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16: Urban Plants + Black Carbon = ?


For this  episode we talk with Dr. Alexandra Ponette-Gonzalez, an Associate Professor in the Department of City and Metropolitan Planning and Curator of Urban ecology at the Natural History Museum of Utah. Ponette-Gonzalez’s work focuses primarily on urban ecology.  She studies forests and trees and how they interact with the atmosphere and urban environments. She’s done a lot of cutting edge research on things like urban ecology, urban black carbon, and what happens to smoke and dust. By studying how we humans impact our urban ecosystems, which in turn impacts the climate, she hopes to better understand what the future could look like, and where climate solutions may exist in urban environments.

Listen to the Interview:


Transcript:

Ross Chambless
Well, Alex Ponette-Gonzalez, welcome to the Wilkes Center.

Alex Ponette-Gonzalez
Thank you! Thank you for the invitation and excited to be here.

Ross Chambless
So Margaret and I are excited to talk with you about your research, and I’m gonna let Margaret go with the first question.

Margaret Call
So just to get us started, if you wouldn’t mind introducing yourself a little bit, telling us about your background and how you’re involved on campus?

Alexandra Ponette-González

Alex Ponette-Gonzalez
Okay, So I am new to the U, I have been here for a year, started on January 1st of 2023 and I have a joint position. I’m an Associate Professor in City and Metropolitan Planning and I’m a Curator of Urban Ecology at the Natural History Museum of Utah. Those are interesting titles for me because both are actually new environments. I have previously spent most of my academic career in a geography department. And so I’m a geographer by training, and I have a pretty interdisciplinary background. I actually got to this place in an interesting way.

I like to share this story for people who are on the path. So, I studied psychology and then studied geography and then studied ecology before I kind of made my way back. So this position at the U is really interesting because it’s a place where I can do science, and then the planning department is where I can apply that science and see action on the ground. So really excited to be here.

Ross Chambless
So I wanted to ask, I know that you’ve been involved with a number of really interesting research projects, and so I’m sure we don’t have time to get into all of those, but maybe you could touch on what have been some of your most interesting projects recently that that ties into your background that relate to climate change generally?

Alex Ponette-Gonzalez
Sure. So I’ve been studying forests and trees and how they interact with the atmosphere for a pretty long time. But I would say that where my research relates most to climate and climate change is a project that we started about, I guess it’s about six or seven years ago now, maybe a little bit longer. That project is focused on elemental carbon, which people refer to commonly as soot. And if you know a little bit about soot or elemental carbon, you know that it’s an important climate forcing agent. Maybe I should just say what elemental Carbon is? So it’s a byproduct of the incomplete combustion of fossil fuel and biomass, and it’s a component of particulate matter and fine particulate matter. It’s also called black carbon. We’ll stick with black carbon. The names are used in different ways depending on the methods that you use. But we can stick with black carbon or soot.

What’s really interesting is, you know, we hear a lot about CO2 here at the U. We hear a lot about black carbon, too, which is why I’m so excited to be here. But a lot of people don’t realize that black carbon has a warming potential that’s about 700 times that of CO2. So it’s a pretty important in our atmosphere in terms of climate change. So about, you know, whatever, back in 2017, we realized that there were a lot of people studying black carbon in the atmosphere, and there’s quite a few people looking at black carbon in soils and sediments, probably people you know in geology, for example, but not a whole lot of people looking at black carbon deposition to ecosystems, between the atmosphere and the soils.

We started to look at this question and we wanted to know how much black carbon was depositing to vegetation into trees, specifically in urban areas where there are a lot of sources of black carbon. We have a lot of diesel-powered vehicles, which is a major source. And so we were really curious to know how much black carbon was landing on these trees and then how much black carbon was then being delivered to the soil on the leaves and with water and subsequently how much black carbon is actually then stored in the soils.

This is kind of an interesting question because some people have suggested that black carbon lives in the atmosphere for anywhere from days to weeks. And so people have said, hey, you know, if we cut black carbon emissions or if we find ways to remove it from the atmosphere, it’s a fast way to sort of begin to mitigate climate change faster than with CO2, for example. So we kind of thought about it in this way about, you know, how is vegetation, what role is vegetation playing in an urban environment in capturing black carbon and then sending it to a place where it could be stored potentially for hundreds to thousands of years, which is the soil below the trees.

