Posts Tagged: Yana Valachovic
Preventing embers from getting inside may save homes
Photos and video of the Northern California communities that have been hit by wildfires show buildings reduced to ash. How could so many homes and businesses burn so quickly in the 2017 Wine Country fires? Many houses that burned to the ground in the Northern California fires likely burned from the inside out, says Yana Valachovic, UC Cooperative Extension forest advisor for Humboldt and Del Norte counties.
Red hot embers carried on the wind can enter the attic via the venting. “In the case of the wind-driven fires on October 8, these fires created ember storms that blasted little coals into everything in their pathway,” Valachovic said. These embers also create small spot fires near the home that fuel new sources of embers.
Weather played a large role in these fires and generated a fire storm of embers that ignited grass, shrubs, trees and anything in its path. “While the landscape can be the fuse, the homes really can be the most burnable part of the landscape,” Valachovic said. “These embers likely lodged in the small spaces and openings of homes and buildings. A common location is for the embers to enter via attic venting or HVAC systems distributing little fires into the buildings.
“Embers also landed on receptive leaves, outside furniture, and other flammable materials outside the buildings that created fires adjacent to the buildings. Once enough buildings were engulfed in fire, the radiant heat of each building fire led to exposures on the neighboring buildings, creating a house-to-house burn environment.”
Residents can reduce the risk of embers setting their house on fire by removing dry plants around the structure.
“These fires remind us that everyone in California could help the fire situation by managing the vegetation, leaves in the gutters and decks, newspaper piles, brooms and other flammable sources near to their houses now before they get the evacuation call,” Valachovic said. “If you are likely to have to evacuate soon, temporarily covering or sealing up the vents with metal tape or plywood can help harden your home to an ember storm.”
Steve Quarles, UC Cooperative Extension advisor emeritus, who spent his career studying fire behavior on building materials and around homes, created an online Homeowner's Wildfire Mitigation Guide at http://ucanr.edu/sites/Wildfire. Quarles, who did research for the Insurance Institute for Business and Home Safety, demonstrates how embers can ignite and quickly engulf a house in flames in a video https://www.youtube.com/watch?v=IvbNOPSYyss. After the 3-minute mark, video shows embers drifting up and flying through a screened vent into the house, where they could ignite combustible materials in the attic resulting in fire starting on the inside of the home.
To show homeowners how to harden their homes against wildfire, Quarles will be presenting a free webinar July 28, 2020, with UC Cooperative Extension forestry advisor SusieKocher and ChristinaRestaino, assistant professor and natural resources specialist with University of Nevada, Reno Extension and the director of the Living With Fire Program. To register, visit bit.ly/TahoeRetrofit.
“If you have time to prepare your home, use the wildfire last-minute check list at https://ucanr.edu/sites/fire/Safety/Evacuation/,” Valachovic said.
Valachovic has co-authored publications in home survival in wildfire prone areas http://anrcatalog.ucanr.edu/pdf/8393.pdf and how landscape plants near homes can create more vulnerability to wildfire http://anrcatalog.ucanr.edu/pdf/8228.pdf.
“Past wildfire events have shown that this is the common way homes in the wildland urban interface (WUI) burn, and this scenario was likely translated to the urban environment,” she said.
California oak woodlands are highly prized ecoregions where stately trees, many of them hundreds of years old, are cornerstones of a habitat for wildlife and native plants. Sadly, some of these ecosystems are seriously threatened by exotic pests and diseases, encroachment by less desirable vegetation, and wildfire.
Each year, UC Cooperative Extension hosts workshops to share scientific developments aimed at conserving these important habitats – and the economic value of ranching – on oak woodlands, which are found on the lower elevation slopes of the Sierra Nevada, the Coast Range and other foothill areas of California.
Typically, the workshops are held in person and draw moderate-sized audiences for presentations, questions and answers, and field trips. Because of the COVID-19 pandemic, this year's workshop was offered online in April with pre-recorded presentations available for viewing at the participants' convenience and a live question-and-answer session on Zoom.
The retooled event garnered 500 registrants, over 300 views of the YouTube videos and 140 participants in the live Q&A session. The presentations and Q&A session are still available online for future viewing as well at http://cemendocino.ucanr.edu/Forestry/Workshops/California_Oak_Health.
“People from all walks of life participated, including those with professional and personal interest in oak woodlands,” said Yana Valachovic, UCCE forest advisor in Humboldt and Del Norte counties and a conference organizer.
