Woodsense: American Chestnut

WoodSense: American Chestnut

Down, but not out

A keepsake box. This lift-off lidded box was finished with two coats of wipe-on polyurethane, adding protection and a subtle sheen in keeping with chestnut’s rustic character.

It’s been said that in Colonial times, a squirrel could travel from Maine to Georgia solely on the intertwined branches of the American chestnut (Castanea dentata). But one of the first things European settlers unpacked were axes that felled those trees for cabins, barns, split-rail fences, and a host of other needs. Water- and steam-powered sawmills accelerated the availability of the lumber until it was a literally a cradle-to-grave proposition: using chestnut for baby beds, adult caskets, and everything in between.

At the same time, wildlife, farm animals, and humans all enjoyed eating chestnuts. The trees were so bountiful that Appalachian residents talked of “summer snows,” when the chestnut’s yellow-white flowers covered the forest’s floor, and excess nuts became a cash crop in autumn.

Enter the blight

Human destruction of chestnut trees paled in comparison to the epic annihilation caused by a parasitic fungus accidentally introduced with chestnut trees imported from east Asia for commercial cultivation. The fungus arrived in about 1904, and by 1940 virtually every mature chestnut tree in the United States—an estimated four billion—was dead.

As a result of the blight, the American chestnut tree is functionally extinct. The trees simply don’t survive to maturity. But don’t be in a hurry to sign the death certificate. As Miracle Max explained in The Princess Bride: “There’s a big difference between mostly dead and all dead.” The still-healthy roots often push up shoots that can grow about 15 feet tall before succumbing to the fungus—over and over. But there are several teams working hard to break that cycle and restore the tree to American forests.

Side-stepping the blight

The American Chestnut Foundation has been pursuing multi-prong strategies to overcome the blight. In one effort, they are using traditional hybridization techniques to retain most characteristics of the American chestnut while adding the blight-tolerant advantage from the Chinese chestnut. Meanwhile, the State University of New York has genetically modified an American chestnut cultivar that can survive the blight. Interestingly, should a traditional hybrid prove successful, it can be immediately planted in the forest, but the DNA-altered cultivar must pass regulatory scrutiny by multiple Federal agencies to help ensure that there are no potentially catastrophic unintended consequences.

It’s a character-building experience

Despite the fact that virtually no living chestnut trees have been harvested for a generation, the wood is remarkably available, though the price is relatively high for a domestic hardwood. Extremely durable and rot resistant, dead chestnut trees can survive standing for a long time, but often suffer damage from borers. Demolished barns, industrial buildings, and other structures serve as another chestnut source. This salvaged lumber may also be wormy and/or have holes and mineral staining from extracted nails and other fasteners. This defaced wood is called “wormy” chestnut and usually commands a premium price. Go figure.

Chestnut in use

These days, chestnut sees use as paneling, wainscoting, interior millwork, cabinetry, furniture, and small projects such as boxes. Some dealers intent on selling chestnut by the truckload tout its use for flooring, but given the wood’s softness, I question the wisdom of that. Chestnut has a Janka hardness rating of 540, identical to poplar, but less than half of red oak’s 1220 mark.

In my mind, chestnut’s relative softness and coarse grain structure, combined with the fact that it’s ring-porous, rule it out for cutting boards and kitchen utensils. The open grain structure also means that you would likely need to fill the pores if you want a glossy surface (see Pore Filling in the Feb/Mar 2023 issue of Woodcraft Magazine). But I personally feel that chestnut’s rustic character would be out of step with a slick finish.

Note that chestnut’s coarse grain makes it vulnerable to splitting—great for fence rails—but a potential problem in smaller woodworking projects. Exercise caution with nails, make sure screw pilot holes are properly sized (or even slightly oversized), and dial back on your driving torque.

As I was making the box pictured above, I was pleasantly surprised with the smooth surface I got from running boards though my thickness planer, and the chestnut worked easily with both hand and power tools. I didn’t use any stain on the wood, but it’s reported to readily accept colorants without problems. There are no acute allergic or respiratory cautions linked to chestnut, but you’ll be wise to follow your usual best shop practices.

A stately giant. During its heyday, chestnut trees routinely grew 60 to 100 feet tall, with trunk diameters of 2 to 4 feet. But vintage photos also show massive specimens that would have intimidated any pioneer woodcutters not named Paul Bunyan.

Bristly pods. The spiked exterior of the chestnut fruit often cracks open while still on the tree, spilling two or three seeds ½- to ¾-inch long that develop a deep brown color.

Chestnut trivialities

Composing a cool song. The Christmas Song, commonly subtitled “Chestnuts Roasting on an Open Fire” was written during a blistering heat wave in July, 1945. Originally, Bob Wells and Mel Tormé were merely trying to think of winter scenes to cool themselves. They began by scribbling four lines into a notebook, but forty minutes later, both music and lyrics of the classic song were virtually complete.

On the Red List. The American chestnut tree is listed as critically endangered by the International Union for the Conservation of Nature (IUCN).

It’s a truly towering mountain. You can see small groups of living American chestnut trees along the Blue Ridge Parkway near Mount Pisgah, North Carolina. That landmark is easy to identify because its summit sports a 339-foot television transmission tower.

Not the new kid on the block. There’s evidence that humans have cultivated chestnut trees since 2000 BCE. Soldiers in Alexander the Great’s army reportedly planted seeds when they weren’t busy conquering the world.

Not in the family tree. The American chestnut tree is not related to the horse chestnut (Aesculus hippocastanum), nor the Ohio buckeye (Aesculus glabra), and definitely not to the water chestnut.

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