In any season, you can explore trees with your nose by scratching and sniffing twigs to find those species that have fragrant inner bark.
We don’t usually connect trees with smell, the way we do with flowers, but there is a surprising number of tree species whose inner bark has a distinctive odor. A fun activity to do with kids is to go from tree to tree, seeking the aromatic species. Of course, you must find an area with lots of different types of trees and lots of low branches so you can reach the twigs. (Note: It happens that the aromatic species are not generally planted on city streets, with the exception of ailanthus.)
As a teacher, I love to watch the look on my students’ faces when they first encounter a sniff of the wintergreen fragrance of sweet birch bark (or silver birch, which smells the same but milder). They are startled, delighted, and can hardly believe their noses.
The smell is a big help in identification of trees. For instance, young sweet birch and wild cherry trees have very similar bark, smooth and shiny, with horizontal, raised lines. Both have aromatic inner bark, but sweet birch smells sweet like wintergreen, and wild cherry is harsh, with a bitter almond tone.
Sweet birch and hornbeam have almost identical leaves, oval and toothed, but hornbeam bark has no distinctive odor.
Trees with feather-compound leaves can be difficult to tell apart, but black walnut and butternut can always be identified by the medicinal fragrance of their bark and leaves. Ailanthus, which also has compound leaves, smells like peanut butter.
A list of trees with fragrant bark, and their identifying characteristics, can be found in the article Aromatic Trees.
