RECAP - CW 14/2025

This is your weekly summary of the Talking Trees podcast – bringing you expert insights and practical knowledge from Monday to Saturday. Here’s what we covered this week:

🌱 Monday 121 - Function of Assimilation Apparatus
We explored the role of the assimilation apparatus – leaves and needles – in photosynthesis and stress adaptation. Learn how tree anatomy supports vitality, how morphology reflects pollution exposure, and why this matters when choosing trees for urban environments.

🧷 Tuesday 122 - Soil Decompaction
This episode tackled compacted urban soils and how they hinder tree health. We reviewed air spading, vertical mulching, and the use of biochar or compost to restore root zones and improve soil structure.

✂️ Wednesday 123 - Practical Pollarding
Pollarding returns to the spotlight! We discussed how this traditional technique supports sustainable urban forestry, the difference between pollarding and topping, and how to handle neglected trees.

📋 Thursday 124 - Tree Value Calculation
We examined how arborists and municipalities calculate the economic, social, and ecological value of trees. The episode broke down methods like Replacement Cost and Amenity Valuation.

✨ Friday 125 - David Lonsdale
A tribute to David Lonsdale, a cornerstone in arboriculture. We revisited his work on tree pathology, risk assessment, and decay, and celebrated his lifelong contribution to arboricultural knowledge.

🐝 Saturday 126 - Erwinia amylovora
We wrapped up the week with fire blight: the bacterial disease Erwinia amylovora. Learn how it affects apple and pear trees, how to identify symptoms, and strategies for managing and preventing outbreaks.

Don’t miss a single episode of Talking Trees – your daily source of arboricultural inspiration and expertise. 

Chapters

• 0:00 Weekly Recap Introduction
• 1:45 Leaf Science and Urban Stress
• 3:08 Soil Improvement Techniques
• 4:10 Pruning Legacy and Ecological Impact
• 5:05 European Tree Valuation Standard
• 6:13 Tribute to Dr. David Lonsdale
• 6:57 Battling Fire Blight Research
• 10:31 Future of Urban Forestry
• 11:31 Dr. Lonsdale's Continuing Legacy

Transcript

Roger: 0:02

Talking Trees with Lily and Jad. Welcome to Talking Trees. This week, we've crafted a special recap to guide you through the many facets of our green companions. On Monday, we dive into the world of leaves, the essential organs powering photosynthesis, and explore how trees adapt to urban challenges, from pollution to permafrost. And explore how trees adapt to urban challenges, from pollution to permafrost. Tuesday spotlights innovative soil care, from compressed air injections to phytoremediation, ensuring our urban forests flourish. Wednesday takes us back in time with the art of tree pruning, a practice that shapes landscapes and nurtures biodiversity. Thursday introduces the new European Tree Valuation Standard, a modern approach to appreciating the ecological, economic and social worth of our trees. Friday is a heartfelt tribute to Dr David Lonsdale, a pioneer whose passion and expertise in arboriculture continue to inspire. And Saturday, we examine the battle against fire blight, uncovering insights into Erwinia amelivora and sustainable biological control methods. Get ready for a week full of inspiring stories, scientific insights and a renewed appreciation for the beauty and complexity of nature. Welcome to Talking Trees. Welcome to Talking Trees.

Jad: 1:27

Hey everyone, I know you're all busy out there keeping our urban forest healthy, but this week's Talking Trees episodes were just packed with information. It's a lot to take in, even when you aren't up to your elbows in mulch. So we're doing a deep dive on the highlights from Monday to Saturday, specifically what's most relevant for you as professional arborists.

Lilly: 1:45

You know, it's true, there's always something new to learn in arboriculture, and this week was really no exception.

Jad: 1:51

Right, so let's jump right into it. Monday's episode was all about leaves, stress and the city and honestly, I got a little geeky over all that leaf science, but it did get me thinking, you know how often do we really think about leaf stress in our day-to-day work?

Lilly: 2:06

It's a good question. I think that episode really highlighted how, understanding the science behind it, it can be so useful when you're diagnosing problems and figuring out how to treat a tree Like, for instance, they talked about Egrov and Kuligin's research on how permafrost thawing is affecting tree roots, which is, you know, a huge concern for urban forestry, especially as the climate changes.

