in: Outdoor/Survival, Podcast, Skills

• Last updated: July 10, 2023

Podcast #907: How to Read a Tree

When you’re walking in the woods, you’re often surrounded by trees. But you probably don’t notice them much, and when you do spot some irregularity, like a strange bulge in the trunk of a tree, you likely don’t have any idea how it got there. But my guest says that these trees you’re passing by have all kinds of stories to share, and once you learn their language, they can tell you all sorts of secrets about the world, and even help you navigate it.

Tristan Gooley is an adventurer, expedition leader, natural navigator, and author of How to Read a Tree. Today on the show, he unpacks the clues in a tree’s shape, branches, bark, roots, and leaves, what they can tell you about the environment, and how they can help you find your way. We also talk about what looking at a tree stump can reveal, the hidden seasons in trees, and the first place to look in a tree to spy fall foliage. We end our conversation with how to get started with reading trees today.

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Read the Transcript

Brett McKay: Brett McKay here, and welcome to another edition of The Art of Manliness podcast. When you’re walking in the woods, you’re often surrounded by trees, but you probably don’t notice them much, and when you do spot some irregularity, like a strange bulge in the trunk of a tree, you likely don’t have any idea how it got there. But my guest says these trees you’re passing by have all kinds of stories to share, and once you learn their language, they can tell you all sorts of secrets about the world and even help you navigate it. Tristan Gooley is an adventurer, expedition leader, natural navigator and author of How to Read a Tree. Today on the show, he unpacks the clues in a tree’s shape, branches, bark, roots, and leaves, what they can tell you about the environment, and how they can help you find your way. We also talk about what looking at a tree stump can reveal, the hidden seasons in trees, and the first place to look in a tree to spy fall foliage. We end our conversation with how to get started with reading trees today. After the show’s over, check out our show notes at

Alright, Tristan Gooley, welcome back to the show.

Tristan Gooley: Thanks, Brett.

Brett McKay: So we’ve had you on the podcast a few times to talk about how to navigate your world just by looking at your environment. And you got a new book along the same lines, but this is called How to Read a Tree: Clues and Patterns From Bark to Leaves. So this is how we can look at trees, and we can navigate with trees, get our bearings in the world. But also what I love about it is you answer some questions that I’ve had whenever I’m out on a hike and I’m looking at a tree. For example, one we’ll talk about today, I hope, is you walk in, you see this tree, and there’s this weird bulbous growth in the middle of the trunk, and then it goes back to normal. You’re like, “What is going on there?” And what I love about all your books, and I got this with this book too, is when you read it, you immediately have things that you started looking at in your environment that just opens up new worlds that you didn’t know existed. You kinda… It feels like you’re in on a secret, and so we’re gonna learn about the secrets of trees today. But before we talk about that, you start off the book saying that, In order to read a tree, it’s not really important for people to know the different species of a tree to get the benefit of reading trees. Why is that?

Tristan Gooley: I think people can be put off nature by thinking it’s about identification, but we have to remember that we’ve evolved to find meaning in nature without names. All over the world, you’ll find different names for exactly the same tree. So there is not a correct one. Latin is no use to indigenous people, and they have some of the strongest skills in this area. So names are not the answer to finding meaning. What we have a lot of success with is if we realize that nothing is random, and every color, every shape and every pattern is trying to reveal something about the life the tree has been through. And once we just sort of take that little shift in philosophy, we find we are surrounded by clues. Every single thing we see is revealing something.

Brett McKay: And so while you don’t say we should focus on individual species, it is useful to know about broad families of trees, because different families of trees will tell us different things about the environment, and the broadest categories we can look at when it comes to trees are whether they’re a conifer or a broadleaf tree. What can we learn about the environment depending on whether we see more conifers or broadleaf trees there?

Tristan Gooley: Yeah, I think even people new to the idea of looking at trees are comfortable with the idea that if we’ve got very dark, needle-like foliage, that it’s a conifer. And the conifers as a group evolved first, and they have a simple tough architecture, and they are really good when the going gets tough. If the environment is particularly cold, particularly hot, very exposed to winds or very dry, or the soil is a bit inhospitable, then conifers have… They’ve grown up to deal with that. Broadleaf trees came later, and they’re more efficient, but they have a more delicate system. So if the going is easy, if there’s enough moisture in the soil, it’s not too hot, not too cold, the broadleaf trees are more efficient, so they will start to out-compete the conifers. And what we find is if we see loads of broadleaf trees, and again, we don’t have to worry about names, we can just sort of go, “There are a lot of broad leaves there,” then we can say the going is pretty easy, there’s enough moisture and it’s not too tough, which means we are likely to find a lot of other smaller plants, a lot of animals, a lot of insects, a lot of birds, and most likely a lot of human beings as well.

