Coffee… from a tree? On campus?

All photos by Jonathan Zhao

If you have ever taken a stroll along University Place in the fall, you may have noticed dark red seed pods littering the sidewalk. No, these are not mutant string beans from a Northwestern biology lab; the pods are the fruit of Gymnocladus dioicus, also known as the Kentucky Coffeetree. The tough shells contain hard, brown seeds the size of an AirPod head, surrounded by pulp. True to the tree’s namesake, Coffeetree beans can actually be used to brew a coffee-like beverage. Just make sure to roast the beans first, as they may be toxic when raw. 

The Kentucky Coffeetree is deciduous, meaning that it sheds its leaves every year (as opposed to evergreens). As such, the trees are still bare during the winter, leaving only a few seed pods that remain clinging to the branches from the previous growing season. In fact, its genus (Gymnocladus) is derived from Greek for “naked branch”, referencing its lack of leaves for up to half of the year. 

Though its natural distribution does not include the Chicago/Evanston area, Gymnocladus dioicus is still common to the Midwest and is often planted as a street tree because of its ability to adapt to a variety of soil and weather conditions. It is extremely resistant to drought and can even tolerate pollutants such as runoff from the rock salt that blankets campus sidewalks after every snowstorm. 

Though they are certainly appreciated for their majesty, the Coffeetree isn’t planted for merely aesthetic purposes. The large spread of its branches combined with its dense leaf cover provides excellent shade, sheltering the pedestrians below from the oppressive heat of the summer months. The evaporation of water transpired (the process of moving and excreting excess water) by the plant also lowers the temperature around trees. Perhaps keeping cool is the least of your concerns in February, but you will thank the trees when walking to class later in spring quarter!