Jad: 2:25

Kermifrost thawing. See, that's not something that's top of mind for me usually.

Lilly: 2:29

Right, but it shows how these environmental shifts can have some pretty significant impacts on tree health, impacts that you might not expect at first glance.

Jad: 2:36

And, speaking of unexpected impacts, they also discussed Hunity's research about using the photosynthetic efficiency of trees to actually assess the quality of the urban environment.

Lilly: 2:47

Yeah, that was fascinating. It's like they're connecting the health of the trees directly to the health of our cities, and they talked about some really interesting techniques for measuring that, like using the concepts of functional adaptation and biological indication basically how trees adjust to their environment and how we can use trees as indicators of overall environmental health.

Jad: 3:06

OK, so if we're talking about urban environments, we have to talk about soil. Right Tuesday's episode was titled Giving Trees a Leg Up Soil Deep Dive all about soil improvement methods and, man, they got into some pretty wild techniques.

Lilly: 3:19

For sure. Healthy soil is just absolutely essential, especially in urban areas where compaction is such a big problem. Soil is just absolutely essential, especially in urban areas where compaction is such a big problem. They covered a lot of different approaches, but the one that really taught my attention was injecting compressed air into the soil.

Jad: 3:31

I know right At first I was like what, but apparently it can be incredibly effective breaking up that compacted soil, improving drainage and aeration. Think about how useful that could be in those really tough urban sites.

Lilly: 3:42

Exactly. It could be a game changer for so many arborists. And they talked about other methods too, of course, like decompression with specialized equipment, fertilization, mulching, even fighter remediation, using plants to actually clean up contaminated soil. Oh, and they mentioned this device called Terrigant. It uses compressed nitrogen for soil decompaction. So many options, depending on the specific site you're dealing with.

Jad: 4:04

Then Wednesday's episode took a bit of a different turn, a cut above the legacy of tree pruning. They went into the history and the ecological impact of pruning.

Lilly: 4:13

Yeah, that was a fascinating look back in time how pruning practices have shaped not just the look of the landscape but also the ecology of forests, especially in northern Spain and central Europe. They focused on specific types of trees like oaks, beaches, ashes, willows, and talked about traditional techniques like pollarding and coppiceum.

Jad: 4:35

And they really made the point that pruning isn't just about aesthetics. It can have a huge impact on the whole ecosystem, like they talked about how pruned trees create these unique habitats for animals, fungi, lichens, a whole world in there.

Lilly: 4:47

It's like building little ecosystems within the trees themselves. And they talked about the threats these traditionally managed trees are facing overgrowth because they're not being managed, being filled for timber and they argued that pruning can actually be a valuable conservation tool.

Jad: 5:00

All right, let's shift gears now to something that's probably top of mind for a lot of arborists Money. Thursday's episode was what's a Tree Worth? All about the new 2025 European Tree Valuation Standard.

Lilly: 5:12

That's a big one. This standard is going to change how we assess the value of trees. It goes way beyond just the monetary worth. It's about considering the ecological benefits, the economic benefits to the community, even the social value.

Jad: 5:25

So it's a much more holistic approach.

Lilly: 5:26

Exactly, and they got into the specifics of different valuation methods looking at property values, replacement costs, assessing ecosystem services like carbon sequestration, even considering the tree's contribution to biodiversity.

Jad: 5:40

It seems like this standard is pushing us to think about trees in a much bigger context.

Lilly: 5:44

It is. They even talked about the potential negative impacts a tree might have, like root damage to infrastructure or blocking views. It's about having a balanced assessment. They emphasized comprehensive assessment, interdisciplinary collaboration, community involvement.

Jad: 5:59

It's not just crunching numbers. It's understanding the tree's role in the community and getting people involved in the valuation process.

Lilly: 6:06

Absolutely Recognizing the true value of trees in all their complexity.

Jad: 6:11

Then Friday's episode took a more somber tone. Talking Trees paid tribute to Dr David Lonsdale in Remembering a Giant.

Lilly: 6:18

Dr Lonsdale was a true pioneer in our field, both in arboriculture and entomology. His work has been so important for understanding trees and how they interact with insects.

