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Alessandro Ossola is a scientist who gets very excited about the challenge of climate change allowing for an opportunity, and he describes it as an historic opportunity for all of us, scientists, gardeners and all types of decision-makers, to really challenge the status-quo and come up with innovative solutions.
“Where we can change the narrative though, is we’ve always seen cities, this is true globally, as the foci of extinctions. Both for animals and plants. I really want to change that narrative. I see the city itself as an opportunity to help horticulture, but also biological conservation.”
-Alessandro Ossola, PhD, University of California, Davis, CA
Sarah Beck: You’re listening to Garden Futurist. I’m Sarah Beck, here with Adriana López-Villalobos. Oh, I’m so glad to be back with you. It’s been a long time.
Adriana López-Villalobos: Hi Sarah. Yes, it’s been a long time. I’m really excited to be back, and what a way to be back with this amazing guest we had today.
Sarah Beck: I’m always excited when we meet someone who really appreciates a challenge. Alessandro Ossola is a scientist who gets very excited about the challenge of climate change allowing for an opportunity, and he describes it as an historic opportunity for all of us, scientists, gardeners and all types of decision-makers, to really challenge the status-quo and come up with innovative solutions.
Adriana López-Villalobos: Yeah, and it is very interesting, the way he approaches these types of questions from a very holistic way. He takes urban environments and asks questions related to infrastructure, climate change, and the day-to-day problems from a lens that not only involves the understanding of ecological processes, but also considering the way people move around and function in these urban areas.
It integrates the cultural component, plants, nature, and the infrastructure of cities.
Sarah Beck: I agree. The cultural piece, and the specificity of a given place or a city, and what the place is like and even who the people are in that space comes into play a little later, too, and he really does share some great examples of that.
Adriana López-Villalobos: He’s also a big data person, with substantial examples of using innovation and new science. Sarah, it doesn’t get more Garden Futurist than this.
Sarah Beck: There are some examples that are just really mind-blowing in terms of having the technology and the large data sets. It’s all about nature and ecology in a city, so this is nature integrating with technology in a really new way.
Dr Alessandro Ossola is an Assistant Professor at the University of California, Davis. He’s also and Honorary Research Fellow with the School of Ecosystem and Forest Science at the University of Melbourne, Australia and Macquarie University in Sydney, Australia.
Dr. Ossola’s research encompasses a lot of topics we are very interested in: urban ecology, climate change, forestry, water management, urban planning, the list goes on and on.
Adriana López-Villalobos: Yeah, the conversation covers a lot of ground. So why don’t we just dive right into it and listen?
Sarah Beck: It’s really interesting to me that you are attracted to these extremely issues around climate change and I think it takes a really special sort of brain to be able to not get overwhelmed when you’re looking at these huge conversations.
I wanted to just jump into the fact that I know you did a lot of your work in Australia recently. We know they are ahead of us—not just in the clock, they are like a day ahead of us—but they’re also ahead of us in terms of climate impact and pressure. Is that what drew you to go to Australia in the first place?
Alessandro Ossola: So Australia, yes, we live in the future. I was lucky enough that I spent 12 years on my research time in Australia between Melbourne and Sydney.
In many ways, we are experiencing the impacts that hopefully we are going to be able to mitigate in California and on the West Coast, in Arizona, and so on. I still remember I was in Sydney on January 4th, 2020 during the austral summer, just before COVID hit. And we recorded 51°C, so 124°F.
Sarah Beck: That’s a little hard for me to comprehend. Can you describe what that was actually like to experience?
Alessandro Ossola: We didn’t have air conditioning inside our place and inside there were like 37°C. so you are literally, your skin is evaporating. Of course you have to consider that that’s a temperature that you experience in the Death Valley, but in a city of 5 million people.
We have couple of post-docs actually. We took the roads and we drove through western Sydney with a car, of course air conditioned, and we managed to measure mortality, I think, of 5,000 stems.
What we found was actually that all the exotic species of trees that are mostly native from Europe, most of them, they failed. They had a lot of damage, and whereas the Australian species was just doing okay. They were hanging in there possibly because they’ve been historically subjected to heat and drought from an evolutionary point of view. So they were just fine.
