The American chestnut may well be the greatest and most useful forest tree to ever grow on this Earth. Its decline is considered by many ecologists to be one of the greatest ecological disasters to strike the US since European contact. But how did it happen? And are we on track to bring back this amazing tree?
The following excerpt is from Trees of Power by Akiva Silver. It has been adapted for the web.
It is hard for us today to understand what was lost because we did not witness it.
Imagine working in your yard and noticing an apple tree with wilted leaves. A few weeks later, the tree dies. You’re sad about this and tell a friend, who tells you that they had the same thing happen. Then you hear it from lots of people. It’s on the news. Apple trees are dying, orchards are wiped out, wild trees disappear. No one knows what to do. Before you know it there are no cider barns, no crisp fruits to sink your teeth into, no apple blossoms in the spring, no fruit in the supermarket. How would you feel? As the years go on, you might try to explain to young people what an apple tasted like, what it felt like to bite into apples; you might describe the trees’ gnarly growth habits or the smell of cider in the barn or the taste of applesauce. They would never understand. The apple tree would be gone and life would go on. Other trees would be there, but none would be the apple. This is basically what happened to the American chestnut. The chestnut was no less loved or used than apples are today. It was a tree with full cultural, economic, and wild significance. We are the people who were born after its loss. All we have are the stories and a handful of pictures to go by.
Castanea dentata dominated the eastern US, making up roughly one-fourth of the trees in its range. This is a huge percentage, considering the diversity found in the eastern deciduous forests. Even maples, oaks, and ash are not that common.
American chestnut trunks were massive, often 10 feet or more in diameter, with canopies reaching 130 feet in the air.
These arrow-straight, towering trunks were made of high-quality, rot-resistant timber. The wood was used for barn beams, house framing, furniture, telegraph poles, fence posts, paper pulp, caskets, and cradles. There is no wood so versatile as American chestnut. It has the durability of black locust, the straight grain and splittability of ash; it’s as stable and easy to work as pine, and very fast growing.
The wood value alone would have made the American chestnut a highly valuable tree. Adding the dependable crops of nuts makes this tree stand alone in its excellence. The wildlife value of American chestnut was unparalleled, as nuts could fill the forest floor more than a foot deep in some years. Along with wildlife, people also ate wild American chestnuts. They grazed their animals under these magnanimous giants during the fall and gathered nuts by hand. Chestnuts were collected in great quantities throughout the Appalachian Mountains, and roasted and sold on the streets of towns like Boston, Philadelphia, and New York. Train-car loads were filled with this wild crop. Today many families find financial relief with their end-of-year tax credit. Back then people found their Christmas bonus in the form of selling what chestnuts they could gather in the mountains.
The American chestnut was a keystone species in the ecology of the Appalachians.
It was culturally fixed in the minds of Americans, and used widely. Tanneries cranked out leather that was processed with the tannins of chestnut bark, paper mills pulped the wood, railroad companies laid track with timbers, people built barns and houses, fences, and chairs. They ate the nuts raw and roasted every fall. And then it all crashed.
In 1904 chestnut blight, Cryphonectria parasitica, was discovered in the Brooklyn Botanic Gardens. From there it spread like a wildfire, consuming trees and turning forests of green into silvery gray ghost woods. Within just 25 years an estimated four billion trees died. An entire ecology, an entire culture, was wiped out. While the trees were dying, the US Forest Service advised people to have all their chestnuts logged. Believing there was no hope, they told folks to get some lumber out of it while they still could. We will never know how many resistant trees were killed in this shortsighted practice. Sadly, this mindset persists today, as foresters commonly advise landowners to log all their ash and hemlock trees before the coming crash.
Cryphonectria parasitica is a fungus whose spores spread by wind. Its origins lie in Asia, where trees there have co-evolved with the fungus. When Japanese chestnut seedlings were brought over to the US for people’s gardens, no one noticed that these seemingly healthy trees carried the blight with them. The American chestnut had never encountered this fungus and so had almost zero resistance. People scrambled to save the chestnut tree in vain, employing all sorts of strange strategies over the next several decades before giving up for the most part.
There were some really wonderful early attempts at saving the American chestnut, notably the work of Arthur Graves. He planted several thousand seeds of anything he could get his hands on, including every species of chestnut from around the world. He crossed every species and then crossed the resulting hybrids. Many of his trees are still alive and maintained to this day at the Connecticut Agricultural Experiment Station by the committed and innovative work of Dr. Sandra Anagnostakis. Graves was never able to find the winning combination of a true timber-type tree and full blight resistance—though he found many trees that came close. The work of Graves and Anagnostakis continues today. Dr. Anagnostakis continues to plant trees, make controlled crosses, and spread hypovirulence. Today the Connecticut Agricultural Station and Sleeping Giant State Park are home to the largest repository of chestnut genetics in the world.
Other attempts at saving the American chestnut included cutting out all the trees in a large swath of land across Pennsylvania to act as a kind of rebreak. The budget for this project was enormous but could not keep up with the winds that carried blight spores. In the 1950s, when nuclear power was at the height of popularity, people irradiated nuts to hopefully invoke a mutation. Of course, this failed miserably.
As the years wore on, and generations passed, interest in the chestnut grew less and less. The American chestnut became a legend, with little practical hope of recovery. That is, until two visionary men in the 1970s, Dr. Charles Burnham and Phil Rutter, came up with a plan. It was simple enough: Cross American trees with resistant Chinese trees. The resultant seedlings would then be backcrossed with American trees again and again until they had a tree that would behave like the American chestnut of ancient forests. The tree they worked to create would have fifteen-sixteenths American genetics. This would take several generations of crosses. Dr. Burnham knew he would never live to see the full breeding program to its completion, but he started it nevertheless as a selfless act. This was the beginning of The American Chestnut Foundation (TACF).
TACF would go on to plant thousands and thousands of seeds from multiple lines of genetics. For every tree they leave to grow, hundreds are cut down in this rigorous and highly organized breeding program. Today TACF has trees that are fifteen-sixteenths American and display both timber form and blight resistance. These trees are being planted experimentally in parks, at private homes, at institutions, and in reforestation efforts.
Many folks continue to plant and grow 100 percent pure American trees as well as hybrids. American chestnut seed is available through TACF state chapters. The trees grow quickly. They typically live for 15 years before succumbing to blight. In this time they produce small crops of nuts and excellent pole wood. Since the blight cannot kill the root system, the trees sprout back after the blight knocks them down. They can be kept going indefinitely in a coppice system. Growing American chestnuts from seed also expands the genetics of this magnificent species.
There are other programs in action today. The American Chestnut Cooperators’ Foundation grows only 100 percent pure American chestnuts. They maintain trees that exhibit resistance through grafting and seed collection.
SUNY’s College of Environmental Science and Forestry, along with the New York chapter of TACF, is genetically engineering blight-resistant chestnuts. They have introduced a wheat gene to resist the fungus. The trees are currently not released for public planting pending government approval. This program is considered by some native-plant enthusiasts to be superior to the traditional breeding program of TACF because the trees are less “contaminated” with Chinese genetics. However, it’s interesting to note that Chinese chestnut and American chestnut share most of each other’s genes; the hybrids that TACF grows are actually over 99 percent genetically American chestnut.
The story of the American chestnut is far from over.
Today we can grow resistant hybrids or pure American trees. We can bring this species back into our parks, homes, and wildlands. There really is no reason not to. Millions and millions of people live in the range of the American chestnut. If just 1 percent of them chose to plant a few trees, we’d have a lot of chestnut trees around.