RESURRECTING THE AMERICAN CHESTNUT

Resurrecting the American chestnut
by Joe Schibig, Biology Professor, Volunteer State Community College

One hundred years ago, magnificent American chestnut trees dominated the forested hills and mountains over much of the eastern U. S. They made their best growth on the slopes of the Appalachian mountains where some towered up to 100 feet and had diameters greater than 10 feet. In some places, chestnut trees formed nearly pure stands. It has been estimated that one out of four trees in the Appalachian forests was an American chestnut (Castanea dentata) prior to the arrival of the lethal chestnut blight, a fungal disease which destroys the bark tissues of the chestnut.

The chestnut blight was first noticed in New York at the Bronx Zoo in 1904, but according to chestnut researcher, Sandra Anagnostakis, the blight was probably first brought into the northeastern U. S. sometime in the late 1800s on Japanese chestnut trees. The blight spread like wildfire from the northeast southward killing almost every American chestnut tree throughout the eastern U. S. Our chestnut trees had little or no resistance to this exotic fungus (Cryphonectria parasitica), because the American chestnut had evolved in North America isolated from the Asiatic chestnut trees which had evolved with this parasitic fungus and had developed some resistance to it. By 1950, billions of American chestnut trees in the eastern U. S. had been killed by this exotic fungus.

Now, only rare sprouts remain, clinging to life in the forests--puny relicts of the giant trees they once were. Very rarely, a sprout lives long enough to flower and produce nuts but they are usually infertile from lack of cross pollination; even this is cause for celebration among American chestnut enthusiasts, but the euphoria is short-lived because these fruiting trees usually die just a few years later. Most do not live more than 15 years due to the blight and/or other diseases; competition from nearby trees also takes a toll. Most of the trees died from the blight in the 1930s and practically all were gone by 1950, but the blight did not directly harm the roots. The king of coppice sprouted back with a vengeance. Some chestnuts have repeatedly died and sprouted again from their root collars for the past 70 years, but the vigor and number of these sprouts have been declining. After all, they can't be expected to forever battle the blight, other diseases such as root rot, ravenous insects, browsing by deer, competition from other trees, unfavorable weather conditions and habitat destruction by humans. It was hoped that in some parts of its natural range there would be pockets of chestnuts that would have resistance to the disease and would be reproducing successfully from their nuts, not just by sprouting. To my knowledge, such populations, sometimes called the "holy grail" by American chestnut fans, have never been found. It appears that human intervention will be necessary to restore the American chestnut to the forests of the eastern U. S.

There are some naturalized American chestnut populations in Canada, and the northwestern U. S. that were established from seeds the settlers took with them as they migrated. These trees are not resistant to the blight, but they thus far have been sufficiently geographically isolated from the blight fungus in the East that they have attained large size and are reproducing by seeds. There are some populations in Wisconsin (outside of the chestnut's original range), but in recent years the blight has found them and many of these trees are falling despite efforts to check the disease.

Today, plant breeders, genetic engineers, foresters, land owners and other concerned individuals are working hard to develop chestnut trees that are resistant to the blight and adapted to local environmental conditions throughout the tree's former range. The gene pool of our native chestnut has been dwindling as chestnut sprouts have become more and more scarce; biologists will tell you genetic diversity is the key to long term survival of any species. Although efforts are underway to map and conserve some of the remaining American chestnuts in Tennessee and elsewhere, these efforts should be expanded. Ed Greenwell (Director of ACCF projects in Tennessee), Hill Craddock (chestnut expert at U. T./Chattanooga) and others are actively conserving American chestnut germplasm in Tennessee. Small twigs (scions) are taken from surviving sprouts and grafted; then they may be planted in orchards where they can later be crossed with blight resistant trees and finally their disease resistant progeny would be planted in forested areas to which they are adapted. It is hoped that within the next 50 years the dream of the American chestnut becoming a viable tree in our eastern forests will be become a reality. Members of two organizations, The American Chestnut Cooperators Foundation (ACCF) and the American Chestnut Foundation (TACF) are among the chief participants in this effort. Both are non-profit private scientific organizations.