With bunch of economists, we went and tried to calculate, okay, we know that these species are failing. If we were to replace all of them across the entirety of the greater Sydney metropolitan region, how much is it going to cost? And we project that it’s going to be dozens, if not hundreds of millions of dollars.
Sarah Beck: Yeah, it’s a big project.
Alessandro Ossola: So I would imagine that if in the future, LA or San Francisco are going to be experiencing similar situations, climatically, we all might need to face a similar bill down the line.
Sarah Beck: This is such an interesting question, and Garden Futurist recently spoke with the Climate Ready Trees researcher Greg McPherson, and this 50°C city, that’s super scary. In the Pacific region, should that be our primary concern? There are other possibilities too, right?
Alessandro Ossola: Correct. So the issue is not a single day at 51°C. Most plants and people can do it, we can tolerate it. The issue is when we have repeated heat waves with very high frequency, very high intensity, and the time in between these extreme events is shortening. We are not allowing ourselves to take a rest, both us and plants.
So this is the compounded factors that are decreasing our ability to adjust to these types of stresses. So that’s the issue that climate change is going to bring upon us, and also the fact that we are swinging suddenly from drought, La Niña to El Niño in a matter of weeks or days. And we get 12 atmospheric rivers, one after the other.
Like us, we are not able to adjust if you go from a seven-course meal to a diet straight away, we need time, right? So that’s the overwhelming bit that we need to figure out how to innovate in an urban space, in terms of urban greening, planting, and growing plants that can adjust to these new situations really fast.
Sarah Beck: Can you talk a little bit more about that and how that can be achieved?
It’s wonderful that you have this international perspective because you’re able to see a lot of these systems in different places. You talk about this urban nature-based solutions idea. Could you define that first and maybe we can talk about what that really means?
Alessandro Ossola: Sure. Urban nature-based solutions is essentially an extension of concepts like green infrastructures or green-blue infrastructures, and so on. Green infrastructure was actually born in the United States, really, and is a way for us to use water-sensitive plants to be able to deal with storm water and urban storm water management.
Nature-based solution is actually a concept that comes from Europe maybe a decade ago, and that’s the logical extension of the green infrastructure idea where we are not just looking at water as an issue, but holistically the entire landscape and the multitude of different stressors and problems that we have and we have to deal with.
So in a way we can use nature and plants are one side of nature, of course. There is the soil, there is water, there is other things. And we need to learn how we can use these natural elements to complement the shortfalls and the benefits of, for example, infrastructure and traditional engineering approaches, also including people.
If we don’t include the social aspect in all of this, we already fail.
Imagine that with our growers, we might be able to increase our diversity of plants that we have in production by 20 percent. If people don’t like them, they’re not going to buy them, and they are not going to plant them.
So we need to have an integrated system where growers have a certainty to be able to grow the plants. Some plants are very tough to grow—so I understand there are difficulties, particularly with some natives—but also people, we need to convince them that plant is important, it looks great, it uses less water, and so on. If we don’t have this discussion between all these different actors, ideally help by decision makers at multiple levels, we already fail the discussion.
Sarah Beck: It sounds like what you’re saying is you can’t just take great innovation and throw it into a city and get the result you want in terms of resilience. There really needs to be a cooperative or a more multifaceted approach.
I’m curious if you could share an example where some human adaptation or a change in the culture or a change in the way that we do things, might actually be more supportive of one of these nature-based solutions and resilience building.
Alessandro Ossola: Yeah, I make a case again from Australia simply because I live there for a long time. A few years ago, talking about Aboriginal issues and this type of issue was complicated. And then little by little we changed the narrative to the point that we started planting bush tucker gardens that are gardens that are providing food that is of value: of nutritional value or historical values or cultural values for Aboriginal communities, and now you can find these bush tucker gardens downtown Sydney as well.
So that’s an example of how we can use cultural legacies and benefits to be able to create something in the landscape that is innovative and actually helps us to redress historical issues related to Aboriginal communities or, in our case, Native American communities. Now there are Aboriginally led businesses, horticultural businesses, in Sydney. They are actually making money and they are helping us to create a better landscape that tells a story, and it has a function attached to it that, in the case of Sydney, is trying to cope with extreme climate events.