Presentations at the 2020 conference included the following topics:
Encroachment by Douglas-fir
In Northern California, the biodiversity of oak woodlands is being threatened by Douglas-fir encroachment. The oaks' shade helps the young conifers get established with protection from harsh sun. In time, the fast-growing Douglas-fir trees pierce the oak canopies and begin to crowd out the areas' native understories, which are important for the diversity of birds, mammals and reptiles attracted to oaks.
As the Douglas-fir continue to grow and multiply, they threaten the very lives of the oak trees and the unique ecosystem they dominate.
To better understand the Douglas-fir encroachment, Valachovic established 10 research sites in Humboldt and Mendocino counties to gather information about the fate and the age of oaks. She and her research partners determined the ages of the oaks and firs, and counted the seedlings, saplings, snags and understory vegetation.
“With this research, we were able to demonstrate that even though the oak trees can be smaller in diameter, they are much older than the Douglas-fir trees,” Valachovic said. “The encroachment process is happening quickly, and the oaks are falling out of the system.”
The shift appears to have been initiated in the mid-19th and early-20th centuries, coinciding with the Gold Rush and wildfire suppression.
With the data confirming Douglas-fir encroachment, Valachovic turned her attention to oak woodland restoration. At 14 sites in Humboldt and Trinity counties, her team studied the effects of Douglas-fir removal.
“Grasses and forbs under the oaks reestablished. Diameter growth on the oaks increased,” she said.
These research findings contributed directly to changes in policy that had previously limited landowners' ability to remove and sell conifers encroaching on oak woodland. The research also helped create new funding opportunities to support oak woodland restoration and conservation in Northern California.
Case study of oak woodland wildfire recovery
In July 2018, about two-thirds of the 5,289-acre UC Hopland Research and Extension Center was burned by the River Fire.
The transformation of the land, which had likely been without a large wildland fire for at least 100 years, was intense and stressful, said UC Cooperative Extension forest advisor Michael Jones. However, it also provided a unique opportunity for researchers to compare the impact of wildfire on the resiliency of vegetation on grazed and ungrazed oak woodland.
Jones established 35 one-fifth acre research plots at the research center and collected data two months following the fire and one year later. The research will continue in the future to better understand long-term impacts, but Jones was able to share revealing early results at the workshop.
Right after the fire, in severely burned areas areas, the future of the oaks looked ominous. Jones predicted 40% tree mortality.
“The oaks were exposed to persistent, intense heat. They were cooked,” he said. “But two months after the fire, we were already seeing basal sprouts. This was an amazing response by the trees. Oaks are pretty damn tough.”
A year after the fire, surveys showed that tree mortality in the burned areas was 25%, much less than Jones' early predictions. While some management for specific situations in severely burned areas may be necessary – such as removal of hazard trees, reducing fuels in defensible spaces or removal to control invasive species – the results of this work show the trees recover naturally.
“Esthetically, I know these systems aren't as pleasing as they were before, but ecologically, they are healthy and recovering,” he said. “In 100 years, it will look just as good as before the fire.”
Fire impacts in woodland areas previously grazed and not grazed
The fire on the research station also permitted Jones to compare the fire's differing impact on non-grazed and grazed oak woodland. At first, the grazed areas looked almost unscathed with minimal flame scorching on the bark, while an area where the pasture hadn't been grazed for 25 years had evidence of much higher severity fire.
“Grazing is a phenomenal way to help manage fuels,” Jones said. However, the grazed areas displayed ecological shortcomings a year later.
“In grazed pastures, the large mature trees were still alive, but there was no oak regeneration (basal sprouting or seedlings),” Jones said. “In the ungrazed area, a lot of biomass had been killed, but there's nearly 100% resprout of oak trees and we have an impressive amount of oak seedling recruitment.”
Jones said he isn't discouraging grazing.
“But it is important to protect sites from grazing, and especially wildlife browse, when a landowner or land managers' objectives are to regenerate or conserve oak woodlands,” Jones said.
New ambrosia beetle another threat to California oaks
Akif Eskalen, UC Cooperative Extension specialist in the Department of Plant Pathology at UC Davis, has identified a new insect-fungus team that causes oak borer wilt in Northern California Valley and Blue Oaks. It is an ambrosia beetle, commonly known as Mediterranean Oak Borer, which carries several fungi in its mouth. The beetle bores into the tree and introduces fungi to grow for food. The fungi spreads and disturbs the transportation of water and nutrients, causing wilt in the tree.
