It has been said that when colonists settled the peaceful woodlands of the eastern United States, the overstory of the forests there was around 30-40% American Chestnut. American Chestnut (Castanea dentata) was an important food source for nearly every animal in forests across the eastern United States and Canada (see Figure 2). It was also the origin of the traditional “chestnuts on an open fire” cooed by so many holiday time singers (Asian varieties of chestnuts are used today).
But something happened beyond the power of our imagination.
During the 1800s and well into the 20th century, ornamental plants from Europe and Asia were regularly important into the “New” World.” Never in its geological or cultural history had the North American continent seen so many new plant species being introduced onto its soils, and so many were planted at once across the landscape. To compliment the beloved American Chestnut, a large variety of exotic Chestnuts were important – primarily though for ornamental purposes. Accidentally imported in the cargo was a small, nearly microscopic fungus that became known as the Chestnut Blight.
This disease ended up killing nearly every American Chestnut tree in the country. In the “Old” World, the chestnut blight fungus had natural controls in place, but in the “wilderness” of the new land there was nothing ecologically adapted to stopping this voracious disease. Today, any remaining chestnuts are reduced to mere shoots and sprouts that seldom survive more than a few years before giving way to the blight.
The fact that a dominant tree of the eastern forests quickly dropped out of sight left a void in the forest ecosystem. In its place now stands the Tulip Tree (Lirodendron tulipifera), sometimes referred to as a ‘Tulip Poplar” although it is actually the northern most representative hardwood tree of the Magnolia Family (see Figure 1) (Sibley, 2009).
Figure 1: The showy flower of the Tulip Tree. Photo by P. Gibellini.
Figure 2: American Chestnuts were important for people, too. This cabin is made from the sturdy wood of the now defunct American Chestnut tree.
Although the tulip tree stands near or just above the former abundance of the American Chestnut, there are nevertheless some serious consequences. The tulip tree is a fast growing tree that can tolerate a moderate amount of disturbance in the soil. In fact, I have even seen small tulip tree saplings growing out of a sidewalk crack! Also, their root system sprawls out quite far horizontally, but vertically its roots go down no more than a few feet. The tops of these trees can reach heights in excess of 150 feet, which makes them rather top-heavy. These factors combined with an erect profile make tulip-tree dominated forests and neighborhoods vulnerable to blow-downs from wind storms and heavy precipitation events (see Figure 4). And that’s exactly what happened in the forests and rustic-style communities of Southern Maryland during Hurricane Irene of 2011 (see Figure 3 to give you an idea of the extent that the dominance of Tulip Trees has had in Southern Maryland).
Figure 3: Damage to a tulip-tree dominated forest as a result of microburst winds from Hurricane Irene.
Therefore, in this context, the chestnut blight could be labeled as a ‘hurricane fungus.’ If I’m right, the effects from Hurricane Irene in August of 2011 could have produced significantly lower damage if wooded areas were still dominated by the American Chestnut. This would then perhaps reminds us that invasive species, whether introduced purposely or accidentally, can have a domino effect on the landscape…and on our wallets (for example, FEMA recently exhausted its budget).
Here is what you can do, now that our so-called hurricane fungus is among us:
- Avoid planting Tulip Trees near your house. Even if you do not live in a hurricane-prone region, high winds from any weather system could make this weedy and wobbly tree a hazard.
- Cut down any tulip trees that may be growing close to your home or yard.
- Use native plants in landscaping from local sources.
- Support environmental initiatives to help control and reduce the occurrence of exotic plant and animal breakouts.
- Educate yourself about the presence of non-native and invasive species by visiting a local nature center or any natural resources education facility
- Encourage neighbors and friends to use native plants in their yards.
- Get active! Contact your local politicians and state representatives and encourage them to pass legislation that would create improved regulations on plant and animal trades and imports.
Sibley, D. A. (2009). The Sibley guide to trees. New York, NY: Alfred A. Knopf, Inc.
Figure 4: A large tulip tree uprooted after Hurricane Irene.