So if we merge the social aspect of it, the ecological aspect of it, the horticultural aspect of it, that’s a win-win-win situation, where it’s no brainer to me, but it’s tough to do.
Sarah Beck: This isn’t easy work to do, and I think it’s important for us to be able to take cues from cultural groups about how we should be learning about some of these plant interactions, but it does seem like there’s a lot for us to gain socially, especially in these urban environments. We can understand all these layers of our relationship to nature, our relationship to plants, that have some history with people.
Alessandro Ossola: Correct. The urban landscape is just a canvas, in my opinion, where we can draw the story that you, we are really more passionate about plants.
We need to be more than the narrative where plants are just something beautiful to look at. To something that actually functional to provide us an available landscape with a particular function we want to maximize, like shade or evaporative cooling, or reduce water use and so on, or food.
As there are many plants, even trees that are edible. so what, why not using. nutritional values of these plants to be able to redress some of the issues that we have in some human communities where access to fresh food is tough. in California, even fifth largest economy and still we drive through some communities that they are extremely underserved.
To what extent we can actually create an edible neighborhood, an edible city, and using plants in a creative way that is not there yet
Sarah Beck: You mentioned blue-green infrastructure. I was hoping you could define that, I know you defined green infrastructure. I don’t know that I have heard blue-green.
Alessandro Ossola: I guess that’s like a scientist dream to invent new terms, but are pretty much the same thing. Blue because there is more emphasis on the aquatic side of plants. Okay. Particularly if you’re looking rather than talking to like a, let’s say a park or a bioswale, you’re looking at more freshwater type of environments or like riparian corridors or lakes or ponds and all of that. That’s why the blue comes into play.
Now in Chicago, there is a new Wild Mile. This is a new river corridor that essentially the idea is to, to rewild the city, how we can learn how forests are functioning their native environment and bring back elements to it. It might be the microbes, it might be the mycorrhizae, it might be other plants that are important to facilitate our trees or shrubs or whatever. To be able to create a system that works better is more resilience to stress, it can recover faster or better after we have, for example, a pathogen or a disease coming through.
So we know, I’m an ecologist myself. We know nature provides us with a lot of solutions. The challenge is to bring them back to town and trying to scale them up.
There are great gardeners in Davis and in California. They know much more than me. It’s great to walk around in neighborhoods. I spend a lot of time walking and peering into people’s yards. This is what I do for a living. I see great examples. Now, the challenge is to scale it up from a single yard to the entire landscape. We need to help people that are not engaging in gardening just to be able to try safely and try with trial and error.
Failure is good. I tell my students at the university all the time, fail safely. Fail all the time because you can learn a lot of things from failing. I failed so many times in my life. Plants are failing, too. We just need to take the time after failure to sit down quietly and understand why we fail, so we can actually improve next time.
Sarah Beck: What you just said is fascinating to me about the small scale to the big scale.
Just going back to this idea of some of the infrastructure pieces, there’s a lot of science and innovation right now in water management. I’m curious if there are pieces of that, first of all, that you think are really exciting that we should be watching and looking for and seeing applied in city spaces. But also, this idea of trying things at a small scale. Do you think there’s a role for the gardener and for the community-scale or home-scale gardener to be experimenting?
Alessandro Ossola: Absolutely. I mean, just think about California. I mean, we have 6,000 native plant species. It’s a huge diversity. There is no way, as a single scientist, I could test this diversity in my lifetime. Not even with my students.
So if we can find a way to some to create some sort of living labs, even in people’s yards so we can test the same plant species or the same cuttings or the same provenances in many different areas along, let’s say the West Coast, where we have several different climate zones, we can actually try to see to what extent plants can survive in environments that are way beyond their native niche. Plants are very flexible and we can do all the climate models that we want and they can spend decades doing modeling, but the best way to try is actually to try in the landscape. Because failure, sometimes, it can’t be predicted with a computer model, despite us using big data and now artificial intelligence and all that thing. Plant intelligence is not that artificial.
Sarah Beck: Are there some examples of ways you would encourage a gardener who is really open to this idea of testing something?
