Questions and Answers
Q: What is the current test planting about?
A: The test plantings represent the first field tests of blight-resistant seedlings of the American chestnut, developed through a backcross-breeding program. The test planting includes seventh generation trees resulting from six successive generations of selection and breeding led by The American Chestnut Foundation in cooperation with several partners. The Southern Research Station of the U.S. Forest Service is leading the effort to field test the seedlings.
Q: How are the blight-resistant American chestnuts different than historic American chestnuts?
A: The blight-resistant American chestnuts have Chinese chestnuts in their pedigree, exactly six generations back. It is from these Chinese ancestors that the blight-resistant genes have been passed down to the current generation. In ratios or percentages we can say that, on average, the trees produced by this backcross method are 15/16ths or 94 percent American. At each generation, selection has been practiced for blight resistance derived from the Chinese ancestors and for all other traits derived from the American ancestors, resulting in current blight-resistant American chestnut with the same look and ecological function as the historic American chestnut.
Q: Who is involved in the test plantings of the blight-resistant seeds?
A: Many individuals and organizations have been involved in the effort to restore the American chestnut. The American Chestnut Foundation (TACF) has led the effort to breed a blight-resistant American chestnut tree for restoration to its native range in the eastern United States over the past 26 years. The Southern Research Station (SRS) of the U.S. Forest Service has led the research planning for field implementation of the first forest planting of blight-resistant trees. The Southern Region of the U.S. Forest Service has written and is directing the Memorandum of Understanding document with TACF. Silviculturists and a regional geneticist from the Forest Service have worked with partners to determine which National Forests and specific sites would be best suited to plant the blight-resistant seedlings. Since 2003, the Forest Health Protection division of the Forest Service has provided funding to TACF in support of the backcross breeding program. TACF’s tree pathologists have worked with various partners in testing planting sites for suitability for chestnut growth. The University of Tennessee’s Tree Improvement Program (TIP) provided the necessary infrastructure for SRS to implement nursery and field studies of chestnut material. This program has provided technical assistance to develop the experimental designs for testing, and will assist the SRS in monitoring the research.
Q: What is the significance of these restoration efforts?
A: Hardwood forests comprise 28 percent of the Eastern U.S. land base. The American chestnut was once one of the most important tree species in the eastern United States, making up one out of every four trees, or 25 percent of the hardwood canopy. Referred to as the “Mighty Giant,” they often grew to heights approaching 130 feet with diameters of five feet or more. Restoring the American chestnut will create benefits for wildlife, people, timber, commerce, and culture. For these reasons, the American chestnut was and is hoped to once again be an important component of the ecology and historical culture of the Southern Appalachians. If successful, this chestnut restoration project could represent one of the most important conservation success stories in the history of the Forest Service, and can provide hope for restoration of other tree species decimated by exotic pests.
Q: How does the restoration of the American chestnut create healthy forests?
A: The eventual restoration of the American chestnut to its former range benefits all plant and animal species that were historically associated with it, as well as those that exist today. The seeds from the American chestnut are highly nutritional and also provide a more reliable food source for wildlife because the tree blooms later in the year than many other species, rendering it less susceptible to late freezes. The American chestnut was a long-lived tree that was historically susceptible to few insect or disease problems and its wood was also decay resistant. The restoration of this tree will contribute to a healthy forest by increasing species diversity and thus the overall diversity of the forest ecosystem. Biodiversity of keystone tree species, i.e. a species maintaining a significant place in determining the composition of a biological community, is indicative of a healthy forest.
Q: How and when were the test trees planted?
A: The plantings were established using carefully crafted experimental design so that in future years, scientists can gain the most valuable scientific information from these plantings. This design protocol was developed in order to test and compare the differences in survival and growth of both pure American and Chinese chestnuts, as well as several generations of American x Chinese chestnuts. The data collected will be used to help guide future restoration efforts and to help TACF’s breeding program by identifying superior genetic families. The planting includes all generations of material produced in the TACF’s breeding program, from pure American and pure Chinese chestnuts to all generations in between. The first seedlings were planted in the early 2009 on three national forests in North Carolina, Tennessee and Virginia. Two additional plantings will be established in 2010 in Tennessee and Virginia.
Q: What is the current status of the blight resistant American chestnut trees?
