RECAP - CW 15/2025

This is your weekly summary of the Talking Trees podcast – bringing you a full week of arboricultural knowledge, inspiration, and science.

🌱 Monday 128 - Tree Interactions with Other Organisms
We began the week exploring how trees coexist with fungi, animals, and microbes. Learn how mycorrhizal networks, competition, and symbiosis shape forest resilience and biodiversity in both natural and urban settings.

🧷 Tuesday 129 - Structural Substrates
This episode took a deep dive into engineered soil systems like CU-Structural Soil®, offering practical solutions to soil compaction in urban environments. Discover how to support root growth beneath pavement without sacrificing infrastructure stability.

✂️ Wednesday 130 - Tree Injections
We discussed vegetative endotherapy, a targeted method of delivering treatments directly into a tree’s vascular system. Explore the tools, applications, and best practices for pest, disease, and nutrient management.

📋 Thursday 131 - Who Should Pay to Protect Trees
We tackled the complex intersection of urban tree ordinances, legal frameworks, and environmental ethics. The Canton Township case revealed the challenges of enforcing tree protection policies.

✨ Friday 132 - Mark Johnston - Lifelong Arborist
A tribute to the impactful career of Dr. Mark Johnston, urban forestry leader and educator. From the UK to global influence, his work has helped shape arboriculture policy, education, and public engagement.

🐝 Saturday 133 - Chalara fraxinea
We ended the week with a sobering look at ash dieback. Learn how Chalara fraxinea, the emerald ash borer, and other stressors are decimating Fraxinus excelsior populations, and what science offers in response.

From fungal pathogens to engineered soils and tree protection law, this week brought a dynamic mix of knowledge. Stay curious and rooted – only on Talking Trees.

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Chapters

• 0:00 Weekly Preview of Talking Trees
• 1:16 Forest Biodiversity and BF China Research
• 4:50 Urban Innovation with CU Structural Soil
• 6:10 Vegetative Endotherapy Techniques
• 7:46 Mark Johnston's Urban Forestry Journey
• 9:58 Battling European Ash Tree Threats
• 14:20 Final Thoughts and Episode Closing

Transcript

Weekly Preview of Talking Trees

Roger 0:02

Talking Trees with Lillian Jadd. Welcome to Talking Trees. This week, we explore a range of insights. On Monday we examine how interactions among trees shape forest health and support mixed stand restoration, with studies like BF China setting the stage. Tuesday highlights urban innovation with Cornell's CU Structural Soiler, a solution that nurtures tree and turf growth even under paved surfaces and improves stormwater management. Wednesday focuses on vegetative endotherapy, showcasing new injection techniques designed to protect our trees. Thursday tackles the legal and ethical challenges of tree protection, drawing on landmark cases from Michigan. Friday shares the journey of Mark Johnston from his Scottish roots to a celebrated career in urban forestry. And Saturday we delve into the challenges facing European ash trees, exploring the impacts of invasive species and pathogens. Join us for a week of scientific discoveries, innovative solutions and personal stories. Welcome to Talking Trees.

Jad 1:16

Hey everyone, Welcome back for another deep dive with us.

Lilly 1:19

Yeah, always a pleasure to be back.

Jad 1:20

You know how it is out there in the field, right? I mean, it's a busy time for all of us arborists.

Lilly 1:24

Yeah, it springs just around the corner, so everyone's getting ready for the busy season.

Jad 1:28

Exactly so much to do, so little time. But even with all that going on, it's still important to stay up to date on the latest happenings in the world of trees right.

Lilly 1:36

Absolutely Got to keep learning and growing, just like our trees.

Jad 1:39

That's why we do these deep dives, you know, taking the time to really dig into the latest research, news and insights that are coming out each week.

Lilly 1:45

And there's always something new to learn, isn't there Always something new?

Jad 1:52

And this week was no exception, we went deep into the Talking Trees podcast this week. Oh yeah, talking Trees, those guys always have their finger on the pulse?

