Granite Geek: Restoring American Chestnut Trees Will Take a Little (Ok, a LOT) of Patience

Dec 29, 2015

Credit American Chestnut Foundation

  These days our world seems to grow ever faster. Of course, faster is a relative term - for the scientists trying to revive the American chestnut tree, even the fastest work still takes years.

David Brooks wrote about a chestnut tree restoration effort in New Hampshire in his latest Granite Geek column for the Concord Monitor and GraniteGeek.org. He joined All Things Considered for a fast update. 

You noted how fast a blight wiped out the American chestnut tree, which once numbered in the billions.

Literally billions. It was one of the really great trees in the Eastern forests, very valued for its lumber and particularly valued for its nuts- "chestnuts roasting on an open fire" and all that stuff - and in 1870-something or other, Japanese chestnuts were imported because they were pretty. [They] brought a fungus with them, and by 1920 or 1930, all the American chestnuts had been wiped out.

There have been efforts to restore the American chestnut ever since. What about the one going on in between the New Hampshire towns on Weare and Deering? 

It's the American Chestnut Foundation, which is leading efforts to breed a blight-resistant chestnut tree. Basically what they do is they cross-breed it with the Chinese chestnut, which is resistant to [the blight], whereas our trees are not. [They] let them grow for a few years, inoculate them with some fungus, see which one of the ones you've grown survived, take those, let them grow old enough that they can produce nuts, take those nuts, cross-breed those with Chinese chestnut, let those grow, inoculate them, see which ones survive...

There's a big farm down in Virginia, which is their main research farm, where they have cross-bred six generations. They've done it six times, so that the tree is 15/16ths American chestnut. Those are the trees - 500 of those were recently planted at Vincent State Forest on the Weare-Deering border. Some of them were also planted very recently at UNH, on land for the Agricultural Experimental Station.

It's easy to see why this is complicated work that takes a lot of time. The catch is, even if the tree does resist the blight, it can face other hurdles, like wildlife that love to eat chestnuts. 

A particular problem they're facing when trying to grow [chestnut trees] is the fact that we've done a pretty good job of bringing wildlife back to New Hampshire. So turkeys, bears and deer and other animals that have returned to the forests all love the nuts. The 500 trees that were planted in Vincent State Forest - I talked to Will Guinn, who's a forester with the Division of Forests and Lands - some of them were planted just nuts stuck down in the ground, and some of them were planted inside protective tubes, and pretty much all the ones that were unprotected were eaten. As soon as they grew up through the tubes enough that they started sticking out the deer were foraging on them. So that's another issue they've got.

There's actually another complication: these trees were from Virginia, but in other parts of the state they're also planting other strains between American chestnut and Chinese chestnut that are specifically cross-bred with New Hampshire or Vermont trees. The idea is to develop a localized strain of resistance. Those have not been cross-bred for as many generations, so they're still working on those.

This kind of work really goes beyond the admittedly large issue of the American chestnut tree, because this isn't a unique problem.

The American Elm had exactly the same thing, with a different pathogen. Now we have insects - for all practical purposes probably our ash trees are doomed because of the emerald ash borer, which carries a fungus with it. That's what kills the tree.

Climate changing is causing new diseases to come in, but even more is that humans are carrying stuff all around the globe, and we tend to carry bad stuff as well as the good stuff, and the bad stuff can go crazy. 

So we want the chestnut to be restored because there might be fewer species out there in the forest in 10, 20, 30 years, which is how long it's going to take.

It really will take generations then? Maybe not centuries, but generations at least?

Yeah. I mean, it's a minimum of probably five years for a tree to grow and produce nuts. You need to do six generations - that's a minimum of 30 years if all goes well. This is nature, so all won't go well. 

It would be nice if someone developed some kind of chestnut restoration app. Maybe every tweet saves a tree.

Or a microwave or something that does it with weird waves and speeds it up. But that's not going to happen. This biology stuff is really complicated.

Patience is a virtue sometimes.

It's a necessity.