Dirk Dujesiefken

In this Friday episode of Talking Trees, we pay tribute to one of the most influential figures in modern arboriculture—Prof. Dr. Dirk Dujesiefken. His career has shaped the way we understand, teach, and care for trees in urban environments across Europe.

We discuss:

• His early fascination with nature protection and the urban role of trees, which led him from studying wood to researching living trees and tree care systems
• The founding of the Institute for Tree Care and its three central pillars: education, research, and consulting
• His pioneering work in advancing the CODIT (Compartmentalization of Decay in Trees) model and tree condition assessment methods
• His contributions to national and European standards for tree management, helping unify and raise the quality of arboricultural practices
• How he addresses emerging challenges such as climate change, tree diseases, and urban pressure, and his advice for the next generation of arborists

Dirk Dujesiefken’s work continues to inspire a science-driven, practical, and respectful approach to working with trees.

Background information:

• ArboChat Plus / Dirk Dujesiefken / Hamburg / 2023

Chapters

• 0:00 Introduction to Dirk Duyesefken
• 1:52 Early Career and Turning Points
• 3:55 Founding the Institute for Arboriculture
• 5:24 Groundbreaking Research on Trees
• 9:43 Facing Urban Tree Threats
• 13:07 Advocacy and Future Vision

Transcript

Roger: 0:02

Talking Trees with Lillian Jad. Welcome to Talking Trees. In today's episode we bring you an inspiring conversation with Dirk Duyesefken, a highly respected German arborist. We'll explore his lifelong dedication to tree care, his journey to founding the Institute of Arboriculture in Hamburg and his vision for the future of the field. To watch the full interview, head over to youtubecom at Arbor East. The link is in the description. Let's dive into this enlightening conversation.

Jad: 0:39

Welcome back everybody for another deep dive.

Lilly: 0:41

Yeah, this time we're really branching out, aren't we?

Jad: 0:44

We are it's all about urban forestry this time're really branching out, aren't we? We are it's all about urban forestry this time, and we've got an amazing interview to dig into from the 2023 Arbor Chat and this interview with Duk DeJosefekian. It's packed with insights.

Lilly: 0:57

He really is a legend in the field.

Jad: 0:58

Okay, so for those just tuning in who might not be familiar with DeJosefekian's work, set the stage for us.

Lilly: 1:04

Well, you could say he's been a champion for trees his whole life. I mean, we're talking decades of experience, research and advocacy. What I find most fascinating about him is how his own path kind of mirrors this growing awareness of trees in urban settings.

Jad: 1:19

Right, it's like his career blossomed right alongside the field itself.

Lilly: 1:22

Exactly.

Jad: 1:23

So take us back to his early days. He starts out studying forestry right Back in the 1970s.

Lilly: 1:28

Yeah, which think about it back then arborist as a term, as a profession, it wasn't really a thing yet.

Jad: 1:33

It's crazy, isn't it, how much things have changed.

Lilly: 1:37

It really is. But even back then, during his forestry studies, you can see this fascination with the urban environment starting to take root for Dujasifkin.

Jad: 1:45

And a lot of that stemmed from a pretty unique experience he had right, the 1973 International Garden Exhibition in Hamburg. Oh, absolutely a turning point for him. I can only imagine this young Dujasifkin, probably surrounded by concrete, his whole life up to that point.

Lilly: 2:00

And suddenly, boom, he's immersed in this world of urban green spaces, seeing firsthand how they could transform a city. You know.

Jad: 2:07

It must have been eye-opening.

Lilly: 2:08

Completely. And what's really interesting is this was all happening right when the book the Limits to Growth was making waves.

Jad: 2:14

Yeah, that was a big one 1972. Right Long before like mainstream environmentalism Right ahead of its time Right, but it really got people thinking about our impact on the planet and I imagine, for Dujas, ifikan, those two things the garden exhibition and limits to growth it all just clicked, didn't it.

Lilly: 2:32

Yeah, it did. Yeah. He saw the vital role trees play in a city's well-being and, at the same time, this growing need to protect them, especially with cities becoming more and more concrete jungles.

Jad: 2:44

Right, because it's not just about planting trees. It's about understanding them, advocating for them, making sure they're actually thriving.

Lilly: 2:51

And that's really the heart of Dujasufan's work. He doesn't just love trees, he fights for them.

Jad: 2:56

And a big part of that fight was recognizing a need for, like formal structures around tree care, which leads us to the late 1980s right.

Lilly: 3:05

Exactly DuJasifin. At this point he's deep into his research but he starts to see this glaring gap in the field of arboriculture.

Jad: 3:13

Like what was missing.

