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Posts Tagged: wildfire

Utility to turn off power when fire risk is high

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.

Lenya Quinn-Davidson, the UC Cooperative Extension area farm advisor who serves Humboldt, Siskiyou, Trinity and Mendocino counties. (Photo: Larry Luckham)
Posted on Wednesday, March 28, 2018 at 2:31 PM
  • Author: Jeannette Warnert

Mysterious mistletoe

To see dwarf mistletoe seeds is to experience them. These are not typical seeds that gently drop from a mature plant. Rather, they are explosive — forcibly ejected from their fruits at high rates of speed. I remember learning about this in college: that dwarf mistletoe seeds can travel up to 60 mph and fly more than 60 feet from their hosts (Hinds et al., 1963). This process is triggered by internal heat production (called thermogenesis) within the mistletoe fruit — something that's never been observed in another plant (Rolena et al., 2015). It wasn't until many years after college that I actually experienced the phenomenon for myself. I remember driving along the Trinity River here in northern California and seeing a sudden splattering of little gelatinous green balls all over my windshield. I still remember how excited I was when I realized what they were: seeds that had flown as fast as I was driving. 

Dwarf mistletoe fruits. Credit: Thompson Rivers University shared via Flickr Creative Commons.

It turns out that the seeds are only one of many intriguing things about mistletoe. There are more than 1,300 species of mistletoe; they grow all over the world (on all continents except Antarctica!); they support and interact with wildlife in all kinds of neat ways (Watson, 2001); and they are part of human culture and tradition (even evoking a kissing response in some!). And yet they're parasitic — not usually our favorite type of organism. More specifically, they're hemi-parasitic, meaning that they obtain all of their water and minerals from their host plant, but have some ability to provide for themselves. For example, leafy mistletoe, which is common in oaks where I live, is fully photosynthetic and therefore has a limited impact on its host trees. Dwarf mistletoe is a more demanding guest, requiring water, minerals and other nutrients, and taking a much greater toll on the many species of plants that it inhabits.

Leafy mistletoe is fully photosynthetic and therefore has a limited impact on its host trees. Credit: Dan Kidwell shared via Flickr Creative Commons.

As a major forest pathogen, dwarf mistletoe has a strong and well-studied connection to fire. Studies conducted in the 1970s clearly noted the relationship, pointing to fire suppression as the primary driver of increasing dwarf mistletoe abundance in many North American forests (Alexander and Hawksworth, 1975). At that time, dwarf mistletoe was recognized as one of the most damaging pathogens in many important forest types, and its impacts on the timber industry — with estimated losses of 3.2 billion board feet annually (Shea and Howard, 1969) — spurred quite a bit of research into its ecology and potential control tactics. Wildfire and prescribed fire naturally emerged as focal points for research, and those topics have continued to lure researchers, just as dwarf mistletoe has continued to wreak havoc. In a 2008 paper, Paul Hessburg and others argued that due to its wide distribution and habitat versatility, “dwarf mistletoes are probably responsible for more tree growth and mortality losses each year than all other forest pathogens combined.”

Like most forest pests and diseases, the relationship between fire and dwarf mistletoe is a two-way street: mistletoe affects fire, and fire affects mistletoe. For example, research has shown that mistletoe-infested stands of ponderosa pine have higher snag densities and higher fuel loads than uninfested stands, and that infested stands have higher crown fire potential (Hoffman et al., 2007). Mistletoe also has a number of tree-level effects that increase flammability and fire behavior potential, including the establishment of witches' brooms (dense, twiggy growth around areas of infection) and resinous stem cankers (Alexander and Hawksworth, 1975). Other research has documented reduced self-pruning and stunted growth in infected trees, both of which effectively lower the height of the live crown and thereby increase the potential for torching and canopy fire (Conklin and Geils, 2008).

The effects of mistletoe on fire behavior are fairly intuitive, but I find the effects of fire on mistletoe to be a little more intriguing. For instance, a study by Zimmerman and Laven tested the effect of smoke on the seed germination of three species of dwarf mistletoe, and they found that smoke exposure can reduce germination or prevent it altogether (when exposure exceeds 60 minutes) (1987). Earlier work by Koonce and Roth had also indicated that heat and smoke might have a disproportionate effect on dwarf mistletoe compared with their effects on the host plant (1980). Other studies have looked at the sanitizing effect that fire can have on mistletoe-infected trees. Conklin and Geils studied ponderosa pine stands in New Mexico, and they observed reductions in the dwarf mistletoe rating (DMR) — a categorical system for assessing infection (Hawksworth, 1977) — in 12 of 14 frequently burned plots (2008). This sanitizing effect was associated with average tree scorch above 25 percent, and it points to the potential utility of prescribed fire for dwarf mistletoe management, assuming that fire intensity is able to meet these minimum “scorch pruning” thresholds. Hessburg et al. also found that thinning and burning could be effective treatments for dwarf mistletoe in ponderosa and Douglas-fir forests, but that treatments would have to be implemented on regular intervals, as effects diminished after 20 years (2008).