Lilly 1:55

Yeah, they really do, and this week they covered a huge range of topics, everything from forest ecosystems to urban planting techniques, to even some legal battles over tree protection ordinances.

Jad 2:07

Oh wow, that sounds like a lot to cover.

Lilly 2:09

It was, but don't worry, we've distilled all that info down to the essential stuff that you need to know as a professional arborist.

Jad 2:14

Okay, perfect. So where do we want to start?

Lilly 2:17

Well, let's branch out a little bit, no pun intended, and talk about forest ecosystems.

Jad 2:21

Okay, I'm intrigued.

Lilly 2:22

So you know how we're always talking about the importance of tree diversity.

Jad 2:25

Yeah, absolutely. Monocultures are a recipe for disaster.

Lilly 2:28

Exactly Well Talking Trees highlighted some really fascinating research that's being done in China, called the BF China Project.

Jad 2:35

BF China. What's that all about?

Lilly 2:37

It stands for Biodiversity Ecosystem Functioning, and it's this massive experiment where they're studying how tree diversity impacts the overall health and productivity of forests.

Jad 2:48

Wow, that sounds ambitious.

Lilly 2:49

It is. They've been running this experiment for over a decade now and they're finding some incredible things, like, in more diverse forest, trees actually use resources like water and nutrients more efficiently.

Jad 3:00

Huh, how does that work?

Lilly 3:02

Well, think about it. Different species have different root depths and nutrient requirements, so in a diverse forest they're not all competing for the same things in the same way.

Jad 3:10

Oh, I see they're kind of sharing the resources more effectively.

Lilly 3:13

Exactly, and this leads to greater overall productivity in the forest. They're better at capturing sunlight and converting it into biomass.

Jad 3:19

So more diversity equals healthier, more productive forests. That's a pretty powerful argument for promoting biodiversity in our planting and management practices.

Lilly 3:28

Absolutely, and here's where it gets even more interesting for you as arborists. The BF China study also looked at how tree diversity impacts pest and disease resistance.

Jad 3:38

Okay, now we're talking. That's something every arborist is dealing with on a daily basis.

Lilly 3:42

And what they found is that in more diverse forests, outbreaks of pests and diseases are actually less severe.

Jad 3:48

Really, that's amazing. Why is that?

Lilly 3:50

Well, for one thing, in a diverse forest there's a greater chance that some tree species will be naturally resistant to a particular pest or disease. So even if one species gets hit hard, the others can help to buffer the impact.

Jad 4:03

So it's like having a backup plan built into the ecosystem.

Lilly 4:06

Exactly. And second, diverse forests tend to have a greater variety of natural enemies to pests, like predatory insects and birds, so there's more natural pest control happening.

Jad 4:17

That's fascinating. So by increasing tree diversity, we're not just creating healthier forests, we're also making them more resilient to threats.

Lilly 4:24

Exactly. The Bee of China study provides strong evidence for the benefits of biodiversity, not just in terms of ecological health, but also in terms of practical management outcomes.

Jad 4:34

I bet this research is sparking a lot of new ideas for our listeners.

Lilly 4:37

I hope so.

Jad 4:38

So we've talked about forest, but let's face it, not all of us are working in vast wilderness areas. Many arborists are tackling the unique challenges of urban environments.

Urban Innovation with CU Structural Soil

Lilly 4:46

Right, where space is limited and trees have to compete with concrete and asphalt for every inch of soil.

Jad 4:52

Exactly so. What did Talking Trees have to say about that?

Lilly 4:55

Well, they highlighted a really interesting innovation from Cornell University called Q-structural soil.

Jad 5:00

Q-structural soil. What's that?

Lilly 5:02

It's basically a super soil that allows trees and lawns to thrive, even under paved surfaces.

Jad 5:08

Wait, really, how is that even possible?

Lilly 5:10

It's pretty ingenious it's a blend of crushed stone, soil and a special binding agent that allows roots to breathe while providing the structural support needed under pavement.

Jad 5:18

Wow, I can already see the wheels turning in our listeners' heads right now.

