Roger: 0:02

Talking Trees with Lily and Jad. Welcome to another episode of Talking Trees. Today we're stepping back in time to explore the fascinating history of Europe's forests. We'll delve into how their vegetation has evolved and the role large herbivores have played in shaping these landscapes. From the impacts of livestock grazing to the influence of wild animals, we'll uncover how these factors affect tree regeneration and forest biodiversity. We'll also discuss the groundbreaking work of Franz Vera, whose theories challenge conventional views on forest ecosystems. Get ready for an intriguing journey into the past and the dynamic forces that continue to shape our forests today. Intriguing journey into the past and the dynamic forces that continue to shape our forests.

Jad: 0:48

today, you know, as arborists, we work with these amazing ancient trees day in and day out, and we probably appreciate their majesty more than just about anybody. They're like these living monuments, you know, shaped over centuries. But what if almost everything we thought we knew about the landscapes that formed them? What if it was wrong?

Lilly: 1:09

That's exactly the challenge that this Franz Vera guy he's a Dutch ecologist he's thrown at like the whole scientific world.

Jad: 1:16

Okay, so who is this Franz Vera Right, and why are his ideas so, so radical?

Lilly: 1:21

Well, Vera, he's got a really interesting path. He didn't start out in academia or anything. He started managing nature reserves, you know, like getting his hands dirty, really seeing how these natural systems work firsthand. And this led him to start questioning this really ingrained idea in ecology that if Europe was left alone, you know, no human intervention, it would just turn into this dense forest, like completely covered with a thick canopy of trees.

Jad: 1:46

Oh yeah, that's that climax forest concept right the idea that if you just let nature do its thing, it all ends up as a forest.

Lilly: 1:52

Exactly, yeah, and that idea, that concept of the climax forest has had a huge impact, like it's basically dominated how we think about conservation for decades, you know, leading to this focus on protecting forests from us, from humans. You know, especially things like grazing animals and stuff.

Jad: 2:11

So what made Vera start doubting this? I mean, it seems pretty obvious, right, like if you leave a field alone, it turns into a bunch of shrubs and then eventually trees take over.

Lilly: 2:20

Wait, yeah, that's what we all thought. But Vera, he noticed something was missing, something big.

Jad: 2:24

What's that?

Lilly: 2:27

He realized that people had forgotten about the role of large herbivores, you mean like deer. Deer, yeah, but I'm talking bigger, much bigger. Think aurochs, bison, wild horses. For like thousands of years these animals roamed all over Europe in huge herds and they shaped the landscape you know they're grazing and had a huge impact.

Jad: 2:45

Wow, it's like we're so focused on the trees that we forgot about, you know, the giant plant eaters that were there with them the whole time.

Lilly: 2:51

Yeah, exactly, it's like we forgot about the elephants in the well, not literally elephants, but you know what I mean. Right right. So, vera, he realized that these missing herbivores, they weren't just like hanging out in the forest, they were key to how the whole thing worked. They're grazing. It actually prevented those dense uniform forests that we think of as natural.

Jad: 3:12

Hold on. You're saying just these animals eating their way across the landscape that could change the whole structure of European forests. How is that even possible?

Lilly: 3:21

Well, various theories that all that browsing and trampling from these big herbivores it would create all these different habitats. You'd have open grasslands and scrub land and clumps of trees, almost like a park, rather than this dense, dark forest.

Jad: 3:37

That's so different from what I usually picture when I think of these old forests. Yeah, you know just like a wall of trees. But could a landscape like that, like a park, could it actually support those massive ancient trees?

Lilly: 3:50

That's where it gets really interesting, especially for you as an arborist. Think about what those old trees need to grow Sunlight, space, you know, even disturbances sometimes to clear out the competition. Those conditions they would have been a lot more common in a landscape that's being grazed right than in some thick forest where the canopy's closed.

