Episode Description
Every day, with few exceptions, I eat a handful of nuts. Usually a combination of almonds, walnuts, pecans, cashews, and pistachios. And they taste good for sure. But I'm responding mainly to research showing that consumption of nuts is related to less chronic disease. In particular, eating nuts lowers levels of inflammation related to heart disease and diabetes, and may improve cholesterol levels among other benefits. So, I saw it as welcome news that someone has just published a book about nuts, all aspects of nuts, actually. Today we're joined by NPR, food Writer Elspeth Hay author of a new book called Feed Us with Trees- nuts, and The Future of Food. And I had no idea. Nuts were so interesting until I dove in a little bit. Elspeth has gathered stories from dozens of nut growers, scientists, indigenous knowledge keepers, researchers and food professionals. She writes that humans once grew their staple crops in forest gardens of perennial nuts, such as oaks, chestnuts, and hazelnuts in these species. Particularly important to the environment as well as to human wellbeing.
Interview Summary
Elspeth, thanks so much for joining us and for writing such an amazing book.
Thank you so much for having me. And it sounds like you have the same habit as my dad. He makes sure to eat a little bit of mixed nuts every night, ever since I can remember for his health.
Let’s start by having you describe your book. Tell us about Feed us with Trees. Why did you write it and what's it about?
I wrote it because I've been reporting on food in the environment for a long time, a little more than 15 years. And I had never heard anyone mention anything about eating acorns until a few years ago. And someone sent me a TEDx talk by a woman in Greece named Marcie Mayer, and she said, you can eat acorns. And not only that, but they're a super food nutritionally, and one of humanity's oldest foods. And I live in this giant oak forest that's protected on Cape Cod as part of the Cape Cod National Seashore. And I had always seen this forest as a sort of impediment to local food production, right? There's all this land that can't be farmed. And all that time, it turns out there was food literally raining down on my roof, underfoot in my driveway, and I just wasn't equipped to see it. The stories that I had grown up with hadn't mentioned that. And so that was a real eyeopener for me and I just couldn't stop thinking about it and I kept researching.
So, have you started consuming acorns?
I have, yes. I've collected them the past probably five falls and, you know, oaks do something called masting. Some years they have a really big production and some years smaller production. Some years I've gotten more than others. But I have started processing them at home and experimenting with different ways of using the flour. And I've also ordered online acorn oil. There are actually three food products that you can make from acorns. You can make starch, which works just like corn starch or potato starch. Thickens things. You can make flour and with some species you can make oil. It's actually a pretty diverse crop.
That's so interesting. You know, I have a series of oak trees right outside my window and I never thought that they might be producing food I could consume. It's so interesting to hear your history with that.
Yes, I mean I had no idea. And it turns out that actually acorns are very similar to olives in the way that they need to be processed. They're very high in these compounds that are very bitter, called tannins, just like an olive. I had the experience once of going to Italy with my husband, and we saw this olive grove and we thought, oh cool. Olives growing right here. And we picked one off the tree and he put his in his mouth and immediately spat it out and said, oh, that's awful. Tannins are not something that we want to eat. They don't taste good, but obviously they haven't hampered the olives rise to glory in terms of a human food source. And Acorns need the same kind of processing. So, tannins are water soluble. You pull them out with water. You know, you always get olives in brine, right? And so Yes, just started learning more about how to work with them and then also more about our relationship with oak trees. And I started seeing them differently in that light too. Going from sort of the species that I'd always seen as natural and wild and better off without humans, to actually understanding that we have a really long history with oak trees and in some places, they actually really depend on us. So that was total game changer for me.
There's more to the story than oaks and acorns. Tell us what you learned about the history of humans eating nuts like acorns, but also things like chestnuts and hazelnut.
