Check out the first episode of our new weekly podcast, Resources Radio. Each week we talk to leading experts about climate change, electricity, ecosystems, and more, making the latest research accessible to everyone.
In our first episode, host and RFF Senior Research Associate Daniel Raimi talks with Matthew Wibbenmeyer, a fellow at RFF, about wildfire. They consider the role that climate change and other factors play in the growing risk from wildfires to communities and ecosystems. Daniel and Matthew discuss the recent fires in California, looking not only at their causes but also how to mitigate their risk in the years and decades to come.
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Top of the Stack
- "The Relationship between Trees and Human Health: Evidence from the Spread of the Emerald Ash Borer," a US Forest Service Study by Geoffrey Donovan et al.
Daniel Raimi: Hello and welcome to Resources Radio, a new weekly podcast from Resources for the Future. I’m your host, Daniel Raimi. In this, our first episode, we talk with Matthew Wibbenmeyer, a fellow at RFF, about a topic that’s been in the headlines in recent weeks: wildfire. I’ll talk with Matt about the role that climate change and other factors play in the growing risk from wildfires to communities and ecosystems. We’ll talk about the recent fires in California, looking not only at their causes, but also how to mitigate their risk in the years and decades to come. Stay with us.
Matthew Wibbenmeyer, thank you so much for joining us today on Resources Radio.
Matthew Wibbenmeyer: Thank you.
Daniel Raimi: So, Matt, we’re going to talk today about wildfire and, in particular, some of the fires that have been burning in California in the last weeks and months.
But before we get into talking about that, can you just tell us a little bit about yourself and how you became interested in environmental issues and wildfire in particular?
Matthew Wibbenmeyer: Yeah, so I grew up in western Oregon, in Eugene. And my family spent a lot of time while I was growing up hiking and camping in the Cascades and the Doug Fir forests out there. And so an awareness of forests and environmental issues was just part of how I grew up. Also while I was growing up, the controversy over the Northern Spotted Owl was raging and particularly affected western Oregon. A lot of logging communities were in decline during that time. So that was part of my consciousness growing up. So that’s kind of how I got interested in environmental issues in general, and then wildfire in particular, I first got involved with while I was working in Missoula, Montana for the US Forest Service after college.
I worked as a researcher focused on human dimensions of wildfire management with a Forest Service group there. Missoula is kind of a center of wildfire research for the Forest Service.
Daniel Raimi: Right, great. Yeah, the northern spotted owl. So I’m sort of an energy and climate guy—I’m a little bit out of my element today in our conversation. And that sounds like another potential podcast episode that we could talk about maybe.
Matthew Wibbenmeyer: Oh, yeah.
Daniel Raimi: Great, so let’s talk about wildfire and, in particular, what’s been happening in California over the last few weeks, just because it’s so top of mind for many of us. Particularly the Camp Fire, which I checked earlier today. We’re recording in late November and the numbers that I saw suggested that the Camp Fire had destroyed roughly 13,000 homes. Over 80 people had been confirmed killed in the fire and potentially more coming in the future. So this has been an enormous tragedy and what I’m hoping you can do, just to get us started, is to maybe put this fire and this fire season in some perspective for me (who’s not an expert) and for our listeners—some historical context both in terms of the geographic scale of the fire. So, the physical size of these fires, as well as the human impact, things like fatalities and property destroyed.
Matthew Wibbenmeyer: Yeah, so, I think it’s important to note that the fires that we’ve seen in the last three years, including the Camp Fire in California, are part of a much longer-standing trend in wildfire activity over the past 30 or 40 years across the western United States.
So, over that period, there’s been an increase in area burned by large wildfires and the number of large wildfires. The area burned by large wildfires has increased by about 1,200 percent over that time.
Daniel Raimi: Over the last 30, 40 years?
Matthew Wibbenmeyer: Yeah, exactly. And the number of large wildfires has increased by about 500 percent. So this is a long-standing trend—but even accounting for that, what California has seen in the last few years has been outside the norm.
