The demise of the queen of the forest

By Dr. Robert A. Hedeen


The American chestnut was once known from Maine to Minnesota, and southward to Florida and Mississippi, as the queen of the forest. But the children and most adults of today have been deprived as a part of their birthright, to a significant species of our native flora.

A few generations ago, there was no finer sport for youngsters than to go hunting for chestnuts on a crisp autumn day when the first frost had opened the big burrs, with the fierce-looking prickles on the outside. The open burrs meant there were chestnuts to be found on the ground below.

When I was a boy, my grandmother described to me her childhood joy of gathering chestnuts in the hills of her native eastern Tennessee. The nuts were usually taken home and roasted in the fireplace, but they were sometimes boiled, mashed, or eaten on the spot. She described the flavor of the nuts as delicious whether they were eaten raw or cooked.

I remember with pleasant nostalgia the smell and taste of roasting European chestnuts sold in the fall by vendors along the Champs Elysses in Paris during the years I lived in France.

If children prized the American chestnut for the nuts it produced, others held it in high esteem for other reasons. Its straight-grained timber split easily, burned almost without smoke, and was resistant to rot because it was impregnated with tannin.

Being resistant to decay and insect damage, the wood was ideal for fence posts, rail fences, telegraph poles, ship masts, furniture, construction and many other uses. Tannin extracted from the tree supported the leather tanning industry in many areas.

Now, for all intent and purpose, the American chestnut is no longer with us, having fallen victim to a blight caused by a virulent fungus introduced into this country from Asia about 1900. The deadly blight was first noticed to be attacking chestnuts growing on the grounds of the Bronx Zoo in New York City in 1904. Unimpeded by natural barriers and a completely defenseless host, the invasive fungus spread like a prairie wildfire, and by 1950 it had decimated the chestnut throughout its range east of the Mississippi River.

Plant pathologists worked to no avail to stem the spread of this disease or to find a cure. There was hope at first because from the roots of the skeletons new shoots frequently grew (the fungus kills only that part of the tree above ground). But the disease-producing organism invariably cut down these new growths before they reached reproductive age. Until fairly recently, it seemed there was no hope that the American chestnut would ever again occupy a place in our forests.

Now the situation has changed. In 1938 the blight gained a foothold in Italy and quickly went to work destroying the European chestnut in that country and in France. But, due to the fact that European chestnuts do not occupy a continuous range as they did in this country, the spread of the disease was much slower.

French and Italian botanists were elated when in about 1960 they noted that the cankers caused by the fungus on some trees had stopped enlarging and were actually healing over. It was discovered that the fungus had mutated and changed from a hypervirulent strain to a hypovirulent type that was much less toxic.

When the less toxic strain of fungus was used to treat a dying tree, the hypovirulence was incorporated into the old strain, and the infected tree was able to fight off the ravages of the blight.

Researchers in this country have not yet been able to replicate the results obtained with the European chestnut, but continuing experiments are promising. Botanists at the Connecticut Agricultural Experiment Station have been able to deter the growth of cankers in greenhouse seedlings by injecting them with this hypovirulent strain of the fungus. But survival of these seedlings in the wild did not occur. In the late 1970s, however, an American brand of the hypovirulent fungus was found in a rare, mature American chestnut in an isolated location in Michigan. Work continues with this American strain of the non-virulent pathogen, and hopes are high.

Though most of us living today will probably never see a fully mature American chestnut growing in its rightful place in our forests, it is quite possible succeeding generations will have that pleasure. Let’s hope the poet Robert Frost was correct when he penned the following:

“Will the blight end the chestnut?

The farmers rather guess not.

It keeps smoldering at the roots,

And sending up new shoots,

Til another parasite shall come

To end the blight.”

Dr. Robert Hedeen is a former resident of Maryland’s eastern shore and resided in the Chicago area from 1960-1971. He is a retired professor emeritus of biological sciences in the University of Maryland system. He has published more than 30 scientific papers, has written numerous magazine articles, and is the author of two books on the natural history of the Chesapeake Bay.

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