A: The blight resistant American chestnut trees are currently two years old and have survived their first growing season after being planted in the forest. They are approximately four feet tall, with an average growth of 10-12 inches per year for the species. Two of the blight resistant trees flowered in this first year in the wild, a significant measurement of advanced maturity. They were examined in September 2009 and the survival rate is above 90 percent. The trees appear healthy overall, and are expected to be very competitive with natural tree vegetation in the forest. Deer browsing was affecting growth on some of the trees, so deer repellent was applied to trees to dissuade deer from eating the leaves and stems.
Q: How are test plots chosen?
A: The selection process includes looking at a variety of site conditions that are similar to the original range and habitat requirements of the American chestnut. All test plots are within national forests in the eastern part of the U.S., the original home range of the American chestnut. Exact locations of the test plantings are not being announced to ensure the trees grow undisturbed during these critical early years.
Q: What is the next step in the American chestnut restoration effort?
A: In 2010, the Southern Research Station, the University of Tennessee, and national forests in Tennessee and Virginia will establish two additional test plantings that comprise approximately 1200 seedlings. Plantings will test all generations of the American chestnut produced from TACF, including approximately 500 of the blight-resistant seedlings.
Q: I thought the American chestnut was extinct, but I saw one the other day. How can that be?
A: The American chestnut tree is not extinct. There are still millions of sprouts throughout its native range, mostly in forest areas. However, there are very few large, mature American chestnut trees. Most sprouts are less than eight inches dbh (diameter at breast height). The American chestnut tree is threatened with extinction from blight because very few trees reach maturity and therefore are unable to flower and produce seeds. Very few of the small sprouts will live long enough to flower, and when trees do flower, they tend to die fairly quickly. It is unclear how long it will take for most of the small sprouts to die out. On average, the large surviving trees measure only up to 18 inches in diameter, compared to up to five feet in historic times.
Q: Why should I care about restoring the American chestnut? The tree has been gone now for many decades and we seem to be doing okay without it, right?
A: Restoring the American chestnut to its historic range is important for several reasons. Below are reasons to consider:
Wildlife Food Source — Native wildlife from birds to bears, squirrels to deer, depended on the tree's abundant and dependable crops of nutritious nuts.
Organic Food Source for People — As winter came on, attics were often stacked to the rafters with flour bags full of the glossy, dark brown nuts. Springhouses and smokehouses were hung with hams and other products from livestock that had fattened on the harvest gleanings. What wasn't consumed was sold. Chestnuts are still enjoyed today, roasted and prepared other ways.
Timber Products — The tree was one of the best for timber because it grew straight and often branch-free for the first 50 feet. Loggers tell of loading entire railroad cars with boards cut from just one tree. Straight-grained, lighter in weight than oak, and more easily worked, chestnut was as rot-resistant as redwood. It was used for virtually everything—telegraph poles, railroad ties, shingles, paneling, fine furniture, musical instruments, even pulp and plywood. The timber quality of the blight-resistant American chestnut is yet unknown.
Q: How was the blight introduced? What causes the blight? Where is it from? How did it get here?
A: Imported on plant material in the late 19th century, and first discovered in 1904 in New York City, the blight, an Asian fungus to which our native chestnuts had very little resistance, spread quickly. In its wake it left only dead and dying trees. Except for the shrubby root sprouts the species continually produces (which quickly become infected), the keystone species had disappeared from some nine million acres of eastern forests by the year 1950. Nearly four billion trees were killed by the blight.
Q: When does the blight occur?
A: The spores of the fungus, which cause the blight, are in the environment; spread by wind, on animal fur, and by other means. They can infect American chestnut trees at any time. The blight can attack a seedling at any age, but typically the blight does not start to negatively affect the tree until age 5 or older.
Q: What happens to the trees once they get the blight?
A: For a pure American chestnut seedling, there will be very little resistance to the blight. Most pure American chestnut trees will succumb to the blight after 5 to 10 years. Very few trees survive after being infected with the blight. Some trees live with the blight for a few years through recurrent dieback and sprouting from the root system in the ground, prolonging the tree's life for a few more years. Some individual trees are more susceptible than others, and a few trees seem to be somewhat resistant. As part of the American chestnut reintroduction research, the wild trees that are mature and surviving in the wild are the source of pollen or are pollinated to eventually produce the blight-resistant nuts. Seedlings that have some Chinese chestnut genotype in them will be more resistant to the blight. While they will become infected with the blight, they can live with the blight longer than a pure American chestnut. The blight-resistant seedlings are expected to look like a pure American chestnut seedling, but will be highly blight-resistant, able to overcome the blight by quickly healing over wounds.