The ACCF is intercrossing only selected pure American chestnut trees showing some blight resistance trying to perfect a more blight-resistant strain that will be able to thrive in the eastern forests. In some cases the ACCF inoculates mildly resistant trees with hypovirulent strains of Cryphonectria which fuse with the lethal strains infecting the trees and neutralize their virulence. Gary Griffin, plant pathologist at Virginia Tech, has demonstrated that American chestnut trees with some blight resistance which are inoculated with hypovirulent strains of the blight fungus will grow rapidly and produce loads of nuts on good forest sites with a minimum of human assistance. Ten percent of these ACCF trees are expected to show some resistance to the blight. A tree is said to have some resistance if the tree cankers are swollen and slow growing, but if the cankers are sunken and fast growing, they will destroy the bark and the vital cambium tissue which will kill the tree. For a detailed description of this organization, see the link to the ACCF at the bottom of this page.

TACF has crossed the American chestnut with the Chinese chestnut to produce blight resistant hybrids. Their plan as envisioned by Charles Burnham is to backcross blight resistant hybrids with pure American chestnut trees for a few generations so as to develop blight resistant trees that are about 15/16 American and 1/16 Chinese; these offspring are expected to have the attributes of the American chestnut (fast-growth, straight timber form, ability to thrive in the forest, and sweet-flavorful nuts) coupled with the disease resistance of the Chinese chestnut. The latter produces nuts which are of good quality but it has the growth form of an apple tree--it does not succeed in the forest or in very cold climates. An important component of TACF's breeding program is to cross resistant hybrids with American chestnuts from different locations throughout the country so as to develop a diverse gene pool. TACF expects to have some blight resistant, forest-ready, and predominantly American chestnut trees in a few years, but many years may be needed to develop trees with blight resistance that are well adapted to the different regions of the eastern U. S. Breeding for blight resistance has been the major goal, but further breeding to develop trees resistant to ink disease and insect pests is also needed.

On another front, genetic engineers may eventually be able to plant genes directly into American chestnut trees to give them resistance to the blight. The prospects for this approach also look bright. With such intensive efforts underway, and with tangible progress already, there is growing optimism that many of us will live to see this majestic tree towering again in our forests. Science will prevail!

Vanishing Trees--a poem

Publications

Chestnut Photo Links:

Bill Rickman selects a site for his chestnut orchard in Trousdale County in north central Tennessee (Feb. 2008)

Jack Torkelson and Joe Schibig harvest chestnut wood from a dead American chestnut tree in Metcalfe Co., KY (January, 2008).

The TN-TACF field trip to Frozen Head Mountain (Sept. 29, 2007)

Chestnut photos in KY, TN, and VA (September, 2007)

American chestnut specimens on the western edge of their range in Mississippi and Tennessee (August, 2007)

Nature photos (posted July, 2007)

Images of the Allegheny chinquapin, a cousin of the American chestnut (posted June, 2007)

Recent chestnut pollination photos (June, 2007)

Dr. Don Sudbrink, APSU Agriculture Professor, starts a chestnut orchard at the Austin Peay State University Farm, May 16, 2007.

Land Between the Lakes chestnut photos, May 2007

Clark Cropper plants a chestnut orchard in Monroe County, Kentucky (May 10, 2007).

Chestnut exhibit at the Science Expo held at Volunteer State Community College, April 2007

Monster chestnut found on the Cumberland Plateau of TN

First prospective mother tree for Humphreys County, TN

A new mother tree in Sumner Co., TN

Yellow Mountain chestnut trees in North Carolina

A new mother tree in Macon County, Tennessee

2006 Pollination season in Kentucky and Tennessee

A close encounter of the dangerous kind

Sam McInturff is a tireless chestnut worker in East TN

Chestnut researchers resume their field studies at
Mammoth Cave National Park on May 16, 2006

Chestnut researchers escape lightning and downpours in southwestern Tennessee

Chestnut tree planting at Volunteer State Community College
to celebrate Earth Day, 2006

Defeating the blight with systemic fungicide

Chestnut exhibit at Science Expo held at Volunteer State Community College,
April, 2006

