| Location |
| Between 0.5 mile and 0.75 mile markers |
| Fact about this tree and why it was chosen |
| Most of the sweet birch trees along the Allegheny River Trail grow in isolation from each other. One exception is this group of four trees lining the trail near the south end of the rugby fields. These trees are all leaning toward the field as if they are trying to achieve a better vantage point of the match.. |
| Latin name |
| Betula lenta |
| Fun facts |
- Like maple trees, sweet birches can be tapped and the sap collected. However, the sugar content is far less than for maple requiring a lengthier and more arduous boiling process. Fermented sap is the foundation of "birch beer," recipes for which date at least to the 17th century. Soft drinks flavored with birch bark extracts are reputed to taste is similar to root beer and are especially popular in eastern Pennsylvania. So was the original root beer float, or its cousin the "black cow" using chocolate ice cream, actually a birch beer float?
- Sweet birch, and yellow birch to a lesser extent, produce methyl salicylate, an aromatic compound with which most of us are familiar. This is distinctive smell and taste we associate with wintergreen. The actual wintergreen plant, also known as the eastern teaberry, produces the identical compound. When we compare the stature of a birch tree to the diminutive wintergreen plant, it is no surprise that the former became the principal source of the chemical. So great was the demand for wintergreen oil that until chemists were able to synthesize the compound, sweet birch trees were at risk of over-harvesting.
- The structure of oil of wintergreen is similar to salicylic acid of aspirin fame, and it is a component of many topical analgesic creams used to relieve sore muscles and arthritis symptoms.
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How to identify this tree:
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| Leaf |
| Birch trees, in general, are known for their finely toothed doubly-serrated leaf margins. The sweet birch leaf is egg-shaped with the widest point near but not at the leaf base. Fully expanded leaves are two to four inches long, and in the fall turn a brilliant yellow color rivaling that of aspen. |
| Bark |
| Since the leaves are virtually identical is size and shape, sweet birch is most commonly confused with yellow birch, Betula alleghaniensis. In fact, these two species are closely related and attempts have been made to hybridize the two. Yellow birch, especially in younger trees, has a bronzer hue compared to the more grey-black color of sweet birch. Sweet birch bark breaks away in large plates, much like that of cherry, hence the origin of cherry birch as a common name. Yellow birch, white birch, and river birch, all have bark that exfoliate in thin curling strips reminiscent of the shavings from a small pencil sharpener. Only the river birch does not give away the color of these strips with its common name. For the record, they have an orange tinge that you might have recognized from the river birch trees outside of Murphy Hall and the Reilly Center. |
| Flower and Fruit |
| Sweet birch produces clusters of separate male and female flowers on the same tree. The male clusters are easily recognized in the spring as they are up to three inches long and droop from the branch tips. At this time, female flowers are less conspicuous, in part because they are less numerous, but also because they are smaller and curve upward. As they mature, they increase in size and become scaly and cone-like. They break apart in late summer and fall, releasing small winged fruits resembling miniature Mickey Mouse ears. |
| Other |
Sweet birch is a native North American tree distributed primarily along the length of the Appalachian mountains from Maine to northern Alabama. It is most common in southern New England, southeastern New York and Pennsylvania. Sweet birch is at home in Cattaraugus, Allegany, and Erie counties of western New York, but does not reportedly grow in neighboring Chautauqua, Wyoming, and Steuben counties.
Sweet birch grows best on moist, well-drained soils. It tends to be replaced by oaks or conifers on drier sites. At the extreme northern and southern portions of its range, protected northern and eastern slopes are the most favorable habitat. As is expected from a shade-intolerant species, sweet birch grows rapidly as a seedling, about twice as fast as hemlock and maple, reaching a final height of 70 to 80 feet on the best sites. Sweet birch commonly survives beyond 100 years with reports of 200- year old individuals growing in Pennsylvania. Following the demise of the American chestnut in the early 20th century, sweet birch populations expanded in many locations, partially filling the ecological void. |