Human beings are pretty soft creatures as nature goes, so we tend to live in places where there are broadleaf trees. If we see conifers, there’s something tough in the environment. So whenever we see conifers, we just pause and go, “What’s tough?” Sometimes it’s obvious because we’re looking halfway up a big mountain, but it’s always worth asking the question.

Brett McKay: Yeah, I think you’re in Oklahoma, so a lot of broadleaf trees., but then you get into sort of the more rocky mountainous parts and you just see pine trees primarily. So I’m thinking like Southeast Oklahoma. So you think, “Well, the soil is rough here, so obviously, a conifer would grow here.”

Tristan Gooley: Yeah, and that’s… One of the ways I think of it is when you might be happier in an all-terrain vehicle, a 4×4 or something like that, the moment you’re thinking that that’s the moment the conifers are going to the broadleaf trees, “Okay, step aside. It’s our turn now. We’re gonna take it from here.”

Brett McKay: Let’s talk about the shapes of a tree. So every tree is different. They’re gonna be shaped differently because of the environment they find themselves in. So what can the shape of a tree tell us about its environment?

Tristan Gooley: Well, all trees are a balance of a number of factors, but two of the biggest factors are the genetic, so the nature, and then the environment, the nurture. So a pine tree, for example, will never look like an oak tree, whatever goes on in the environment. So conifers, generally speaking, tend to be tall, fairly skinny with branches that aren’t horizontal, they tend to flow down more, and this is very good at dealing with snow, for example. But then what we find is the environment will shape each individual tree. And one of the core philosophies in the book is no two trees on the whole of planet Earth are identical. So they might start life with an identical genetic package, but then Day one, they’re experiencing slightly different things, and we see that in their shape. One of the simplest things is sunlight makes trees shorter and fatter, because they don’t know what they’re gonna have to deal with in life, so their basic plan is to grow up and to grow tall and skinny until they find some sunlight.

And then when the top of the tree, what’s known as the apical bud, senses direct sunlight, it changes the messages to all the branches in the tree and says, “Okay, we can slow the race for the sky now and we can start spreading out.” So the sunnier a place is, the shorter and the fatter a tree is. So if there’s a particular type of tree you see a lot of, just notice how when you see it surrounded by other trees or in other shady places, it tends to be tall and skinny, and when you see it out on its own drenched in sunlight, it’s shorter and fatter.

Brett McKay: What can the shape of a tree tell us about the weather and an environment? I think the last time we had you on, we talked about this sort of micro-climate. So there’s broad weather patterns, but even in a specific area, there can be different types of weather. So what can the shape of a tree tell us about that?

Tristan Gooley: Each tree will respond to every day of weather. I sometimes think of both the sun and the wind, and indeed, rain, leaving footprints on trees. And if anyone is new to this, the wind is a good place to start, because a light breeze is not gonna change a tree in a way that will pick up in a dramatic sense. But if you look in exposed areas on high ground, if you’re in a town or a city, there are places where the part of the park where a long street leads up to, you’ll find these gusty winds, and what you find is, for example, the branches go shorter on the side the winds come from, and there are patterns here, long-term trends. So in many parts of the world, we get more winds from the west or the southwest, and we find that, that leaves footprints. You will notice the tops of the trees are bent over. And indeed, every single branch, and actually, every single leaf can be read in this way. But when anyone’s new to this, I recommend, look for the really bold, dramatic stuff, go… Whenever you have the opportunity to look at a tree on its own on the top of the hill, it will just… It will scream a direction, and it will tell you a whole story about what the wind has been doing to it.

Brett McKay: Okay. So that’s one way a tree can help you navigate. So if you’re looking at it from a long distance away, if it looks like one side has shorter branches than the other, that’s where the wind is hitting it. And so you know wind typically comes from the west, so you can say, “Well, that short side, that’s west, and then the longer side is east.”

