American Chestnut – Down But Not Out

Could American chestnut be the wood of choice for future generations of woodworkers? Well, I’m not quite ready to make that prediction but there is reason for optimism. As some of you may know, chestnut was one of the dominant tree species in the eastern forests of North America a hundred years ago. It’s estimated that in the early 1900’s, one in four hardwood trees in this region was a chestnut! The trees grew tall and fast, providing habitat and food for wildlife and humans. And the lumber had a myriad of uses: railroad ties, fence rails, poles, flooring, framing, molding, shingles, musical instruments, caskets, cabinets, tables, chairs, chests and many other types of furniture.

But then the zombie apocalypse happened to the American chestnut in the form of the chestnut blight. Asian chestnut trees were brought to the U. S. in the late 1800’s, carrying with them a fungus that effectively chokes off the tree by blocking the flow of water and other nutrients through the tree. The Asian varieties of chestnut had long since evolved a resistance to the fungus blight but the American chestnut had almost no resistance. The effects were devastating. By the 1950’s, the American chestnut was virtually wiped out – over four billion mature trees died en masse.

Growing up in the mountains of eastern PA, I would occasionally discover a chestnut in the wild but these trees were the walking dead. They would last for perhaps a decade or two before succumbing to the blight.  The young trees had grand aspirations but the blight had other plans – it was too mighty a foe. Yet I couldn’t help but admire the chestnut’s persistence – it managed to survive for years as living roots and stumps, continuously producing saplings seemingly intent on regaining their place as mature trees in the upper echelons of forest society. Alas, this scenario has yet to play out.

I recall my dad lamenting how he used to pick chestnuts as a kid (roasted on a coal stove, they were a holiday season delicacy) but over time, the trees died off and the tasty chestnuts disappeared. I felt bad for my dad and the American chestnut.  As a forest science student at Penn State, this feeling was reinforced when I learned more about the former majesty of the American chestnut and the important role the tree played as a food source and building material. It was hard to grasp how a tree that was a major component of the eastern forests for centuries became nearly extinct within such a short amount of time.

The good news is that efforts to produce a blight resistant chestnut (which have been underway since the 1930’s, believe it or not) are showing a lot of promise in recent years. Most of the focus has been on breeding American chestnuts with blight resistant Chinese chestnuts. For the first 40 years or so, this breeding program appeared destined to failure as most of the offspring exhibited very poor survival rates when planted in the wild. But then a savvy corn geneticist by the name of Charles Burnham got involved and realized much improved results with the introduction of a technique known as backcrossing. The basic idea here is to cross American and Chinese trees, then breed successive generations of young trees back to the American parent. Over time, this produces a hybrid with most of the desired characteristics of the American chestnut but with the blight resistance of the Chinese tree. The final hybrids are typically 1/16 Chinese and 15/16 American chestnut.

In 1983, Burnham and other plant scientists founded the nonprofit American Chestnut Foundation (ACF), with the goal of restoring the American chestnut to the U.S. eastern woodlands, relying on backcross breeding and other advances in plant breeding. The ACF in conjunction with several universities and government entities such as the USDA, has established a number of plots in the eastern U.S. where thousands of small hybrid chestnut trees are currently growing. The ultimate success of these plantings won’t be known for decades but early indications of blight resistance are encouraging.

In another encouraging development, researchers at SUNY have successfully created a blight resistant American chestnut using genetic engineering. They managed to identify a gene from a wheat plant that when introduced to chestnut tree cells, imparts blight resistance to the resulting plant and it’s offspring! This variety is almost 100% American chestnut and so far, has exhibited no ecosystem-unfriendly side effects. Currently, these trees are only grown in research plots. Before they can be planted in the wild, several more years will be required to get through the approval process of the FDA and other federal agencies.

Chestnut wood is straight-grained, rot resistant (ideal for exterior applications), light-weight, stable in service, and easy to work with both hand and power tools. It strongly resembles oak. It finishes easily, responding well to most any finish. In short, chestnut is a dream wood for woodworking. The only catch is the price since the only available supply is decades-old wood, typically reclaimed from old buildings. A wood that was once so common, people thought nothing of using it for cheap railroad ties or fence posts, now commands a premium due to its scarcity. I did a quick check online and found chestnut flooring going for $9 to $12 a board foot from several vendors.

I’m keeping my fingers crossed that the American chestnut blight resistance breeding programs will be successful and that someday woodworkers will once again have access to affordable chestnut lumber. I’m not sure that will occur during my lifetime, but who knows?

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