Ross Chambless
Yeah. It seems like it touches on a lot of interesting, you know, urban vegetation or urban planning policies, perhaps.

Margaret Call
I’m kind of curious with all the research you’re doing with urban ecology, and then you talked about how being in the Urban Planning Department kind of helps you to apply the science that you’re doing in more of a practical sense. So, I’m curious if you have any experience in that way with the application of your science and then how you’ve seen that over time. Like what has your research been doing in urban planning?

Dr. Alex Ponette-Gonzalez is investigating to what extent city trees function as ‘urban air filters’, capturing black carbon particles from the atmosphere and then depositing them to soil where they can be stored over the long term.  Photo Credit: Matt Fry.

Alex Ponette-Gonzalez
That’s a great question, and I think I’m going to say that that’s kind of where I’m headed. That’s why this this opportunity to be in a planning department was so exciting to me because we began by asking the question of how much black carbon is captured by trees and vegetation in an urban area. And we found that it was a lot, by the way. We are just finding now that quite a bit of that black carbon is stored in the soil below the trees. But the next logical question is, well, if you have a lot of carbon that’s being captured by these trees and stored in the soils below. Well, if you’re a planner or an urban designer, the next logical question is, where can we place these trees? What locations on the urban landscape would make the most sense to plant them, if our goal is to capture black carbon or other particulates or other you know, particulate matter.

So I think that’s kind of what got me excited about urban planning. And you probably know that a lot of people are very interested in planting trees and conserving trees in urban areas right now. It’s a major thrust of the federal government. A lot of cities are really thinking about this. And you have to think from a planner’s perspective, you have limited resources, you have limited time, money, people. So you have to think strategically about where to plant trees. It’s a very geographical question, but it’s also a very applied planning question. And that’s kind of where my research is headed. You know, some of this research is headed in the direction of, well, we where would we plant the trees and what configurations? Because just planting a tree anywhere doesn’t necessarily mean that you’re going to get the same benefit.

Ross Chambless
Yeah, I was just going to bounce in and say again from there. Yeah, I think I find that whole conversation very interesting about the urban tree planting strategies, sort of like how do we plan for future climates as far as our urban trees and perhaps that can be content for another conversation, certainly in that aspect.

I’m wondering, if you have ideas on how best to take what you’re learning and efficiently provide it in usable ways for, you know, urban foresters or urban planners in ways that they, even if they don’t fully understand the science behind it, they can take those really important takeaways that good ideas and apply it. Do you have any thoughts on how that might translate?

Alex Ponette-Gonzalez
That’s a really great question. And I feel like most people, I think, would agree that we’re always learning. So this is what I’m learning now in my own in my own program. I feel like I’m a student in the planning department because I’m learning from my colleagues about how we engage and translate information. And so in the past, what I did was really information through oral presentations and posters and such, but I’m really realizing now that there are opportunities for direct engagement with urban forestry departments and the Urban Planning Department and the Sustainability department here in the city, for example, where it’s more than just, here’s what we’ve done and here’s what you might want to know. But, it’s we’re doing this. How can we work together? You know this place better than we do, can we work together on how we design sample? And what are some questions that you might be interested in?

So I think for me, what I’m learning now is how you begin the community engagement process, not only with the communities of people on the ground, but the planners as well, before you begin doing the project and then work together to make that project what you want it to be and what they might want it to be as well. So I don’t know if that’s a great, you know, specific enough answer, but I will speak to and maybe I could speak to this later. But I do have some comments on thinking about tree planting in the context of a changing climate. So that’s something that we’re starting to think about as well.

Ross Chambless
Excellent. Yeah. Do you have any other follow up questions?

Margaret Call
A little bit. So, some of the research that I’m doing talks a lot about how trees in your yard, because I do a lot of work with like road based pollution and combustion based particulate matter, we talk a lot about how houses, the trees in their front yard next to the road, pick up a bunch of particulate matter, and then the trees behind their house have less because those trees have blocked the movement of that pollution through the air, into the houses and things like that. So I had a question, is there a way that your research can apply not only to the planning community and things like that, but to people who are just concerned, about like lessening those particulates from coming to their house.. Here in the Salt Lake Valley, we deal with a lot of those health concerns regarding our air quality. So do you have any ways that your research applies to that in measuring how it’s impacting the people as well as the environment?