Tristan Gooley: Yes, absolutely. And every single part of the tree is responding to that. The tree itself will grow shorter in the wind, and this leads… When you’ve got a wood that you can see from a little distance, so you’ve got a little bit of perspective, it leads to something I call the wedge effect, and this is where trees grow shorter in the wind. So what we find is the tree the wind would edge, the wood will be the shortest. And then the next tree downwind, just a couple of steps to the east, is getting a little bit of shelter from the first tree, so it grows a tiny bit taller, and this leads to a wedge. It sometimes, from a distance, looks like a sports car driving into the wind. And we find there are lots and lots of little layers that we can add. So the trees are shorter, but they’re also denser, because the branches are shorter. So we find it looks much darker on the side of a wood that the wind has come from, and this is the sort of thing where you might go a couple of days and not see it, and then the first time you see it, it just screams out to you, and our brain absolutely loves that, so it kind of stores it. It goes, “I like this. I like being able to find meaning in a simple pattern,” and that starts a relationship with these signs, which all our ancestors had.

Brett McKay: So that’s sort of looking at trees overall, the shape of a tree. But then you start getting more specific, different things we can look at in a tree to learn more, and one of them is the branches of a tree. What can a tree’s branches, when you look at them closely, what can they tell us about the environment? And then how can they potentially help us navigate?

Tristan Gooley: So this is a good example of nature and nurture. So again, the tree doesn’t know the world it’s growing up in, so it has to respond to what it finds. And the branches, the exact angle they start life will depend on their genes, on their species, but we don’t need to know that. But if we imagine branches starting by growing, let’s say 45 degrees up, then from day one, the growing bud is responding to light. So on the south side, the branches grow out towards the southern sky, leading to a more horizontal pattern in the branches. On the north side of the tree, there’s no direct sunlight. The only light those growing buds get is from directly above, the blue sky above them, and so that leads to branches on the north side that grow up towards the sky. And seen from the side, if you look from the east or west side of a tree, it sometimes screams out. You see these horizontal branches on the south side, more vertical branches on the north side, and it can look like a check, and so I nickname it the check effect, or in this country, we call it the tick effect.

Brett McKay: Well, another one too related to this is this idea of the Southern eye. And this is something you’ve discovered recently. You kind of discovered it serendipitously when you’re out on a hike.

Tristan Gooley: Yeah, I was exploring a small nature reserve called Snitterfield. It’s in Stratford near Shakespeare Country. And it was the end of the day’s micro-exploring, and I’m always looking for signs. That’s what I do, that’s my job, but it’s what I do for joy as well. And it had been a long, fun, interesting day, and I just stopped. And so often, stopping, it just allows our sensors in our brain to notice things that we’ve been passing. And I was just having a snack, and I just suddenly saw the trees looking at me, and I thought, “That’s odd.” And what I was seeing was something that I’ve subsequently nicknamed The Southern eye. But what it is, it does look on smooth bark trees… And we might come on to talk about bark. But on smooth bark trees, it’s more dramatic. On rough bark, it’s a little bit harder to make out. But you see this… The shape that really does sometimes look exactly like an eye, and all it is is where a tree has pruned its own branch off.

So again, trees, they’re not given any advanced information, they don’t know what they’re gonna grow into. So what they do is they put out a branch when there’s lots of light, and then they grow branches higher up, and they end up shading their own branches or another tree shades them. So instead of keeping a branch that’s doing no good and not harvesting any energy, they… Actually, they change the message to that branch, they shut it down and they seal it off. It’s almost like closing a gate. And that branch will eventually die and fall off, and it leaves… If the process has gone well and there haven’t been any sort of fungi problems or anything like that, you’re left with this little scar on the bark. And depending on the size of the branch, the eye, it might be very small, it might not be much bigger than a coin. Very often, it’s sort of palm-sized.

And the thing is, because you get more branches on the south side, because there’s more light, eventually, you end up with more branches pruned on the south side, so more of these Southern eyes. And the reason I love it is because it’s a really good example to me personally, where I’ve spent literally decades looking for these sorts of things, and yet something which is quite… It does stand out when you know to look for it. It had passed me by for years and years, and then as soon as you know to look for something, it’s pretty hard to miss. And that’s a sign I’m onto something. When it’s obvious in hindsight, but we can go our whole lives and almost miss it.

Brett McKay: Well, another navigation sign you found on trees, similar to the Southern eye is a trunk shoot compass. What’s a trunk shoot compass?

Tristan Gooley: Yeah. So trees have a… It’s like an emergency plan. They have a load of branch buds that are dormant, and they sit under the bark, and we never see them if things are going well. So the chemical messages that typically are coming from the top of the tree down are saying to these dormant buds, “You just chill out. There’s no need for you guys to do anything. We’ve got… This plan A is working.” And then if the tree experiences a trauma or stress of some kind, it might be fungi, it might be a structural problem, it might be a storm, basically, if the tree senses it is under attack and things are going very badly, the tree changes the chemical messages, and these dormant buds, which might have sat there for years and years doing nothing, suddenly get a different message. It’s like pulling the emergency cord. The message is, “Okay, you guys now need to spring into action,” and what happens is these buds, known as epicormic buds, they start to sprout out through the trunk, but they respond most dynamically to light.

