American chestnut

The American chestnut, Castanea dentata, a member of the beech family (Fagaceae), was once the most important forest tree throughout much of the eastern United States. A rapidly growing tall and broad deciduous hardwood tree, it reached up to 150 feet tall, 100 feet across, with a trunk up to 10 feet in diameter, and ranged from Maine to Missippi and from the Atlantic coast to Appalachia and the Ohio valley. While there are several related chestnut species such as the European, Chinese, and Japanese Chestnuts, the American species has distinctive saw-toothed edges of its leaves, as "dentata" is Latin for "toothed". Chinese chestnuts are diminutive. The Chestnut is a member of the Beech family, as are beech, and oak and entirely unrelated to the European horse chestnut, Aesculus hippocastaneum, which is a buckeye.

Table of contents

1 Chestnut Blight 2 Surviving trees 3 Nuts 4 Lumber 5 Importance to Wildlife 6 Breeding for Blight Resistance

Chestnut Blight

Once an important hardwood timber tree, the chestnuts are highly suceptable to an Asian bark fungus or "chestnut blight" Cryphonectria parasitica (formerly Endothia parasitica) accidentally introduced to America on Chinese Chestnut ornamental nursery stock at the Bronx Zoo in 1904. While Chinese Chestnuts evolved with the blight and are immune, the airborn bark fungus spread 50 miles a year and in a few decades girdled and killed the millions of American trees. Fortunatly, the stumps survive and send new shoots, and so the species has been saved from eradication, although the stump sprouts rarely reach more than 20 feet in height before blight infection.

Surviving trees

It is estimated that one out of four trees within its range were American chestnut, for a total of some 3.5 billion trees. The number of surviving mature trees can now be counted in the mere dozens, due to the blight. The finest surviving sample (featured in National Geographic) can be found in Sherwood, Oregon, where from the roadside, one can glimpse the giant spreading tree, as much of the West is still free of blight.

Nuts

The American chestnut is a prolific bearer of nuts, usually found in sets of three, enclosed in a spiny green burr, lined in tan velvet. The nuts develop through late summer, the burrs opening and falling to the ground near the first fall frost. These nuts were once an important economic resource in the U.S., even being sold on the streets of larger cities, as they sometimes still are during the Christmas season (usually "roasting on an open fire" so their smell is readily identifiable many blocks away). Chestnuts are edible raw or roasted- though preferably roasted. The European variety sold in many stores. One must peal the brown skin to acess the yellow edible portion. (Note that the horsechestnut 'conkers' are poisonous)

Lumber

The wood was straight grained, strong as oak, although easier to saw and more easily split, lacking radial end grain found on most other hardwoods. The tree was particularly valuable commercially since it would grow at a rate five times faster than oaks. Being rich in tannins, the wood was highly resistant to decay and therefore used for a variety of purposes, including furniture, split-rail fences shingles, home construction, flooring, piers, plywood, paperpulp, and telephone poles. Tannins were extracted from the bark for tanning leather. Although larger trees are no longer available for milling, much chestnut lumber has been reclaimed from historic barns to be refashioned into furniture and other items. "Wormy" chestnut refers to a defective grade of lumber that has insect damage, having been sawn from a blighted tree. This "wormy" wood has since become fashionable for its rustic character.

Importance to Wildlife

The American chestnut was also a critically important tree for wildlife, providing much of the fall mast for wildlife species such as white-tailed deer and wild turkey and formerly the passenger pigeon.

Breeding for Blight Resistance

Several organizations are attempting to breed blight-resistant chestnuts. One of these is the American Chestnut Cooperators Foundation, at
" class="external">http://www.ppws.vt.edu/griffin/accf.html
which breeds surviving all-American chestnuts, which have shown some native resistance to blight. Another is The American Chestnut Foundation at
http://www.acf.org
which is backcrossing blight resistant American/Chinese hybrids to American parents, to recover the American growth characteristics and genetic makeup, and then finally intercrossing the advanced generations in order to breed consistantly for blight resistance. The eventual goal is to reintroduce the species to the wild.