August- willow oak
Some of the best things in life are made when two equally great things come together and form another, more remarkable thing. For instance, a menu item like chicken and waffles is the perfect fusion of two delicious food staples, each complementing one another in a larger meal.
Brushing aside the fact that I am writing this too close to dinner, tree enthusiasts feel the same way about certain tree species – namely August’s tree of the month.
The willow oak (Quercus phellos) is the perfect example of how nature can get creative with the “combination” of two different species. The willow oak is a bona fide member of the oak genus (Quercus) and part of the overarching Fagaceae family, which includes other oak species along with beeches and chestnuts. So scientifically speaking, this tree is an oak, but its looks are where the lines start to blur.
If you find one of these trees, you might be surprised by the shape of the leaves. Most oaks native to this area sprout a notoriously distinct array of lobed leaves depending on the tree. Some species, like the pin oak, have jagged edges to their leaves. Others, such as the white oak, have soft curves.
But the willow oak tosses the rulebook aside and forms a unique leaf shape. Like the thin, elongated shape of the willow tree leaf, this particular oak develops narrow and smooth leaves, without any protruding lobes. Typically, they are about five inches long and one inch wide, so even the size is similar to some willow species. This creates a hybrid effect to the onlooker if they are unaware of the mimicking.
Despite their leaf trickery, willow oaks can be easily identified by other characteristics. The average height of an individual can reach a range of 40-75 feet tall, with some larger species reaching 100 feet with the right conditions. Its crown is rounded and usually stretches to widths of 25-40 feet. Its bark, starting out smooth and reddish-brown when young, turns dark brownish-gray with furrowed, shallow ridges with age.
Threats have hampered the health of the willow oak population in recent years. In Pennsylvania, the tree is listed as imperiled due to diseases such as oak wilt, chestnut blight, shoestring root rot, anthracnose, oak leaf blister, cankers, leaf spots, and powdery mildew, to name a few. But habitat loss, invasive species, and excessive grazing by deer compound the issue.
However, the range of the willow oak is quite vast, with some states reporting much healthier populations. This tree is commonly found in lowlands of the Coastal Plain, from New Jersey and Pennsylvania, south to Georgia and Florida, and west to Texas and Oklahoma. Throughout this large swath, the willow oak tree can be found in both urban areas and dense forests.
Similar to July’s linden tree, the willow oak provides an array of benefits to its community – even just one tree can sustain a myriad of life. The acorns a single tree produces can feed ducks, squirrels, deer, turkey, black bears, blue jays, and red-headed woodpeckers. Its trunk also offers lodging for mice, flying squirrels, and birds like grackles and flickers.
Here in Philadelphia, we are lucky enough to be in the willow oak’s northernmost range. If you are on Awbury’s grounds, look no further than the picnic area behind the Cope House to locate one of our very own willow oak trees!
Sources:
https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/quercus/phellos.htm
https://plants.ces.ncsu.edu/plants/quercus-phellos/
https://www.naturalheritage.state.pa.us/factsheet.aspx?=13902
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a191
