Posts Tagged: Lenya Quinn-Davidson
During periods of "extreme fire conditions," PG&E will shut off electric power lines to prevent wildfires, reported Dale Kasler in the Sacramento Bee.
The reporter spoke to Lenya Quinn-Davidson, UC Cooperative Extension area fire advisor in Northern California, about the utility's proposed actions. She said PG&E will have to give communities plenty of advance warning before turning off power so residents aren't left without a means of receiving emergency information.
"They're going to have to do a lot of good community outreach so people will be prepared," she said. Still, she called it "a reasonable short-term solution while they're figuring out other things" to reduce fire risks.
Reposted from the Fire Adapted Communities Learning Network blog
I was nine years old when my dad's family home burned in the Oakland Hills Fire. As a country kid from one of the most fire-prone counties in northern California, I was no stranger to wildfire. Still, I remember the shock of driving through his childhood neighborhood in the weeks after the fire, seeing nothing but the skeletal remains of vehicles and homes — so different than the forest fires that I was used to back in Trinity County.
Those images came back to me a few weeks ago when I gave a presentation at a workshop in Redwood Valley, California. That community, which is in Mendocino County, suffered a devastating wildfire in October, during the same week that fires were burning throughout Sonoma and Napa counties. During the Redwood Valley Fire, nine people were killed and more than 500 structures were destroyed. Now more fires are burning in southern California, and in some ways, it seems that the human connection — the loss of lives, the loss of homes — is the defining feature of this year's fire season in California.
One of my close colleagues at the University of California Cooperative Extension, Yana Valachovic, has no doubt felt the human implications of the 2017 fire season. Her phone has been ringing off the hook for months because of her expertise and experience in home ignitions and home survival: concepts that people are desperate to understand and implement in light of the ongoing losses throughout the state.
In some ways, the research on home survival during wildfire is intuitive; most people understand defensible space concepts and the basics of fuels management. But there are so many ways that most of us could do better — ways that are well illustrated by my own friends, colleagues and family.
Yana talks about how even she — someone who studies this topic — stores paper bags full of her kids' old schoolwork in her attic, right next to the vents. And if you read the literature on this topic, you know that vents represent a major vulnerability during wildfire. Most homes burn from the inside out, meaning that embers make their way into the home through vents and other crevices, and they then ignite fuels inside the house. Once embers infiltrate, it's hard to slow them down — hence the photos we often see of blackened homes surrounded by green trees and intact neighborhoods.
Current research supports the use of finer mesh vent screens (typically a second screen behind the outer screen), and/or temporary vent covers during wildfire events. There is an impressive amount of information available on home venting and fire, including the desired fineness of screen meshes, the use of ridge vents and the appropriateness of unvented attics (PDF, 213 MB). Much of this work comes from the Insurance Institute for Business and Home Safety (IBHS). Steve Quarles leads IBHS's fire-related research program and has published a number of papers on this topic, including a new report, Vulnerability of Vents to Wind-Blown Embers.
Homes can also burn from the outside in, thanks again, in large part, to embers. A few years ago, when a wildfire came within a half mile of my mom's house, I found her gutters packed with dry leaves. This is a classic problem, and one that I was surprised to see at my own mom's house. How did we let the gutters fill up like that, knowing what we know? Gutters full of debris, if ignited, will provide direct flame and ignition to the edge of the roof; if the roof is not adequately protected by metal flashing, or if the gutter is below the roof edge exposing the vulnerable roof sheathing, it can be difficult to keep fire from spreading from the gutter into the house. In 2010, when Quarles was with University of California, he co-authored a great publication that discusses rain gutters, vents, roofing, decks and other home vulnerabilities (PDF, 4.87 MB).
There is also a fair amount of research on features adjacent or attached to the home — features like decks, fences and landscaping (PDF, 416 KB). Still, on a recent trip to a research station in southwest Georgia (a place known for its fire science research and active fire management), I was surprised to see that the landscaping around every building had a thick mulching of longleaf pine needles — literally one of the most flammable types of leaf litter in the world. It looked great but wouldn't be particularly helpful if a fire came through. And IBHS wildfire demonstrations, like this one from 2011, have shown that mulches and other near-home landscaping can become serious points of weakness during wildfire. (I highly recommend checking out their video demonstrations if you haven't before; they have a lab where they actually burn down full-sized homes.)
Now I know that this information is likely old news to many of you; I hesitated to write about this topic because our readership is probably fairly fluent in the research on home ignitions and survival. But the images of Yana's attic full of well-cured paper, my mom's gutters full of leaves, and the pine needle mulch at the research station in Georgia reminded me that we all have more we can do — even if we're well-versed in how homes burn. Home hardening is, of course, only one facet of fire adaptation, but this year's fires reinforced the importance of all efforts at all scales, from the vent and the gutters to the community wildfire protection plan and the prescribed burn.
Reposted from the Fire Adapted Community Learning Network blog
For many years, we at the University of California Cooperative Extension (UCCE) have fielded questions from landowners about using fire as a tool. Ranchers and forestland owners in Humboldt County have voiced interest in using fire to improve range resources, enhance wildlife habitat, reduce fuels, and beat back the trees and shrubs that are quickly engulfing their prairies and woodlands, but we have struggled to provide them with good options.
In recent history, CAL FIRE led the majority of burns on private lands in California. In the 1980s, their Vegetation Management Program (VMP) was responsible for 30,000–65,000 acres of controlled burning every year. In recent decades, however, those numbers have consistently fallen short of 10,000 acres a year — a drop in the bucket given the habitat and fuels issues that we face in California. CAL FIRE is currently revamping and reinvesting in the VMP, which is great news, but it's clear that other pathways are needed for landowners to reclaim fire as the important tool that it is. Last year, UCCE started looking into prescribed fire models from other parts of the country. We know that other regions have impressive burn programs that blow California out of the water, and in most of those places, they've been successful because landowners are doing the burning themselves — something that's almost unheard of in California.
Over the last year, we worked with private landowners in Humboldt County to plan and implement burns. In June, we burned a 19-acre grass unit on a ranch in eastern Humboldt County, treating a patch of invasive medusahead. This Halloween, we burned 140 acres of coastal rangeland invaded by shrubs and trees. For both of these burns, we hired a qualified burn boss to write the burn plan and direct the burn, but we staffed the burns entirely with volunteers, including volunteer fire department members, landowners, and other interested community members. This model of burning — where the landowners take the lead — is truly an exciting and novel development in California, and I believe it is the critical ingredient to burning at a meaningful scale.
Reposted from the Fire Adapted Community Learning Network Blog
I'm sure many of you are familiar with the kids' book “Going on a Bear Hunt.” The family in the book is on an adventure that takes them through rough terrain: a swirling, whirling snowstorm; a deep, dark forest; thick, oozy mud; long, wavy grass; and a narrow, gloomy cave. For readers, the suspense builds toward the cave, where a bear awaits in the darkness. But as someone who's done a lot of fieldwork, it's actually the long, wavy grass that makes my skin crawl. What about ticks?!
On Sunday, my son and I made a site visit to a nearby burn unit. As I talked with the property manager about the burn, my toddler ran through the tall grass happily yelling “swishy swashy, swishy swashy” (a line from the book), and it got me thinking — not only about ticks, but about the interactions between ticks and prescribed fire. Ticks have been getting a fair amount of attention in the media lately, and many of the stories are saying that 2017 is going to be a particularly bad year for ticks and tick-borne illnesses. And it's not just Lyme disease that people are concerned about; ticks can cause other health complications, including an allergy to meat products (one of my favorite fire scientists actually has this!). Given the emergence of these novel complications, and the increasing incidence of tick-related diseases in general, it seems more important than ever to understand and explore the various tools we have for reducing tick populations.
To me, it seems intuitive that prescribed fire would be an effective way to impact tick populations. (Have you ever put a tick on top of a woodstove? Toasted ticks don't fare too well!) But there are ecological interactions that can complicate the effectiveness of prescribed fire for tick reduction, and treatment and study design can also have a strong influence on these types of research projects. Thus, it is no surprise that results regarding the relationship between ticks and prescribed fire have been quite variable over the years.