Lilly: 3:14

Well, for one, there wasn't really a unified approach to research, like arborists were doing great work, but it was kind of scattered, you know, and there wasn't a central place for sharing knowledge, for learning.

Jad: 3:24

So there was this need to bring it all together Exactly, and that's where Drew Jasekin steps in and founds the Institute for Bound Flage.

Lilly: 3:31

Huge moment. He saw a need and he took action.

Jad: 3:35

He really did, and this wasn't just some vanity project. This institute became the foundation for so much of the progress in urban forestry we see today.

Lilly: 3:44

Totally agree, and it's all rooted in those three pillars. He established education, research and consulting.

Jad: 3:50

Okay, so unpack those a little for us. How did they work together? What was the vision there?

Lilly: 3:59

Well, the education part was huge. It was about taking all this complex tree science and making it accessible, not just for scientists but for practitioners, for enthusiasts, for anyone who wanted to learn.

Jad: 4:06

So almost like democratizing tree knowledge in a way.

Lilly: 4:08

right, yes, and then, of course, you have the research pillar, which, for Dijasifkin, it wasn't just about doing a few studies here and there, it was about this ongoing dedicated exploration into how trees function, especially under stress in urban environments. I mean his dedication to research over 40 plus years. It's incredible really.

Jad: 4:28

And it's that research that really forms the backbone of everything else right, the education, the consulting, it all stems from this solid foundation of knowledge.

Lilly: 4:37

A hundred percent. But then you need that third piece, the consulting, because knowledge is only as good as its application.

Jad: 4:44

Exactly so how did that play out? The consulting?

Lilly: 4:47

Well, it's about bridging that gap between the science and the real world, taking all those research findings and working directly with communities, with cities, to actually address tree-related problems.

Jad: 4:59

So it's like this beautiful cycle the research fuels the education, which then informs the consulting, which then sparks new research questions.

Lilly: 5:08

A perfect ecosystem for urban tree care.

Jad: 5:11

I love it, and it's through this multifaceted approach that Dujasufcan makes some of his most significant contributions, wouldn't you say?

Lilly: 5:18

Absolutely.

Jad: 5:19

And his research on pruning. It revolutionized the way we think about tree care.

Lilly: 5:23

It really did, you see, before Dujasufcan pruning. It revolutionized the way we think about tree care. It really did, you see, before Dijazifkin pruning. It was often seen as this oh, I don't know, like a purely aesthetic thing.

Jad: 5:30

Right, just making the trees look nice and tidy.

Lilly: 5:32

Exactly, but his research showed how crucial proper pruning is for a tree's health. Like if you don't prune correctly, you can actually weaken the tree's natural defenses.

Jad: 5:41

So it's not just about making them pretty, it's about understanding their immune system essentially.

Lilly: 5:46

Precisely and how to work with those systems, not against them. Dujazivkin's research showed that with the right techniques, pruning can help trees thrive. They live longer, healthier lives, and the impact of this I mean his work on pruning has been translated into like 10 languages, with more on the way. I think they're working on Chinese and Hebrew versions as we speak.

Jad: 6:07

Wow, that's incredible Talk about a global movement for better tree care.

Lilly: 6:12

It really is and this deep understanding of tree biology. It's also at the heart of his work on the Kodite model.

Jad: 6:17

Okay, kodite, compartmentalization of decay in trees Right Sounds kind of intense.

Lilly: 6:24

It is, but it's also fascinating. Basically, Duterte-Zivton cracked the code on how trees heal themselves.

Jad: 6:30

OK, I'm listening.

Lilly: 6:31

Yeah.

Jad: 6:31

Tell me more, because I thought trees didn't heal the same way our bodies do.

Lilly: 6:36

They don't. So when a tree gets wounded, it doesn't just like regenerate new tissue. Instead, it compartmentalizes the injury. It basically walls it off to stop the decay from spreading.

Jad: 6:46

It's like it builds an internal barrier or something.

Lilly: 6:48

Yeah, and the CODIT principle as Dujazifkin expanded it. It helps us understand how those barriers form, how effective they are, even how different pruning practices can impact the process. It's like having this like x-ray vision into the inner workings of a tree. Having this like X-ray vision into the inner workings of a tree.

Jad: 7:04

That's a great way to put it, like we can now read a tree's history, its health, by understanding how it's compartmentalized. These past injuries.

Lilly: 7:11

Exactly and that knowledge. Then we can use that to make more informed decisions about how to care for them. Moving forward and this is where his work in Hamburg comes in, because in the 80s his team they pioneered the first tree risk assessment system in the city.