And that’s outside the norms in terms of structure losses, fatalities, area burned. These fires have set records in all of those categories.
You can think of the Thomas Fire, which was California’s largest fire ever, surpassed within a year by the Mendocino Complex Fire. The Camp Fire, last I saw—88 fatalities—probably, unfortunately, that number will go up. That’s dramatically outside the norm. In the past, there have been wildfires that have caused fatalities. You can think of the Tunnel Fire in Oakland, in 1991, for example. There were 25 fatalities in that fire. But for the most part, historically, wildfires have not been too costly in terms of fatalities. Where there were fatalities, they were often firefighters that died. But it was pretty unusual for quote, unquote “civilians” to be killed in these events.
Daniel Raimi: Yeah.
Matthew Wibbenmeyer: But what we’re seeing now is with the speed that these fires are moving in some cases—that was the issue with the Camp Fire—it’s just too fast for people to get out of the way and evacuate.
Daniel Raimi: Right.
Matthew Wibbenmeyer: And, similarly, for structural losses, these fires have been record-setting in terms of structural losses. The Camp Fire—you said, what, 11,000 homes?
Daniel Raimi: 13,000 was the number that I saw.
Matthew Wibbenmeyer: 13,000 homes?
Daniel Raimi: Yeah.
Matthew Wibbenmeyer: Okay. And I saw 18,000 structures total. So that’s a pretty dramatic record, I believe, for number of structures destroyed.
Daniel Raimi: And you answered part of this question in your run-up to the answer to the previous question, but these wildfires have become much more destructive in terms of their human impact, both lives lost as well as property destroyed, particularly this year. But those other fires, you mentioned the Mendocino Complex and the Thomas Fires—are these wildfires having a greater impact on communities and property because of differences in their size? Or differences in their intensity or speed, which you mentioned a moment ago? Or differences in the—just simply the number of people exposed to these fires? People being out in the line of fire, if you will. Or is it some combination of all of these things? Or maybe this is, you know, something that’s too difficult to tease out at this point.
Matthew Wibbenmeyer: I think it’s some combination of all of those things, and what factor is important depends on the specific impact that you’re looking at. So in the case of fatalities, the speed that these fires are moving is really the important thing.
When fires are moving across the landscape at a slower speed, generally people can get out of the way and fatalities are avoided. In terms of structures destroyed, intensity is more important. So when fires are burning with greater intensity, greater heat, it’s harder for fire managers to come in and prevent their spread. And speed is important there too. In terms of impacts on air quality or impacts on watersheds, area burned is really important in those cases. Particularly when fires are burning with high intensity and burning through a high percentage of the vegetation in an area. So in those cases, when the fire is burning a large area, it’s putting more smoke into the atmosphere, it’s harming a greater portion of the watershed’s landscape.
Daniel Raimi: Okay, so we’ve got some context in place and I think some background in place as to what’s going on here. Let’s talk a little bit about the contributing factors to these fires and to the Camp Fire in particular. Or, you can talk as much about the Camp Fire or other fires as you’d like. President Trump has cited poor forest management as the primary reason for these recent wildfires. Can you talk a little bit about what types of forest management are or aren't done in California and the United States, and what role forest management generally plays in terms of managing wildfire?
Matthew Wibbenmeyer: Yeah, so first, I think it’s important to say that forest management is only important for determining outcomes on wildfires in forests. And wildfires don’t only take place on forest land, they take place in other types of vegetation as well.
The primary concern with forest management is build-up of fuels over time. And this is particularly a concern in particular kinds of western forest types. So these are dry western forests, like Ponderosa pine forests, mixed conifer forests, those types of forests. And historically in those forest types, you had sort of a mix of old growth forests and younger forests, and there were more areas where older trees were quite spaced out with sort of park-like settings, with older trees and not very much fuel on the forest floor. Now, due in part to 100 years of wildfire suppression throughout the western US and, in part (in some cases), to logging practices—clear cut logging—now you have areas where forests are very homogeneous and crowded with fuels. And so in these places, when fire starts, it spreads very quickly through these forests dense with fuels. And it also spreads up into the forest canopy. When these fires burn into the forest canopy, they burn with very high heat, and so they become much harder to control.
