I have a new column this week on OnlySky. It’s about how human carelessness wiped out a beloved tree, and whether we can bring it back from the dead.
The American chestnut tree used to be part of the fabric of everyday life in the United States. Its nuts were a reliable and abundant source of food for humans, livestock and wild animals. Its timber was used to build homes, ships, railroads, and more. But in the early 1900s, an imported fungal blight destroyed it in the wild and drove it to the edge of extinction.
Almost since the chestnut was decimated, plant scientists have tried to bring it back, breeding and genetically engineering new varieties that they hope are resistant to blight. And now, after decades of labor, these efforts are beginning to bear fruit. A New York nonprofit is distributing a thousand (hopefully!) healthy, blight-immune hybrid seedlings to anyone who wants to plant and care for them. Can we restore it to the wild and bring back the glory days of the chestnut? Should we even try?
Read the excerpt below, then click through to see the full piece. This column is free to read, but paid members of OnlySky get some extra perks, like a subscriber-only newsletter:
To restore the chestnut, we’d have to make it resistant to blight. There are two approaches that have been tried to achieve this.
One is traditional hybridization, the same method used by farmers for millennia to breed plants with desirable characteristics. Plant breeders cross the blight-resistant Chinese chestnut with its American cousin, then backcross the hybrid with American chestnuts. They repeat this process over multiple generations, with the goal of creating a tree that has the blight resistance genes of the Chinese chestnut, but is otherwise almost identical to the American chestnut.
The disadvantage of this method is how much time it requires. It’s essentially a form of guided evolution, and evolution doesn’t run on human timescales. It takes about seven years to breed each new generation of trees, plus years more to grow them and evaluate whether they can fend off the blight. Plant scientists have been working on breeding blight-resistant chestnut trees since 1922, and their efforts are still ongoing.
I read this on Only Sky and I agree with the commenter who said the efforts are to restore the chestnut to its historical location. While the tree is undergoing genetic manipulation, time will tell if it’s enough to work.