Jad: 7:26

This was at a time when, wasn't it like, if a tree looked even a little bit iffy, they just like chop it down.

Lilly: 7:32

Pretty much Decisions about removing trees. Yeah, they were often driven by fear back then, right.

Jad: 7:37

Big tree, scary Old tree, get rid of it.

Lilly: 7:41

Yeah, and due to Sifkin's system, it really challenged that. It brought in this new era of like informed decision making, using science-based assessments to figure out, ok, which trees actually pose a risk and which ones can be, you know, safely preserved.

Jad: 7:56

It's like moving away from this, like knee-jerk reaction to a more nuanced data-driven approach.

Lilly: 8:02

And that was huge, especially for mature trees, which Duzisifkin always emphasizes how important they are. They're like the crown jewels of our urban forests.

Jad: 8:09

Oh, I bet, because those older trees they just provide so much more, don't they?

Lilly: 8:13

So much Shade carbon absorption they clean the air. Losing a mature tree, it's like losing a vital organ, almost.

Jad: 8:20

Right. And speaking of knowledge, do you see, if you can? He's not one to keep all his discoveries locked away in a lab somewhere. He's written like tons of books and articles, hasn't he?

Lilly: 8:29

He's incredibly prolific. He really wants to make this knowledge accessible to everyone, not just scientists. He's written about tree biology care protection. His writing has been so influential even beyond academia.

Jad: 8:41

And it's not easy to take complex scientific concepts and make them understandable and, dare I say, interesting for a wider audience.

Lilly: 8:50

He's really good at it and on top of all that, he's an honorary professor.

Jad: 8:54

Talk about dedication. He could just be relaxing on a beach somewhere.

Lilly: 8:58

He's got this passion for nurturing the next generation of arborists Absolutely. And it's not just formal education either. He's also like a driving force behind these massive conferences the Deutsche Bonfleischetage, for example.

Jad: 9:11

Okay, for those of us who don't speak German, what is that?

Lilly: 9:13

Oh sorry. It's one of the biggest arboriculture conferences in Germany. It brings together scientists, practitioners, policymakers everyone who's passionate about trees.

Jad: 9:22

What a cool idea.

Lilly: 9:24

It is, and Dujeskin has been a lead in voice at those for years advocating for better communication and collaboration in the field.

Jad: 9:31

So it's like he's building bridges between research and the real world, making sure that all this knowledge is actually being used to make a difference.

Lilly: 9:38

And that's what's so inspiring about his work. He's not content with just studying trees, he wants to protect them. But he's also realistic about the work. He's not content with just studying trees, he wants to protect them.

Jad: 9:47

But he's also realistic about the challenges. Oh, I bet, because even with all the progress we've made, there are still some pretty big threats facing urban trees, aren't there?

Lilly: 9:53

Absolutely, and Dujasifkin himself identifies three main ones climate change, emerging diseases and, of course, good old fashioned urbanization.

Jad: 10:03

Okay, yeah, those are pretty big ones. Let's dive into those. Climate change first, I guess, because that feels like the 800 pound gorilla in the room these days, doesn't it?

Lilly: 10:11

It really does. As temperatures rise and rainfall patterns change, even established trees are showing signs of stress.

Jad: 10:17

We're seeing it everywhere, aren't we? Drought, heat, stress, trees are struggling.

Lilly: 10:22

And it's easy to forget how much we rely on those trees, especially in urban environments. They do so much for us, you know cooling our cities, cleaning the air.

Jad: 10:32

They're not just pretty decorations right, they're essential for our well-being and, like you said, it's not just climate change they're dealing with no.

Lilly: 10:39

There are all these new diseases and pests popping up too which do you just?

Jad: 10:43

seeievkin talks about a lot, right, like he mentions those diseases myceria on plain trees and pseudomonas on horse chestnuts. They're becoming more and more common.

Lilly: 10:52

Yeah, and those are nasty worms. They can wipe out entire populations of trees and because they're often introduced from other parts of the world, our trees they haven't had time to build up any resistance.

Jad: 11:08

Their immune systems just aren't ready. So it's like they're being hit with this double whammy climate change is stressing them out, and then these new diseases come along and it's like game over, exactly.

Lilly: 11:12

And then, on top of all of that, you've got urbanization, which is almost like a silent killer.

Jad: 11:18

How so.

Lilly: 11:18

Well, think about it this way as more and more people are crammed into cities, our urban forests, they're losing their habitat.

Jad: 11:27

It's like we're loving them to death almost. We want more trees for all the good they do, but we're also squeezing them into these tiny little spaces.