Snow-coated chestnut trees

Photos of newest big mother tree

Photos of the Ozark chinkapin and Allegheny chinkapin

Chestnut photos (summer 2005)

Chestnut photos (spring 2005)

Chestnut photos (winter 2005)

Chestnut photos (mid to late summer 2004)

Chestnut photos (early summer 2004)

Chestnut Photos (Spring 2004)

Photos of the annual TN-TACF meeting held at
Volunteer State Community College (Feb. 21-22, 2004)

Chestnut photos (Winter 2004)

Chestnut photos (Summer-Fall 2003)

More Chestnut Information:

What We Lost

Big Chestnuts

"Large" American Chestnuts on the Highland Rim of
Kentucky and Tennessee

Power Point Presentations on the American Chestnut
(fast internet connection needed)

Several Power Point presentations on chestnut research, pollination, and orchards were delivered at the Jan. 19, 2008 meeting of the TN-TACF Chapter meeting at Volunteer State Community College.

To see Power Point chestnut presentations at the Tennessee Academy of Science meeting held at Volunteer State Community (Nov. 16, 2007), click these links: Ecology of American chestnut west of the Tennessee River in Kentucky, Tennessee, and Alabama by Joe Schibig and Establishment of a backcross chestnut orchard by Clark Cropper

Eclectic nature images (compiled July, 2007)

Power Point presentation showing Sam and Elberta planting their second chestnut orchard in Greenback, TN,
March, 2007. (Photos and commentary by Hill Craddock)

Chestnut trees and chestnut people II (compiled February, 2007)

Ecology of flowering American chestnut trees; presented at the Appalachian Studies Association Conference on Saturday, March 24, 2007 at Maryville College, Maryville, TN.

The American chestnut still lives in Tennessee; presented at the Mar. 16, 2007 meeting of the Daughters of the American Revolution in Gallatin, TN.

American Chestnut site affinities at Mammoth Cave National Park; presented at the Feb. 24, 2007 TACF Southern Regional Meeting at the University of Tennessee/Chattanooga.

New Mother trees on the Highland Rim and Cumberland Plateau of Tennessee; presented at the Jan. 24, 2007 meeting of the TN-TACF meeting at the Ellington Agricultural Center in Nashville, TN.

Ecology of the American chestnut at Mammoth Cave National Park, an update; presented at the annual Tennessee Academy of Science meeting at Austin Peay State University on November 17, 2006.

Ecology of Flowering American chestnut trees in Kentucky and Tennessee; presented at the annual Tennessee Academy of Science meeting at Austin Peay State University on November 17, 2006.

What kind of chinkapin is this? A chinkapin specimen with a diameter of 7 inches and height of 40 + feet has been discovered in northern Alabama--can it be an Ozark chinkapin?

Earth Day - American chestnut tree planting ceremony at Volunteer State Community College on April 24, 2006

Clint Neel's great slide show proves chestnut people know how to have fun; presented at the annual TN-TACF meeting at the Bridgestone-Firestone Learning Center in McMinnville, Tennessee, on Jan. 28, 2006.

Ecology of flowering American chestnut trees in Kentucky and Tennessee by Joe Schibig presented at TACF's Southeastern Regional meeting at Bendabout Farm, near Chattanooga, Tennessee, on Feb. 5, 2006.

The 2005 chestnut harvest and prospective mother trees for 2006 by Joe Schibig presented at the annual TN-TACF meeting at the Bridgestone-Firestone Learning Center in McMinnville, Tennessee, on Jan. 28, 2006.

Ecology of the American chestnut at Mammoth Cave National Park presented at the annual TACF meeting in Lexington, Ky., Oct. 29, 2005 and at the Tennessee Academy of Science meeting at the University of Tennessee/Martin, Nov. 18, 2005.

Ecology of the American chestnut on the Cumberland Plateau of Kentucky and Tennessee
presented at the Tennessee Academy of Science meeting at the University of Tennessee/Martin, Nov. 18, 2005.

Ecology of the Allegheny chinkapin on the Cumberland Plateau of Tenessee
presented at the Tennessee Academy of Science meeting at the University of Tennessee/Martin, Nov. 18, 2005.

