Thread by @CharlesCMann

Well-known: American chestnut was wiped out in the 20th c. by an exotic fungus. Less well-known: chestnut was an agricultural industry. Now blight-resistant chestnut is here. Last week we had a kickoff brunch to bring back the industry. (Image: young American chestnuts.) 1/16

Some of the food: (clockwise from lower L) chestnut biscotti; castagnaccio (Tuscan chestnut cake), chestnut spice cake; Mont Blanc (chestnut meringue, chestnut puree, whip cream); chestnut crumble coffee cake. All from 100% chestnut flour (gluten-free, important for some). 2/16

Most were made w/ European chestnuts, which are already blight-resistant (due to an RNA virus). But breeders have developed blight-resistant American chestnuts by breeding w/ genetically resistant Chinese chestnut. Either species could be the center of a revived industry. 3/16

Chestnut has ~ the same nutritional profile as brown rice. It’s a staple, like potato or corn. [Chestnut-flour crepes with chestnut-mushroom ragout (vegetrian, small brown pot; non-veg, big pot); chestnut-miso pork (orange tongs); chicken-chestnut pot pie (copper pot, left)] 4/16

And they produce calories/acre roughly = to staple cereals like wheat. Old rule of thumb: a single big chestnut grew enough annually to feed a family of 4. If you plant a lot of them, they would **scale**, as @TamarHaspel has put it. [Picture: big chestnuts from 1910] 5/16

@TamarHaspel At the same time, chestnuts (like other tree crops) use way less water and fertilizer and cause much less erosion than cereals. In theory, you could get the same calories at less cost, economic and ecological. (Picture: American chestnuts at harvest last fall.) 6/16

@TamarHaspel Many putative alternatives to conventional agriculture require tons of labor. Chestnuts (and other tree crops) should be able to avoid this, if the enabling R&D occurs. (Photo: Han B. Janssens, CC, mallorcaphotoblog.com almond harvest in Mallorca) 7/16

@TamarHaspel You don’t even have to *like* chestnut. Lots of ag is done to produce sugars, starches, and animal feed. Chestnut—tree farming (agroforestry) in general--is fine for these industrial uses. (Chestnut-flour crepes w/ honeyed ricotta, chestnut bread, non-chestnut muffins) 8/16

@TamarHaspel Chestnuts also sequester a whole lot of carbon. This is important—land use is responsible for roughly ¼ of global emissions. The bulk of that is traceable to agriculture, either directly or through deforestation, which is mostly done for agriculture. (Picture: IPCC 2014) 9/16

@TamarHaspel As @ramez & others say, we know basically what to do with the first ¾--electrify everything, then generate the electricity renewably. But we don’t have good ideas for about land use. And we have to do something—it’s not enough to mostly decarbonize, we have to get to zero. 10/16

@TamarHaspel @ramez Here’s a photo from the excellent @Jimrichardson illustrating the issue. On the left: perennial grass of the sort that used to cover the Great Plains. On the right, bread wheat. Those root systems stored a crapload of carbon. Also they foster microbiomes that store more. 11/16

@TamarHaspel @ramez @jimrichardson Tree agriculture—agroforestry, to be technical--sequesters more carbon than row crops, almost no matter how or where you do it. (Charts: onlinelibrary.wiley.com/doi/abs/10.100…) 12/16

@TamarHaspel @ramez @jimrichardson In theory, tree crops like chestnuts could step in for row crops in many places with way less ecological cost. If climate change makes agriculture riskier in warm areas, cold places like New England, not so suitable for row crops, might be able to fill in some slack. 13/16

@TamarHaspel @ramez @jimrichardson Or you can plant row crops between trees (alley-cropping), and inject some carbon in the soil and create a hedge against crop failure. (Chestnuts bloom later than cereal, so bad weather is unlikely to hit both crops.) Wageningen research on this: wur.nl/en/Research-Re… 14/16

@TamarHaspel @ramez @jimrichardson Another version is silvopastoral systems, especially in dryer areas. As people like @SarahTaber_bww emphasize, integrating trees and livestock can have pretty big positive effects (though we need to know much more): link.springer.com/article/10.100… 15/16

@TamarHaspel @ramez @jimrichardson @SarahTaber_bww The case for investigating this is strong. It may reestablish a once-vibrant industry. It may help w/ the ecological costs of agriculture w/o losing yield. If you’re curious, you can order (good, pricey) chestnut-flour bread here to try it out: zingermans.com/Product.aspx?P…
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@TamarHaspel @ramez @jimrichardson @SarahTaber_bww Maybe necessary post-thread caveat: this is not a magic bullet. It's an alternative that merits exploring and has some (I believe) truly exciting potential upsides.