The oozing and staining lesions on the bark are similar to other oak fungal diseases, such as sudden oak death. The beetle – native of Mediterranean basin countries in Africa, Asia and Europe – cannot fly far, so most likely is transported for long distances on infested firewood.
During the workshop, Eskalen suggested not moving firewood, removing heavily infested trees and chipping infested wood into 1-inch particles to reduce the spread of the ambrosia beetle and its fungal partner. He asked viewers to report any suspected oak tree infestations to the local agricultural commissioner, CDFA Diagnostic Laboratories, UC Cooperative Extension advisors or CALFIRE. Chemical options for sparing oaks from the ambrosia beetles' devastation are under investigation.
Threats to oaks and other native plants from root rotting Phytophthora
Restoration plantings have inadvertently introduced plant pathogens to native oak woodland ecosystems in California, said Ted Swiecki of Phytosphere Research, an organization that provides consulting services related to natural resource management, horticulture, urban forestry and agriculture. The group of pathogens causing the damage are largely from the Phytophthora genus, first described in the 1860s. The name translates from Greek to “plant destroyer.”
Swiecki has observed when Phytophthora infested plants and soils are introduced to native habitats, the pathogens can attack various native plants, including toyon, madrone, manzanita and full-grown oaks. Once established, the pathogen can spread along drainages, by moving soil from one area to another and by hitchhiking on equipment, tires and hiking boots.
The pathogen can easily be overlooked at nurseries, which, by their nature, have conditions that favor Phytophthora development. Plants at nurseries are well watered, have high root density and are often placed on the ground where they can pick up pathogens.
He said the best approach to tackling Phytophthora is not using nursery stock for restoration or beautification of natural oak woodland. Direct seeding, using natural regeneration, or onsite propagation are safer ways to enhance vegetation in oak woodland.
“It's easier to prevent Phytophthora from being introduced in the first place and much cheaper and more effective than trying to eradicate it later,” Siewcki said.
Central Valley residents from Visalia to Sacramento look forward every year to the beginning of strawberry season in early April, when roadside strawberry stands operated by Hmong and Mien farmers open to the public.
These farms grow strawberry varieties such as Chandler and Camarosa that haven't traded flavor for shelf life – they don't ship or store well, but they are far sweeter than varieties usually sold in stores, and they reach their peak ripeness and flavor in the fields next to the strawberry stands.
As strawberry season opens this year, farmers are hoping that customers will still stop by the stands to pick up their fresh, seasonal strawberries, and also that they will observe 6-foot social distancing and other guidelines to reduce the spread of COVID-19. UC Cooperative Extension agricultural assistant Michael Yang and I were interviewed on a local news station to encourage Fresno residents to practice these guidelines while supporting local farmers.
To assist Fresno strawberry farmers, the UCCE small farms team in Fresno County developed, printed, and distributed signs for roadside strawberry stands reminding customers to observe social distancing and other safety practices, as well as guidelines for farm stands to reduce the spread of COVID-19. Versions of the signs were also developed for strawberry stands in Merced and Sacramento, as well as a general sign for local produce at any farm stand.
Signs and safety guidelines were printed with funding from the Western Extension Risk Management Education Center, and Michael Yang distributed large printed versions of the signs to all strawberry stands on the Fresno County Fruit Trail map in Fresno County. These materials have also been shared with UCCE small farms and food systems advisors as well as nonprofit and agency partners and county Agricultural Commissioner's offices, and they are available for printing on the UCCE Fresno strawberry website.
Even as Californians shelter in place to contain the novel coronavirus that causes COVID-19, nutritious food remains vital to the health and well-being of our communities.
“Eating fruits and vegetables is known to benefit our overall health and help our immune system,” said Lorrene Ritchie, director of the UC Nutrition Policy Institute. “At a time when we need to be especially vigilant about staying healthy, eating healthy is essential.”
Farms, farm stands and farmers markets are listed as “essential businesses” in the state shelter-in-place order because they are important parts of the food supply. Urban farms are included in this category. As large produce distributors struggle to switch from selling large quantities to restaurants, schools and institutions to supplying supermarkets, these small businesses may offer a better selection of fresh foods, and may be closer to homes and less crowded.
To help minimize exposure and risk of spreading of the virus, urban farms need to follow some key guidelines from the CDC , said Jennifer Sowerwine, UC Cooperative Extension metropolitan agriculture and food systems specialist in the Department of Environment, Science, Policy and Management at UC Berkeley.