Yes, I was really surprised. At first, I thought, okay, this is going to be an isolated thing where some people in really hilly areas or areas that aren't good for row crops are eating these nuts as staple foods. But when I looked back, actually all over the Northern Hemisphere in a huge variety of cultures, people have been in relationship with these nut trees as a staple food for a lot of the past 12,000 years. So, there's records in Japan of this ancient society that was sort of the first known chestnut cultivators in Japan. The burr size increased a lot. The nut size increased a lot during that early era of cultivation. There's a really interesting history of chestnut cultivation throughout Europe during what we call the quote unquote dark ages, although I'm starting to think maybe it was lighter than we thought during that time. There was a lot of cool stuff happening with Agroforestry. And in some areas of Europe, people ate an average of 330 pounds of chestnuts per person, per year. To put that in perspective, today, the average American eats about 150 pounds of grains per person per year. So that is a pretty serious level of chestnut consumption. You know, it's called in some places the bread tree. And I just started finding all these examples. There was a time in the British Isles known as the Nut Age, between about 7,000 and 5,000 years ago. There were just all these examples of different people at different times tending to these trees and harvesting a huge amount of food from them.
You've written that trees like oaks and chestnut and hazels and also humans are what ecologists call keystone species.
Yes.
Tell us what you mean by that and how such species play an outsized role in local ecosystems.
So, a keystone species, the first time I ever heard of them I think I was in Jamaica, and someone was talking about the sea urchins on the reef and the beach there. And it turned out that when they disappeared, for a variety of reasons, this whole ecosystem fell apart. And there's different types of keystone species, but a keystone species is as important to its ecosystem as the keystone in a Roman arch, right? So, if you pull that keystone out, you have this cascade of effects where everything kind of falls apart. And oaks are a huge life support tree. I don't know if listeners have heard of the work of entomologist, Doug Tallamy. He's done some really interesting studies on different families of plants and how much life they support by looking at insects. And in most counties where they occur, oaks are the top life support plant in North America. They're this incredibly important basis of the food chain. They provide food for a ton of insects. Those insects in turn feed birds and mammals and other creatures. And you know, at first as I am learning all this, I thought, okay, great oaks are important. Well, you know, I kind of already knew that, but that's exciting that we can eat from them. But then I started getting to know some fire practitioners. Especially an indigenous man in present day Northern California named Ron Reed. And he's a member of the Karuk Tribe there. And he started telling me about the relationship between cultural fire, prescribed fire, and oak trees. And what I learned is that oaks and human fire have actually been in relationship for millennia. And there's this whole, on the east coast, this hypothesis called the Oak Fire Hypothesis. And most ecologists that I've spoken with ascribe to it and believe that the reason that white oak and hickory have been this sort of dominant forest type through a lot of Eastern North America for the past 9,000 years, despite some really dramatic climate changes, is because humans have burned to keep them dominant on the landscape. And that in doing that we actually play a role as a keystone species too, right? So, if our fire is supporting this incredibly important keystone species, oaks, and other nut trees, we're in the category that they call ecosystem engineers.
Mm-hmm.
So, a beaver is an example of an ecosystem engineer, right? You take the beaver out of the wetland and the whole thing falls apart. And a lot of fire historians and ecologists see us as the fire animal. And historically, in a lot of different ecosystems, that has been our largest and most important role is creating ecosystems for other wildlife habitat, for other wildlife, with fire.
So, it sounds like there was a time in human history when humans would selectively burn other things in order to protect these trees.
Yes, and truly not just these trees. If you look at other places, other continents, there's human burning in Australia, there's human burning in the Amazon, there's tons of examples. But around here where I live, at least in New England and in the East, fire has been used intentionally to keep these nut trees dominant. Because what happens is. oaks are a mid-succession species. If folks don't know a lot about succession, early is like bare dirt, right? When we have an open field that's been plowed up, that's the beginning of succession. And then it proceeds all the way to an old growth forest. And oaks, if they get shaded out, they're not a particularly shade tolerant species. So, a lot of these nut trees like that kind of middle, sweet spot of succession. Where it's still a little open, there's still plenty of sun for regeneration. And so that can be intentionally preserved with fire or with other methods. But that's been a major one historically.
Well, that's so interesting. In your book, you draw a comparison between the yield from these trees to more modern agriculture or industrial farming of things like corn and soybeans. That tell us about that. That's a very interesting point to make.