Foresters using prescribed fire to treat mistletoe infestations in the 1970s. Credit: U.S. Department of Agriculture shared via Flickr Creative Commons.

Of course, the relationship between fire and mistletoe — and the approach to fire-based treatments — is highly dependent on the fire regime of the specific forest type in question. Much of the literature on dwarf mistletoe and fire comes out of frequent-fire forests like ponderosa pine and western mixed conifer, but lodgepole pine and black spruce are also common hosts, and their fire regimes are much different. In those types of forests, which are adapted to less frequent, more severe fire regimes, stand-replacing fire may be important for protecting future cohorts of trees from infection. Research in Rocky Mountain lodgepole pine forests showed that the time elapsed since the last stand-replacing fire was a good predictor of mistletoe infestation, and that the presence of remnant infected trees increased rates of infestation in younger, post-fire stands (Kipfmueller and Baker, 1998). In these forest types, the authors suggest that effective prescribed fire treatments would need to be intense and stand replacing.

I've always thought that mistletoe was interesting, but working on this blog opened a whole can of unexpected worms. Who knew that it was mistletoe, with its many interesting wildlife synergies, that inspired Charles Darwin to study evolution (Watson 2001)? Or that the term “mistletoe” is an ancient reference to some mistletoe species' reliance on seed dispersal by birds, who eat the seeds then deposit them on tree branches — the name comes from “misteltan,” an Anglo-Saxon word meaning “dung twig” (!!). Mistletoe has also been used by humans to bait deer for hunting (the foliage is quite tasty!); to treat infertility, syphilis, bubonic plague, epilepsy and other ailments; and to celebrate the return of summer, which mistletoe hints at with its evergreen foliage (Paine and Harrison, 1992). So with this blog, I celebrate mistletoe — i.e., dung twig, kissing plant, ballistic seeder, fire friend and foe — as quite possibly the coolest plant ever!

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References cited:

Alexander, M. E., & Hawksworth, F. G. (1975). Wildland fires and dwarf mistletoes: a literature review of ecology and prescribed burning (Vol. 14). Rocky Mountain Forest and Range Experiment Station, Forest Service, US Department of Agriculture.

Hawksworth, F. G. (1977). The 6-class dwarf mistletoe rating system. The 6-class dwarf mistletoe rating system., (RM-48).

Hinds, T., Hawksworth, F. & McGinnies, W. Seed discharge in Arceuthobium: a photographic study. Science 140, 1236–1238 (1963).

Hoffman, C., Mathiasen, R., & Sieg, C. H. Dwarf mistletoe effects on fuel loadings in ponderosa pine forests in northern Arizona. Canadian Journal of Forest Research, 37, 662-670.

Kipfmueller, K. F., & Baker, W. L. (1998). Fires and dwarf mistletoe in a Rocky Mountain lodgepole pine ecosystem. Forest ecology and management108(1-2), 77-84.

Koonce, A. L., & Roth, L. F. (1980, April). The effects of prescribed burning on dwarf mistletoe in ponderosa pine. In Proceedings of the Sixth Conference on Fire and Forest Meteorology, Seattle, Wash (pp. 22-24).

Paine, L. K., & Harrison, H. C. (1992). Mistletoe: its role in horticulture and human life. HortTechnology2(3), 324-330.

Rolena, A. J., Paetkau, M., Ross, K. A., Godfrey, D. V., & Friedman, C. R. (2015). Thermogenesis-triggered seed dispersal in dwarf mistletoe. Nature communications6, 6262.

Shea, K. R., & Howard, B. (1969). Dwarf mistletoe control; a program for research and development in the West. West Forest Conserv Assoc West Reforest Coord Comm Proc.

Watson, D. M. (2001). Mistletoe—a keystone resource in forests and woodlands worldwide. Annual Review of Ecology and Systematics32(1), 219-249.

Zimmerman, G. T., & Laven, R. D. (1987). Effects of forest fuel smoke on dwarf mistletoe seed germination. The Great Basin Naturalist, 652-659.

