Tree of the Month: Swamp White Oak
What to Know About the Swamp White Oak
The Wet Oak
There’s an oak for almost every situation, and for clay-heavy or lowland ground, the swamp white oak just might be the right fit! A robust native tree, this beautiful white oak species is a huge, long-lived shade tree that is very important to the local ecosystem, making it all the more fortunate that these tough oaks do well in urban and neighborhood areas.
Characteristics of a Swamp White Oak
The swamp white oak grows in wet areas in the central portion of the eastern US, with Tennessee and South Carolina being about as far south as it reaches. These trees have a straight trunk with flaky light brown to medium gray bark, with ridges that run vertically in an interlacing pattern. The bark tends to peel along branches in particular, which spread outward to create a wide, rounded pyramidal crown.
Swamp white oaks have the familiar leaf shape of other oaks, with wavy lobes, wide upper halves, and an ovular shape. These oaks can be distinguished from others by the uneven lobe formation, rounded tips, and shallow sinuses (the spaces between lobes). The face of the leaf is a glossy, deep green, while the underside is a pale silver color. This leaf coloration gives the swamp white oak its scientific name, Quercus bicolor.
As its common name suggests, the swamp white oak grows in lowland and bottomland areas that tend to flood when it rains. This gives them a real tolerance for clay-heavy soil and areas that are saturated with water seasonally. Swamp white oaks prefer somewhat acidic soil (5-7.5 pH), making them a good choice for urban and neighborhood areas.
The flowers of the swamp white oak are short yellow-green catkins, which drape from the tree in spring and release pollen into the wind to fertilize nearby oak trees. Their acorns are about an inch long on average, with caps that cover between a quarter and a third of their top.
How Big Does a Swamp White Oak Tree Get?
The swamp white oak is among the largest canopy trees found in Tennessee, growing to an average mature height of 80 feet. This sun-loving tree also likes to spread out, reaching 50 to 60 feet wide. These big trees shouldn’t be planted near power lines or ground utilities.
How Fast Do Swamp Oak Trees Grow?
These big, hardy trees are also long-lived, potentially surviving for hundreds of years. One of the best ways to help a newly planted swamp white oak live on for generations is to give it a good start, attentively caring for a specimen over its first few years as it establishes itself in place.
The Swamp White Oak in the Nashville Ecosystem
Nashville is a swamp white oak kind of city! The tree grows happily in the Cumberland River lowlands where Nashville is situated, and oaks are a keystone species in our local environment. This means the swamp white oak has complex, foundational relationships with local wildlife of all kinds, including spiders, caterpillars, frogs, lizards, birds of all kinds, and mammals, from mice to bears. The spacious crown offers shelter to wildlife, while the leaves, acorns, and even the tree’s inhabitants are important sources of nutrition for the members of the food web.
In addition to wildlife habitat, these large oaks perform the various ecosystem services that canopies offer, such as carbon dioxide absorption from the air, provision of shade, water management, and soil stabilization. The swamp white oak’s preference for moist soil makes it an especially important soil stabilizer since it can provide structure to saturated ground that might otherwise be rinsed away over time.
Due to their large size, swamp white oaks can perform these ecosystem services with greater impact than smaller trees, adding to the many reasons it’s essential that these oaks be present and preserved across Nashville.
To purchase a swamp white oak through the Nashville Tree Conservation Corps’ tree sale, check out its listing here! You can also support NTCC’s activities by volunteering with us, signing up for our email newsletter, and staying informed on Nashville’s canopy!