Yes. I spent a lot of time on what I started calling the yield thing because it seemed really important, right? If these trees are actually a viable alternative to the industrial monocultures that we're struggling to maintain, well then, they need to really feed us, right? There needs to be enough food. And there are a number of different ways to look at it. I think, you know, one thing that we don't talk about a lot is when we talk about a monoculture of corn, for instance, I think the record, I'm not going to remember the exact statistics. But the average is maybe12,000 tons per acre or something. But there have been these huge records, and what we don't talk about is that yield is a ratio, right? If land is the limiting factor for us to produce food. And we're just talking about what's coming off this one acre, but we're not talking about the land it took to produce the fertilizer. We're not talking about the land it took to produce the tractor or the fuel or all these other inputs. And when you factor those in, those high yields completely disappear. When we actually look at how much land we need to produce food, an ecosystem based on these keystone trees will always produce the most because they produce the most life, right? And, you know, we tend to get caught up in other measures, but ultimately life comes from photosynthesis and these relationships between different species. And when you have a piece of land that is producing an abundance of life, you also have an abundance of food. And I broke the yield question down in a lot of different ways, but there have been some direct comparisons between oak savannah versus cornfield ecosystems and the amount of photosynthesis and food production that's happening. And the oak ecosystems, I mean, if you just think about the size of an oak tree and its photosynthetic capacity versus the sort of short grass, it can do a lot more.
Well, if you happen to park your car under an oak tree, you get a good sense of exactly how many acorns one can produce.
Yes, it's quite a bit. And actually, another cool thing about acorns, is that because of the tannins, which are kind of a pain, right, for processing. People often wish they didn't have these tannins. But tannins are an incredible preservative. So, from a food security standpoint, if you gather some acorns and you dry them out a little, just by letting them sit in an airy, dry spot, they can store for decades. So, even if the acorn production isn't consistent year to year, like say a hazelnut or a chestnut or a field of corn might be. Those fluctuations are not as big of a deal because of that food security potential. There's a lot of different ways to break it down. But I was a skeptic, a yield skeptic. And by the end of the research, I felt quite confident in saying that these trees produce plenty and it's definitely not a yield issue why we moved away from them.
Well, I'm glad you decided to dive into the yield thing because it's actually very interesting once you get into it. Let's talk about something else that you wrote about. A little-known part of US history. You wrote that in the not-so-distant past, the US government considered keystone nut trees as a solution to some of our biggest environmental and economic challenges. I had no idea about that. Tell us about it and what happened.
I had no idea either. When I first started researching the book, I went on this trip through Appalachia talking to different people who had some knowledge of this stand of trees that was planted in between the late 1920s and the 1960s by a guy named John Hershey. And I just thought, oh, cool, I'll go see these old nut trees. This sounds really interesting. But what I learned when I got there and started talking to the folks who had found where the trees were and were sort of caretaking them, was that Hershey was part of, Roosevelt's depression recovery plan. And he had this experimental fruit and nut tree nursery where he had ads in the newspaper and people all over the eastern seaboard were sending in entries of their best nut seeds, best trees. He got these genetics that probably represented, you know, hundreds if not thousands of years of human breeding in the east. And he started planting these experimental nurseries. And as part of Roosevelt's tree army, not only were they planting trees to try to prevent erosion and reforest areas that have been cut over. They were also planting these nut trees and seeing them as a really viable solution to hunger, to environmental crises, and to reviving rural economies. And unfortunately, Hershey ended up getting cancer. His other buddy who was doing the program with him got in a fight with one of the Roosevelt administrators, and the program fell apart. Also, World War II began. So that was another reason that things kind of fell apart. But for a moment there it was at the highest levels of government. The officials saw, wow, this could actually solve a lot of problems at once. And I think it's a bummer that it didn't catch on then. But it's not too late now. We still have a lot of problems as we unfortunately all know. And these trees still offer a lot of solutions.
So given the long human history of this, the story of indigenous cultures becomes really fascinating. And you've talked about how the indigenous cultures tended oak trees and other trees with what you called forest farming. And I'm interested in that concept and if you would tell us what that means and also, why haven't these things caught on? And why don't most Americans eat acorns or even know that one can eat them?