Posted on Thursday, February 22, 2018 at 8:39 AM

When Wildfire Hits the Ranch: Lessons Learned from the Thomas Fire

Reposted from the Fire Adapted Communities Learning Network blog


Posted on Friday, February 9, 2018 at 2:42 PM
  • Author: Matthew Shapero
Tags: Matthew Shapero (1), range (1), Thomas Fire (1), wildfire (39)

Testing Sonoma Ash and Air for Fire-Formed Pollutants

 When fires ripped through suburban subdivisions in Santa Rosa last October, they may have done more than reduce homes to ashes. By incinerating all kinds of materials — insulation, electronics, furniture, cleaning products, pesticides — at very high temperatures, they could have created unknown or previously unrecognized health hazards in the smoke and ash. Researchers from the University of California, Davis, are trying to figure out just what is in that ash and air.

“What we're interested in looking for are transformation products of household products that have burned in the fires,” said Gabby Black, a fourth-year graduate student in agricultural and environmental chemistry at UC Davis.

According to Tom Young, professor in the Department of Civil and Environmental Engineering and Black's faculty advisor, the health hazards these compounds pose are not yet known.

“Conventional assessments rely on things that we already know are pollutants, such as industrial chemicals,” Young said. “But we don't know what new chemicals might have been created from combustion.”

The Northern California Fire and Health Impacts project, also known as “Wildfires and Health: Assessing the Toll in NorthWest California” (WHAT NOW-California) is led by Irva Hertz-Picciotto, professor of public health sciences and director of the UC Davis Environmental Health Sciences Center. In addition to sampling ash and air, researchers from the center plan to survey residents of Napa, Sonoma and other Northern California counties affected by the fires or the smoke. The survey asks about how the fires have affected them and other household members, including their experiences as well as their health before, during and after the fires.

Black, who was born and raised in Sonoma, has collected ash samples from a series of sites burned by the Tubbs Fire in October, from wildland in Robert Louis Stevenson State Park into the city of Santa Rosa.

In addition, researcher Keith Bein and colleagues from the UC Davis Air Quality Research Center plan to regularly collect air samples from these sites as the area recovers from the fires. While the fires were still burning, Bein's team collected samples of smoky air in the Bay Area and Davis. But for years to come, they expect, dust in the burned area will contain particles of fire ash. The researchers will look specifically at airborne particles less than 2.5 microns in size that can penetrate deep into the lungs.

Air and ash samples will be analyzed by the latest techniques that can generate high-resolution profiles of hundreds or thousands of molecules in a sample. The researchers will compare the samples to existing databases and also look for new compounds.

“This was a very unique type of fire, an urban wildfire,” Bein said. “We know what wildfire smoke is composed of, but we have no idea what will be in this — we expect it to be very different.”

The air quality team has set up a mobile air sampling unit powered by an electric vehicle. The system can carry out 24 hours of continuous sampling in a remote area with no accessible power. They plan to begin monthly sampling in the Sonoma and Napa areas this spring. In future, Bein hopes that the mobile unit can be deployed quickly into an affected area.

The project has received initial funding from the UC Davis Environmental Health Science Center, sponsored by the National Institute for Environmental Health Sciences. Black is supported by an NSF graduate student fellowship. 

Posted on Monday, January 29, 2018 at 3:23 PM
  • Author: Andy Fell
Tags: ash (1), Gabrielle Black (1), Irva Hertz-Picciotto (1), public health (1), Sonoma (1), wildfire (39), WUI (2)
Focus Area Tags: Environment Health

Newly minted UC fire scientist Kate Wilkin moves into fire country

Reposted from the UCANR News

Kate Wilkin inspects a ponderosa pine on her property with an old fire scar, undeniable evidence that fire has swept through her neighborhood in the past.

Newly minted UC fire scientist Kate Wilkin moves into fire country

Fire scientist Kate Wilkin was on the job just a few weeks when ferocious winds whipped up the Northern California firestorm of 2017. The national media focused on Napa and Sonoma counties, where the deadly Tubbs fire became the most destructive wildfire in California history, while devastating fires also broke out in Butte, Nevada, Yuba and other counties.

It was crunch time for Wilkin, who stepped in as the new forestry, fire science and natural resources advisor for UC Cooperative Extension in Sutter, Yuba, Nevada and Butte counties that fall. Four lives and 200 homes were lost in her new work community. Wilkin will now host workshops to help families and businesses recover from the firestorm and rebuild in a way that is more resilient to fire. Fire resiliency will start at her own home.

The Wilkin-Johnston home is at the top of a rise dotted with cedars, ponderosa pines and black oaks. The dying plants in the foreground are Himalayan blackberry bushes that were treated with glyphosate (RoundUp) to remove them. The invasive weed forms a continuous understory that climbs into tree canopies and can carry fire with it. Wilkin removed one blackberry stem from a cedar tree that was more than 30 feet long.

From the Bay Area to the small town of Grass Valley

Wilkin and her husband Josiah Johnston moved into their first home, a ranch-style rambler atop a hill in Grass Valley, on Sept. 15, three days before Wilkin reported to work in the Sutter-Yuba County UC Cooperative Extension office in Yuba City.