Lilly 5:25

Yeah, I mean think about all those sidewalks and parking lots that could potentially support healthy trees. This stuff could be a game changer for urban forestry.

Jad 5:29

It really could. So it addresses those issues of limited soil volume and stormwater management in a pretty clever way.

Lilly 5:36

Exactly.

Jad 5:37

Did they mention anything about how it's actually installed?

Lilly 5:39

They did. They said there's a detailed guide on the Cornell website that covers the composition, installation and maintenance of the soil.

Jad 5:46

Okay, perfect. So anyone who's interested can go check that out.

Lilly 5:49

Definitely a valuable resource.

Jad 5:51

You know I'm thinking about all the potential applications for this stuff. It could really transform the way we design and manage urban landscapes.

Lilly 5:57

I agree. It's a great example of how innovation can help us create more sustainable and livable cities.

Vegetative Endotherapy Techniques

Jad 6:03

OK, so we've got biodiversity in forests and super soils in cities. What else did Talking Trees cover this week?

Lilly 6:10

Well, they also delved into the world of vegetative endotherapy. Vegetative endotherapy Now that sounds pretty high tech, it is. It's basically injecting substances directly into a tree's vascular system.

Jad 6:21

Oh, like giving the tree an IV drip.

Lilly 6:22

That's a good analogy, and it can be used to deliver a variety of treatments like infendicides, fungicides or even nutrients.

Jad 6:29

So it's a very targeted approach.

Lilly 6:31

Exactly, and it's becoming increasingly popular as arborists seek more precise and environmentally friendly ways to care for trees.

Jad 6:39

I can see why that would be appealing. Did they talk about any specific applications of this technology?

Lilly 6:44

They did. They mentioned that it's being used to combat pests like the emerald ash borer, which, as you know, is a huge threat to ash trees across North America.

Jad 6:52

Right, a very timely topic, for sure, yeah.

Lilly 6:55

And they also talked about how it's being used to treat diseases like oak wilt, which can be devastating to oak populations.

Jad 7:01

So it's a pretty versatile tool.

Lilly 7:02

It is, but it's also a complex one. It requires specialized equipment and training, so it's not something you just want to try on your own.

Jad 7:09

Definitely best left to the professionals.

Lilly 7:11

Agreed, but it's definitely a technology to keep an eye on as research advances. We can expect to see even more innovative applications of vegetative endotherapy in the years to come.

Jad 7:21

Okay, well, that's a lot to digest already, but we've only just scratched the surface of what Talking Trees covered this week.

Lilly 7:26

That's right.

Jad 7:27

So stay tuned, because we've got a lot more to unpack in this deep dive.

Lilly 7:30

And you know, one thing that really struck me from this week's Talking Trees was that episode about Mark Johnston's memoir.

Jad 7:36

Oh yeah, the arborist who worked all over the UK and Ireland. Yeah, exactly.

Lilly 7:40

His story just really highlights how our work goes beyond, you know, just the trees themselves.

Jad 7:46

It's about the people, the communities and really the legacy we leave behind.

Lilly 7:50

Exactly Like we're not just managing trees, we're shaping the landscapes that people live in and experience every day.

Jad 7:56

It's a big responsibility when you think about it that way.

Lilly 7:58

It is, and you know, Johnston's story also touched on some of the social and political aspects of working with trees.

Jad 8:05

Oh yeah, Like how our decisions as arborists can impact things like development and conservation efforts.

Lilly 8:11

Exactly. It's a reminder that our work is connected to so many other issues and that we have a role to play in advocating for the things we believe in. Definitely a thought provoking episode it was, and you know, speaking of thought-provoking, let's circle back to that Q, structural soil for a minute. Oh yeah, the super soil stuff I'm sure some of our listeners are thinking, OK, this sounds great, but what are the downsides?

Jad 8:32

Right Like, is it too good to be true?

Lilly 8:40

Well, it's not a magic bullet of course, like any technology, it's not as effective at filtering pollutants as natural soil.

