Chestnut Trees Coming Back?

[BillTre]

The American Chestnut tree used to be common in certain eastern US areas. A blight (fungal in nature) that came in to the US on an imported Chinese Chestnut. The fungus reeked havoc on the native American version. The big forests of chestnut trees are gone but some more isolated trees survived. the Chinese version is resistant to the fungus (which allowed it to get access to the American trees). The Chinese version is shorter, so, not so much a canopy tree as the American Chestnut is.
There is a long standing breeding program of making hybrid crosses between the American and Chinese versions. This gives you a 50-50 mix of genes from the two parents. They then take the 50-50 hybrids and make back crosses to one of the parents. This gives you a 75-25 mix of genes. Back crosses like this can go on indefinitely. It will (on average) reduce the percentage of genes in the off spring by half of what the previous generation by half.

At each step a variety of selections are possible that should enhance fungal resistant genes:

• success against possible exposure to the fungus
• success against intentional exposure to the fungus
• using sequence based markers to identify genes in individuals with greater resistant. this will allow for directed breeding since the sequence will let you see which individuals have resistance aiding genes.
• selection for traits (like height, a trait of the American version that is desired in the hybrids).

This has been going on for several generations by a decentralized collection of people trying to set up little test forests.
This Science Friday podcast talks about this ongoing program.

 

[phyzguy]

That would be wonderful if they could succeed. The old pictures and paintings show large stately trees with a huge spreading canopy. The wood was also very beautiful.

 

[Astronuc]

The American Chestnut tree used to be common in certain eastern US areas. A blight (fungal in nature) that came in to the US on an imported Chinese Chestnut. The fungus reeked havoc on the native American version. The big forests of chestnut trees are gone but some more isolated trees survived.

I just watched a program (video) on this subject last night. The Amercian Chestnut was apparently very productive was a significant food source to rural communities in the Appalachian Mountain region. Not only did the fungus attack the trees, but timber companies pressured state governments to allow the companies to harvest the forests, which lead to a rapid demise. While the timber companies made profits, local folks were deprived of a valuable food source, which provided families a source of income from the sale of excess chestnut stores.

Fortunately, the root systems survived and some chestnut trees started sending new shoots. In addition, some American Chestnut trees with apparent resistance to the fungus survived, so there is hope that the trees can re-establish themselves. Otherwise, there are isolated population of American Chestnut trees around the Eastern US and Canada.
https://en.wikipedia.org/wiki/American_chestnut#Surviving_specimens

There are groups dedicated to reviving the American Chestnut, e.g.,
The American Chestnut Foundation (TACF) - https://tacf.org/
https://tacf.org/wp-content/uploads/2016/09/Volume-XXVII-No.-2-Mar-April-2013.pdf (note date from 2013)
American Chestnut Land Trust - https://www.acltweb.org/
University of Wisconsin-Madison Arboretum, Longenecker Horticultural Gardens
https://arboretum.wisc.edu/news/arb...chestnut-conservation-in-longenecker-gardens/

A bit of history (from January 1989) -

American chestnut was introduced at West Salem, Wisconsin, about 1880 and had begun to replace native tree species in adjacent oak-hickory woodland before 1930. Chestnut is now an important canopy species over about 20 ha of forested ridge extending north and south of the original plantation.

https://www.usgs.gov/publications/r...species-introduced-american-chestnut-castanea

I'm inclined to obtain a seedling and plant it in my back yard.