Why is restoration of the American chestnut so important?
The American chestnut was an important foundation species in eastern forests before getting wiped out by an invasive pathogen. With restoration, we have the opportunity to reverse a catastrophic loss facilitated by human action. Restoration of the American chestnut would provide a valuable food source for wildlife and humans, a prized timber product, and the opportunity to sequester carbon and help to mitigate climate change.
What does The American Chestnut Foundation do?
The goal of The American Chestnut Foundation (TACF) is to restore the American chestnut tree to our eastern forests. TACF is restoring a species, and in the process, creating a template for restoration of other tree and plant species. We operate the Meadowview Research Farms in Meadowview, VA and rely on an expansive network of volunteer state chapters to advance our work.
What do TACF State Chapters do?
TACF state chapters are the backbone of a breeding program for regional adaptability and are essential partners in the effort to capture sufficient genetic diversity to permit long term survival of the species. Chapters participate in TACF’s breeding program, manage plantings, inventory wild trees, participate in outreach events, and give talks and presentations in their local communities. To find out what’s going on in your state visit the Chapters page.
How do I purchase American chestnuts?
At this time, TACF only provides chestnuts to members. Seedlings are rarely available; seeds are often what are distributed in the spring.
TACF’s potentially blight-resistant chestnuts are available to Seed Level Members. The blight-resistance of these trees cannot be guaranteed; they are for initial testing and research and are not available to the general public. These chestnut seeds are also available to TACF members on a seniority basis (i.e. the longer one has been a member the more likely one will be able to receive seeds for the cost of shipping and handling).
Note that these seeds or seedlings are not being sold, but are a benefit of membership. By participating as a seed level member, you help TACF continue to do its important work and continually improve material for release.
“Pure” American chestnut seeds are also available to members on a limited basis. These trees are not blight-resistant, but they are fun to grow and can live over five years.
My organization would like a demonstration planting. Is that possible? Who should we contact?
Demonstration plantings can be a great way to help TACF raise awareness about the American chestnut and our mission. Our potentially blight-resistant chestnuts are currently available to members only and, while membership doesn’t guarantee installation of a demonstration planting, it is a good first step. Demonstration plantings are generally handled by the local TACF state chapter – you can find your local contact here.
How was chestnut blight introduced? What causes the blight? Where's it from? How did it get here?
The chestnut blight fungus, Cryphonectria parasitica, was accidentally imported on plant material in the late 19th Century and first identified as a new pathogen in New York City in 1904. The blight–an Asian fungus to which our native chestnuts have very little resistance–spread quickly. By 1950, except for the shrubby root sprouts the species characteristically produces (and which also quickly become infected), the foundation species that had could be found across 180 million acres of eastern forests had disappeared.
I thought the American chestnut was extinct, but I saw one the other day. How can that be?
This is a common misconception. There are still millions of American chestnut sprouts throughout the native range, mostly in forested areas. Unfortunately, these sprouts rarely survive to maturity and for that reason we consider American chestnut to be “functionally extinct” in the wild, although these survivors make our breeding program possible. Very few of these small sprouts will live long enough to flower, and when trees do flower, they tend to die fairly quickly. Very few trees are producing nuts and it is unclear if or how long it will take for these small sprouts to die out.
What do I do if I think I found an American chestnut?
Please let us know if you think you have found an American chestnut by submitting a Tree Locator Form and leaf sample. We are always looking to expand our inventory of chestnut trees across the native range. Samples should include leaves and stem/twig from the tree in question, as well as a completed Tree Locator Form. For more information on how to send in a leaf sample for proper identification in our Field Guide.
How is TACF restoring the American chestnut?
TACF engages a multi-pronged effort for creating a disease-resistant American chestnut including traditional breeding techniques, genetic modification, and reduction of fungal virulence. A majority of TACF staff and volunteers are involved in a traditional breeding approach. Requiring a minimum of 6 generations of breeding, progeny from this program are selected at each generation to exhibit American characteristics and some level of blight resistance, and efforts are made to increase the range-wide diversity of this growing population of trees. TACF’s NY Chapter, in affiliation with SUNY-ESF, are working to create a genetically modified American chestnut.
No matter the method, be it singularly or in combination, the goal is to produce American-type chestnuts capable of surviving and reproducing in the forest unassisted.
Besides direct improvement work for disease-resistance, TACF and its affiliates are conserving genetic diversity of the species, assessing susceptibility to other pests and pathogens (in addition to chestnut blight), and exploring the ecology of the species to prepare for landscape-scale reintroduction.
