Chuck Cannon moved to Chicago in 2015 when he accepted the position as the first Director of the new Center for Tree Science at the Morton Arboretum to spearhead a new initiative around tree science, study and education. The Morton Arboretum is an unusual place, a tree museum, essentially, where visitors travel to observe a highly curated collection of different indigenous and nonindigenous trees. The first time I went there to meet Chuck we walked around the grounds discussing whether or not trees know things, a conversation that since had a lasting impact, eroding my assumptions about where thought is located and how it might be retained.

Caroline Picard: Can you talk a little bit about your work at the Morton Arboretum? What is it like to be a tree doctor working in a tree museum?

Chuck Cannon: The best thing about going to work at the arboretum is literally being surrounded by thousands of very cool trees. They have been brought into our living collections from all over the world. Our collection’s staff have been bringing in interesting trees for almost one hundred years. I go for a short walk and compare an American and European oak side by side. Or a Japanese elm to one that is a hybrid between an American and Chinese elm. These trees evolved on different hemispheres. They have been separated for a very long time and we’ve done this unusual thing of bringing them together again, perhaps after two million years or more of separation. It’s like going on the Voyage of the Beagle without ever getting sea sick or even on a boat.

And trees largely remain a mystery. Despite the fact that trees are probably one of the most essential creatures on Earth, and despite the fact that they grow everywhere, we know little about them. We know the broad elements of their life and about forests, but we are missing a lot of the day-to-day details. We think of trees as behaving slowly, over long periods of time, but it is the accumulation of daily behaviors, of a chronic water deficit or nutrient imbalance, too hot with low humidity, that leads to the eventual decline or vigor of a tree. You walk by a tree for years and then you suddenly notice one day that a substantial part of the crown is leafless and might be dead and we think how did that happen? We don’t have any easy cues to understand the “mood” of a tree. As a kid, I helped my parents raise a lot of animals and you learn to tell whether a young calf is feeling sickly just by looking at it. It’s head hangs down a bit, it’s eyes are watery, and its nose a bit snotty. How do you notice that a tree is not feeling so well? How does it act if it is being attacked by an internal fungal infection? Does it ooze sap, or wilt? We have little native intuitive ability to read a tree’s mood or physical condition but they certainly do send signals, both intentional and unintentional. That’s to me the essential mystery of a tree and what draws my curiosity. They are a very alien life form compared to animals but they are enormously successful. A tree doesn’t have a brain or a nervous system but yet it makes animals and insects do its dirty work all of the time.

CP: Given that strangeness, how do you approach trees contextualized by such a longstanding institution?

CC: As a tree doctor, I feel very fortunate to work at an institution devoted to the scientific study and sustainable care of trees. The leadership of the arboretum has always held scientific research to be a central part of the arboretum’s mission. I was hired last year as the Director of The Center for Tree Science to lead an ambitious goal for the Morton Arboretum to somehow overcome the  neglect of tree biology. Although research has long been a major part of the Arb’s activities, we are creating several new programs to get our small in-house team of scientists aligned with a global network of scientists of all stripes. The hope is to work together to advance meaningful research on trees, fostering appreciation and understanding among students and early-career scientists for basic tree science.

CP: Why now?

CC: I have a real sense of urgency. One has to only glance briefly at the basic trends around the world—the astounding explosion of the human population and the accompanying and equally disquieting explosion in our per capita consumption; take that alongside the degree to which forests have been converted and damaged so that nothing can be considered outside the direct impact of human activity. Clearly, we can’t continue doing what we are doing and expect a good ending. Something fundamental has to change. Our economic system? Wouldn’t be the first time.

CP: It must be strange that you are immediately happy to live and work alongside trees every day, while being nevertheless especially aware of the ecological crisis we inhabit by virtue of the trees’ proximity.

CC: Basically, I feel like the kid who got the golden ticket but now, we have to try and fill Willie Wonka’s shoes and make trees somehow wondrous and magical to the rest of the world.

CP: As I understand it, you started working as a researcher studying primates in Borneo, but shifted your research to trees. How did that transition happen?