Jad: 6:27

They mention tributes from all kinds of organizations the Arboricultural Association, the British Mycological Society, the Arboricultural Journal.

Lilly: 6:35

The Arboricultural Association actually has a ton of resources available now to honor Dr Lonsdale's work articles, research papers, recordings of his presentations Definitely worth checking out.

Jad: 6:44

They highlighted a webinar, too, where he talked about wood decay, tree defenses, tree health and safety.

Lilly: 6:50

It's a fantastic opportunity to learn from one of the greats.

Jad: 6:53

For sure. Ok, let's wrap up part one of our deep dive with Saturday's episode. It took us into the lab with battling blight the science of Erwinia amelovora. Fire blight, as you all know, is a huge concern. So what stood out to you from this one?

Lilly: 7:08

Well, they covered a lot of ground diagnosis, ecology, biological control methods but I think the focus on the IPTC standard was really important for detection and identification.

Jad: 7:18

The IPPC standard.

Lilly: 7:19

Yeah, it's an internationally recognized standard, so you know you're getting an accurate diagnosis and preventing the spread. As an arborist, you need to notice stuff to keep your trees healthy.

Jad: 7:27

Makes sense. They also discussed some really interesting research happening in Kyrgyzstan right.

Lilly: 7:31

Yes, they're looking at using beneficial bacteria, specifically actinomycetes, to combat fire blight.

Jad: 7:38

So using nature to fight disease instead of harsh chemicals.

Lilly: 7:41

Exactly. It has the potential to lead to some really effective biocontrol strategies. And they talked about the ecological side of things too Biofilms, insect vectors, microbial communities, how they all play a role. It's a reminder that fire blight is complex and we need to think about the whole ecosystem.

Jad: 7:56

And we wrapped up the episode mentioning some promising research on genetic resistance in trees and the potential of using bacteriophages viruses that attack bacteria.

Lilly: 8:06

Definitely encouraging to see all these different approaches emerging. It gives me hope for the future of our urban forests.

Jad: 8:12

That's a great note to end on for part one, but we still have a lot more to unpack, including Dr Lonsdale's legacy and some thought-provoking questions about the future of urban forestry. We'll be back right after this break to continue our deep dive into this week's Talking Trees episodes.

Lilly: 8:27

Welcome back everyone. I hope you had a moment to think about all that we talked about in the first part, because it really struck me how much of what we heard on Talking Trees this week you know it really directly relates to what you're doing out there every day as arborists.

Jad: 8:40

Yeah, absolutely. This isn't just theory, it's stuff that you can actually use in the field.

Lilly: 8:43

Exactly Like. Think about that soil improvement episode, knowing about injecting compressed air or using the terranin. That could be a total game changer when you're dealing with compacted soil which, let's be honest, is like a constant battle in urban areas.

Jad: 8:56

Oh for sure, and I loved how Wednesday's episode reminded us that pruning it's not just about making trees look pretty right. It's about the long term impact ecologically, how our choices affect the entire ecosystem.

Lilly: 9:09

Yeah, it's about seeing the forest for the trees. Our decisions today can have consequences for years to come. So that historical perspective, the ecological perspective, it's essential.

Jad: 9:20

OK, so let's circle back to that 2025 European tree valuation standard. It seems like that's going to require a pretty big shift in thinking for a lot of arborists.

Lilly: 9:28

It is a big change. We're not just putting a dollar value on a tree anymore. It's about understanding the ecological benefits, the economic benefits for the community, even the social value that trees bring.

Jad: 9:39

So it's not just how much would it cost to replace this tree, it's what is this tree actually doing for the environment and the people around it?

Lilly: 9:45

Exactly, and that means we need to get better at communicating that value to clients, to policymakers, to the public. We need to go beyond just the dollars and cents.

Jad: 9:54

It's about telling the whole story of the tree.

Lilly: 9:56

Yes, the ecological benefits carbon sequestration, air curification. The economic benefits property values, energy costs, the social benefits, mental health, community cohesion.

Jad: 10:08

Painting that complete picture.

Lilly: 10:10

Exactly. And then, of course, we have all this exciting research happening on fire blight and the potential for biocontrol using nature to fight disease.

Jad: 10:18

I know, it seems like science is finally catching up.