Jad: 4:09

This is really making me rethink some things. So if this park idea is right, I mean that changes how we think about managing these old trees today, doesn't it?

Lilly: 4:18

Absolutely yeah. It means we might need to change how we think about grazing, maybe even, you know, reintroduce it in certain ways, to kind of copy those natural processes that helped shape these trees for centuries.

Jad: 4:29

Whoa, that's a big idea, but before we get too far ahead of ourselves, what's the evidence for all this? Did Vera just come up with this idea, or is there actual science behind it?

Lilly: 4:39

Oh, Vera's not just speculating. He's got evidence from a whole bunch of different areas of science and he's put it all together to make a really strong case for this wood pasture idea he has.

Jad: 4:50

OK, so let's hear about this evidence. Then. What convinced him that he was onto something? What kind of data did he find?

Lilly: 4:56

So one of the biggest pieces of evidence comes from pollen records. You know pollen grains. They're tough, they can survive in the soil for like thousands of years and by analyzing these old pollen deposits, scientists can figure out like what plants were growing where way back when.

Jad: 5:14

Oh, so it's like looking back in time, but with plants.

Lilly: 5:17

Exactly. And when they did this, they found something pretty surprising, even during periods when everyone thought Europe was covered in these dense, thick forests. The pollen records. They showed high percentages of pollen from species like hazel Hazel. What's special about hazel? Well, hazel, it needs a lot of sun. It likes to grow in open areas, the kind of places you'd find if you had large herbivores grazing and keeping things open. So, finding all this hazel pollen? It doesn't really fit with the idea of this continuous, you know, wall-to-wall forest covering all of Europe.

Jad: 5:50

So it's not just about what's missing from those forests, like the herbivores, but also what's there in the pollen, showing us that it was probably more open.

Lilly: 5:59

Exactly.

Jad: 6:00

Did Vera find any other evidence to back up his ideas?

Lilly: 6:02

Yeah, he looked at a bunch of historical accounts from the Middle Ages and he found descriptions of landscapes that were way more open than we usually imagine with, you know, just scattered trees here and there and these big areas of grassland.

Jad: 6:16

It's amazing how these old stories can give us clues about ecosystems. It's a whole different kind of scientific data, adding this human element to it. But as interesting as this is, I'm curious about how this all works in the real world. Did Vera just write papers about this, or did he actually test out his ideas?

Lilly: 6:36

Oh, Vera, he was all about getting out there and seeing how things worked. One of his most famous projects was at this place called the Oostvaardersplassen. It's a nature reserve in the Netherlands.

Jad: 6:46

I think I've heard of that. It's a huge area, right. They reclaimed it from the sea, or something.

Lilly: 6:50

Yeah, that's right, they were going to develop it for industry, but then the plans changed and they just kind of left it alone. To go back to nature and, vera, he saw this as a perfect opportunity to test his ideas, you know, like on a massive scale. So what did he do? Well, he brought in these animals that are kind of like the extinct large herbivores cattle, conic horses, red deer and he just let them loose to graze.

Jad: 7:17

Wow, like a giant experiment to recreate the past. So what happened? Did the Ouse-Vardersplassen turn into that park-like landscape he was talking about?

Lilly: 7:26

Yeah, it pretty much did. The grazing from those big herbivores it created this mosaic of different habitats grasslands, scrublands, woodlands, just like Vera predicted, that's amazing, but were there any downsides?

Jad: 7:39

Did the grazing hurt the trees at all?

Lilly: 7:41

Well, it's complicated. Some species like willows and poplars, they did really well in the wetter areas, but others, like oak, they had a hard time growing back with all the grazing.

Jad: 7:51

So it's not as simple as saying grazing is always good for trees.

Lilly: 7:54

Right, it's all about balance. Too much grazing, and the trees can't recover, but too little and the forest gets too thick and nothing else can grow. You got to find that sweet spot. You know where both the trees and the grasslands can do well.