CC: Yeah, as a young boy growing up in West Texas, I had an intense interest in human evolution but you know a lot of people weren’t comfortable talking about it. At college, I wanted to understand how humans became “human” instead of being just another primate. I was fortunate to be chosen as a research assistant to live and work at a remote research station in a national park near the western coast of Indonesian Borneo for a year. While doing my research on primate behavior, I was also responsible for monitoring vegetation plots where all of the trees were measured and tagged. Each month, we’d go look at them and observe whether they were flowering or fruiting. Now, this is a mature tropical rain forest; the trees are quite tall. They are massed together and tangled with vines and epiphytes, and deciding whether a tree was flowering or not was difficult. Doing it properly was a lot of work. It easily took hours to finish a single plot. You can imagine, much of my time as a research assistant was spent looking up into the forest canopy, trying to see flowers and fruits in a confusing chaotic green mass of leaves and branches tens of meters over my head.
CP: How did that compare to the research you conducted on primates?

CC: My primate research was quite difficult because I was studying gibbons and they were not well-habituated to human presence. To find them, I got up in the dark, early morning, typically putting on wet clothes, throwing together some crappy cold lunch, and going out to listen where the male gibbon was singing. Gibbons are territorial and monogamous, so the pair sing a duet most mornings, starting with a bit of male soloing before daybreak. Even when I managed to get out there before they disappeared on their morning forage, it was very difficult to follow them and gather the data I needed. So, after many months of going through this, I only had a few minutes of quality data on primate behavior but pages and pages of quite invaluable data on tree reproduction. Also, trees don’t go anywhere. You can stagger out of bed at 8:30 am, scratch around a bit, take your time getting to work and when you go out, the trees are still exactly where they were last time you visited them. Basically, perhaps unflatteringly, studying trees fit my metabolism. I’m a lousy failure at being a birder. Also, I began to realize that very few people were studying the trees themselves. Lots of conservation biologists were talking about the endangered animals that live in tropical forests but few were actually talking about the trees that make up the forests, so I began to see that shifting over to studying trees and forests could provide a more meaningful and significant contribution. We tend to take trees for granted. They are a ubiquitous part of the landscape, everywhere you look practically, and they form the structure and productivity of any forest community, but few scientists devote their research specifically to trees.

CP: When did you realized you were more sympathetic to trees?

CC: I just remember one day, while I was working in the forest, and I was standing in front of some massive tree that was covered with climbers, its bark deep and furrowed, completely oblivious to me but covered in living things. A little movie of its life played in my head—imagining this grand old tree as one of thousands of tiny seedlings, so vulnerable and hopeful, while people were just starting to sail around the world; and that it grew in that same spot for hundreds of years, unknowing to all of the great events in human history. The rise and fall of empires seemed like ant hills. The New World was still innocent of the Europeans. Some trees in that forest are so old. A single individual, a single lifespan, was possibly longer than much of humanity’s history. I found that very intriguing.

CP: During a talk you gave last winter at Sector 2337, you explained that trees know when they reproduce. Can you describe how you’ve observed that knowledge? What is it like for a tree to know?

CC: That’s a tricky question because we have a very poor understanding of tree awareness. We have a pretty poor knowledge of even their basic behavior. While they don’t have a nervous system or musculature for active movement. they are not passive organisms. They have fine control of their breathing rates, down to the leaf level, through their stomata. So while you look at a tree and see it as a single unit, each leaf is responding to the exact light, wind, and heat conditions it is experiencing. This behavior is not controlled in a centralized way but each branch can be thought of as a competing “lineage” of clonal cells. As they grow, they have to maintain their balance, simply not falling over, while responding to the light and wind conditions of where they germinated. They have complex behavior each day as they respond to the weather as it changes with the seasons. They interact with many animals and fungi, resisting attack from insects, signaling to other trees about the attack. Their behavior changes dramatically as they grow from a tiny seedling into a mature tree. How this behavior is organized and coordinated is not understood.

The reproductive behavior of trees or tree sex is particularly poorly understood but obviously it is a critical piece of the puzzle. First of all, there is the timing. You must flower when the rest of the individuals in your species are flowering, so that the pollen isn’t wasted on the wind. How do trees know when to flower? In the temperate areas, it’s relatively easy because you have a very strong environmental signal—freezing weather in the winter and a big thaw in the spring. But in the tropics, in places where it rains year round and the weather and day length etc. remain pretty much constant, how do you synchronize yourself with potential mates? Frankly, we don’t know.