Most studies agree that tick populations are reduced immediately after a prescribed burn. For example, a paper by Stafford et al. (1998) showed that two spring burns in Connecticut reduced nymphal abundance of the blacklegged tick (which causes Lyme disease) by 74 and 97 percent in units with moderate and severe fire effects, respectively. However, by fall of that same year, the abundance of adult blacklegged ticks was no different in the burned areas than in the controls. Similarly, prescribed burning in tallgrass prairies in Kansas significantly reduced the abundance of the lone star tick (which is responsible for the meat allergy issue I referenced above, in addition to other diseases). However, this decline was only during the year of the burn, with no effect in units burned on longer intervals (Cully 1999). These and other papers (e.g., Drew et al. 1985) make it clear that prescribed fire affects tick populations, but results are strongly correlated with the time since burn and with the severity of the burn.
Other research demonstrates the importance of larger ecological interactions in determining post-fire tick populations. A study by Allan (2009), which took place in oak-hickory forests in the Missouri Ozarks, found that only two years after a burn, tick densities were six times higher in burned areas than in controls. In that study, improved forage in the burned areas caused disproportionate usage by white-tailed deer, which are an important carrier of the lone star tick and likely reintroduced them in high numbers to the recently burned areas.
As a whole, these studies don't offer much clarity on the utility of prescribed fire for reducing tick populations — the results are so variable! But a more recent paper in PLOS ONE (Gleim et al. 2014) helps navigate and explain some of the scientific tensions in this collective body of work, and offers a more encouraging and comprehensive perspective on prescribed fire and ticks.
In this study, the authors focused on long-term prescribed burning programs in Georgia and Florida, and they accounted for a number of site conditions, including the burn regimes surrounding each study area. The study included 21 different sites across the region and involved monthly tick sampling, trail camera monitoring of tick hosts, weather measurements and vegetation surveys. In these ways, it is one of the most robust studies of tick-fire interactions to date. And the results are encouraging!
Gleim and her colleagues found that ticks were much more prevalent in unburned controls, and their modeling efforts showed that total tick counts were related to a number of variables, including the long-term use of burning, season, litter cover and tree density (2014). Of particular note is their finding that adjacent burn regimes (burned or unburned) had a significant effect on post-burn tick populations, both in numbers and species. This may explain some of the variance in past studies, and it highlights the importance of considering the larger landscape management context and the importance of edge effects when assessing the effectiveness of prescribed fire projects. We know this to be true in the invasive plant context (e.g., Berleman et al. 2016), but it also appears to be true for ticks.
But perhaps the most important finding in Gleim et al. is that the effective control of tick populations depends on the long-term use of prescribed fire. I appreciate this point because all too often, studies are based on a single prescribed fire treatment, even though we know that in many cases, it is the fire regime — and not just the individual burn — that we are trying to understand through our research.
In any case, I've decided that the unit my son and I visited on Sunday probably wouldn't be a great candidate for a tick-focused burn. It's only about three acres in size, probably hasn't been burned in 100 years and is surrounded by fields of tall grass. (Luckily, tick reduction is not the goal of that burn.) However, I think there is potential for a great new kids' book: “Going on a Tick Hunt,” complete with a section on the long-term benefits of prescribed fire!
Allan, B. F. (2009). Influence of Prescribed Burns on the Abundance of Amblyomma americanum (Acari: Ixodidae) in the Missouri Ozarks. Journal of Medical Entomology, 46(5), 1030-1036.
Berleman, S. A., K. N. Suding, D. L. Fry, J. W. Bartolome and S. L. Stephens (2016). Prescribed Fire Effects on Population Dynamics of an Annual Grassland. Rangeland Ecology and Management, 69(6), 423-429.
Cully Jr, J. F. (1999). Lone Star Tick Abundance, Fire and Bison Grazing in Tallgrass Prairie. Journal of Range Management, 139-144.
Drew, M. L., Samuel, W. M., Lukiwski, G. M., and Willman, J. N. (1985). An Evaluation of Burning for Control of Winter Ticks, Dermacentor albipictus, in Central Alberta. Journal of Wildlife Diseases, 21(3), 313-315.
Gleim, E. R., Conner, L. M., Berghaus, R. D., Levin, M. L., Zemtsova, G. E., & Yabsley, M. J. (2014). The Phenology of Ticks and the Effects of Long-Term Prescribed Burning on Tick Population Dynamics in Southwestern Georgia and Northwestern Florida. PLOS ONE, 9(11), e112174.