Daniel Raimi: Right.
Matthew Wibbenmeyer: So there’s definitely room in some places for forest management to improve some of those conditions, and that’s something that forest managers think about. So one of the tools is what are called fuel treatments, and these would be prescribed burns.
Under favorable conditions, forest managers will come in and set fires, control their spread and use those fires to try to restore forest conditions so that when a fire does occur, it’ll burn with lower intensity and it will be easier to control.
Daniel Raimi: So you mentioned 100 years of wildfire suppression and how that may have contributed to the build-up of fuel on the forest floor. Can you talk a little bit about the decisions made either by public policymakers or maybe private landowners on these types of wildfire suppression techniques over the last 100 years? And sort of how they made those decisions, why they made those decisions, and how it’s contributed to the issue today.
Matthew Wibbenmeyer: Yeah, so since the beginning of the twentiethth century, sort of led by the US Forest Service, we’ve viewed fire as a bad thing, a thing to control. You can think about Smokey the Bear here: “only you can prevent forest fires.” Fires were viewed as a negative, hazardous phenomena. And we didn’t fully appreciate the ecological role that fire played and the consequences to the landscape of just excluding fire.
Daniel Raimi: Right.
Matthew Wibbenmeyer: And so what’s happened as we’ve excluded fire is, as I mentioned, these forests have become just dense and crowded with fuels. And so it turns out it’s pretty impossible to exclude fire completely from the landscape—and so now when these inevitable ignitions do occur, in part because of forest conditions, they’re becoming much more dangerous and harder to control.
Daniel Raimi: Right. So we’ve talked a little bit about forest management, but my hunch is that forest management is not the full story here. So what about the role of climate change? How might climate change be affecting these wildfires that we’re seeing today and maybe even over the next couple of decades?
Matthew Wibbenmeyer: Yeah, so climate is a really important driver of these really extreme fires that we’ve seen in California, especially in the last three years. As I mentioned, forest management is really only a factor [...]can really only be a factor in forests—and some of these fires in California are not just taking place in forests.
Daniel Raimi: Right.
Matthew Wibbenmeyer: They’re taking place in southern California shrub lands, chaparral, etcetera—or even on grasslands. One study found that area burned beginning in 1984 to 2015 nearly doubled specifically due to anthropogenic climate change. So climate has been a really important driver of this increase in wildfire conditions.
Daniel Raimi: Okay.
Matthew Wibbenmeyer: There are a couple of explanations. So one important explanation is just the lengthening of the fire season. We’re getting earlier springs that lead to fuels drying out by the heart of the fire season. Fuels are warmer since snow melt has melted away earlier. Also, fire seasons are running into later in the fall or even the winter in some cases. The Thomas Fire last year in southern California was in December. And so with these fire seasons, especially in California, stretching into the late fall or winter, now they’re coinciding with the Santa Ana wind seasons, where winds blow from inland toward the ocean, which has really led to some of these devastating and fast-moving fires.
Daniel Raimi: Are the timing of those winds pretty consistent on an annual basis? Are they affected by climate change or is it just the length of the fire season itself that’s affected?
Matthew Wibbenmeyer: Yeah, so that’s a good question. I’m not totally sure. I think they tend to take place between sort of mid to late fall.
Daniel Raimi: All right, so those are two important factors that have contributed to the magnitude of the fire, the intensity of the fire, and the human impacts. But when we think about human impacts, we also have to think about the growth of human development into more rural areas, maybe more wooded areas. Can you talk a little bit about the role that human development has played in increasing the risk that people might face from these fires?
Matthew Wibbenmeyer: Any time there’s damage from a wildfire event, it really generally happens because people are in places where hazard exists. There’s a famous quote by a man named Gilbert White who is known as the father of floodplain management. And it goes, “floods are acts of God, but flood losses are largely acts of man.”
