Blight leaves native American chestnut out on limbPast is Prologue / By Dr. Kent Mountford - Bay Journal
“In some parts were found some chestnuts, whose wild fruit equalize the best in France, Spain, Germany and Italy.” — Capt. John Smith, Generall Historie, 1624
This quote from the watershed’s first English explorer/chronicler at first seems faint praise for the American chestnut (Castanea dentata) which would subsequently be described by others as “the most valuable and usable tree that ever grew in the Eastern United States.” A careful look at the chestnut’s natural range, though, reveals that it was not an abundant species in the parts of Southeast Virginia and the Delmarva Eastern Shore where John Smith spent most of his two years (1607–09). In fact, the chestnut was not a dominant forest species in much of the pre-settlement Chesapeake coastal plain and some areas of the watershed.
The abundance of chestnuts may have been underreported. An uncertain (the plant specimen has been lost) collection of American chestnuts by 17th century botanists was originally misidentified as an oak (Quercus mariana) and palynologist Grace Brush of Johns Hopkins University suggests that early settlers may have confused true chestnuts with the chestnut oak (Quercus prinus) during the months when nuts and flowers are absent.
Many early land surveys, especially in Pennsylvania and New York, used sentinel trees to mark boundaries, which might give us an idea about the relative abundance of some species. Chestnuts were used as markers in 5–15 percent, and in some cases, 25 percent of the time. In the same areas, white oak (Quercus alba) was used 25–65 percent of the time and to the north, American beech (Fagus grandifolia) made up 25–75 percent of the markers.
This comparison may not be precise, though, especially if the surveys were made on land suitable for farming, which is flatter than the hilly habitat preferred by chestnuts. Some authorities in Pennsylvania even list chestnut as the dominant tree in the state prior to the American Revolution.
Parts of the James River basin, a high and hilly region with relatively poor, but well-drained soils, contained extensive areas of nearly pure chestnut stands with 100-foot high canopies. One record tells of a giant tree with a 17-foot diameter.
In any case, the chestnut was of great economic importance in the Appalachian areas of what would become Maryland and Pennsylvania. Experts estimated that it represented half of the commercial value of all Eastern North American hardwoods. Eastern loggers sometimes filled an entire train with the straight-grained saw timber from a single giant chestnut.
The chestnut’s increasing abundance may reflect the effects of European settlement on the composition of North American forests.
In 1894, J.T. Rothrock, writing about Pennsylvania’s forests, said that it was the only species that regenerated from stump sprouts as fast as it was cut by greedy 19th century wood harvesters. The practice of “coppicing” or cutting young trees to encourage the growth of shoots, was pretty general.
One writer said of American chestnut: “Hence there is a happy increase of these valuable trees over others in the country.”
Humans are meddlers. Not satisfied with just one chestnut, efforts were made to add others to our horticultural inventory. It began with Thomas Jefferson who, after his diplomatic tour in Europe, imported the European, or Spanish chestnut (Castanea sativa) and grafted it onto native root stocks at Monticello. In 1876, S.B. Parsons, a nurseryman in Flushing, NY, imported the Japanese chestnut (C. crenata). More were brought over in 1882 and 1886.
The Chinese chestnut (C. Molissima) was brought here in 1900 by G.D. Brill from Hankow and Ichang. More arrived from Canton in 1902; most going to a seed nursery in Bell, MD, to see how they could be exploited as ornamentals and nut producers.
In 1904, sharp-eyed nurserymen at the Bronx Zoo found odd cankers on American chestnut shade trees lining the park’s avenues. Beginning with a crack or injury in the bark, they either formed a swelling or a depressed area that would eventually girdle the twig, branch or tree and kill it. While temporary survival is possible as limb after limb dies, the eventual loss of each tree is inevitable.
It spread quickly across New Jersey and southern New England, and was known as Chestnut blight. By 1906, W.A. Murrill reported “the disease is known to occur also in New Jersey, Maryland, the District of Columbia and Virginia.”
Oblivious to the blight and unaware of the coming disaster, Arthur Emerson and Clarence Weed’s 1908 tree book featured the chestnut in its frontispiece, and called it “one of the best known of all the trees of the forest … one of the most promising trees for forestry planting.”
Horticulturalists, too smart by half, found a blight-free area in Pennsylvania and quickly brought in a bunch of the imported trees to form an experiment station. It is likely that the blight was transported with them to create a new epicenter of disease and accelerate its disastrous spread. The blight was transported into minute bark-wounds by boring and flying insects and woodpeckers. All efforts at control were fruitless.
