Roger: 0:02

Talking Trees with Lily and Jad. Welcome to Talking Trees, your weekly dive into the interplay between nature and modern challenges. In today's episode, we explore how urban greenery and climate change are reshaping allergenic pollen concentrations. A study from Florence reveals how tree species and green cover influence local and broader pollen distribution. Over in Poland, researchers used an allergenicity index to assess various urban parks, identifying the most common and potent pollen producers. Join us as we uncover these insights and discuss the challenges of nurturing healthier urban environments, of nurturing healthier urban environments.

Jad: 0:47

Hey everyone and welcome to this deep dive. We've got a really interesting one today all about pollen, pollen Specifically for all of you arborists out there. I know you're dealing with this stuff every day. Yeah so we're going to take a deep dive into some research about urban green spaces, pollen and allergy risks.

Lilly: 1:02

Okay.

Jad: 1:04

We've got some fascinating studies from all over Europe Europe and even a couple from further afield.

Lilly: 1:07

Great.

Jad: 1:07

So yeah, let's jump right in. Sounds good, Okay. So first up, we've got this study from Florence, italy, and the researchers used a really cool method. They used moss cushions to actually track pollen at ground level. You know where people are actually experiencing it.

Lilly: 1:20

Interesting.

Jad: 1:21

And, as you might expect, they found that tree pollen was like the dominant type in the city. Yeah, that makes sense, but what's really interesting is that they found some pretty big differences in how far the pollen travels, depending on what kind of tree it is oh really. Yeah, so like cypress and oak trees, for example, they have a much wider pollen influence than, say, celtus or Linden.

Lilly: 1:40

Huh, so that means that, like a single cypress or oak tree could be triggering allergies over a much larger area?

Jad: 1:46

Exactly, and that makes placement like a really big deal when you're planning urban green spaces.

Lilly: 1:50

For sure, like as arborists, we need to be thinking about that.

Jad: 1:53

Absolutely OK. So then, how can we, as arborists, actually use this knowledge to make healthier urban environments?

Lilly: 2:00

Well, there's this tool called the IOZIA.

Jad: 2:02

The what.

Lilly: 2:02

The IOZIA. It stands for Index of Allergenicity of Urban Green Zones.

Jad: 2:07

Okay.

Lilly: 2:07

And it basically helps us to quantify the allergy risk of a certain green space. So it takes into account not just what kind of trees are they, but like how many there are, how big they are, how they pollinate yeah exactly and how long their pollen season is, how strong the allergens are. It's really a much more holistic picture than just looking at one species at a time.

Jad: 2:26

So can you give us an example of like how this IOZ would actually work in the real world?

Lilly: 2:31

Sure. So imagine you're designing a park, right, and you've got a bunch of cypress trees, maybe near a playground. Okay, well, cypress trees are known for having a long pollen season and pretty strong allergens. Yeah, so that area would probably get a high eye toxicity score which means it's a higher allergy risk and you might want to think about planting those trees somewhere else or even choosing different trees altogether.

Jad: 2:52

That makes a lot of sense. So it's not just about the trees themselves, it's about where they are and how many there are.

Lilly: 2:57

Exactly, and that's where arborists come in right. We're the ones who can pick trees that are both beautiful and low allergy.

Jad: 3:03

Okay, so we can't talk about pollen without talking about the big one climate change.

Lilly: 3:07

Right.

Jad: 3:07

There was this global study that looked at long-term pollen trends and specifically they looked at something called APN.

Lilly: 3:14

What's that?

Jad: 3:15

It stands for annual pollen integral and it basically measures how much pollen is produced in a whole year.

Lilly: 3:21

Okay.

Jad: 3:21

And what they found is that for most allergenic plants, APN is going up globally.

Lilly: 3:26

Because of climate change.

Jad: 3:28

Probably. Yeah, it seems like rising temperatures and changes in rainfall are playing a big role.

Lilly: 3:33

Makes sense, but it's got to be complicated right, Like different plants are going to react differently.

Jad: 3:38

You're right, it's definitely not a simple picture and actually this study found that APN was actually decreasing for a couple of plant families.

Lilly: 3:44

Oh really, which ones.

Jad: 3:46

Berticacia and Artemisia, which are kind of weedy plants that a lot of people are allergic to.

Lilly: 3:50

Interesting. I wonder why they're going down.

Jad: 3:52

Well, one theory is that it's because they're often removed from urban areas because they're not very desirable.

Lilly: 3:58

Oh, so human intervention is playing a role too.

Jad: 4:00

It seems like it's a mix of climate change and what we're doing as humans that's affecting pollen.

Lilly: 4:05

Yeah, and what about rainfall? Does that affect things?

Jad: 4:08

It's really complicated actually. The study showed that rainfall can both increase and decrease pollen production.

Lilly: 4:13

Depending on what.

Jad: 4:15

Well, it depends on the plant, the region and whether it rains during or before flowering.

Lilly: 4:19

So like rain during flowering could wash pollen out of the air.

Jad: 4:23

Right, but for some plants, rain before flowering could actually make them grow more and produce more pollen later.

Lilly: 4:28

Wow, so it's a really complex web of factors.

Jad: 4:31

Definitely. And then, when you add in climate change, it gets even more complex.

Lilly: 4:34

Yeah, for sure. So how can arborists keep up with all this and make good decisions about what to plant? I think the key is knowledge, right Like staying up to date on the research that's coming out.

Jad: 4:44

So like this global meta-analysis.

Lilly: 4:49

Yeah, exactly Because it's a broader perspective.

Jad: 4:50

but then you have to take that global knowledge and apply it locally. So what you're saying is a tree that might've been a good low allergy choice a few years ago might not be the best choice now.