So any time there are consequences of a hazard event, it’s because people have, for whatever reason, placed themselves in a hazardous situation. In the case of wildfire, most of the losses to wildfire take place in what we call the wildland-urban interface. And these are areas where there is vegetation and where there is human development. And these are the places where most of the losses in wildfire events take place. One study found that 69 percent of structural losses in fires takes place in this—what people refer to as the WUI—the wildland-urban interface.
In general, the WUI, the wildland-urban interface, is growing, has been growing over time as more people sort of push away from urban centers and into some of these wilder places where there’s vegetation. So between 1990 and 2010, there’s been about a 40 percent increase in the number of houses in the wildland-urban Interface in the US. And even despite that growth, only 14 percent of potentially developed area in the WUI has yet been developed.
So there’s still quite a bit of room for growth there. As people move into these areas, there’s more potential for damages, and there’s also actually more potential for fire. Nationwide, the majority of wildfires are human caused, and so as more people live in these areas, we tend to see more ignitions and more potential for some of these events.
Daniel Raimi: Right, so sort of compounding the risk?
Matthew Wibbenmeyer: Yeah, but I would say that the growth of the wildland-urban interface has been sort of steady over time. And what we’ve seen in the last three years in California was a really dramatic change in the losses due to these wildfire events. And so I think, given the dramatic spike in those losses, it’s probably better attributed to climatic factors rather than growth in risk exposure over time.
Daniel Raimi: Right. And so it sounds like—of the three main contributing factors that we talked about, forest management, climate change, and human development—climate change is the largest contributing factor, you would say?
Matthew Wibbenmeyer: I would say, yeah.
Daniel Raimi: Yeah. Okay, I wish I had known that you were going to use the acronym WUI, I would have asked you about human development early on so we could say WUI more often in our conversation.
So, we’ve talked a little bit about contributing factors to these fires and their impacts. Let’s think a little bit now about potential ways that communities and policymakers can manage some of these risks going forward. Can you talk a little bit about what some of the more cost-effective strategies might be in minimizing risks to human property and, of course, human lives? And I imagine there’s a really difficult calculation that you would need to make to try to figure out what is the right combination of spending that you would want to do on forest management, compared with climate change mitigation, compared with community planning. Particularly since climate change is a global problem that can’t simply be solved by the actions of one county or even one state.
Matthew Wibbenmeyer: I think all of those three areas you mentioned are important. Climate change mitigation has many other benefits, but it will not directly or very quickly address wildfire hazard.
Daniel Raimi: Right.
Matthew Wibbenmeyer: So it might be worth pursuing in its own right but, in terms of quickly reducing wildfire risk, is not the most direct path. Forest restoration as well is very important in some cases, as I mentioned, in some places, particularly these dry western forests that are very different now than they have been. And so conditions for fire are quite different. The challenge with forest restoration is that so much of the western United States and these forest types are in need of restoration. So this is a really large-scale problem, and right now federal budgets on this federal forest land are just not at the level that would be needed to address this issue in those forests. So in order to really tackle broad-scale forest restoration, what would be needed is either to expand those budgets or to come up with profitable ways for the private sector to get involved. And so logging has been suggested in some cases. I think there are forms of that that can be helpful. Generally, the science indicates that conventional logging practices—clear cut logging, intensive plantation style logging—are not beneficial for reducing wildfire risk, as intuitive as it might seem.
Actually, logging in some cases can increase wildfire risk. So what’s needed is forest management, or forest restoration strategies, that are particularly aimed at reducing fuel loads in the forest. So clearing out some of the small diameter timber that’s fueling some of these high-intensity fires.
Daniel Raimi: How feasible is that at scale with the resources that are available? Is, you know, applying those management techniques to large areas of land in central or northern California, say, is that something that is realistic with existing federal budget constraints?
Matthew Wibbenmeyer: So, I think it hasn’t been yet, but in the future, some kind of economically viable forest restoration strategy would have to be the approach to get this done at a large scale.
Daniel Raimi: So bringing in the private sector?
Matthew Wibbenmeyer: Yeah.