In 1913, botanical explorer Frank Meyer went to Asia and found the source of the cankers: an ascomycete fungus, (Endothelia parasitica renamed in 1978 to Cryphonectria parasitica). He also discovered that the Asian chestnuts are more resistant than the American trees.
Within about four decades, almost all of these remarkable native trees were gone, creating ecosystem shockwaves that still reverberate on the Eastern Seaboard. By 1940, virtually all — an estimated 4 billion — American chestnuts were dead or infected with the blight. Along Appalachian mountain ridges, tall, gaunt skeletons of these once magnificent trees stood — rot resistant — for decades.
Chestnuts became the dominant wood processed at Pennsylvania sawmills in the early 1900s, which Brush says is the result of salvage logging to make use of the dead and dying trees.
In 1912, Congress passed the Plant Quarantine Act, which has helped to reduce, but never eliminated the chance for such a catastrophe to occur again. With the onset of World War I in 1914 and the Great Depression in 1929, resources to study or remedy the infection were all but shut off, assuring the virtual extinction of this marvelous tree.
The American chestnut grew well where the soils were shallow and poor and on slopes, often facing north and east, and at altitudes up to 4,000 feet. It disliked poorly drained, limestone-based soils. The presence of tulip poplars today sometimes indicates the past distribution of chestnuts.
This was the case when we explored the forests surrounding our home on Osborn Cove after we moved there in 1974. At the time, tulip or ‘yellow’ poplars (Liriodendron tulipifera) rose in 100-foot colonnades in two valleys sloping steeply toward a creek. Ring counts on their trunks indicated that the largest of these trees had germinated in the early years of the 20th century.
Former residents said that at the turn of the 20th century, groves of American chestnut covered these north-facing slopes and that people would gather the nuts once their burs had opened.
These were either bartered locally for dry goods (One recollection from Kentucky, circa 1898-99, said the worth of a gallon of nuts was equivalent to 12 to 15 cents.) or taken to Baltimore and sold roasted on the streets. Workers in the field ate them raw, roasted them on a shovel over a campfire or put them in a low oven at home for 20 minutes, having scored around the husk so they’d open easily when hot.
A core driven 87 centimeters into the bottom of Quicksand Pond on our property that dated back to the 18th century was analyzed by Deb Willard and colleagues at the U.S. Geological Survey for the pollen history trapped in its muddy depths. The bottom — and therefore oldest — part of the core showed that chestnut pollen was present in the 18th through the 19th century, but had abruptly vanished early in the 20th century. As this important canopy species suddenly died, the erosion of sediment into the pond sharply increased, accumulating as much in 50 years as it had in the previous 150.
We found the fallen skeleton of an immense American chestnut in 1974 at the head of one of our valleys, where it had crashed after dying in the 1920s or 30s. Its trunk was only about a yard in diameter.
About midcentury, the land’s former owners had gathered and split straight portions of the trunks and limbs from these fallen sentinels to build a “stitch” fence, almost 200 feet long with rails laid in zig-zag rows atop each other.
Chestnut is extraordinarily durable for fencing where it comes into contact with the earth. While the consumption of wood was great — a Virginia rail fence requires about 800 rails of 4-inch diameter, 10 or 11 feet long, to enclose a single acre — farmers avoided the arduous labor of digging post holes and the greater loss to rot of buried fence posts. The fence near our property, for example, lasted to the beginning of this millennium.
The fallen tree in our valley had been there half a century when we came upon it in 1974; and during a wet, winter walk in 2002, I found it again, its remains still strong and long enough to build another, if a trifle moldy, fence!
A lot of chestnuts went into railroad ties in the 19th century. Because they grew straight and tall without lower branches in close woodland habitat, chestnuts were ideal for telegraph and telephone poles. Their durability eliminated the need for creosote or today’s CCA (copper-chrome-arsenate) preservatives with their toxic effects.
Chestnut’s straight grain and tendency to split true, made it ideal for tobacco sticks as well. “Hands” or bunches of leaves were placed over these sticks and hung from rafters in curing barns during the preparation of this valuable colonial product for market.
Chestnut was also easily split into firewood. In 1850, 90 percent of the fuel used in the United States came from firewood, and the figure was still 50 percent in 1880. The energy value of chestnut, though, is only 63 percent that of hickory, and 73 percent that of the more common red oak. The USDA ranks chestnut 12th of 16 in energy content among major native woods used as fuel.
Chestnut was ideal for kindling, and when used in the front of a fireplace it burned brightly enough to light rooms, thus conserving expensive candles in the days before electricity. It also produced a quick, hot fire for hearth or cook stove.