Lilly: 4:56

That's exactly right. It's all about ongoing monitoring and assessment. You can't just rely on old lists of good and bad trees, because pollen production can change from year to year based on the weather, how urbanized the area is, even how the land is managed.

Jad: 5:10

It sounds like arborists are really at the forefront of managing this issue.

Lilly: 5:13

I think so. It's a big responsibility.

Jad: 5:15

So what are some things that arborists can actually do to minimize those pollen risks, especially in cities?

Lilly: 5:21

Well, one thing is being more strategic about what trees we choose.

Jad: 5:25

Like how.

Lilly: 5:25

Like really understanding the pollination characteristics. For example, we might favor trees that are pollinated by insects over ones that are wind pollinated, because wind pollinated trees tend to produce way more pollen.

Jad: 5:37

That makes sense. So are there any specific trees that you would recommend or maybe advise against?

Lilly: 5:43

It's hard to say for sure, because it really depends on where you are and what the climate's like, but I can give you some general ideas.

Jad: 5:50

Okay.

Lilly: 5:50

So take the plane tree, for example.

Jad: 5:52

Okay, I know those. They're pretty popular in cities, right.

Lilly: 5:55

They are. Yeah, they're tolerant to pollution and they give good shade, but they're also heavy pollen producers. And a lot of people are allergic to them.

Jad: 6:04

So maybe not the best choice for like a school or a hospital.

Lilly: 6:07

Right. In those situations you might want to go with something like a hawthorn or a rowan, because they have beautiful flowers, but they didn't make as much pollen.

Jad: 6:15

I see. So it's really about knowing your trees and making informed choices.

Lilly: 6:19

Exactly, and it's not just about individual trees either. It's about how we design and manage the whole green space.

Jad: 6:27

So like that study from Cordoba in Spain.

Lilly: 6:29

Exactly. They found that some parks were allergy hotspots, not because of any one tree, but because of the overall density and mix of plants.

Jad: 6:37

So even if you choose low allergy trees, you could still have problems if you plant too many of them together.

Lilly: 6:42

Yeah, that's right. It's all about balance and diversity. So, we need to think about creating green spaces that have a lot of different kinds of plants. Yeah, a diverse urban forest is going to be more resilient to pest, diseases, even climate change, and it's going to be better for people too Less allergies.

Jad: 6:58

OK, so this is all great in theory, but I'm sure some arborists are wondering how to actually do this in practice.

Lilly: 7:03

I know what you mean, but there are some good resources out there.

Jad: 7:06

Like what.

Lilly: 7:07

Well, some organizations are developing pollen databases and risk assessment tools. That sounds useful. Yeah, they take into account local climate data, pollen calendars, even allergy ratings for different trees. So an arborist could use those tools to see how their planting plan might affect allergies, and then make changes if they need to.

Jad: 7:26

That's awesome. It sounds like things are really moving forward in this area.

Lilly: 7:29

They are. Yeah, it's an exciting time to be an arborist.

Jad: 7:32

It's not just about planting trees anymore.

Lilly: 7:33

It's about so much more. It's about public health, climate change, designing healthy, urgent ecosystems that's a great way to put it. And speaking of advocacy, healthy, urgent ecosystems.

Jad: 7:40

That's a great way to put it. And speaking of advocacy, how important is it for arborists to educate people about these issues?

Lilly: 7:47

I think education is super important.

Jad: 7:48

Like what do you mean?

Lilly: 7:49

Like we need to help people understand the connections between trees, pollen and human health.

Jad: 7:54

So talking to clients, community groups, even advocating for better policies.

Lilly: 7:58

Exactly, it's all about communication between arborists, public health officials, urban planners, the whole community.

Jad: 8:06

We all have a role to play.

Lilly: 8:07

Exactly, and arborists are in a really good position to lead the way because we have that special knowledge of trees and how they affect the environment.

Jad: 8:16

Okay, so it's about moving beyond just planting trees and thinking about the whole urban ecosystem.

Lilly: 8:23

Yeah, it's about creating cities that are not only green but also healthy and livable.

Jad: 8:26

So, as we wrap up this deep dive into pollen and urban forestry, what are some of the key takeaways that you hope people will remember?

Lilly: 8:33

Well, I think the biggest one is that pollen is a really dynamic and complex issue, especially with climate change and all the urbanization happening.

Jad: 8:42

Yeah, it's not just as simple as planting trees anymore.

Lilly: 8:44

Right, we have to think about their pollen profiles we're putting them in the city how they interact with everything else.

Jad: 8:50

And how they affect people's health.

Lilly: 8:51

Exactly, and it means kind of changing how we think about our jobs.

Jad: 8:54

So we're not just tree caretakers anymore.

Lilly: 8:56

We're designers of urban ecosystems. We have the knowledge and the skills to create green spaces that are beautiful and healthy.

Jad: 9:03

And that means staying up to date right, keeping up with the latest research, using tools like the IUGCA, and always evaluating what we're doing.

Lilly: 9:10

Absolutely. The field is changing so fast. We have to stay ahead of the curve.

Jad: 9:14

By taking this holistic approach to urban forestry, we can create cities that are greener, healthier and more resilient For everyone. Exactly Well. Thank you so much for joining us on this deep dive into the world of pollen and urban forestry.

Lilly: 9:26

It was my pleasure.

Jad: 9:27

We hope you learned something new that you can use in your work. Remember, you're not just shaping trees, you're shaping the future of our cities.

Roger: 9:37

Thank you for joining us on today's exploration of urban greenery, climate change and allergenic pollen. From studies in Florence, poland and Cordoba, we've seen how variations in tree species, green cover and rising temperatures are influencing pollen concentrations and affecting allergy risks. We hope these insights encourage thoughtful discussions on building healthier urban environments. Until next time, keep nurturing and protecting our natural spaces.