CP: Accepting that a tree possess knowledge, and even intention about its reproduction, would blow upon traditional ideas about what it means to “know.”

CC: I do believe that trees “know” quite a lot but that knowledge is obviously processed in a very different way. Is it stored some way? If so, where? Some studies have shown that individual trees often wait several years accumulating the necessary resources so that they can reproduce. Somehow the tree knows that it should wait until next year to give it a shot. There is a structural knowledge to a tree, the tissue that is created to conduct water, support branches, etc., build up an understanding of how to live in that particular spot, right? There’s also a dynamic knowledge to a tree, how hormones are produced, pheromones and volatiles released, phenolics and alkaloids concentrated. Again, it is not really centralized but the trees’ slow process of emerging is highly adaptive to its environment.


CP: You also showed a slide during that same talk arguing that we need to let our trees be kinky if they are going to survive the Anthropocene…

CC: My point is relatively simple. We’re heading into a future that seems very difficult to predict. The normal parameters of how things work are no longer valid. That is why I think the Anthropocene is a useful term. The question is whether we will last long enough to leave a trace in the geological record. With both human population and consumption increasing, our impact on the Earth’s biosphere is obvious. Natural areas are mere postage stamps, surrounded for many miles by agriculture monoculture or human infrastructure. The processes that have generated the incredible natural wealth that we enjoy today through millions of years have been interrupted by human activity. And I am sure they will return to normal in the not too distant future but what we need to do is survive the dramatic shift that seems necessary to achieve a new “normal.” We can’t break Nature but it can sure break us.

How do we emerge on the other end of that ‘re-adjustment’ intact? We obviously won’t do that by looking backward and regretting what we are losing. Instead, we need to be looking forward and utilizing the resources that we still have. Much of the invaluable genetic resources and diversity produced by millions of years of evolution are now being lost without a trace.

CP: And the answer is kink?

CC: What I meant by trees being kinky is allowing them to bend the rules of sex beyond their normal parameters. Sex is all about mate choice. But how do you choose a mate as a tree? First of all, you can’t even select your mates yourself. You have to lure some insect to your reproductive parts and reward it with some nectar and then send it off in hopes that it will go find that fateful soul mate out there in the forest. Or, worse yet, if you are an oak, you send massive amounts of pollen on the wind, hoping that it blindly lands where it should and not where it shouldn’t. There are estimates that an oak tree produces more than 100 billion pollen grains during a single spring flowering. To me, this means they have incredible evolutionary bandwidth. Compare this to humans, who might attempt producing offspring with one or two mates. You can have ten kids but you are supposed to only have one mate. But each one of those pollen grains is off on its own adventure, hoping for the best. A single tree could potentially have sex with every tree on the planet during its lifetime.

Typically, we think of individuals being “faithful” to their species. A general assumption is that hybrid crossings lead to less successful offspring, although a certain hybrid vigor does emerge in some circumstances. I think trees are among the most promiscuous organisms on Earth. I think breaking the basic rule of being a “good” species is key to tree sex. They conduct enormous experiments in genetic recombination and they only need ONE successful offspring for all of that exploration to pay off. From the perspective of a tree, because its offspring might only become a mature tree in two hundred years’ time, how do you know what the environment is going to be like at that future time? In a few generations, the local climate might have changed considerably, or a new bug might have come to town, etc. How do you produce an optimal offspring when your own ability to predict the future is quite limited? You try a lot of options and produce a wide variety of offspring!  In the 40’s, a German geneticist named Richard Goldschmidt put forward the idea that major changes in evolution occur through the production of “hopeful monsters”—a dramatic novel shift that fits a new unprecedented niche.  This is sort of what we need now, with the coming of the Anthropocene.

CP: That also seems interesting to think about within the context of a curated tree collection…

CC: I think the arboretum setting is ideal for allowing these kinds of genetic experiments, conducted naturally by the trees themselves. We have the Chinese chestnut by the American chestnut. We have oaks from around the world. I actually don’t believe that it will lead to one huge melting pot where all of the oaks begin to look like some mongrel oak. I do think there are reasons species exist and we can recognize distinct types.  This divergence is necessary and powerful. But it is also quite possible that something entirely new and successful will emerge from this natural experiment.  That “hopeful monster” idea.