It was eminently durable in house and barn construction as well, stronger and lighter than oak. Many of the chestnut sills in surviving log cabins are intact after centuries, despite termites and without care other than shelter from excessive rainfall.
When a parent tree dies from the blight, a stump-sprout response, similar to its reaction to coppicing, often occurs, with small trees rising over a decade or two, perhaps even bearing a crop of nuts, then dying like their forebears.
Northeast of the big downed chestnut at Osborn Cove, one stump sprout grew, setting its last nut crop in the 1980s. It died in 1999. I cut and saved the base of its trunk as a remnant.
The USDA’s Natural Resources Conservation Service suggests stump-sprouts, with their extensive nitrogen-hungry root systems, might be ideal contributors to natural riparian buffers which protect adjacent streams. Carry on, old trees!
Chestnut’s importance to wildlife was immense. Nut gatherers had to be up early to compete with large flocks of wild turkeys that gorged on the fruits during their three-week falling period. Little wonder someone had the idea to put chestnut stuffing in the holiday roast turkey!
The turkeys would sometimes adopt a threat posture, wings wide-spread, and leap or “dance” to scare away deer who had the same feeding objective.
Chestnuts flower long after the last frost and until the blight struck, provided a reliable crop each year. Red oak acorns, another important source of food for wildlife, take two years to develop. Late spring frosts two years in a row that kill its flowers, set the acorn cycle back and can prove disastrous for species like squirrels, which are dependent on them for food.
This might be the case for the Allegheny wood rat, (Neotoma magister) population, which has declined and been extirpated in parts of its range since chestnuts disappeared.
The Chinese chestnuts that today line the path to Osborn Cove on Maryland’s Patuxent are half a century old and extremely productive. In 2000, the largest two produced about 2,800 nuts and in 2001, more than 3,000.
Because turkeys are timid near the house, deer and squirrels are the primary beneficiaries, the former pawing the needle-sharp burs open with a hoof and delicately lifting out the nuts with their mouths. I am left to remove these thousands of burs so that we may safely tread the path in bare feet or sandals — which is how I annually estimate the productivity of these trees.
The Chinese chestnut has a single large nut in most burs, with two smaller ones usually compressed to one side within the spiny involucre. We freeze them because most have “the worm,” a parasite that enters the nut via eggs laid during flowering. The nuts are meaty and tasty, but those who’ve savored the native American species, say the originals are much sweeter.
Chestnuts were as popular a food with Native Americans as they were with native wildlife. They also used its serrate, dark green leaves to brew a tea they claimed controlled coughs. Colonists also found it had a sedative effect on the respiratory system and mixed the extracted tea with honey to make a more soothing, palatable syrup. Extractum castanea fluidum was even included in the United States Pharmacopoeia between 1873 and 1905.
Attempts to salvage the species began as early as 1915, when Meyer suggested hybridization using the resistant species. This approach has been carried out with variations ever since.
A biological control organism for the blight fungus was imported from Europe in 1972. It causes hypovirulence, thus weakening the virus and slowing its advance. This has permitted some American chestnut trees to survive as a seed source, but it is not a cure, only a stopgap.
Today, nurseries from Maine to Georgia sell hybrids with the non-native species by mail order. Seeds are still collected in the hope of breeding blight-resistant natives, and there are web sites for the American Chestnut Foundation and the American Chestnut Cooperators’ Foundation, both advocacy groups for restoring the resource.
As if all that weren’t enough, in 1974, a small wasp native to Asia, (Dryocosmus kuriphilus) was brought to the United States. The female Oriental chestnut gall wasp lays eggs in chestnut leaf and flower buds that irritate the plant, causing it to produce protective tissue galls. Heavy infestations can kill the trees, and it afflicts both American and Chinese chestnuts at the southern end of their ranges.
In the Eastern part of the Chesapeake watershed, one might encounter a similar but smaller tree: the Allegheny chinquapin (Castanea pumila). It was one of the species described by John Smith in 1612 and was one of the first North American plants that explorers took back and are cultivated in England.
It’s just as edible as the chestnut, only the nuts are smaller and the spines shorter. Chinquapin is resistant to the the gall wasp.
The loss of the American chestnut was devastating for Eastern forests and a deep sorrow for a whole generation of Americans. It stands as a warning to all, who for any purpose, however well-intended, would introduce new organisms to North America.
The intent is not what matters. It is the unanticipated, unintended, unpredictable consequences that can, without warning, shake already stressed ecosystems to their core and penalize those who live afterward for a very long time.
Dr. Kent Mountford is an environmental historian and estuarine ecologist.
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