Lilly: 10:20

Right, the research in Kyrgyzstan with those actinomycetes. That's super interesting. It could lead to some real breakthroughs in how we manage fire blight.

Jad: 10:27

Working with nature, not against it.

Lilly: 10:29

And that brings us to a really important point. We've talked about new valuation standards, cutting edge research, the interconnectedness of ecosystems, but it's not enough to just know this stuff. We have to actually apply it.

Jad: 10:40

So what does all this mean for you as a professional arborist?

Lilly: 10:43

That's the question, isn't it? With all these advancements, how do you see the future of urban forestry evolving? Will we start using more ecological approaches? Will things like compressed air injection or biocontrol become standard practice? And how do we actually communicate the value of trees, in all their complexity, to make sure they're protected and integrated into our cities?

Jad: 11:03

Big questions.

Lilly: 11:04

Big questions, but they're the questions that are going to shape the future of our profession.

Jad: 11:09

And we want you to be part of that conversation.

Lilly: 11:10

Exactly. You're the ones out there on the front lines caring for our urban forests, making a real difference.

Jad: 11:16

Absolutely. And before we wrap up our deep dive, we have one more day to cover. From Talking Trees, Friday's episode, a tribute to Dr David Lonsdale. We're back in a moment to discuss his remarkable legacy and what we can all learn from his life's work. Welcome back to the deep dive. We've covered some really fascinating stuff this week, from the science of leaves to the future of tree valuation. But I think it's fitting that we wrap things up by reflecting on Friday's episode dedicated to Dr David Lonsdale.

Jad: 11:48

Yeah it was a really moving tribute. Dr Lonsdale's work was just so important for our field and his legacy continues to inspire us. The episode highlighted all those tributes from such respected organizations the Arboricultural Association, the British Mycological Society, the Arboricultural Journal. It's clear he made a huge impact.

Lilly: 11:58

And it wasn't just about the discoveries he made. It was his passion for sharing that knowledge, for lifting up the entire field of arboriculture.

Jad: 12:05

They talked about his lovely teaching, his dedication to mentoring young arborists.

Lilly: 12:10

It reminds us that our work isn't just about the trees. It's about the people too young arborists.

Jad: 12:13

It reminds us that our work isn't just about the trees, it's about the people too, and the Arbor Cultural Association. They've made so many resources available now to honor his work articles, research papers, recordings.

Lilly: 12:21

You haven't checked those out yet. I highly recommend it.

Jad: 12:23

They also highlighted that webinar where Dr Lonsdale talked about wood decay, tree defenses, tree health and safety.

Lilly: 12:30

He had such a unique perspective, you know, as both an arborist and an entomologist.

Jad: 12:34

That webinar is a masterclass, seriously.

Lilly: 12:36

And you can just feel his passion, even through the recording.

Jad: 12:39

It's inspiring right the impact that one person can have.

Lilly: 12:42

It really is and it goes back to what we've been talking about all week this idea of continuous learning, of sharing knowledge within our community.

Jad: 12:49

From the science to the practical applications. Everything we discussed highlighted how interconnected this work is.

Lilly: 12:55

You need to keep learning, keep collaborating.

Jad: 12:57

And Dr Lonsdale's life. His work is a perfect example of that.

Lilly: 13:01

He never stopped learning, never stopped sharing. He knew that the future of arboriculture depends on us working together.

Jad: 13:07

So as you go back to your work this week, take that spirit with you.

Lilly: 13:10

Go to a conference, read a research article, talk to a colleague. Just observe the trees around you.

Jad: 13:16

With fresh eyes.

Lilly: 13:17

Every tree has a story and every interaction is a chance to learn.

Jad: 13:21

The pursuit of knowledge. That's a lifelong journey.

Lilly: 13:24

And the rewards are immeasurable.

Jad: 13:26

That's a great note to end on. So we'll wrap up our deep dive here. We hope these conversations continue. Keep exploring, keep learning and we'll see you next time for another deep dive into the world of Talking Trees.

Roger: 13:39

Thank you for tuning in to this week's Talking Trees recap. If you enjoyed these insights into the world of trees, we invite you to subscribe to the full episodes at wwwheroherocom. Stay connected with nature and join us next time for more inspiring stories and discoveries.