And again, we get more light from the south side, so we find these kind of really bushy little bunches of branches just poking out of the south side of a tree, but it typically only happens if that tree’s experienced some trauma. But it’s very common if you walk through any woodland that… Particularly if human beings have been doing anything, we tend to make life quite stressful for trees, so you’re very likely to spot one.

Brett McKay: Okay. So if you see those little branch shoots from the trunk, that’s probably gonna be on the south side. That’s a navigation tool there. Let’s talk about the trunk in general. What can the trunk show us about the tree’s environment?

Tristan Gooley: There is some things that are really glaring and leap out. The simplest sign is the texture of the bark. All bark is performing the same function, so it’s quite interesting that we see so many different patterns. One of the reasons for the different patterns is the different ways that trees grow, they have different strategies, to either grow very far or just grow slowly and bigger, and that changes the texture. But the simplest sign to look for is rough bark is a sign that that tree is expecting to deal with harsh environment and possibly animals. So each family of trees specializes in a different area. So birch trees, for example, are known as pioneer trees, and they’re kind of the smash and grab family of trees. If they see an opportunity…

So for example, if we cleared part of a woodland, if you come back in 10 years, there will be loads of young birch trees there, because they scatter millions of seeds in the wind. And a part of their strategy is just to grab a piece of land and grow super fast to just kinda grab it for themselves, but because they’re expecting to grow up sometimes on their own in quite sort of exposed areas, they have this very tough bark, and that protects them against the elements, but also against animals. Other trees have evolved to specialize in woodland settings, and they’re much more gregarious, they are much more social. They like to be surrounded by other trees, typically of their own kind, something like a beech tree, very smooth bark. So the simple sign is rough bark, this is a tree that is more common in open areas at the edges of woodlands. So if we’re finding our way from the centre of a woods out, we typically go from smooth bark to rough bark.

Brett McKay: Let’s talk about those bulges that you might sometimes see growing in the middle of a trunk. What’s going on there? What causes that?

Tristan Gooley: We’ve got different types of bulges, and it can become a very specialist area, so I don’t wanna give the impression that you can diagnose every single thing that’s going on for a tree instantly. But you get sort of semi-spherical swellings, technically known as a spheroplast, but that’s a good example of the tree scientists putting a sort of complex sounding word on something that they don’t fully understand. And these buds I mentioned, which sprout out and can give us the trunk shoot campus, those buds don’t always follow a simple plan, and for reasons we don’t always understand. It could be viruses or fungi. Sometimes the plank goes a bit wrong and it leads to a bit of a bulge, but that’s not always a serious worry for the tree. The other types of bulges you get, come from structural weaknesses. So if there’s a storm, for example, and the trunk suffers a crack. If the crack’s all the way across the trunk, it’s most likely to be game over, but quite often there’ll be a crack which is only partially through the trunk. And the way trees are dealing with these sorts of stresses is to grow extra wood. So we’ll find ribs that are vertical and we’ll find bulges and sort of ring shapes and things like that. The only thing we can say for certain is that the tree is growing some extra wood to deal with the challenge. Identifying exactly what the challenge is can be quite a tall order.

Brett McKay: But if you see that, you can assume there was some sort of challenge. It could have been a fungus, it could have been something broke or whatever, and it’s just compensating for that. So I think that’s interesting. Another interesting thing I learned about trunks from your book is the way trees grow. Let’s say you go to a tree and you carve your initials, you shouldn’t do that, but let’s say you do. If you were to come back 20 years later, 10 years later, I think a lot of people think, well, the carving will be higher, but that’s not what happens. Actually, the carving stays in the same place even though the tree has gotten taller.

Tristan Gooley: Yes, it’s a very popular misconception about the way trees grow. And I believe it springs from the way we sometimes see time-lapse videos of small plants growing from seed and we see them kind of wriggling upwards. And of course, there has to be some upward growth, otherwise, a small plant never becomes a tall tree. But trees have two types of growth. They have primary growth, and that’s when the little seedling and the green bud is moving upwards. And the second a tree forms bark, a different type of growth takes place known as secondary growth. And this is where it gets steadily fatter, but it stopped moving up. So the top of the tree where the bud is, will continue that primary growth. So at the very top of any tree, it doesn’t matter what family or species you’re looking at, there could be growth going on at the very top where the bud is still going on.