Daniel Raimi: So the last question I want to ask about implications and potential policy issues going forward is: Of these three issues, as someone who works on energy and climate change, it’s fairly easy for me to imagine what types of climate policy levers we might choose to deal with climate change. We’ve talked a little bit about what policy measures we might use to deal with forest management issues. We haven’t talked about what policy levers might be available to mitigate risk for communities in fire-prone regions. Could you talk about those a little bit?
Matthew Wibbenmeyer: Yeah, so community planning is another important area, and probably the most direct way that communities can reduce risk from wildfires in the short term. This is making sure that communities are laid out in ways that minimize wildfire risk, so that homes are located in locations across the landscape and relative to one another in ways that minimize risk. And making sure that homes are built in ways that minimize wildfire risk. So that roofs and siding are fire resistant and that homeowners have done things like clear brush away from their home and other vegetation. And that they’ve secured their home so that embers can’t fly in under the roof eaves and those sorts of things.
That can be encouraged through planning laws, building codes, things like that. One of the challenges, though, is—in terms of making sure people are choosing to live in locations where wildfire risk is low—is that people tend to actually like to live in these places where wildfire risk is high. They like living in mountainous areas, they like living amongst trees with vegetation nearby and shade. And these are exactly the things in these fire-prone regions that create wildfire risk. And so really what’s needed is incentives for homeowners and communities to specifically do these things that minimize wildfire risk. To maybe not live in such hazardous locations, and to plan their communities in ways that will reduce hazards.
Daniel Raimi: All right, well that all makes sense. And we’re going to close it out today as we always do with our guests, by asking you about what is at the top of your metaphorical reading stack. Or perhaps your literal reading stack. So, Matt, what have you read or watched or heard recently related to energy and the environment that you think is really interesting and that you’d recommend to our listeners?
Matthew Wibbenmeyer: Something came across my Twitter feed this morning, which is not super recent, but I found it really interesting. So Wired magazine had a write-up of some research that’s come out of the Forest Service in the past few years, focusing on the health benefits of forests. One of the ecosystem services forests provide is they help clean the air and remove pollutants from the atmosphere. So this is something that we know about forests, but it’s a little bit hard to estimate what are the [...] what are precisely the benefits that forests provide in terms of this. So what these Forest Service researchers did was they used large-scale tree diebacks due to pests. And after these large-scale tree diebacks, they were able to link changes in atmospheric pollution to these diebacks, and then link that to health consequences.
What they were able to find is that, in one study, counties with emerald ash borer (which is a tree pest) had an additional 6.8 deaths per year due to respiratory disease. An additional 17 deaths due to cardiovascular disease. So I just thought this was a really interesting way of using some of these changes in forests to actually look at what are the benefits that these forests do provide in terms of health.
Daniel Raimi: Yeah, that’s fascinating. Can you tell us who the authors were or what the source of the Wired article is so people can go find it?
Matthew Wibbenmeyer: The study I just mentioned about emerald ash borer, that was a study by Geoff Donovan. Another Forest Service author writing in this area is Greg McPherson.
Daniel Raimi: Great. So people can go check out those studies and see the effects for themselves. Fantastic. Matt Wibbenmeyer, thank you so much for joining us today on Resources Radio—I’ve really enjoyed the discussion.
Matthew Wibbenmeyer: Thanks Daniel.
Daniel Raimi: Thank you so much for joining us on Resources Radio. We’d love to hear what you think, so please rate us on iTunes or leave us a review—it helps us spread the word. Also, feel free to send us your suggestions for future episodes.
Resources Radio is a podcast from Resources for the Future. RFF is an independent, nonprofit research institution in Washington, DC. Our mission is to improve environmental, energy, and natural resource decisions through impartial economic research and policy engagement. Learn more about us at rff.org.
The views expressed on this podcast are solely those of the participants. They do not necessarily represent the views of Resources for the Future, which does not take institutional positions on public policies. Resources Radio is produced by Kate Petersen, with music by Daniel Raimi. Join us next week for another episode.