Q: Are the blight-resistant American chestnuts genetically modified organisms (GMOs)?
No, these are not GMOs. These blight-resistant trees were developed over the course of six generations of backcross breeding. In contrast, GMOs are produced utilizing laboratory-based gene transfer methods sometimes referred to as gene splicing. Research is ongoing in this area so in the future GMOs may be available to address forest health challenges and assist restoration efforts.
Q: Has TACF harvested any blight-resistant nuts?
A: The current test planting is comprised of seedlings grown from TACF’s first crop of blight-resistant nuts, harvested in 2007. The nuts were planted in a nursery and resultant seedlings were grown there for one year to allow some development before being transplanted to the test sites.
Q: How soon will you know if the harvested nuts are truly blight resistant?
A: The breeding lines, i.e. selected parent trees, from which these nuts were harvested and subsequently grown are still in the testing phase and their value needs to be proven on many forest sites over several years. Test trees are considered healthy and viable if they survive to maturity (flower for several years) and continue to survive for many, many years thereafter.
Q: Who is involved in this test planting of the blight-resistant American chestnut?
A: The following is a list of chestnut restoration partners and their roles:
The American Chestnut Foundation (TACF) – TACF has led the effort to breed blight-resistant American chestnut trees for restoration to its native range in the eastern U.S. TACF scientists, orchard managers, and volunteers have established and are maintaining research farms where they are conducting and testing the backcross breeding method to produce blight-resistant seedlings.
Southern Research Station (SRS) – SRS has led the research, planning, and implementation of the first forest test planting of blight-resistant trees. In coordination with the other partners, SRS is leading the effort to plan, establish, and collect all data (including blight resistance) for the test plantings. They are establishing nursery and forest plantings to determine if the advanced breeding material from TACF will be able to survive, thrive, and compete in a natural forest setting while maintaining blight resistance.
USFS National Forest System (NFS) – wrote and is currently implementing the Memorandum of Understanding agreement with TACF, which was signed in 2004. Silviculturists and the Region 8 geneticist have worked with the partners to determine which national forests and sites would be best suited to plant the blight-resistant seedlings. NFS personnel funded a state nursery to grow the seedlings, prepared sites for planting, helped implement plantings, and will help monitor the plantings of blight-resistant seedlings. In addition, NFS will choose and prepare additional sites for future plantings.
Forest Health Protection (FHP) – FHP in Region 8 of the U.S. Forest Service has funded TACF for the past six years in support of the back-cross breeding program. Pathologists have worked with partners in choosing and testing the planting sites for suitability.
University of Tennessee, Tree Improvement Program (TIP) – TIP provided the necessary infrastructure for SRS to implement nursery and field studies of chestnut material. This program has provided technical assistance to develop the experimental designs for testing. They also will assist SRS in monitoring the research and provide an avenue for partnerships with state forestry divisions for nursery research.
Q: If there are any nuts left, will they be available to the general public?
A: If there are any nuts left that are not needed for the formal, rigorous testing programs, they will be distributed principally to members of TACF and TACF partners for additional testing. Currently there are not enough nuts being produced because the parent trees are still quite young.
Q: Will more of these nuts be available anytime soon?
A: A gradual increase in seed production is expected over the next several years. TACF predicts that within the next decade there should be plenty of nuts available for significant landscape-level restoration.
Q: How can I purchase some chestnut seed/seedlings?
A: Seeds are expected to be available from The American Chestnut Foundation for wider distribution starting in 2011 thru 2026. Today, the public can purchase non-resistant, pure American chestnut seeds and seedlings through www.acf.org.
Q: Where can I find out more about the restoration of the American chestnut?
A: More information can be found at the following websites:
- The American Chestnut Foundation
- U.S. Forest Service, Southern Region
- University of Tennessee, Tree Improvement Program
Q: What can I do to help?
A: If you know of an American chestnut tree that is producing nuts, contact The American Chestnut Foundation. They track fruit-producing trees and utilize the nuts in their research. You also can join a local chapter of TACF. Share your enthusiasm and educate the next generation about the return of this “Mighty Giant.”