But if you see bark, there is no vertical growth at all. What’s happening is it’s getting steadily fatter. And what this means is if you carve something into it, like of course I wouldn’t recommend anybody does that, because it does harm the tree, but we will come across these markings, graffiti, it’s been common for people to do little love messages. Leo for Gemma. And what you’ll notice is, they’re nearly always close to head height, because that’s the height people carve these things. And you can sometimes find graffiti from 50 years ago, maybe even a hundred years ago, occasionally. And you’ll notice it hasn’t moved upwards because the trunk hasn’t.

Brett McKay: We’re gonna take a quick break for a word from our sponsors. And now back to the show. So you’re likely to encounter tree stumps on a hike, and those stumps can be created from a tree falling down naturally or from being cut down. Anything that stumps can tell us about the environment or help us navigate?

Tristan Gooley: Yeah, stumps are a golden opportunity. If time allows, I encourage everybody to pause for at least a minute and just see if you can find a story about that tree. It’s come down for a reason. As you say, it could be a storm and it’s worth just sort of saying there that trees typically come down in one of two ways. There’s what’s known as windthrow, which is when the root ball is torn out of the ground and the tree stays largely intact. And that can be used to navigate because they typically come down in a trend in the direction the storm’s gone through in. But windsnap is when the trunk itself snaps. And that’s very rare unless there’s been some weakening like a fungus or a disease of some kind. But foresters are constantly felling trees, and that’s where we get our cleaner stumps.

And then we can look for slightly different messages, because we get to see the rings. And a lot of these tree signs would’ve been known by our ancestors and are indeed known by indigenous people to this day. One of the few things that is still common knowledge is counting rings to age the tree. But there are lots and lots of subtleties within that. So a lot of people aren’t aware, for example, that we only see the rings because there are two types of growth there, the early and the late growth, and they have slightly different colors, which is why we see rings. But the more interesting thing in my world is that, the heart of a tree, the very center in terms of you count in from the rings, you go to the center there, the interesting thing is that is not the center by which I mean, and it sounds illogical, but the heart of a tree, the middle of the rings, the smallest circle if you like, is very, very rarely in the center of that trunk.

And the reason is, there are three major factors that will change the pattern in the rings, and therefore where we find the heart in the stump. So the three factors are light, wind, and gravity. So for example, a broadleaf tree, because broadleafs and conifers don’t respond to things in exactly the same way. But if we just think about a broadleaf tree for now, more light on the southern side, more branches, more weight there, we end up with the heart slightly close to the southern edge, but then, what we’ll find is it’s contending with the wind as well, and that will actually push the heart to the opposite direction to the wind is coming from, and then there’s gradient as well. I don’t wanna list all the, basically you’ve got conifers and you’ve got broadleafs and you’ve got three different factors.

But the simple truth is, the heart is there for a reason, and what I encourage people to do to keep it sort of straightforward and fun early on is the next time you see a freshly or a recently enough cut tree stump on a steep gradient, just have a look and it’s even better, which is quite often when foresters are doing lots of work, it’s even better when you can see a half a dozen or a dozen of these stumps in one place. You’ll start to notice the trend. You’ll start to go, ah, yeah, I can see. For example that the hearts are much, much closer to the downhill side of the trunk. And once we’ve picked up those patterns, they form a compass and help us with our journeys.

Brett McKay: Well, and the other interesting thing about tree stumps, I didn’t know this, but I’ve noticed this, but I didn’t know what was going on. It’s this cake slice effect. So you’re looking at a tree stump, and it looks like there’s this dark triangle and it looks like a piece of cake has been taken out of the tree stump. And like the bulge in a tree trunk, that cake slice is just a sign that there’s some sort of infection the tree encountered and it was trying to deal with it and just kind of coordinate it off.

Tristan Gooley: Yes. One of the clever tactics that a tree has is, if it’s attacked by something like a fungus, even if it can’t beat the fungus, it can box the fungus in. So trees can stop infection moving vertically up and down the trunk. They can stop a fungus moving in or out eye crossing rings. But the one we’ll see most often is exactly as you’ve described. There is if we imagine the spokes on a wheel, we have these kind of radial walls that go from the heart out to the bark and they can lock an infection into a cake slice. And quite often, this infection will change the color of the wood. So if you find a sawn tree stump or indeed timber stacked, dozens of logs in a pile, just keep an eye out, and every so often you’ll spot this cake slice. I think all of us can probably remember pie charts from school. It just looks a bit like one of those kind of slices there. It’s a different color. And that’s the tree locking a problem into a compartment.

