The Palisades Interstate Park is a National Historic Landmark.
Palisades Interstate Park in New Jersey

Requiem for a Nut

Palisades shore.

Castanea dentata. From An illustrated flora of the northern United States, Canada and the British Possessions, 1913.
Castanea dentata. USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. Vol. 1: 615.

“Requiem for a Nut” was first published in the October 1998 issue of “Cliff Notes.”

The story of the chestnut blight is from Trees: An Introduction to Trees and Forest Ecology for the Amateur Naturalist, by Laurence C. Walker (Prentice-Hall, 1984). Special thanks as always, too, to the staff of Greenbrook Sanctuary for additional insight.


What the...?

Every now and again we get an almost frantic phone call asking if we know what on earth that plant with the “really big leaves” is. They are usually noticed along Henry Hudson Drive. “I mean,” the caller will exclaim, “they’re gigantic!” And indeed they are, often a good two feet long and almost as wide—something you’d expect to see a brontosaur munching on.

The culprit is invariably the Paulownia tree (P. tomentosa), a native of China which, over the past decades, has gained a solid foothold here in the Palisades (this is the same tree whose fragrant lavender flowers frost the cliffs so prettily in the Spring). In all likelihood, our Paulownias descend from someone’s cliff-top estate, planted perhaps a century ago as ornamentals. They’ve come to thrive in our rugged environment, often displacing native vegetation. (Whether they benefit or harm the “natural” habitat here remains a subject of debate.)

The trees grow to about 60 feet tall, but the biggest leaves occur on the youngest trees (this is typical of most trees). The Paulownia, as a by-the-way, was named in 1835 to honor Anna Pavlona, daughter of Paul I of Russia, and it is sometimes referred to as “The Empress Tree.” In its native Orient, its soft wood is valued as building material for crates and boxes, including caskets. Such use has yet to catch on here.


Addendum

Several of our readers have brought an interesting part of the chestnut story to our attention. In a number of laboratories across the country, efforts are underway to develop a strain of C. dentata resistant to the fungus, and preliminary results are promising. At the University of Tennessee-Chattanooga and elsewhere, scientists have met some success in crossbreeding the American chestnut with a blight-resistant Chinese chestnut. Thus far, the efforts show the potential for a blight-resistant tree whose nut is, apparently, every bit as delicious as that of the original American tree, and scientists are guardedly hopeful that the trees can be reintroduced to the wild.

Researchers at the State University of New York’s College of Environmental Science and Forestry in Syracuse, meanwhile, have been working in even more esoteric realms, experimenting with animal genes in the hope of producing a blight-resistant chestnut tree (the African clawed frog has so far proved most promising). They have now been able to use a gene transfer process to produce dozens of “transformed” chestnut shoots in Petri dishes, and the next obstacle is to plant the shoots and see if they can be grown into saplings. They hope to be able to accomplish this by the end of this year.

Our thanks to John Reutershan of the Bronx and Ron Keeney of Teaneck for alerting us to these developments, and to Milt Nelsen of Granville, NY, for sending along a news clipping.


Imperial “Peanuts”?

Our thanks to Fred Binder for tracking us down with a new theory for the local origins of the Asian Paulownia, or “Empress tree,” now so widespread here. It seems a century ago the Paulownia’s seed pods were used as packing material, much as today we use those little Styrofoam “peanuts.” So rather than starting as ornamentals planted on a cliff-top estate — did they gain their toehold by way of someone’s trash pile…?

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“With Blue Sky Above and the majestic Hudson Below … A glorious confusion of color — yellow and orange, scarlet and crimson, intermingled with the eternal green of the hemlock and fir — and above all, a line of perpendicular gray cliffs, standing out against a deep blue sky! Thus at this season of the year appear the Palisades, robed in the glory of Autumnal foliage, while the majestic Hudson — a dreamy haze hanging over its bosom — flows silently past their base on its way to the sea…”

So wrote the New York Recorder in October, 1893. And while we may find the prose a bit overblown, the description still strikes us as quite apt of this most enchanting time of year, when our tall cliffs and their tenacious forests never seem more wildly picturesque.

It may be tempting, then, to suppose that here, at least, a piece of New Jersey’s woodlands has been preserved as it has stood for centuries untold, a sliver of the Forest Primeval just as Henry Hudson came upon in 1609. Tempting — but extravagantly unrealistic. For in truth the forest world is a dynamic one, and even in those places we assume to be relatively “pristine,” dramatic changes have occurred over the centuries — changes now vastly accelerated by human activity.

No tale, we feel, brings this truth closer to home than that of the American chestnutCastanea dentata.