UC Cooperative Extension has compiled a list of resources for farmers, community gardeners and other people working in the food system to ensure that they can continue supplying fresh, healthy and affordable food to Californians.
“Social distancing, heightened health and hygiene practices and cleaning and disinfecting reduce the risk,” said Sowerwine.
Although eating a nutritious diet can boost our immunity, the Los Angeles Times reported produce sales plummeted by 90% or more at Southern California produce markets after the statewide shelter-in-place rules went into effect.
“It's worrisome to see that sales of fruits and vegetables are dropping so sharply, but not surprising,” said Rachel Surls, UC Cooperative Extension sustainable food systems advisor for Los Angeles County. “As people shop during the crisis, they may be prioritizing groceries that can be stored for a longer time in the fridge or pantry. And they may be on a very limited food budget, even more so than usual, so they are likely prioritizing essentials like bread and rice and baby formula.”
To support farmers in California, the UC Sustainable Agriculture Research and Education Program created a directory at http://www.calagtour.org for consumers to find local farms to purchase produce directly.
For families who have lost jobs and income, the risk of food insecurity increases. Some families could supplement their food from gardens and urban agriculture during this crisis.
Consumers must practice safety, too, when visiting farmers markets and farm stands. UC Cooperative Extension small farm advisor Ruth Dahlquist-Willard explained, "Things like keeping the minimum six-foot distance from customers, not touching any produce that you're not planning to buy, leaving as soon as you've made a purchase and washing the produce when you get home would be some good guidelines."
The virus is thought to be spread mainly from person to person, however there is evidence that COVID-19 can last for days on hard surfaces, thus the need to ramp up good health and hygiene practices, social distancing and cleaning and sanitizing of surfaces.
University of California research and extension faculty have compiled a list of helpful fact sheets and resources for farmers, community gardeners and other food system workers to ensure fresh, healthy and affordable food for communities across the state:
- Food-related resources for consumers and members of the food industry for COVID-19
- on the UC Davis Food Safety website.
- Sowerwine's PowerPoint presentation Safe Handling Practices for Fresh Produce in a Time of Coronavirus Disease 2019 (COVID-19) for urban farmers.
- A set of policies and procedures for safe food handling at the farm during COVID-19 provides step-by-step instructions for applying new food and health precautions on the farm including checklists, standard operating procedures and signage posting guidelines for preventing the spread of infection.
- COVID-19 safety guidelines for farm stands.
- Handouts for safe food-handling at home that can be distributed to customers receiving food from the farm.
All of these resources are posted on the UC Urban Agriculture website at https://ucanr.edu/sites/UrbanAg.
“During this challenging time, I am heartened by the quick and thoughtful responses by many extension, grassroots and institutional efforts, including Community Alliance with Family Farm's COVID-19 Responses and Resources for California Family Farms, Mutual Aid organizations where groups of young, healthy and lower-risk people are bringing food and services to vulnerable people who shouldn't be in public at all, and Bayareafood.info that seeks to support local restaurants, farmers, and food systems workers as they weather this latest storm,” said Sowerwine. “Crisis can spawn innovation, and I am hopeful that through this, we will come out the other end with a more compassionate and resilient food system.”
Road side stands selling fresh strawberries and vegetables are opening up around the San Joaquin Valley, and are a excellent option for safe shopping, reported Dale Yurong on ABC 30 News in Fresno.
In keeping with social distancing guidelines, Yurong conducted remote interviews with UC Cooperative Extension advisor Ruth Dahlquist-Willard and agricultural assistant Michael Yang, who work closely with small-scale farmers in Fresno and Tulare counties.
Dahlquist-Willard suggested customers maintain a six-foot space from other shoppers at farm stands and follow other common sense precautions when purchasing the healthful fresh food by, "not touching any produce that you're not planning to buy, leaving as soon as you've made a purchase and washing the produce when you get home . . . . Similar to what we're seeing at farmers markets right now."
Some valley farmers have been selling their produce at farmers markets out of town and have noticed fewer people are out shopping, Yurong said. They hope more people will stop by the local farm stands, away from the crowded grocery stores, and pick up something straight out of the field.
"My farmers that go to farmers markets, even though the farmers market is still open, they only allow a few people at a time. You don't have a lot of customers walk by just like before," Yang said.
San Joaquin Valley strawberry stands were all expected to be open by April 10, Yurong said.