Brett McKay: What can the roots of a tree tell us about the environment and how can they be used to navigate?

Tristan Gooley: This is a lovely, lovely example for me of where I never ever fall into the trap of thinking that I’ve discovered all the interesting stuff there is to discover. I’d be delighted if somebody told me I’d discovered 10% of it. But I’d for many years, used one tree technique, which I’ll discuss in a moment. But I’ve never noticed this, the second one, which I’ll also share in just a sec. So the first one is, roots have two main roles. The first is to supply the tree with water and minerals, and the second one is to give the tree structural stability. Because we can imagine if the trunk just went vertically down into the ground, the first strong wind, that trunk’s gonna topple. So we have Guy roots and these are roots, very light Guy ropes on a tent, which anchor the tree against the winds, and they will grow bigger, stronger, and longer on the side that the winds come from.

Now, it’s tempting to kind of think, well that’s sort of interesting, but I’m never gonna see that because the roots are underground. But this is another very popular misconception, because the trunk and the roots meld into each other just above the ground. So at head height, we’re definitely looking at the trunk and a couple of feet underground, we’re definitely thinking of roots. But between those two areas, the trunk becomes the roots. And what that means is they start to flare out, and we can see the roots in most tree families above ground, particularly close to the trunk. And the simplest way to put it is, if you look at the pattern of roots around the base of a tree, and if it’s the first time you’re doing it, pick some isolated tree that’s a bit exposed to the elements. The root that is furthest from the trunk is most likely to be on the windward side.

So if your winds are coming from the west, that is giving you an indication of west. And that’s a technique I’ve been using for natural navigation for well over a decade, probably 15 years. And something which is so closely related to that, but I’d never noticed, is that, trees are fantastic engineers. They’ve solved so many engineering problems that it took us until very recently to work out. And something engineers know now is that, right angles are not great at dealing with stress. That corner creates a weakness. So if we imagine the tree went down from a vertical trunk, and then turned 90 degrees out to the roots, you’d have a right angle and the first strong wind, it would create huge stresses there. So we end up with this curve from the trunk to the roots, and this can be seen from quite a long distance actually.

So we don’t even have to be a few feet away from the tree looking at the roots in the ground, just above the ground. You can actually be hundreds of feet, even a thousand feet away from a tree and once you’re practiced, you can see the curve in the base of the trunk. It’s what I’ve nicknamed in the book, the elephant’s toes. If we imagine an elephant’s foot, we don’t expect it to be a perfect cylinder. And there are indeed on an elephant’s foot, there’s just a little curve out towards the toes. And that little curve is what we see at the base of trees when we practice looking for it.

Brett McKay: Well, let’s talk about leaves. What can we learn about the environment by looking at the color and shape of either a tree’s leaves or needles, if it’s a conifer?

Tristan Gooley: Yeah, I just find it absolutely, it’s wonderful. It’s almost miraculous the variety there is in leaves and it’s very… I found it very instructive for me and I do write about this because I think it is a really helpful way of understanding that there is nothing random in nature. Nature is super, super competitive. So the idea that anything in the natural world just does something, because it’s decorative or pretty or different for the sake of it, it just, that’s just not how nature works. And of course when we think about it, we know that, but it is kind of tempting to think, well of course, there’s gonna be lots of variety. But in my world of looking for clues and signs, it’s all about turning that on its head instead of sort of going, well that’s just kind of nice and pretty and different. And saying, what is the reason for the difference?

And leaves are a fantastic area to experience this because on a walk of half an hour, we might easily see dozens of different leaf shapes and colors and if we say each one of those differences is trying to tell us something. So how do we actually find the meaning? Well, we start with the big bold, broad pattern. So a big broad leaf is looking to harvest loads of light, but it’s very vulnerable to tough conditions, so it suits trees that shed their leaves in the winter. You’ll find super broad leaves in places where trees are expecting to be in the shade. So we only get tall trees and small trees. There are very few medium trees because it’s a bad strategy, but the smaller trees quite often expect to get shaded, so they throw out these very broad leaves.