At the time of Hudson’s visit, this cousin of the oak was in all likelihood the dominant tree of the Palisades — as it was for much of the Eastern Seaboard, thriving in acid upland soils from New England to Alabama. (In the Appalachian Mountains, it is believed that as many as one in every four trees was an American chestnut.) The chestnut was a blessing to the settlers who followed Hudson, its delicious nuts soon a dietary staple. Its bark was stripped and used for roofing. Boards hewn from its straight trunks and limbs were found to season well and take to gluing and nailing without warping or shrinking. A fast growing tree — one of the reasons it was so successful — it could be harvested with little threat of being wiped out. Hard and lightweight, it was easily worked, with the finished product taking a high polish, making it a favorite for furniture stock, while its graceful form shaded innumerable courthouse lawns. Perhaps best of all, its wood was famously resistant to rot, ideal for fence posts and, later, railroad ties. By the mid-nineteenth century, it had become one of the most important trees economically in North America. (Besides its other virtues, its bark and wood were rich in tannic acid, essential for leather-making, and the chestnut became a mainstay of the American leather industry. Wood pulp, a by-product of tannin extraction, made it a mainstay of the burgeoning paper industry as well, resulting in an often complex, interdependent relationship between the two industries.)

And none of this even hints at C. dentata’s ecological importance to our native forests. In this ancient world, the fast growing, resilient tree with its nutritious fruit was no less a mainstay, in many ways defining the forests in which it grew. (The term “chestnut-oak forest” gets repeated time and again in the descriptions written by naturalists of a century ago.) To say this tree was an integral part of the forest habitat here in the East is, surely, grossly to understate matters.

No wonder, then, that around 1904 and starting here in the New York region, not even professional naturalists seemed to recognize how momentous a tragedy was underway, as the first chestnut trees began to die.

A forester named Herman W. Merkel noticed something wrong with the chestnuts on the grounds of the Bronx Zoo in that year. Cankers had formed on their trunks, encircling them. The cankers were soon to kill the trees above the point of infection. Mycologists in the New York Botanical Garden identified the culprit as a previously unknown fungus, to which they gave the name Endothia parasitica. Still, E. parasitica was at that point seen as an interesting but relatively unimportant event, a topic for specialists to discuss. Even as the blight spread into neighboring states, scientists were slow to recognize the potential enormity of the disaster, and it was not until 1911 that funds were first appropriated — $5,000 by the U.S. Congress — to combat the problem.

By then trees in Philadelphia had begun to die.

The following year Congress upped its appropriation to $80,000, and in 1913 the Pennsylvania legislature would itself weigh in with an appropriation of $240,000 and the creation of a Chestnut Tree Blight Commission. This was an impressive outlay in the dollars of the time, and a strong course of action for a state to take on behalf of a tree.

Unfortunately, it was already too late.

That same year, botanists working in China found the blight on chestnut trees “9 days by bullock cart northeast of Peking.” This seemed to confirm what the Blight Commission had come already to suspect, that the disease had originated in the Orient, most likely arriving in New York Harbor with a shipment of nursery stock from China. But how had it spread so quickly? Certainly, its spores could be carried by the wind, perhaps as far as half a mile on a dry, gusty day. Yet that could hardly account for its spread across hundreds of miles in a few short years.

E. parasitica, it turned out, had two kinds of spores, the smaller of these having the more effective mode of travel. These had thin, gelatinous threads attached to them, and they stuck by the thousands to the feet of birds. (As many as seven thousand were counted on the feet of a single woodpecker.) At last the sobering magnitude of the disaster became apparent: not a single chestnut tree in North America could be considered safe.

By the end of the World War I, the North American “chestnut-oak forest” was a standing graveyard, the dead trunks, in a macabre testament to their famed tenacity, still upright, their wood to be harvested for decades to come. (Much of the wood in the structures built by the New Deal agencies during the 1930s here in the park was chestnut taken from the standing dead on the Palisades.) Fence posts and railroad ties, some cut a century or more ago, are still sought by craftsmen and builders to this day.

Here on the Palisades, a handful of adult chestnut trees still survive (a large specimen only succumbed in Greenbrook Sanctuary about five years ago). Sadly, their fruit remains infertile. Saplings sometimes spring from the stumps of former giants; almost invariably, they soon contract the blight and die.

Extinction is, as they say, as old as the hills. And if, as they also say, there are a million stories in the naked city, then there may be a million more in the leaf-clad world of the forest, where life and death and change are the endless norms. The forest habitat has always been a dynamic one — only the pace has picked up some in recent centuries. The story of the American chestnut is a particularly dramatic example of an ongoing theme in our modern world, as we bring the four corners of the globe into ever closer contact. (The “eternal green” of our hemlock groves has also begun to whither and fade in recent years, another blight brought to this continent from afar.) And as in the case of “natural” extinction, of course, new species are always ready to fill the proverbial vacuum so abhorred by nature (see related story, below).

Certainly, we don’t mean to put a damper on anyone’s enjoyment of fall, a time of year when we tend to notice trees more than at any other—for in the appreciation of nature may begin the road to its preservation. Nor do we offer any handy, pat solutions for the kinds of issues raised by the tale of the chestnut. But as stewards of a “natural” preserve, neither can we safely ignore such tales, as they continue to have a direct bearing on the land in our care. Certain tales of the forest, we feel — even sad ones — should be told.

PIPC

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