the elements, predators and parasites. The galls also exude nectar from their exteriors, which attract ants and wasps, who in turn help protect the oak from herbivores like caterpillars. While galls can appear alarming, they are not dangerous to the trees. Interestingly, certain parasitic wasps bore into oak galls, and lay their eggs inside to feed on the helpless gall wasp larva. Yet still other wasp species are known to parasitize the parasitic wasp that takes over the gall, making them hyperparasites! Up to five levels of parasitism are possible in oak galls, the largest parasitic hierarchy known to occur in nature.
Photo credit: Mary Anne Borge
Galls themselves are extremely concentrated sources of tannins, and historically were used in the production of iron gall ink, which was the most common ink until the early twentieth century. This ink is still manufactured for use by fountain pen enthusiasts.
Big Tree, a Historic Swamp White Oak
from A Natural History of Trees
One of the most famous swamp white oaks was known as the Big Tree, which grew on the edge of the Genesee River in Geneseo, New York. Beneath that tree, in 1797, a conference was held between the Seneca Nation and the United States. The conference resulted in the Treaty of Big Tree, in which the Seneca sold nearly all of their ancestral homeland in New York for $100,000. By 1857, the bank that the Big Tree stood on had been severely undercut by the river, and that year a large flood swept away the historic swamp white oak.