Restoring the Iconic American Chestnut Tree - Maine Coast Heritage Trust.

By Kat O’Connor

American chestnut (Castanea dentata) was once the foundation of many eastern United States forests, shaping the structure and function of the entire ecological community it was a part of. It was among the largest, tallest, and fastest growing trees in forests from the Mississippi River, through the Appalachian Mountains, to the coast of Maine.

In autumn, American chestnut burs would open and drop nuts, feeding bears, birds, chipmunks, deer, racoons, squirrels, and turkeys. The nuts were a major food source for the now extinct passenger pigeon. It is believed the blight of the chestnuts exacerbated the extinction of the pigeon. The trees’ leaves were a preferred food source for many insect and caterpillar species, which in turn, make food for fish and birds. Seven moth species, whose caterpillars exclusively ate American chestnut, are now extinct. Fallen leaves, heavy in nitrogen, phosphorus, potassium, and magnesium, were a favorite of decomposers. This created an extremely nutrient rich soil foundation of the forest floor. The American chestnut shaped eastern forests and cultures alike.

“The American chestnut shaped eastern forests and cultures alike.”

The chestnut tree was fundamental to the livelihood and culture of Indigenous Nations throughout the chestnut’s range. The nuts were an important food source, and forests were managed for chestnut health. Members of many different Nations would burn low fires, not reaching the canopy, that dried the nuts and killed off chestnut weevils. Fires helped the chestnuts spread by suppressing competitive plant growth. This management supported chestnut abundance, and nuts became a diet staple. They were a reliable source of nutrition that could be stored as nuts and pounded into flour. These carefully tended chestnut groves were another important food source that European colonization stripped from Indigenous Nations. An ancient reciprocal relationship was severed as the United States forced Indigenous Nations throughout the chestnuts range off the land and the chestnut became functionally extinct.

European colonizers used the American chestnut in many ways. It has been referred to as “the redwood of the east” due to its extremely rot resistant, straight-grained wood.

The wood was desirable for building furniture, fencing, foundations, flooring, railroad ties, and telephone poles, many of which still exist today. The ripening of the nuts coincided with winter holidays, and in the late 19th century railroad cars would overflow with chestnuts to be sold in major US cities.

In the late 1800s blight was introduced on imported Japanese chestnut trees. Chestnut blight (Cryphonectria parasitica) was discovered at the Bronx Zoo in 1904. By 1950, less than 50 years later, the American chestnut was rendered functionally extinct. The giants were gone, and the foundation of approximately 180 million acres of eastern forests disappeared. The loss of the American chestnut’s function has had cascading effects on the entire food web, dramatically altering population dynamics of the forest.

“Maine has more mature, wild flowering American chestnut trees than any other state.”

In most of the chestnut’s native range limited communities of shrub-like versions of the tree remain. When faced with competition from soil microorganisms, the blight cannot survive underground. This has resulted in colossal root systems of the chestnuts sending out suckering sprouts. These sprouts typically succumb to blight before they can produce nuts. However, here in Maine, that is not quite the case.

Maine is located at the northernmost tip of the American chestnut’s native range and has always had sparser populations of the species than any other regions. In more southern regions there were denser populations of chestnuts, allowing the blight to spread much more readily. In Maine, there are trees which have been isolated enough to allow some survivors that the blight could not reach. Some of these trees still exist today.

Maine has more mature, wild flowering American chestnut trees than any other state. This has allowed the Maine Chapter of The American Chestnut Foundation (ME-TACF) the unique ability to collect wild-type chestnut seeds. These seeds preserve the genetic diversity of C. dentata.

Ten American chestnut saplings were planted at Cousins River Fields & Marsh Preserve (CRFM) in June 2024. They were grown from seeds gathered last fall by ME-TACF from rare surviving wild trees or their progeny. These young trees will hopefully grow old enough to bear fruit, increasing the genetic diversity of the species and creating a new seed source. The trees planted on Friday will eventually succumb to blight, but they will hopefully produce more seeds before that time comes. Every few years, more trees will be planted to create a mixed-aged stand.

As The American Chestnut Foundation works to develop a blight resistant American chestnut, the trees at CRFM will keep the species alive and genetically diverse, in hopes that they can one day be cross-pollinated and produce blight-resistant offspring. Wild Maine chestnuts will be the mothers of blight resistant American chestnut trees.

The seeds produced at CRFM may be used by The American Chestnut Foundation for any of their restoration strategies to research and develop resistant chestnuts including traditional breeding, biotechnology, and biocontrol.

Restoration of the American chestnut tree would bring resistant and genetically diverse chestnuts back into their native range and reestablish their function in eastern forests. By assisting in the advancement of chestnut restoration, Maine Coast Heritage Trust can help protect one of the most vulnerable plant species in America.

Want to learn more? Here are some resources to check out, which Kat referenced to generate this story: