Resurgence of Smokey Bear in the (Smoky) Air?: Higuera et al 2023

Les Joslin’s story last Saturday about Smokey Bear signage reminded me of Nagy et al. ‘s paper, which I wrote about on TSW here on Monday.  There must be something in the atmosphere, because today Nick Smith had a link to an article on this Higuera et al. paper in his newsletter today.

Here’s the story in the Bozeman Chronicle. A few interesting points..

A new study shows that structure loss from wildfires rose nearly 250% across the Western United States over the last decade and 76% of wildfires that burned homes and other structures were human caused.
Just under 80% of the structures that burned in wildfires between 2010 and 2020 were located in California. While that state dominated the trend, the number of structures lost to wildfires increased overall in every Western state, apart from New Mexico.
When it comes to policy solutions, Higuera sees several. First, people can re-emphasize the “Smokey the Bear” message, particularly later in the fire season. Second, they can consider large-scale changes in how, where and whether they build. (my bold)
While solutions may differ from region to region, they could involve rethinking “how power gets transmitted across the landscape” and the affordable housing crisis, which is part of what’s leading to development in flammable vegetation, according to Higuera.

Here are the conclusions from the paper (open access, hurray!). I tried to remove all the page numbers but may not have been entirely successful.

Our study reveals key drivers of the wildfire crisis in the West, and therefore when, where, and which “levers” can be pulled to reduce the chances of future fire disasters. We focused on  structure loss as an acute negative impact of wildfires, highlighting a significant increase in structures destroyed by wildfires, by over 3x between 1999-2009 and 2010-2020 (Fig. 2B).  Critically, we also show that wildfires have become more destructive, with the number of 19 structures destroyed per 1000 ha burned increasing, by 160% between the last two decades (Fig. 20 2C). This West-wide pattern was dominated by California and from events in just three recent  years (2017, 2018, 2020), but nearly every Western state exhibited higher structure loss rates over the second decade of the 21st century (Fig. 4I, S4).

Increased loss rates indicate that wildfire-related structure loss did not increase simply due to  more area burning. Likewise, although our analysis did not resolve structure exposure to  individual wildfires, we estimate that the proportion of structures destroyed by wildfire outpaced  higher structure abundance in flammable vegetation alone (Table S1). The causes of increased  structure loss thus reflect complex human-environment interactions, not “either” more area burning “or” increased development, but both, and more. When and where human-related ignitions occur, how many structures are built among flammable vegetation, and how climate 30 and land use affect fuel abundance and fuel aridity over timescales of days to decades are all interacting to drive trends in structure loss.

Recognizing the complex drivers of fire disasters has important implications for mitigation and adaptation. For example, efforts to reduce structure loss must look beyond simply limiting area burned generically. In fact, across the West 88% of wildfires, accounting for 45% of the total area burned, had no associated structure loss (Fig. 1A). While not explicitly assessed here, much of this burning is not a crisis per se and can provide resource benefits (41–44). The wildfire crisis generally and structure loss specifically are largely driven by extreme events, highlighted clearly in recent years (Fig. 1B). The overwhelming majority of wildfires that result in structure loss are started by human-related ignitions, and they are occurring in regions with increasingly high structure density within flammable vegetation (21; Fig. 4J). Consequently, the number of  structures destroyed by wildfire in the West in any single year was well explained by the total  area burned from human-related ignitions; and, total structure loss in a state over the past two decades was well explained by the number of structures in flammable vegetation (Fig. 5). Both  elements have increased between the past two decades – area burned from human-related ignitions by 51%, and structure density by 39% (Fig. 4) – and are leading contributors to increased structure loss rates.

While numerous studies highlight increased fuel aridity from anthropogenic climate change as a  key enabler of rising wildfire activity in the West (6, 14–17), in parallel to these changes we have shown that human factors operating over shorter time scales are increasingly contributing to  wildfire disasters. The consequences of human-related ignitions, specifically when and where  fuel aridity is high and lightning ignitions are rare, are becoming magnified in the context of  climate change. Therefore, efforts to reduce human-related ignitions will be increasingly  important beyond historical lightning-caused fire seasons, for example in spring, fall, and even  winter months (Fig. 3F, S5).

(my bold, and I would add based on experience in my part of the country “the ability of fire departments to jump on them quickly when they do occur.”)

The patterns highlighted here varied widely across the West, emphasizing the importance of understanding spatial and temporal characteristics of wildfires – fire regimes – as integrated social-ecological phenomena (29, 30, 45). Mitigating anthropogenic climate change, given its impacts on fuel aridity (14, 6, 19), is a clear overarching necessity for addressing the wildfire  crisis. At smaller scales of individual states, policymakers and managers may benefit from emphasizing other aspects driving increased structure loss, including structure expansion into  flammable vegetation, increased ignition from human-related sources, or in states with below- average structure loss, reducing the chances of lighting-ignited fires spreading into developed  areas (32, 43). Mitigation and adaptation approaches in predominantly rural states, like  Wyoming, Montana, and Idaho, may look different than in more densely populated states, like  California, Colorado, and Washington. Additionally, states with low structure loss rates may  look to those with high structures loss as harbingers of future change, and ideally glean ways to avoid similar outcomes as structure expansion and densification trends continue. Two clear  implications emerge from this and other recent work (20, 21, 32, 33) to help prevent wildfires from becoming disasters: reduce unintentional human-related ignitions, particularly near homes  and during periods of extreme fire danger; and carefully consider if and how structures are built, including building with fire-resistant materials, minimizing flammable vegetation near structures, and providing mechanisms to do so equitably across socioeconomic conditions.


I think most of us would agree , as the authors say, that the entire wildfire problem or issue is partially social (as is pretty much everything)  in nature.  So my questions are:

1. Where is the social science around these human factors and what interventions work to change them?

Unplanned ignitions from human sources – ereafter “human-related ignitions” – include backyard burning, downed power lines, escaped campfires, etc., and are a well-recognized component of contemporary fire activity across the
United States (22, 23)

After all, there is a great deal of good literature on attitudes toward prescribed burning and fuel treatments.  But maybe I’m not aware of the literature on strategies to reduce human-caused ignitions.

2. If there is none, why not?

Is it because it’s unstudiable for various reasons (under the litigation cone of silence?), or because there aren’t enough social scientists around, or because it’s not popular with granting agencies, or ???

12 thoughts on “Resurgence of Smokey Bear in the (Smoky) Air?: Higuera et al 2023”

  1. The idea of hoping for a ‘natural ignition’ which stays ‘natural and beneficial’ in a crowded forest seems highly unlikely. Additionally, the idea that (commercial) thinning projects dry out forests (in the Sierra Nevada) is almost always wrong. Those forests get bone-dry every year. They cannot get any drier, fuels-wise. Thinning DOES make more precious water available for the remaining dominant ‘leave trees’, purposely left by the Forest Service.

    • This is even more prevalent in the Klamath. Recent droughts and “winters” have left a wide swath of tree mortality, especially above 5,000 feet, both observationally and via USFS aerial recon flights/data recently released.

      I wish people would acknowledge that the forests were we, humans, screwed around for the previous century, and then abruptly walked away from, need treatments. They are not natural, despite what anyone says or thinks; I also wish certain parties would stop trying to go into the areas to harvest or “thin” where we have not mucked around. The latter just looks bad all around, and doesn’t do much good beyond making dollars, and, well, good 2x4s.
      There’s nothing wrong with good solid wood products for use, opposed to pillaging the world for aggregates/gravel resources that do not regrow, but doing such can’t be done with a cavalier attitude, as some Region 5 National Forests have found (let’s ignore what happens on private timberland for now).

      As to structure loss, 1) embers and flames come from SOMEWHERE, despite what many think, and 2) homes in the WUI do need to be reinforced against embers. But if the 2018 Camp Fire is used one more time as an example by other side for their agenda, I’m about willing to scream and rip a head off. Paradise should never, ever be used as an example. That said, it is a good data point in this paper, which is very well done.

  2. Rural Electrification Act. Patented mining claims fee simple private property inholdings. Railroad Grant checkerboard private-public-private land patterns in West.

    1930s utility rights of way across treeless land 90 years later.. Trees are planted outside narrow rights of way and easements. Trees always grow to light from either side of R/W, thus heavy “lean” towards treeless area. Interminable process litigation delays fuel and tree removals. So many never mentioned conditions to exacerbate ignition sources. “Day late and a dollar short” rules the day.

  3. The clear assumption or corollary is that we should not be spending resources “treating” areas that are not likely to reduce structure ignitions for ecological benefits: “In fact, across the West 88% of wildfires, accounting for 45% of the total area burned, had no associated structure loss (Fig. 1A). While not explicitly assessed here, much of this burning is not a crisis per se and can provide resource benefits.”

    • Of course, there ARE other reasons for doing thinning projects, other than for fire safety. *eyeroll*

      Good luck getting the Forest Service or Congress to even consider limiting thinning projects to the WUI. Same old tired tactics.

    • Jon, there are many other reasons for treating acres… so that forests will be resilient in the case of fires and not become grass fields (not that grasses are bad, but forests provide habitat for different critters).. so that watersheds won’t be devegetated and cause flooding and further erosion, so that old tree habitat will be protected, and so on.

      PODs are designed so that suppression folks can control fires before they do various kinds of damage.
      The same sentence you quote could be read to mean.. “fire suppression thus far has been remarkably successful keeping fires away from structures.
      Also some of those acres were probably for resource benefit, it would have been handy to separate those out.

      • There are many other reasons for treating acres, but which ones are a higher priority than preventing structure ignitions? How would you feel If you lived in an area that is a high fire risk and the Forest Service is off doing backcountry treatments to protect old trees instead of in your back yard to protect you? (This would be a different discussion if we had the resources to do “all of the above.”)

        • PODs help suppression folks manage fires.
          Suppression tactics and strategies consider different values including property, entire communities, species, etc.
          I don’t think it’s either/or.
          Also, in my country it would be hard to find a project that isn’t close to some kind of property. Mostly the State Fire action planning, community needs and project development are in alignment. Is this not true where you live?

          • You posited other reasons besides structure protection. I don’t know how much is actually being done for such reasons.

            • Here’s a sample size of one, randomly selected from the San Juan. This is from a scoping letter.

              Fuels and Vegetation Treatment
              Fuels treatments such as mowing, mastication, chipping, and hand thinning are being proposed on up to 2,500 acres in the Jackson Mountain area. The purpose of the treatments would be to reduce the density of shrubs and small trees that act as ladder fuels which can transition a fire from the forest surface to the crowns of trees. Fuels treatments will also give fire managers more opportunities to safely manage fires in the area. Fuels adjacent to open roads and private land would be targeted to create buffers to allow for increased control options and public and firefighter safety in the event of a wildfire. This would have the additional benefit of increasing site distances for vehicles on highly trafficked roads. Slash from thinning operations may be piled, dispersed, or chipped and the boles of trees may be available to the public for fuelwood.

              Vegetation treatments such as thinning in pine and mixed conifer stands as well as aspen coppice treatments to promote aspen regeneration are being considered on up to 1,000 acres. These treatments would be designed to build upon work that has been completed or is in progress. Objectives of vegetation treatments will vary depending on location but in general including the following: 1) provide a variety of vegetation conditions to support habitat diversity, 2) continue to manage Forest Service lands to provide forest products to local communities, 3) continue to provide conditions where fire can be part of the landscape and 4) provide conditions that help facilitate using prescribed fire as a management tool.


          • Doesn’t your San Juan example make my point for me? The objectives say nothing about structure protection; have they got all the structures protected?

        • The USFS is ‘fully funded’ for the next few years. I’ve seen where they have thinned close to communities, recently. On most timber-producing Ranger Districts, they have already logged those areas close to towns. Those areas aren’t mature enough to “log”. Other methods could be used, in those situations.

          Speculating on what is currently happening with the extra money is useless, until we get a ‘State of Our Forests’ report, touting their triumphs in managing our forests *smirk*

          I tend to think that the USFS tries really hard to keep their troubles out of the public eye.


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