Alexandra Ponette-González has studied how particulate matter is especially harmful to children’s health and often found in elevated concentrations in and around urban schools. Vegetation barriers can protect children from exposure to PM by capturing and accumulating particulates and preventing their dispersion.

Alex Ponette-Gonzalez
So, I think there is potential to do that. It’s not something that we’ve done so far. We did actually measure particulate matter on a vegetation barrier outside of a school in the Dallas Fort-Worth area, which was a really interesting project. But it’s the same principle as what you’re talking about, is that we can establish barriers in front of locations, you know, between a near road environment and a population, whether it’s a home or a school or a daycare center or what have you. And we could do measurements on either side of the barrier and even inside the home, which is something that Daniel Mendoza’s doing to see how that air quality might change. So that’s not something I’ve done directly. I’ve really focused on what’s on the leaves, but I’m excited to collaborate with people to start to find those localized environments where we can couple our measurements of what’s on the leaves or on the trees or on the bark, in fact, which is something that we also are interested in and what’s in the air to see what level of reduction of particulate matter or black carbon those barriers contribute to.  I think that it’s also a really important planning question and it does apply to residences and it applies to students and it applies to renters as well. So that’s a great question.

Ross Chambless
Yeah, well, I have a question and it’s a little bit of a pivot, but I saw that you recently co-published a study about storms and how water moves through ecosystems and your critique was sort of that perhaps too many scientists are becoming too reliant on remote systems and technologies and not getting immersed enough in the actual phenomena that they are studying like storms. And I think the line was scientists need to get wet more? Or need to get into the rain more? Right. And so can you talk a little bit about that, that article and where that was coming from?

Alex Ponette-Gonzalez
Sure. So we’ve talked a lot about what’s in the air, depositing to vegetation, but a lot of what we also do in our lab is to look at how those materials flow through ecosystems. So whether they’re for us or urban trees, by measuring the water that’s underneath those systems. And so we spend a lot of time measuring water, actually, and using water to measure things that come off of canopies.

This article was the result of… there are many, many folks on this who contributed to this article, but this was the brainchild of a close collaborator of mine, John Bandstand. Interestingly, we all use a lot of these technologies. We use the sensors, we use remote sensing. We, like everyone else, rely on remote sensing and other technologies to do our work. But we found that or in talking together, we were mentioning that there’s so much that you see when you’re in the field that a sensor cannot see for you. And this, I think in this new age of technology, we just kind of, I think in my mind it was sort of a little bit of a, hey, everyone with this new generation of scientists coming up, we still want to get out in the field.

Now, you’re a geologist. You don’t need to tell a geologist that. But there are quite a few people who might spend their entire career behind a computer simulating or modeling processes and not spending that time in the field to just experience and live and see. And sort of picking up on that thread of that can really inform interesting and exciting research questions that we might never have thought of. So it was really just more of an opinion piece on how technology is great, but it’s not the answer to all of our problems nor will it always reveal the complexities and mysteries of the natural world.

Ross Chambless
Yeah.

Alex Ponette-Gonzalez
It was fun to write. It was a cool.

Margaret Call
It’s definitely a thing that I think about a lot in my classes.

Ross Chambless
And yeah, I think it’s a really good sort of general advice for, I guess, any scientist to not get too caught up in the technologies and the monitoring systems that we have in that are wonderful. But at the end of the day you need to stay present with your subject matter. Right?

Alex Ponette-Gonzalez
Yeah. Even for people who aren’t field scientists, I think they could still, there’s so much value that comes with just being in the field and experience seeing that environment.

Ross Chambless
Yeah. Well, I know a few other questions we have are just sort of like, what would you say to someone as far as when you’re getting involved in the sort of the climate environmental research space? And first of all, what is your advice for people who get involved in that space? And also, the content can be kind of heavy, right? It can be kind of a difficult subject to tackle. But on the other hand, you know, there there’s so much going on and it’s such a rapidly changing field of research. So, what keeps you sort of motivated and what advice might you have for other students, researchers getting into that space?