Has TACF harvested any blight-resistant chestnuts?
In the fall of 2007 TACF began harvesting the first potentially blight-resistant chestnuts, which we expect to have potential for planting in the forest for testing in a “real-world” setting. Once we finish selecting the most resistant trees from this latest generation, we hope the trees will have enough blight resistance to survive in the forest and resume evolving on their own. We are still in the testing and evaluation stage of development for potentially blight-resistant chestnuts. Selection of potentially blight-resistant chestnut parents is ongoing, and these materials are always improving. Once selection is complete and we determine that resistance is adequate, we will declare them suitable for release.
How soon will you know if the potentially blight-resistant chestnuts are truly blight-resistant?
We began testing our first chestnuts in 2008 and already have some preliminary results on their blight-resistance and general performance. These data sets are being used to improve our material, which will help us develop a stronger, more consistently blight-resistant population. We are working hard to develop this next, improved generation for distribution.
What is the survival rate for potentially blight-resistant chestnuts?
Survival of any tree has a lot to do with proper site selection and care. When planted on appropriate sites (well-drained, slightly acidic soil with good access to sun), stock of potentially blight-resistant chestnuts has initial survival rates similar to native chestnuts. Long-term survival will require both blight-resistance and recovery of American traits for competitive ability and adaptation to our environment, which we are still evaluating. Our members can help with the testing by reporting back on the performance of their trees.
How are potentially blight-resistant chestnuts being tested?
Testing of potentially blight-resistant chestnuts is conducted primarily using progeny testing at our Meadowview Research Farms, as well as in partnership with cooperators assisting in a formal, rigorous testing program. We are also developing genomic tools to help better assess this generation of chestnuts by identifying genetic markers for resistance. In addition, we ask any member with potentially blight-resistant plantings to report back regularly on the performance of their trees.
Does TACF have other goals beyond breeding blight-resistant American chestnut trees?
TACF is continuing its breeding program to make further gains in disease resistance and forest competitiveness, as well as forest health and restoration in general. In addition, we are working to incorporate resistance to Phytophthora root rot, conserve native American chestnut germplasm, educate the public, and collaborate on many other projects to support the overall restoration of the species.
Chinese chestnut is resistant to chestnut blight. Why can't you just take the resistance genes from the Chinese chestnut and put it into the American chestnut through gene splicing/biotechnology?
One of the main roadblocks to this approach is that we have not yet isolated the genes for blight resistance from the Chinese chestnut. Until the gene(s) for blight-resistance from Chinese chestnut can be identified, other genes will need to be used. In conjunction with SUNY-ESF, our New York Chapter has been working for over 20 years to try and insert a gene that would confer blight resistance into American chestnut, and they are having good success. For more information about transgenics, please refer to the this Transgenics FAQ sheet.
What is hypovirulence?
There is a type of virus, called a hypovirus, which attacks the blight fungus. These viruses reduce the virulence of the fungus, often reducing the severity of resulting blight cankers. In the US, hypovirulence works when applied to a given tree and under certain circumstances, but has not yet been shown to spread on its own. Research is on-going to determine how hypovirulence may contribute to the restoration of American chestnut.
Why should I plant pure American chestnuts instead of waiting until the blight-resistant material is available?
There isn’t really any drawback to planting pure American chestnuts. In fact, there are some great reasons to plant American chestnuts:
- To help preserve native sources of trees and the genetic diversity of the species;
- To learn how to grow, care for, and maintain American chestnut trees on your unique site.
Where should I plant American chestnuts?
To start, you’ll need well-drained, somewhat acidic soil. You can have a soil test conducted by your local university, extension agent, or environmental laboratory. A soil pH of 4.5 – 6.0 is best. For the trees to flower they need full sun, and for viable nut production you need at least two trees for cross-pollination.
How do I plant chestnuts?
There are many ways to do this. One method is direct-seeding chestnuts in the spring, as soon as you can work the soil. Don’t plant the seed deeper than about one inch in the ground, and protect it from predation and weeds. You can also start seeds in pots and plant the resulting seedling outside later in the spring, or in the fall. You can find more information about planting from the following fact sheets.
There are worms in my chestnuts! What are they and how do I get rid of them?
The worms that may be found in chestnuts are larvae of the chestnut weevil. There are two species–the ‘lesser’ and the ‘greater.’ The best way to control their proliferation is by collecting all of the fallen nuts in the fall to interrupt their life cycle. The nuts may be heat-treated to kill the larvae and prevent them from developing while in storage.