Jad 8:46

Oh, that makes sense. So if you're working in a heavily polluted area, it might not be the best choice.

Lilly 8:50

Exactly, and another thing to consider is cost.

Jad 8:53

Yeah, that's always a factor.

Lilly 8:55

It's true that Q structural soil can be more expensive up front than traditional soil amendments.

Jad 9:00

But you're also potentially saving money in the long run, right.

Lilly 9:03

Exactly Because trees planted in the soil tend to establish faster, grow healthier and live longer.

Jad 9:09

So you're not having to replace them as often.

Lilly 9:11

Right and healthy trees provide so many benefits to the urban environment. Like cleaning the air, reducing temperatures, improving property value. Exactly, it's an investment in the long-term health and well-being of our cities.

Jad 9:23

So it sounds like Q-structural soil is a valuable tool to have in our arsenal, but like any tool, it needs to be used appropriately.

Lilly 9:30

Exactly. It's not a one-size-fits-all solution.

Jad 9:33

Now switching gears a bit. Let's dive back into that vegetative endotherapy stuff.

Lilly 9:37

Oh yeah.

Jad 9:38

That was pretty fascinating. I'm still wrapping my head around the idea of injecting treatments directly into a tree's veins.

Lilly 9:43

It is kind of mind blowing when you think about it, but it's becoming an increasingly common practice in arboriculture.

Jad 9:49

And it makes sense right, Because you're delivering the treatments right where they're needed.

Battling European Ash Tree Threats

Lilly 9:52

Exactly You're minimizing waste and reducing the risk of harming beneficial organisms in the surrounding environment.

Jad 9:58

So it's a more targeted and eco friendly approach.

Lilly 10:01

Precisely, and one thing I was curious about was how those treatments actually yeah, me too Like what's going on at the cellular level. Well, it depends on the specific treatment. For example, insecticides often work by disrupting the nervous system of the target pest.

Jad 10:17

So it's like a mini neurotoxin that only affects the bad guys.

Lilly 10:20

Exactly, and fungicides typically target the fungal cells directly, either by inhibiting their growth or by disrupting their cellular processes. So they're basically preventing the fungus from spreading and causing further damage processes, so they're basically preventing the fungus from spreading and causing further damage. Right, and then there are treatments that are designed to boost the tree's own defenses, like nutrients or biostimulants.

Jad 10:39

It's like giving the tree's immune system a boost.

Lilly 10:41

Exactly, and this is an area of ongoing research. Scientists are always looking for new and innovative ways to enhance a tree's natural resilience.

Jad 10:50

Now, I know we've talked a lot about the technical aspects of these treatments, but what about the practical side of things? What do you mean, Like what are some of the challenges that arborists face when using vegetative endotherapy?

Lilly 11:00

Well, for one thing, it requires specialized equipment and training.

Jad 11:04

So it's not something you can just pick up overnight.

Lilly 11:06

Definitely not. You need to understand the anatomy and physiology of the tree, as well as the specific injection techniques and safety protocols.

Jad 11:14

Right, you don't want to be injure thing. The wrong thing in the wrong place.

Lilly 11:16

Exactly. It's a skill that takes time, and practice to master.

Jad 11:20

And I imagine there's also the challenge of choosing the right treatment for this specific situation.

Lilly 11:25

Absolutely. You need to actionately diagnose the problem and then select the treatment that's most likely to be effective.

Jad 11:32

And sometimes it's not a clear-cut decision right.

Lilly 11:34

Not always. There might be multiple treatment options available and you have to weigh the pros and cons of each one.

Jad 11:39

It's like being a tree doctor you have to consider all the factors before prescribing a course of treatment.

Lilly 11:45

That's a great analogy and, just like in human medicine, there's always an element of uncertainty.

Jad 11:50

You can't guarantee that a treatment will be 100% effective, right you?

Lilly 11:52

can't guarantee that a treatment will be 100% effective. Right, You're working with living organisms and there are so many variables that can influence the outcome.

Jad 11:57

So it's a combination of science and art really.