Alex Ponette-Gonzalez
So I, I like to tell people, for me it’s personal. So climate change and environmental change are not just things that I’m interested in studying, but there are things that I take home with me. So for me, a lot of practices, things that I do every day, are things that give me hope. So I’ve had a lot of I used to teach very large environmental science classes and there was a lot of despair and sadness perhaps, and worry about the world and climate change, global climate change. And I used to say mostly I think it’s important to focus on you and the people around you and making change in that space, because it’s often one of the only spaces that most of us can change. And I find that that’s empowering and that keeps me uplifted and happy. So I also don’t impose or expect the people around me to do the same things that I do, you know, whether it’s the composting or the gardening, the vegetables or the collecting the water in the shower. But I do I have found that when I interact with students or people and they see those things, then other people want to do them as well.

So I think it’s really important to serve as a model to practice the things that we know matter in the best way that we can. And that that does keep me hopeful because I think if I can do that, then others can do that. And I know that there’s a lot of tension, there’s a lot of discussion around what an individual can do but at the same time, even if there are things I can’t change, I still feel I need to continue doing what I’m doing. It just wouldn’t feel right any other way. And that yeah, that that keeps me happy, that keeps me excited about what I’m doing. I don’t often feel a lot of despair. I think the world is changing and we’re changing with it, and that’s the only constant, right? So we have to tread lightly and do the best that we can do and serve as role models for others and also learn from others and other role models.

Margaret Call
So yeah, while we’re kind of sitting in this space of personal solutions to climate change, I wanted to make sure that while we were talking about your research, we hadn’t skipped over any, potential things that your research can teach us about solutions to climate or like adapting to climate change and things like that. What can we learn from you and your studies and things like that about adapting or finding solutions to our changing climate?

Alex Ponette-Gonzalez
Yeah, I think I don’t want to put forth the idea that planting more urban trees is going to save us from climate change. But I’ve learned there’s some really important outcomes for me, which is one of the biggest generators of black carbon in the environment is transportation. So, you know, transportation as a major source of black carbon in the environment. So we could carpool more a week. And this is all transportation planning, right? We can use more public transit, we can use diminish our emissions on a personal level. That’s kind of the personal solution side of it. I also think it’s important in terms of adapting to climate change.

I’ve thought about… These are interesting thoughts here, so I’m just going to throw them out there and you can make of them what you will. But one of the things that I started to observe a lot and doing my research was, I was thinking a lot about landscaping practices, for example, as well as transportation and how we blow a lot of stuff around with landscaping. And we do a lot of mulching directly on the ground. And I see a lot of landscapers and residents landscaping who aren’t protecting themselves, using masks or other forms of protection against the suspend air. That’s the result of those landscaping practices or the emissions from the tools themselves. I think it’s important to think about other ways of doing our landscaping, for example, as it relates to not only the emissions, but also it reduces our exposures. It’s actually something I think about a lot on campus. When I see blowers, I will take a different path. Sorry, guys, I know. I know that people are doing their jobs and that’s so crucial.

But at the same time, it has made me think a lot about some landscaping practices, transportation and it’s made me think about some other areas that I wanted to speak to that I’m super excited about, which is we can plant trees, but so we can have a tree that might capture a ton of black carbon. But how is it going to do in the increasing heat and the increasing water scarcity that we’re experiencing in Salt Lake? And so part of the planning solution to this is also knowing what trees are most suitable for the future urban environment in a in a variety of ways. And so I just started collaborating with Luis Aparicio in biology, and we’re going to start looking at how plants respond to particulate matter on their leaves and on black carbon on their leaves, because the Win-Win for the Planner would be to know those species that might be great in a vegetation barrier, but that are also hardy y you know, they can deal with drought, they are tolerant of extreme heat. You know what? What is that unicorn plant species or suite of species that we might plant? So that’s also something that is on my mind a lot lately is, you know, it’s great that plants capture materials, but we have to think about the plant and what the impact on the plant is, too. And in this context of a changing environment.