Lilly: 11:34

Exactly. And to Jacev Ken he says this is why we need a fundamental shift. We need to move away from this tree care mindset to a tree site protection mindset.

Jad: 11:45

Tree site protection. Okay, I like the sound of that. What does he mean by that?

Lilly: 11:49

So tree care that's often focused on the individual right. How's the tree doing? What can we do if it gets sick? But tree site protection, it's much bigger.

Jad: 11:58

It's about the whole environment the tree lives in right.

Lilly: 12:00

Yeah, the soil, the roots, making sure the trees have enough space. We have to remember a tree isn't an island, it's part of this interconnected web.

Jad: 12:09

Which we forget sometimes when we're sticking them in these little concrete squares.

Lilly: 12:12

All the time, and Josephkin is a big believer in teamwork. It's not just on arborists, it's architects, city planners, all of us working together to make our cities places where trees can actually thrive.

Jad: 12:27

So it's not just about planting more trees. It's about designing our cities in a way that supports them long term.

Lilly: 12:32

Yes, and this is where Joseph Milliken gets really fired up about preserving mature trees. He's not a fan of that term climate trees.

Jad: 12:40

I've heard him talk about that. It's like a pet peeve of his or something.

Lilly: 12:43

Well, because he's like, all trees are climate trees, they all contribute.

Jad: 12:53

What worries him is this rush to just plant new trees sometimes overshadows the incredible value of the mature trees we already have, because a brand new tree, even if it's some super species or whatever, it's not going to give us the same benefits as a hundred-year-old oak.

Lilly: 13:03

No way, those mature trees. They're the heavy lifters. They're absorbing so much carbon, providing shade, cleaning the air. The root systems are holding everything together. Losing one of those, it's a tragedy.

Jad: 13:15

It's like losing a library or something. All that history, all those benefits just gone.

Lilly: 13:21

It's tough because you need both right. Planting new trees is important for the future, but we can't forget about the ones who are already here working so hard for us.

Jad: 13:29

It's about respecting our elders, at least in the tree world right.

Lilly: 13:33

Exactly, and it goes back to that tree site protection idea creating an environment where trees can thrive for generations.

Jad: 13:39

So, even though Dujasifkin is this like world-renowned scientist, there's also this real activist spirit to his work, isn't there?

Lilly: 13:47

Oh, huge. This isn't just academic for him. He wants to get his hands dirty and save trees, Like right now he's doing this really little project with the University of Hamburg they're trying to save horse chestnut trees.

Jad: 13:58

From that bacteria.

Lilly: 13:59

Yeah.

Jad: 14:00

The one that's been wiping them out everywhere.

Lilly: 14:01

That's the one Pseudomonas. It's nasty, but what I think is so great is they have this goal to have a solution within three years. They're not messing around. This is real world problem solving.

Jad: 14:13

That's so inspiring, though, because it shows how much power there is in applied knowledge, right? They're taking what they know and actually using it to make a difference.

Lilly: 14:22

Absolutely, and Dujasifkin is always pushing for that.

Jad: 14:25

Because it's one thing to say protect trees, it's another thing to actually give people the tools to do that right. Absolutely. It's another thing to actually give people the tools to do that right, especially with all the development happening 100%.

Lilly: 14:33

He wants to make sure everyone, from developers to everyday citizens, feels empowered to advocate for trees.

Jad: 14:40

It's like he's this amazing mix of scientist and advocate, and so humble.

Lilly: 14:46

The best combination and, honestly, that's what makes him such an effective voice for trees, because it's clear he really truly cares.

Jad: 14:52

You can hear it in his voice when he talks about trees.

Lilly: 14:54

You can. This has been a really great conversation.

Jad: 14:57

I agree. I feel like I learned so much preparing for this deep dive into Dirk Dujasuken's work. And you know, it's easy to take trees for granted, especially in a city. But he reminds us they're not just these passive things, they're alive and they're doing so much for us, even when we don't realize it.

Lilly: 15:16

It's true, there are silent partners in this whole urban living experiment, aren't they?

Jad: 15:20

They are and they deserve our protection. So next time you walk by a tree, maybe give it a little nod or something.

Lilly: 15:26

I love that A little. Thank you for all the hard work.

Roger: 15:36

Exactly A little. Thank you for all the hard work. Exactly Until next time everyone keep looking up. Thanks for tuning in to this special edition of Talking Trees. We hope you enjoyed this insightful conversation. We truly appreciate the support of our subscribers, as your contributions make it possible for us to bring you exclusive content like this. If you found this episode valuable, stay with us for more in-depth interviews and expert insights, available only to our subscribers. Until next time. Thank you for your continued support and keep growing your passion for trees. You.