Jeramie and Anne give presentation on American chestnut findings at Mammoth Cave National Park
on Nov. 7, 2005 at Volunteer State Community College.

Prospective Tennessee Mother Trees for 2005
presented at the annual TN-TACF meeting at Interstate Packaging, White Bluff, Tennessee, May 2005.

Ecology of American chestnut at Mammoth Cave National Park
presented at the Tennessee Academy of Science meeting at Columbia State Community College, Nov. 19, 2004.

Ecology of the American chestnut in Kentucky and Tennessee;
presented at the national TACF meeting at Asheville, North Carolina, Oct. 31, 2004.

Chestnut Trees and Chestnut People (A continuous slide show presented at the national
TACF meeting at Asheville, North Carolina, Oct. 31, 2004. This show advances automatically, but the animations and the music don't work like they should.)

Native fruiting American chestnuts in south-central Kentucky and middle Tennessee, their ecology, and prospective mother trees to pollinate in 2004 by Joe Schibig; presented at the TN-TACF annual meeting at Volunteer State Community College on Feb. 21, 2004

The mysteries of c hestnut DNA by Paul Sisco (an abbreviated version); given at the TN-TACF annual meeting at Volunteer State Community College on Feb. 22, 2004

Starting a chestnut orchard by Clint Neel; presented at the TN-TACF annual meeting at Volunteer State Community College on Feb. 22, 2004

Status of the American chestnut at Land Between the Lakes by Joe Schibig and Michael Hill; given at the Tennessee Academy of Science meeting on November 15, 2003

Status of the American Chestnut in Northern Middle Tennessee and South Central Kentucky by Joe Schibig; given at TACF's TN Chapter meeting in Chattanooga on May 31, 2003

The ABCs of Nutgrafting by Joe Schibig; presented at TACF's TN Chapter meeting in Chattanooga on May 31, 2003
(Power Point file)

The ABCs of Nutgrafting by Joe Schibig; presented at TACF's TN Chapter meeting in Chattanooga on May 31, 2003 (pdf file--handout format, 6 slides per page printing)

Site Preferences of Castanea dentata on the Norhern Highland Rim of Kentucky and Tennessee-by Clint Neel; given at the Field Biology Symposium at Land Between the Lakes, Stewart Co., Tn., March 22, 2003

Inventorying Chestnuts by Joe Schibig; given at Mammoth Cave National Park in May, 2003

Status of the American Chestnut in Middle Tennessee by Joe Schibig;
given at Volunteer State College, Gallatin, Tn., in April 2002

Unless otherwise indicated, all photos are by Joe Schibig and if you would like to reproduce any of the text or photos in this website for use on other web sites or to publish them in any way, first seek permission of the author. If you wish to reproduce photos by the other contributors, you should seek their permission.

More Interesting Pathways:

The Tennessee Chapter of The American Chestnut Foundation
http://www2.volstate.edu/tnchestnut

The American Chestnut Foundation:
http://www.acf.org

The American Chestnut Cooperators Foundation:
http://www.accf-online.org/

Ed's A Tennessean's Version of an American Chestnut Page: http://www.geocities.com/RainForest/Canopy/1436/

Hill's Chestnut Links:
http://www.utc.edu/~jcraddoc/chestnutlinks.html
                                                                                                                                                   Photo by Michael Doochin
American chesnut article:
http://en.wikipedia.org/wiki/American_Chestnut

Len's Castanea Breeders Corner:
http://www.angelfire.com/pa3/castanea/

The Ozark Chinkapin Foundation's website:
http://www.ozarkchinquapin.com/

Pennsylvania Nut Grower's Association:
http://www.pnga.net/index.html

(New) Arlen Schibig's: Wickham Stone Park

Wickham's Way--a tribute to my grandfather

Andy Sudbrock's native plants:
http://www.nashvillenatives.com/

To email the author:
joe.schibig@volstate.edu

Mother Nature is a grand artist. Rainbows, chestnut trees, and compre-
hending minds are just a few of the masterpieces She has created on a
beautiful oasis in space we call Earth.