Alessandro Ossola: Something easy to do and something challenging to do. Because the easy stuff gives you like the good vibe that yeah, you did it. It makes your green thumb even greener. the challenge for many native plants in California, in Australia and South Africa elsewhere, is that they’re really hard to propagate or to grow to size.
So I understand that even in a university setting, we fail to germinate some plants simply because their biology, it’s really tough. That’s why some plants are facing extinction simply because they are maybe at the end of their life cycle, which is totally fine. If you think biologically, 99.9% of organisms that ever lived on our planet, they are extinct. They are not living. So it’s part of the process.
Where we can change the narrative though, is we’ve always seen cities, this is true globally, as the foci of extinctions. Both for animals and plants. I really want to change that narrative. I see the city itself as an opportunity to help both horticulture, but also biological conservation.
I make the example of this study that we did a few years ago. We reviewed three planting records for 474 cities and towns globally in what we call the Global Urban Tree Inventory or GUTI for friends. Guess what? We found six species of trees planted somewhere in some cities that are actually extinct in nature. We have dozens of species that are listed as endangered or critically endangered in the IUCN red list of species facing extinction.
So it means that historically as humans, somehow, we got lucky and we imported plant species into our cities, and we actually saved them from oblivion. So why not do this on a massive scale? Why not think in our global cities?
If you’re thinking in the US we have 755 cities and 17,000 towns. We have a massive network of resources, space, talent to do this. We just need to have the framework and the willingness, helped by our decision makers at all levels and supported by our beautiful businesses growing plants to be able to do so, and citizens, in my opinion I like in very important part of this narrative.
Sarah Beck: What are some examples of technology that you feel is moving really quickly right now that you think can assist the work that you’re doing?
Alessandro Ossola: I actually have a project with Sydney Water, and Sydney Water spends dozens of millions of dollars to service pipes, sewer pipes every year because of tree intrusion, which is an issue, particularly during drought years, when the trees are thirsty, they sense like, “Oh, that’s yummy water. We have a lot of nutrients. Let’s get into it.”
So we’ve seen the water. We have a paper under review right now where we use our big data of all the trees planted across Sydney. Their sizes, their health status. We have 651 tree species planted across Sydney, which is a crazy diversity. And we didn’t know which ones are problematic.
So in this case we used this data set on trees. We used a lot of remote sensing data about soil qualities and death and all of that, and then we integrated that with Sydney Water’s pipes data. So like how deep they are, the diameter pipes, the materials and so on.
So we were able to churn all this data sets through artificial intelligence. And now we are starting to see some trends where, for instance, if you have several fig tree species, They’re really, really intrusive. They get into the pipes. They are problem. And you can see clearly that you have some species that are very, very uncommon in the landscape, but when they occur next to a pipe, most likely they are intruding in the pipe.
So now we have a post doc who is actually using genomics, all the DNA magic that we can do. She’s working with Sydney Water’s crews to be able to sample the roots from the pipe. And we have a genomic library of the leaves of the trees above ground and we can validate whether that or that species was actually intruding, through genomics.
So we can validate our big data, artificial intelligence study with something that is completely different, related to DNA.
Sarah Beck: I’ve never seen like a plumbing and plant overlay before. That is just really a fascinating set of tools. Thinking about that being used at such a scale, were you surprised? Was it not necessarily what you would’ve predicted if you didn’t have that set of analysis?
Alessandro Ossola: So, provided that we still need to do like the validation through genomics. Some trees, they make sense. If you look at fig trees overall, many species, particularly in Australia, they’re called strangler figs. They have very, very powerful root systems. I was actually pleased to see that our big data approach was actually able to pick them up because biologically or ecologically, or physiologically, yeah, that’s clear that they intrude.
The issue is then how we mitigate the problem in the urban landscape? If you had been to downtown Sydney, fig trees are really, really ubiquitous because we planted them, because they were great choices 200 years ago. Now, not so much.
So the idea of having a platform where we can be able to maximize the outcomes when we manage a city with the biology in the city, this is where the beauty of my work comes into play. I can get multiple streams of evidence and I can try to solve real issues that our urban managers and urban foresters, architects, whoever wants to work with me, is experiencing every day.
Sarah Beck: Do you think there are cities in the world, since you look so globally at things, that have found ways forward to do some of these integrations that are really worth us looking at?