Stafford III, K. C., Ward, J. S., & Magnarelli, L. A. (1998). Impact of Controlled Burns on the Abundance of Ixodes scapularis (Acari: Ixodidae). Journal of Medical Entomology, 35(4), 510-513.
Reposted with permission from the Fire Adapted Communities Learning Network
I recently found myself venting about the idea of “nature.” The concept has always bothered me. There's an inherent separatism in it—an implicit line in the sand between humans and nature, where we can and should appreciate it, but we think we aren't really part of it.
I struggle with these ideas often in my work. I've had people question the naturalness of frequently burned landscapes if they know that humans had a role in ignitions—even if human ignitions extend thousands of years into the past. The dichotomy runs deep.
So it's always refreshing to see
scientific reinforcement of what I know in my heart to be true: people are a part of the landscape—a very powerful part.
This is the theme of a recent paper by Alan Taylor, Valerie Trouet, Carl Skinner and Scott Stephens in the Proceedings of the National Academy of Sciences (PNAS). The paper looks at California's Sierra Nevada over the last 400 years, and it finds that socioecological change—human activity—has been the primary driver of changes in the region's fire regimes, more so even than climate.
The paper, which came out late last year, incorporates a unique blend of fire history and human history. The authors were able to reconstruct a 415-year fire record for the region using a combination of tree ring studies and 20th century data on annual area burned. From there, they calculated a “fire index” for every year since 1600—basically a metric that combines fire occurrence and extent, and tells us how much fire activity was going on during that time. Those indices were used to identify large-scale shifts in regional fire regimes, which the authors compared with patterns of human settlement and management, and with climate.
The authors identified four major fire regime periods since 1600, which they were able to link to patterns of human activity. The first regime shift occurred in 1776, triggering a 90-year period of enhanced fire activity. During that period, the mean fire index was almost twice what it had been before 1775. The paper shows that this regime shift was coincident with the timing of Native American contact with Spanish missionaries in the region, which occurred in 1769. It's not exactly intuitive, but the authors explain that the decimation of Native Americans—and a subsequent reduction in light burning—allowed for an increase in fuel continuity and wildfire activity during that period. This connection is further evidenced by the increased sensitivity of fire activity to climate—a relationship that was relatively weak when Native Americans were conducting widespread burning.
The second regime shift occurred in 1866, at which point fire activity dropped back to pre-1776 levels. The authors attribute this shift to major land use changes across the region—mostly associated with intensive livestock grazing, which denuded herbaceous vegetation and had notable effects on fuel continuity and fire spread. During this period, fire activity was also less sensitive to climate than it had been during the previous period because of a lack of fuels.
The third shift is the one we're all most familiar with: the beginning of the fire suppression era in the early 1900s. During the fire suppression period, in which we're still operating today, fire activity has been 4–8 times less than in any other period in recent history. Likewise, the fire-climate relationship has been weak for most of this period; the 20th century has shown increased warming trends, yet fire activity has largely been squelched by human activity. Only in recent decades have we seen a strengthening of that relationship, as a perfect storm of high fuel accumulations, longer fire seasons and drier conditions enables fires of unprecedented severity and size, appearing to override the moderating effects of human management.
My last statement should give us pause. Are we entering an era—perhaps a new fire regime period—where changes in climate are overwhelming our human capacity to influence our landscape? The work of Westerling and others (check out my first Science Tuesday blog from last February) would indicate that we're headed in that direction.
But the really valuable thing about this new paper by Taylor et al. is that it gives us a larger context to work within. Yes, recent decades have had increased fire activity and increased sensitivity to climate—we've all seen it. But let's remember that our collective frame of reference is relatively short; for most of us, our vision of what's natural or normal in terms of fire comes from the mid to late 20thcentury—the height of our fire disconnect. This paper allows us to look back and see that the human relationship to fire is enduring and powerful, and that our biggest mistake in the last century has been to deny ourselves that intimacy—to value “nature” over nurture. History tells us that we should be able to buffer climate effects, but only if we actively engage at a grand scale. I think we're ready.
Taylor, A. H., Trouet, V., Skinner, C. N., & Stephens, S. (2016). Socioecological transitions trigger fire regime shifts and modulate fire–climate interactions in the Sierra Nevada, USA, 1600–2015 CE. Proceedings of the National Academy of Sciences, 201609775.