Margaret Call
Yeah, that’s really cool! I have a question just kind of as an undergrad who discovered my passion for climate and environmental science already into school. And so we talked about kind of being on the path and finding your way for your love of science or urban planning or climate mitigation, all those things. What advice do you give as someone that kind of took a less traditional path to environmental science? What advice do you have to someone who’s passionate about these issues, who’s interested in them but doesn’t know where to start or doesn’t know how to get involved or anything like that? What advice would you give to an undergrad?

Alex Ponette-Gonzalez
I’ll just use my own story, and this is harder for some people. Everyone is different. So this may be harder for some students than for others, but I say find a mentor. Find a mentor, somebody who you can talk to you about your interests, somebody who you feel comfortable with and who’s going to support you. That was crucial for me as an undergrad. I would not be here today if I didn’t have people behind me saying, Oh, well, you’re interested in the environment. Why don’t you move from psychology into geography where there’s some space for people who come with the social science background and there’s physical science, and that might be a good place for you to begin this journey into the sciences. And so I think finding a mentor is really crucial. I think that’s really hard for undergraduate students, and I’m very extroverted that came naturally to me. But I do think it’s important for students to kind of just go for it. You have nothing to lose. You don’t know until you know.

That’s another big piece of advice is you have to learn by doing. We learn what we like and what we don’t like by living the experience. So I always try to sort of convey the idea that nothing is a failure. You’ve just learned what you don’t like to do, just move on to something else. So I would say find a mentor, just go for it and keep following your passion and that will take you a long way. I do think that staying focused, even within the uncertainty of not knowing the answers to all the questions, that, okay, I’m going to try this and if it doesn’t work out well, I’ll just try this next thing is really important. So if you’re on the path, I always tell people, if you’re on the path, you will find what you are looking for. But there’s a lot of fear. At the undergraduate level, I find there was fear for me, and I find that in undergraduate students today, there’s a lot of fear of, you know what? If this doesn’t work out and what does it mean if I don’t succeed? And what will my parents think and what my family think? And it’s kind of like, well, it’s your life, it’s your journey. Kind of got to go for it.

Ross Chambless
Yeah. Now, I think that’s really good advice. Yeah, Really solid advice for a lot of students. Well, just, I guess two more questions before I get to wrap up. One is how do students or anyone else listening to this learn more about your research if you have a website or yeah, what? Where can they go? Where would you direct them? If they want to learn more about what you’ve been learning and working on?

Alex Ponette-Gonzalez
Yeah. So I have a website. It’s linked to my faculty profile at the U. So the website is not perfect because it has just a list of publications and descriptions of projects and lots of pictures of students doing stuff in the lab. But that’s one place that students can learn about me and my research. But a better place would be to find me on the third floor of the architecture and planning, building and knock on my door during office hours and walk in and talk to me. I love talking to people and so my door is always open and we’re actually advertising for undergraduate, a group of undergraduate research assistants at this moment, and that’s posted on the Office of Undergraduate Research. So if you are that person that’s looking for something and you’re on the path and you want an opportunity, you know, reach out great.

Ross Chambless
Nice. That’s great. And then the last question is what we ask everyone is what do you do for fun? What do you do when you’re not doing research? What do you do in your free time if you have free time?

Alex Ponette-Gonzalez
I do have free time. And when I moved to the U I decided I would make more free time. And fortunately, I’ve met a lot of people who are wonderful examples of how to take advantage of this environment. So in my free time, I love to cook. I’m not a fancy cook, I just love to cook all the things and do a lot of shopping at the community market and cooking all the things that my partner grows in the backyard. I also love to hike in the foothills, so right now I am determined to hike every significant trail in the avenues because there are so many of them and they’re wonderful. And I spend a lot of time with my dogs. Like a lot of people in the city, I have learned I am not unique at all in that way.

Ross Chambless
There’s a lot of dogs.

Alex Ponette-Gonzalez
There’s a lot of dogs.

Ross Chambless
Well, awesome. Alex, thank you so much for taking the time to talk to Margaret and I. Thanks again.

Alex Ponette-Gonzalez
Yes. Thank you so much. And have a great weekend. Happy Friday!

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https://ponettelab.cargo.site/