CP: After your talk, I remember someone asked how we should relate an interest in tree kinkiness with traditional agricultural and horticultural strategies—specifically with regards to wine. Certain grapes have been carefully and conservatively reproduced to ensure that the resulting wine is the same as it has always been. To me, the question illustrated an interesting tension between the Romance of cultural traditions and the controlled goods they yield—goods that so often encapsulate human identity and accomplishment, i.e., wine, cheese, yogurt, maybe even apples. It’s hard to square that tradition against a dismal future, where human identity may not even exist. Should we give up the ways that winemaking, for instance, informs our approach to the landscape?

CC: A leading researcher for Gallo Wines recently spoke directly about this issue because wine breeders feel tightly constrained by the market. Everyone demands that Merlot remain Merlot, somehow sacred, while in fact, when you consider all of the research that they have performed about mouth feel and volatiles and aromatics etc. etc., all the things that make up the taste and value of a wine, they know how to grow grapes that taste fantastic and yet, you can’t sell them because this new fantastic grape variety doesn’t have a recognizable name and didn’t emerge out of the Old Country. It’s a bit ridiculous. It’s like demanding that new automobile technology not be introduced because we really like our Model T. There is nothing sacred about wine varieties. In fact, they are a hybrid plant, with these varieties grafted onto an American rootstock that was brought over to Europe to save the vineyards which were being attacked and killed. If you really remained true to these varieties, you should have let them go extinct.  We can still continue to improve them.  It’s not as if the ancient Romans perfected the wine grape and we have no power or ability to modify or improve them to our own modern tastes and climates.

CP: That makes sense, and maybe highlights a strangely human propensity to impose a kind of changelessness on the world. But it’s heartbreaking also somehow, and maybe that’s one of the ways I feel very much implicated in this Anthropocene question. On the one hand, I’m all for crazy tree evolutions and multispecies enthnographies, and let’s disrupt the status quo, or redistribute wealth etc., and yet funny things like coffee, cheese, wine, bread—I would miss those things. Even further, I admire the generational craft they contain.   

CC: It’s a problem with purity. Purity and diversity are almost naturally opposed to one another. Demanding purity  negatively impacts diversity.  To maintain a particular type of grape, you have to propagate it clonally, and to refine it further, you would have to breed it with itself, which leads to inbreeding. If you demand that a particular natural product, like perfectly consistent ears of corn or just so long fat potatoes, remains utterly the same and mechanizable, you have to basically break one of the fundamental tenets of evolution—that the population varies. Nature is all about change and exploring that change, exposing the potential of that change. Nothing ever remains the same in nature. There is no “right” way to do anything.

It’s that reason that I promote tree kinkiness. We emphasize diversity and freedom of expression in humans but we demand an unnatural level of consistency in nature. As we enter the Anthropocene, there is no way to predict the future climate or most appropriate land use or the dominant economic drivers of the future. We cannot hold trees to a level of fidelity that we don’t expect of ourselves. Going forward, we should be willing to imagine unnatural sex in trees in order to create a new type of tree that meets the needs of the future. Tree breeding is difficult.  I was discussing the process of breeding a new variety of tree and it takes roughly 15 years, under the best circumstances, to develop and test a new type of tree and get it into the marketplace.
CP: Do you think standards will continue to make sense in our Anthropocene future?

CC: Nature is all about change. We are trying to hold nature to a standard that it rejects. It is always poised to mutate and change and adapt to the new reality, which throughout history is generally unpredictable and the process is rather chaotic. We talk about sustainability a lot these days without recognizing that sustainability itself is an unnatural concept itself. Populations naturally boom and bust, species teeter on the edge of extinction and then expand across a continent as conditions change over tens and hundreds of years. What we are trying to do is reach some type of steady state with high levels of constant production, completely predictable and standardized natural products, like the utterly predictable potato, indistinguishable from a vast field of identical potatoes? I’ve always struggled a great deal with the idea of sustainability because I don’t see it anywhere in nature and so we are trying to invent something that is basically supernatural.  To me, going back to my search for what makes us ‘human’ versus a ‘primate’, it is the spiritual, the belief in good, the quixotic search for sustainability.  To make the transition into a new bright and shiny world without causing the sixth great extinction or plunging ourselves into a new dark age, we will have to defy or at least bend some rules of nature.


Caroline Picard