The couple moved from a small apartment in Berkeley, where Wilkin was conducting research as a post-doc in the lab of UC Agriculture and Natural Resources researcher and UC Berkeley fire science professor Scott Stephens. The move from a hyper-urban Bay Area city to a small hamlet in the hills wasn't too much of shock to their systems. Johnston was raised on a farm with chickens and goats. Wilkin grew up in the rural Appalachia community of Abingdon, Va. After completing her bachelor's degree at the College of William and Mary, an internship with the Nature Conservancy in Kissimmee, Fla., introduced Wilkin to fire science.

“In the Disney Wilderness Preserve, the landscape would burn then flood every year,” Wilkin said. “I became fascinated with how these disturbances catalyzed diversity.”

What better place to continue a fire education than California?

Wilkin enrolled at CalPoly, San Luis Obispo, earning a master's degree in biology. She spent the next three years in Yosemite National Park, working with a team of scientists to understand the impacts of packhorse grazing in mountain meadows.

“We found that the current policies led to meadow degradation,” Wilkin said. Yosemite then changed its policy to reduce the amount of horse grazing on these tender, sensitive mountain resources.

Kate Wilkin and her husband Josiah Johnston in front of their Grass Valley home.

In 2011, Wilkin started work on her doctorate at UC Berkeley, where she studied the relationship between fire, forest diversity and water. Wilkin signed up for the pilot Graduate Students in Extension program at Berkeley, launched in 2014 to train and recruit graduate students for careers in research and outreach.

“The … internship gave me an amazing set of professional skills that I could practice, including media relations, public speaking to different audiences, and conference organizing and facilitating,” Wilkin told Science Magazine for an article about the innovative program. “Many of my colleagues and I see environmental problems and want to do applied research because we want to help find solutions.”

The railing and both sides of the siding on the deck were covered in wooden lattice by the previous homeowners. Wilkin and Johnston found a squirrel cache between the layers of lattice, with acorns, pinecones, needles and other dry plant debris. “It was the perfect place to start a fire,” Wilkin said.

Beginning at home

With full knowledge of the dangers of living in fire-prone areas, Wilkin and Johnston purchased a home close to the outdoor amenities they adore – hiking, backpacking and skiing.

“Tahoe is just an hour away,” Wilkin said. “I love the view from the house and the wooded setting. But we live in an area CalFire has designated as very high fire danger.”

As a fire scientist, Wilkin was well equipped to make changes to the home and landscape to minimize the risk.

“We moved in during peak fire season,” Wilkin said. “We didn't hang artwork. My priority was to make the home and deck more fire resistant. We put in one-eighth-inch mesh over the vents, caulked around doors and windows, blew leaves off the roof and deck, removed lattice wrapping the deck and cleaned the gutters. Then we created defensible space starting close to the house and working our way outward."

The couple labored about 200 hours and spent about $800 in the first six weeks buying and renting tools, including a chipper, saw and a truck to haul away tinder-dry lattice, foliage and pine needles. With the most critical fireproofing completed, the couple is now tallying the work that should be done to further enhance the fire safety of their home.

“We probably need another $6,000 to $7,000 of work,” Wilkin said.

To reduce large, hot embers from drifting into the basement and starting a fire in the home, Wilkin and Johnston installed one-eighth-inch mesh over the vents. Before next fire season, they will upgrade to vents that close during fires.

When the North Winds blow

Wilkin recalled the terrifying time about a month after moving into their new home when howling winds whipped around the house and fires were breaking out across Northern California.

“The North Winds are haunting,” she said. “I hadn't felt wind like that since I lived in Florida and experienced hurricanes.”

Wilkin and Johnston were fortunate. The closest fire to their home was the McCourtney Fire, which burned 76 acres in Grass Valley. The wildfire stayed two miles away.

A thick hedge of camellias borders the side of the home. Although ideally homes should have a five-foot zone immediately surrounding the house clear of burnable objects and plants, she didn’t have the heart to pull them all out when they were full of flower buds, but removed them after they bloomed.
Complex features on the roof – such as skylights, solar panels and a valley that can capture debris – require frequent maintenance to keep the roof fire safe. Johnston tacked down loose flashing on the roof and blew leaves off the roof and out of the gutters.
The previous homeowners installed a shrub-lined wood fence that went under the deck and attached to the house. “It was a perfect way for a fire to wick into the house,” Wilkin said. The couple removed the shrubs and fence slats and plan to remove the posts as well.
Posted on Tuesday, January 16, 2018 at 10:24 AM
  • Author: Jeannette Warnert

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