A broad leaf is telling you this is a tree that’s obviously gonna shed them, but also is expecting lots of shade. A point at the end of a leaf, a really marked point in broad leaves, is telling you you’re in a wet area, because points are good at channeling rainwater off a leaf. Rainwater is, it’s weight and stress that a leaf can do without. So anything it can do to shed that weight is good news and points at the end, at the tips of leaves are a sign you’re in a wet area. That’s why in jungles, we find lots and lots of pointed leaves. If a tree’s expecting to cope with very tough conditions, it has to get smaller, and that’s why conifers have needles, not broad leaves. And every single color is telling us something as well. So for example, in conifers, trees love sunlight, but sunlight is damaging. The radiation in sunlight is very powerful, and so leaves have this dilemma. They want the energy from the sunlight, but they have to protect themselves. So sometimes, on conifers you’ll see a white or occasionally a blue sheen, and that’s wax, which is protecting the leaves. And because there’s more sunlight on the south side, we get more of a blue or white color on the south side.

Brett McKay: And this, you can see this like in a single tree, like a tree might have darker green leaves on one side compared to the other.

Tristan Gooley: Yes, what we find is if a tree’s leaves are getting enough light, then the signals in the tree are you just keep doing what you’re doing. If however, there are leaves on a branch and there’s not enough energy coming back, the tree senses this, and it changes the signal, and it changes the message, and it changes the leaves from sun leaves to shade leaves, which means they get bigger, darker because they pump in more chlorophyll, and they actually get thinner, because they’re effectively spreading out. And what’s happening here is it’s a sort of last roll of the dice. So the tree is saying to the leaves, look, we’re gonna change you to shade leaves, but you need to really start delivering now. If after a season that hasn’t worked, the tree changes the signal again and it’ll start shutting that branch down, which leads to the pruning we talked about earlier. So all the time, trees are reacting to the environment, changing from the leaf level and then that in turn leads to branch changes, and that’s why no two trees are identical.

Brett McKay: When people often depict the seasons, like if they say, draw a picture of the four seasons, they’ll usually include a tree. They’ll show what a tree looks like in winter, there’s no leaves, it’s bare. Spring, you’re starting to see the flowers blossom, the leaves come on. Summer, it’s just green leaves, and then in fall, the leaves change colors. But you highlighted the fact that trees, besides those four broad seasons, they actually have hidden seasons. What are those hidden seasons, and what can they tell us about that tree?

Tristan Gooley: Yeah, it’s a fascinating area because I think as you’ve highlighted there, our busy modern lives mean, we tend to compartmentalize everything to simplify it, which can be very helpful. But when we are reading trees, we’re talking about just going up a level and wanting to notice things that have passed us by. And that’s where four seasons is an oversimplification. So if we take spring for example, spring doesn’t hit one country all at the same time, we know that. It won’t even hit one region at the same time. So spring moves across a region, but it also moves across trees. So one of the most dramatic signs you can look for is how spring starts lower, moves up. You’ll find that there are flowers on the ground, wild flowers that come out before any of the trees come into leaf, because they’re trying to steal a march. They’re trying to get, they’re trying to jump the gun almost.

But the smallest trees, and the lowest branches will come into leaf next and then spring moves upwards. So by the time most people are walking around going, oh, it’s spring, the leaves are out. Actually, we’ve seen two springs already and there are half a dozen other ones that we can see. So in each individual tree, the tree is sensing the seasons in all of its growing areas. So it can actually tell that it’s gonna be colder near the ground, because of a frost and respond to that differently. So we can actually see the seasons move almost branch by branch up a tree. At the other end of the broadleaf growing season, we have fall and again, we sort of get used to this idea that there’s this sort of magical moment or maybe a magical two weeks where there are fantastic golden colors and reds and things like this.

But actually, each tree again is, it’s not interested in putting on a show for us. Lovely when it happens, but that’s not the tree’s aim. The tree’s aim is to be efficient and do things in a practical way. So what we find is that the leaves will turn at the furthest point from the roots, so the highest part of the tree, but also in the warmest areas first. So we find that the colors will start in the highest southern part of a tree. So it’s very, very common to notice fall arriving in the high southern part of a tree weeks before in a big tree, a couple of weeks, maybe three weeks before the low northern part of the very same tree.

Brett McKay: How does a tree figure out when it needs to start blossoming in the spring, and when it needs to start shedding its leaves during the fall? What is it looking at in the environment to figure that out?

Tristan Gooley: The tree senses two different things. It senses the length of night. We tend to think of the day as getting longer, but the tree’s looking at it a slightly different way. The shorter the night, the closer to the growing season the tree gets. So that’s the astronomical cue. And that will be the same every single year pretty much to within a few hours. So the tree could just base itself on the length of night, and that would mean that the leaves came out on the same day every single year, which would be a tiny bit boring, but it would work in one sense. But the problem is, we know that spring is a tough season to call. The way I put it is for anybody who’s ever organized an outdoor event in April, we know that this is a tricky thing to call.