Alessandro Ossola: I have an example from Boston. We did a study maybe five years ago where we looked at the entire metropolitan area. We were really focusing on how people are doing landscaping between front yards and backyards. So we published a series of papers on this, and in one paper we found that there was some sort of correlation between your architectural style of your house, of your home and the type of landscaping that you were doing.
So there are some particular, Bostonian architectures, but some, it could use to be able to somehow, implicitly or explicitly change how people are doing by landscaping and in for landscaping. I mean, the amount of tree cover, physical tree cover people are putting in the landscape.
In the same study in a different paper with colleagues from USDA, we were able to manage, to manage to measure the amount of mimicry that neighbors are extending.
Sarah Beck: Oh, that’s amazing.
Alessandro Ossola: Let’s say that this is true, particularly for front yards because they are more visible private green spaces. You can see clearly that in Boston, here is a five-degree separation between neighbors. So it means that your action is affecting five neighbors from you, and then these actions are decreasing.
So if I know, for example, in San Francisco, this amount of mimicry’s related to maybe three neighbors, then we can actually create policies or actions. So we can actually target this sweet spot that are in the landscape because the data tells me that neighbors are affecting in Boston, in this particular way, in Chicago, in that particular way, and so on. That’s why finding a universal rule for cities is not going to happen. Every city, every town has a different history, has a different cultural background, has a different climate, so we really need to be able to use science to tailor solutions that are sensible for your particular local area.
Sarah Beck: I think it’s incredible that you, coming from this very broad, high-level expertise, are basically saying, “In order to be effective, we should be working at a. localized grassroots level,” which first of all is just incredible, but I love what you’re talking about with this sphere of influence for the gardener.
I mean, at Pacific Horticulture, I cannot tell you how often we’ve had this conversation about specifically front yards and hell strips, because this idea that you can demonstrate all kind resilient gardening solutions for your neighbors to be able to see and come by and experience.
Alessandro Ossola: That’s beautiful. That’s passing the baton to the next generation, also. One thing that, with my students, we are trying to fight every day is that overall young generations can’t even recognize the plants around us or other organisms, animals, and so on. So we really need to work backwards and go back to K-1 schools to make the difference very early on in life.
I think the first couple of years in your life are extremely important. I grew up in a semi-rural area, northern Italy, and I was blessed when my father was keeping taking me out all the time in our woodlands. That’s why I ended up being what I am today. We need to bring the classroom outdoors. That’s my opinion. We can’t avoid, ostracizing ourselves from nature.
A few years ago we co-edited a book on urban biodiversity, with a colleague of mine from Finland who unfortunately passed last year. And the fore of that book was Penn by the director General of WWF International. And WWF that is historically has been an NGO focusing on the Panda bear and native environment. And for us was the first time that they recognize that they need to work in urban areas because this is where the people are, and this is the only way 99 percent of the population is actually touching nature, smelling, nature is physically proximal to it.
If we are missing this conduct, then even an NGO that is connected to fight global conservation and all of that is losing opportunities. So, to me it’s just critical that every day we remind ourselves that this has to be part of our life.
Sarah Beck: Obviously we’ve been touching on the human element integrating with stewardship. But there’s also this human health wellbeing and there’s our mental health. You can’t really separate these things when we talk about this city of the future. As you just mentioned, most people are in urban environments and we need to make sure that as we move forward, the climate reality of tomorrow that we are living in this space that we can all feel good and be healthy human beings.
Did you take away anything you didn’t expect from looking at people gardening?
Alessandro Ossola: During the pandemic, I was in lockdown in Sydney and I had a lot of colleagues locked down pretty much everywhere in California, in Germany, and so on. So instead of just watching Netflix, we decided to have a more proactive approach.
And we noticed that our partners on the ground complaining about shortages of seeds globally. And then I say, oh, well, okay, let’s Google this. Actually, Google has a tool called Google Trends. And you can Google how a particular keyword like gardening is trending in the search engine. So, we did this on steroids and correlated this with essentially the week of the peak of the first infection of Covid 19 in 39 different countries. Of course, we changed gardening to the respected native language for that country. And while we found that pretty much there was a wave of people going in lockdowns and at the same time, Googling gardening because these guys were stuck at home and I guess they ran out on Netflix material, and at some point they were Googling what to do with garden.