So, the history of forest farming in the US is pretty long and violent. Our government has pursued a policy of trying to eradicate a lot of these indigenous food production systems because people are easier to control when they're hungry and when they don't have access to the resources that they need. We often talk about our industrial style of farming that we have today as inevitable, right? Oh, well, these older methods didn't produce enough food and so we had to transition from quote unquote hunting and gathering to farming. And what I found as I looked through the history is that is a completely made-up story. Instead, what was happening is that as Euro-American colonists kept trying to expand our land base, you know, kept trying to move West, force into new areas, is that it was very hard to gain access to more land without also using violence and a tactic that, some historians have called a feed fight. Targeting indigenous food production and then forcing survivors to assimilate into grain crop culture. And that, we've been told was because it was a way of producing more food. But in fact, often it yielded less food and was actually a war tactic. And there's a lot of talk right now about regenerative farming and there's also a lot of talk about racial healing and having real conversations about racial history in the US and trying to move forward. And I think that this food aspect is really key to that conversation. And if we want to build a better future, it's something that we really have to reckon with and talk about, you know? We can't change what happened, but we also can't move forward without knowing what happened and really understanding it.
So interesting how the history of this particular food was so shaped by politics, colonialism, things like that. And also by things like Mr. Hershey getting cancer and, you know, his, his colleague having a fight. I mean, it's just an incredibly interesting history and it's too bad that it played out like it did for a million tragic reasons. But whoa, that's interesting.
I found some of the historic literature just totally confounding and fascinating because there would be, you know, sometimes the same people would be commenting on how they'd gotten to present day California. You know, these Euro-American soldier, settlers, they got there. They couldn't believe how much food there was. You know, wild geese, as far as you can see, wild oats as far as you can see, salmon filling up the rivers. And then in the same letter sometimes saying these indigenous people don't know how to produce food. They have nothing to eat. It was a really important reminder to me of the importance of stories and the stories that we internalize. Because I can now think of examples in my own life of, you know, I live in this national park and on the website of the National Park, there's one page about the importance of human fire in the ecosystem of this place over the past 10,000 years. And on another page of the same website, there's a description of this natural, pristine wilderness, that is supposedly also here. Of course, those two things can't really both be true. But until I started learning all this about oaks and these other trees, that didn't set off any alarm bells in my head. And we all have internalized narratives that we forget to question. For me, for whatever reason, these acorns have been this huge opener of like, okay, what else am I missing? What else do I need to reexamine about the stories around food that I've grown up with and the stories around our relationship with the living world around us. Because there's a lot of layers there to unpack.
Well, there sure are. One other thing I wanted to ask you about, because you brought up this issue earlier of forest succession. And in that context, tree pruning is an interesting topic. And you write that tree pruning, this could happen by fire, or it could also happen with other things like pollarding. I didn't know what pollarding was. But those could hold some surprising opportunities when it comes to food production and climate change. And you write that regularly pruned and burned landscapes aren't like the typical old growth forest that we often associate with climate solutions. So why is this?
So, we often think of old growth forests as simply a forest that looks really old, right? The trees are tall and they're broad. And there are forests that can be really old but can be in an earlier stage of succession. So, what happens with a lot of these interactions over time where people are either burning or coppicing or pollarding, which I'll define for your listeners. Because I also had no idea what those words meant when I first started researching. But coppicing is where you cut a woody plant back to the ground year after year. It could be every year. It could be in a rotation of every eight or 15 or 20 years to produce new stems. Like it's a plant that will resprout. And pollarding is the same idea but was often done in systems where livestock were also involved. You're cutting much higher off the ground, typically above animal head height, so that they can't graze those tasty young shoots. And there are a lot of traditionally managed forests in Europe that have been managed with coppice and pollard. What's happening is when we produce food in a farm field, right? We're taking succession back to zero every year. We're re plowing the field. Every time we do that the carbon that the plants had stored in their roots and had sent down to the soil gets burped back out into the atmosphere. I talked to a great soil scientist about this, and he was just like, oh, it's carbon dioxide burps everywhere. It's awful. But when we work with these woody plants where you're not taking out the roots, you're not taking out the trunk necessarily, if you're pollarding, right? You're leaving these trees. And these trees can get really old and really big around the trunk, and then they're getting pruned up top and sending out these new shoots. It is more like giving the plant a haircut. You're not killing it back. You're not losing all that carbon that's stored in the soil. And you're kind of renewing its youth and vigor. There are some studies indicating that trees that are coppiced and pollarded can actually live longer than trees with no human interaction. And so, there's this really fine line between, you know, too much interference where we're messing up the succession cycle of the forest and taking it back to zero. And maybe some interference, but not going all the way back to zero. And that has huge climate implications.
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