So trees could take the safety first strategy and say, okay, I’m just not gonna put any leaves out until the risk of frost is completely gone. So let’s just wait till the 1st of June, for example. The problem then is, they’ve lost the competition, because trees that go earlier will get lots and lots of lovely warmth and light. So what trees do is they count warm hours, so they’re aware of the length of night, but they’re also counting warm hours. And this is how trees sense that winter has been. They count cold hours and then when the number of warm hours reaches a certain number, and in commercially valuable crops like peach for example, the science is amazing. We know almost exactly to the hour, how many hours, for example, a peach cultivar like Mayflower or something like that will need, so it needs the night to get to a certain length shorter than a certain number of hours and it needs X thousand hours of warmth. And then it just goes, right, it’s spring, let’s get this show on. But then as we’ve discussed it, it won’t do it all over the tree at exactly the same moment. That’s when it starts the process in the warmest part of the tree and it’ll move over the rest of it.

Brett McKay: So we’ve talked about some of the signs we can look for in trees and there’s lots more in the book, but I’m curious, someone is listening to this episode and they wanna start reading trees, like right now, they walk out their door and take a walk in their neighborhood. What are like three or four things that you think are easy to start noticing in how to read a tree and looking for signs on how to navigate?

Tristan Gooley: The three areas I’d encourage people to look for are water, sun, and wind. And depending where you are in the world, one or two of those, you might get to almost immediately. But whenever you’re standing anywhere near water, it doesn’t need to be a vast amount of water. It can be a small pond or lake. If there happens to be a tree next to it, just start to notice. And again, we don’t need the names. It’s fantastic that we’ve barely mentioned a species name in our chat. So just notice what the trees look like there. And then the next time you are well away from water, just look at the trees there. And if you do that a few times, you are starting the simplest practical end of map making using trees. Indigenous people would find it hilarious, the idea that we find water by looking for water.

The trees will tell us where water is. All trees are sensitive to water, so we get things like willows close to water, and lots of dry soil-loving trees further away from that. But the next thing to look for is the sun changing the shape of trees. So notice how no tree is symmetrical. Every single tree on planet Earth of all the billions of trees, there is not one symmetrical one. And just start to notice how the light is changing the patterns. We get more branches on the south side and there’s slightly closer to horizontal in the broadleaf trees. And then look for wind patterns. Notice how trees in windy places are shorter, but look at how the very top part of the tree will quite often be bent over by any strong winds giving you a compass. So water, sun, and wind, really really sort of good place to start. Look for those footprints and that will get you up and running.

Brett McKay: I’ve been looking for the Southern eye. That’s the thing I’ve been focusing on when I’m out in my, sort of in a wooded area. And yeah, you see them, it’s interesting, like sometimes they’re really small, sometimes they’re really big, but they’re there. It’s really cool once you notice it. Well, Tristan, this has been a great conversation. Where can people go to learn more about the book and your work?

Tristan Gooley: Thanks. How to Read A Tree can be ordered through all the usual places and I love it when people support their local bookstore, if that’s an option. For information, my website, has lots and lots of examples. You can get a real taste for the signs you can find in trees and indeed in nature. Tons and tons of information on there. So yeah, will give you lots of fun info.

Brett McKay: All right, well Tristan Gooley, thanks for your time. It’s been a pleasure.

Tristan Gooley: Thanks so much Brett. Really enjoyed our chat.

Brett McKay: My guest today was Tristan Gooley. He’s the author of the book, How to Read a Tree. It’s available on and bookstores everywhere. You can find more information about his work at his website, Also check out our show notes at You can find links to resources where you can delve deeper into this topic.

Well, that wraps up another edition of the AOM podcast. Make sure to check out our website at, where you’ll find our podcast archives, as well as thousands of articles that we’ve written over the years about pretty much anything you could think of. And if you’d like to enjoy the ad-free episodes of the AOM podcast, you can do so on Stitcher Premium. Head over to, sign up and use code MANLINESS at checkout for a free month trial. Once you’re signed up, download the Stitcher app on Android or iOS, to start enjoying ad-free episodes of the AOM podcast. And if you haven’t done so already, I’d appreciate if you take one minute to give us a review on the Apple podcast or Spotify, it helps out a lot. And if you’ve done that already, thank you. Please consider sharing the show with a friend or family member who you think would get something out of it. As always, thank you for the continued support and until next time, it’s Brett McKay reminding you to not only listen to the AOM Podcast but put what you’ve heard into action

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