Jad: 8:06

That makes sense. So if we take what we've learned from Vera and apply it to how we manage ancient and veteran trees today, what would that look like? What are some specific things arborists can take away from this?

Lilly: 8:19

It's like Vera's work gives arborists this whole new set of tools. You know, it's not just about pruning and bracing anymore. It's about like really understanding the whole ecosystem these trees are part of and managing them as part of this dynamic system where everything's connected.

Jad: 8:37

So we need to stop thinking about trees as individuals and start seeing them as a piece of a larger web of life.

Lilly: 8:44

Exactly yeah, it's a pretty big shift in how we think about things.

Jad: 8:48

It sounds like it. So what are some ways that arborists can actually put Vera's ideas into practice?

Lilly: 8:54

Well, one big thing is managed grazing Instead of thinking of grazing animals as bad for trees. You know, we can learn to work with them. Use their natural behavior to help us.

Jad: 9:05

That's pretty different from how we usually do things. How would that even work?

Lilly: 9:09

Oh, you could set up these temporary grazing areas, like around specific trees or groups of trees, and let the animals in there to clear out the underbrush and stuff. It'll create more space for the trees, let in more light.

Jad: 9:22

So we'd be using the herbivores to kind of mimic those natural disturbances that Vera was talking about, the ones that shaped these trees for so long.

Lilly: 9:31

Right.

Jad: 9:32

Are there any other techniques from Vera's work that arborists could use?

Lilly: 9:36

Oh yeah, definitely you can encourage thorny shrubs to grow around young trees. Those shrubs, they act like natural fences, they keep animals from browsing too much and they create these little protected areas, kind of like nurseries for the trees.

Jad: 9:51

It's amazing how we can use these old ideas, combine them with modern science, to help us manage trees today.

Lilly: 10:00

Yeah, pretty cool.

Jad: 10:01

But beyond grazing, is there anything else from Vera's research that that arborists should keep in mind?

Lilly: 10:07

I'd say, I'd say Vera's focus on on the history of a place that's really important. If you know how a landscape was used in the past, you can get a much better understanding of how the ecosystem works now, and it can lead to better ways of taking care of trees. You know, for example, if you know that a site used to be grazed, you might be more likely to include managed grazing in your plan for that site.

Jad: 10:32

Makes sense, but I'm sure not everyone agrees with Vera's ideas, right?

Lilly: 10:36

Oh, of course not. Vera's work has. It's caused a lot of debate. You know there are definitely people who disagree with them, and they have good points too. But even the people who disagree they admit that Vera's made us rethink some things, look at forests in a whole new way.

Jad: 10:52

That's what science is all about, right, Always questioning, testing and trying to get a better understanding of how things work.

Lilly: 10:58

Exactly.

Jad: 10:59

Well, this has been a fascinating deep dive into Franz Vera's work. It's definitely made me realize how much we still don't know about these ancient trees and the ecosystems they're a part of Me too, I hope our listeners, especially arborists out there. I hope they come away from this with a new appreciation for these trees.

Lilly: 11:19

And a willingness to you know, to challenge the way we think about things, to embrace how dynamic nature is and to see ourselves as more than just tree caretakers, to see ourselves as stewards of these ancient giants and the ecosystems they support.

Jad: 11:33

That's a great way to put it, and on that note, we'll leave you to think about these ideas and maybe even go out and look at those ancient trees with a fresh perspective. Until next time, keep diving deep.

Roger: 11:48

That's a wrap for today's episode of Talking Trees. We hope you enjoyed this deep dive into the history of Europe's forests and the fascinating role large herbivores play in shaping them. From Franz Vera's innovative ideas to the delicate balance of grazing, regeneration and biodiversity, it's clear our forests are shaped by complex interactions over time. If this episode sparked your curiosity, be sure to share it with fellow nature enthusiasts and leave us a review. Join us next time as we explore more stories from the world of trees and forests. Until then, stay inspired and keep exploring the roots of our natural heritage.