That was potentially millions of people that we are talking about here, if not hundreds of millions of people. So that was mind blowing. It’s like this is unexpected, very strong statistical trend, too.
So there are these global trends that we were able to measure and now we are trying to advise many municipalities in United States and overseas, and even the federal government and USDA on the lessons that we learn about gardening during covid and how we can completely change the perspective of gardening, because that’s not just a passion anymore, like most of your audience may have, is actually something that we should think as a public health strategy.
Sarah Beck: I am so ready to lobby for that policy.
Alessandro Ossola: Let’s do it.
There is also medical evidence if you look at our microbiome, our gut microbiome, our skin microbiome, yeah. The first two years of your youth are dictating how you’re going to be functioning in terms of your microbes and bacteria and so on for the rest of your life.
If we are not giving our kids the opportunity to touch and smell and learn about the plants very early on in life, we are affecting their life and their wellbeing for the rest of their life. It’s too late. The first two years are extremely important. I want my my kids and my nephews and everybody I see to go and touch the soil. Yes, it’s dirty, but it’s good for you. Trust me.
Sarah Beck: Oh, this is like one of my favorite topics. I’m so glad you brought this up. We actually did a fantastic interview last year with Martin Breed. He’s an Australian. He even told us about the aerobiome and how the microbiome relating to nature and plants that he was looking at in terms of human.
He had hypothesized that someday we might be able to plan infrastructure in cities in ways that people would just be like naturally moving through spaces where they would get those benefits.
Alessandro Ossola That would be amazing.
Sarah Beck: So think about like, oh, let’s say you’re entering transit right here. Oh, we better make sure that you’re like getting plenty of nature microbiome on your way.
Alessandro Ossola: So the good news in my opinion is that the science is evolving fast and we are trying our best at Davis and like everywhere with my colleagues, globally, our students and postdocs and staff, everyone, we are making a lot of effort. We are spending our lives to try to create more evidence based on what we need to be able to, to go towards greener, more sustainable and healthier cities and towns.
Overall, I don’t think climate change is all bad news, if I need to be honest. I think it’s actually an historic opportunity for all of us, scientists, growers, citizens, decision makers, to challenge the status quo and implement finally, truly innovative solution to thrive, not just survive under climate change.
Adriana López-Villalobos: Wow, I’m really impressed with how this conversation ended. It’s a really positive way of taking a really hard and difficult problem and putting it as something that we have to tackle.
So following that, Sarah, what do you think about this concept of a sphere of influence of a gardener?
Sarah Beck: Right, yeah, I thought that was really interesting, this idea that the kinds of landscapes that are in public spaces – I think he talked about front yards, right? This whole idea that there is an influence across 5 other neighbors deep, or something like that. It’s just so exciting to think there’s scientific evidence that a gardener could have a great deal of influence over what their own neighborhood looks like by planting certain plants.
He was saying it was so specific to place. This wasn’t like, hey, this is something that works the same everywhere, he was basically saying you need to get to know the neighborhood, the architectural characteristics. What the people are like, what the climate is like, what is going on in that place?
There’s so much more to learn about this idea. There may be potential for partnerships and other research projects that could help us place this interplay between, it’s not just infrastructure, it’s not just plant selection, there’s this human cultural component. If we can get that formula right, and really figure out how to do this, we could make so much change happen. We can actually influence what is growing in our cities on a huge scale. We can have these habitat-supporting plant, we can have all this amazing blue-green infrastructure.
Adriana López-Villalobos: Blue-green systems, yeah. It ties really nicely with all those nature-based solutions that he talks about.
Sarah Beck: I think my big takeaway is, if you’re a gardener, you can make a difference. You can change things.
If you can figure out what makes a place special and how people can relate to gardens in that place, you might be able to get that incredible influence going across neighborhoods. It’s just amazing to me that this person who works in such large-scale data sets really is saying that the thing that’s powerful to make change is a grass-roots solution.
The Global Urban Tree Inventory: A database of the diverse tree flora that inhabits the world’s cities
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