Lilly 11:59

I think that's a great way to put it, and it's one of the things that makes our bar culture such a challenging and rewarding profession. Yeah, it really is a fascinating field and it's constantly evolving. Speaking of evolving, we should probably get back to those ash trees and the threats they're facing.

Jad 12:14

Oh yeah, the emerald ash borer and the ash dieback disease, tough stuff.

Lilly 12:18

Yeah, those are some serious challenges for arborists right now.

Jad 12:20

For sure, and it seems like there's always new research coming out about these threats. Just trying to stay ahead of the curve.

Lilly 12:25

Exactly, and luckily Talking Trees did a deep dive on some of that recent research.

Jad 12:29

They did. They highlighted three research papers in particular that I think are worth discussing.

Lilly 12:33

The first one was by Davy Danko and colleagues, and it looked at the combined impact of the emerald ash borer and ash dieback disease in Ukraine.

Jad 12:43

Oh wow, so like a double whammy for the ash trees over there.

Lilly 12:45

Exactly, and their findings were pretty concerning. The borer is weakening the trees and making them much more susceptible to the disease.

Jad 12:52

So it's like a one-two punch.

Lilly 12:54

Yeah, a pretty devastating combination, and their research really highlights the need for integrated pest management strategies.

Jad 13:00

So we can't just focus on one threat in isolation. We need to address them holistically.

Lilly 13:04

Precisely, and the second paper by Przybylski and their team had some really interesting findings about the timing of ash tree budding and its connection to dieback resistance.

Jad 13:15

Oh right, that's the one where the early butters seem to have an advantage.

Lilly 13:18

Exactly. It seems that those early butters are able to develop their leaves and their defenses before the disease really takes hold.

Jad 13:24

So it's almost like they're getting a head start in the fight.

Lilly 13:27

Exactly, and this insight could be really valuable for breeding programs. You know, selecting for trees with earlier bud bursts to create more resistant varieties.

Jad 13:35

That's a hopeful thought.

Lilly 13:36

It is. And then the third paper by Leidis and other added yet another layer of complexity to this whole ash tree saga.

Jad 13:42

What was that one about?

Lilly 13:43

Well, they identified a fungus called Armillaria sapis types as a major contributor to ash decline.

Jad 13:49

A fungus, huh, so it's not just the borer and the dieback disease we have to worry about.

Lilly 13:53

Nope. This fungus causes root rot, which weakens the trees and makes them even more susceptible to those other threats.

Jad 13:59

Like a triple threat.

Lilly 14:00

It really is, and it's a good reminder that we need to be thorough in our tree inspections, looking for signs of stress or decline both above and below ground.

Jad 14:08

You know, it's kind of like being a detective trying to piece together all the clues to figure out what's going on with a tree.

Lilly 14:12

Exactly. You've got to be observant and use all the tools at your disposal.

Final Thoughts and Episode Closing

Jad 14:17

Well, I have to say, I feel like I've learned a lot from this deep dive into talking trees.

Lilly 14:21

Me too, it's been a great reminder of how much there is to learn and how important it is to stay up to date on the latest research and innovations.

Jad 14:29

Definitely, and it's also been inspiring to hear about all the amazing work that arborists are doing all around the world.

Lilly 14:35

Absolutely. We're all in this together, trying to make the world a greener and healthier place.

Jad 14:40

So, to wrap things up, I just want to encourage all of you listening to check out the full episodes of Talking Trees that we discussed today.

Lilly 14:45

Yeah, they're definitely worth a listen.

Jad 14:47

And we'd love to hear your thoughts on these topics. What resonated you? What new ideas did you spark?

Lilly 14:52

You can find us on social media or leave a comment on our website.

Jad 15:00

We always love hearing from our listeners and until next time, happy tree climbing everyone.

Roger 15:08

Thank you for joining us on this week's Talking Trees journey. If you enjoyed our dive into forest dynamics, urban innovations and the personal stories shaping arboriculture, be sure to subscribe for the full episodes at wwwheroherosadkolashtalkingtrees. No-transcript.