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Autumn's Majesty: Tithonia

A Gulf Fritillary, Agraulis vanillae, lands on a Mexican sunflower. (Photo by Kathy Keatley Garvey)

If there's any flower that should be crowned "Autumn's Majesty," that would be the Mexican sunflower (Tithonia rotundifolia), aka "Torch."A member of the sunflower family (Asteraceae), it carries "the torch of life" throughout spring, summer and autumn,...

Posted on Wednesday, October 18, 2017 at 5:00 PM

Houses likely burned from the inside out, says UCCE forest advisor

Reposted from UCANR News

 

Fire damage from the 1991 Oakland Hills fire. Buildings can burn quickly if embers get inside and fall on flammable materials.
 

Preventing embers from getting inside may save homes

Photos and video of the Northern California communities that have been hit by wildfires this week show buildings reduced to ash. How could so many homes and businesses burn so quickly in 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.”

Embers carried on the wind can ignite dry plant material like pine needles and create more embers that may enter homes through vents.
 

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 now does 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.

“If you have time to prepare your home, use the wildfire last-minute check list at http://disastersafety.org/wp-content/uploads/2016/07/IBHS-Wildfire-Last-Minute-Checklist.pdf,” 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.

Once these fires are extinguished, a more detailed analysis will be possible.

“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.  

Posted on Tuesday, October 17, 2017 at 9:04 PM
  • Author: Pam Kan-Rice
Tags: embers (2), home loss (1), wildfire (126), Yana Valachovic (13)

Why This UC Davis Course Is Sweet

Home is where the bees are. A beekeeper at the Harry H. Laidlaw Jr. Honey Bee Facility, UC Davis. (Photo by Kathy Keatley Garvey)

"The bee hive is the ultimate home sweet home," Amina Harris, director of the UC Davis Honey and Pollination Center,  told the crowd at the Western Apicultural Society's 40th annual conference, held in early September at UC Davis. She's right. Just...

Posted on Tuesday, October 17, 2017 at 5:00 PM

Hybrid oak trees muddle identification at California Naturalist Regional Rendezvous

Knowing the names of trees is a point of pride for many California Naturalists. So a walk among the diversity of oaks at the Pepperwood Preserve left many feeling humbled.

The three-hour excursion was part of the UC California Naturalist Regional Rendezvous in October at the 3,200-acre nature preserve nestled in the foothills between Napa Valley and Santa Rosa.

Excursion leader Steve Barnhart, academic director emeritus at Pepperwood, said there are 500 oak species in the world; 21 in California. But cohabitating on the rolling hills and valleys of the Golden State, many oaks have produced hybrids that combine characteristics, making identification challenging.

Steve Barnhart opens the 'Oaks of Pepperwood' excursion during the California Naturalist Regional Rendezvous.

Doctoral candidate Phrahlada Papper, who is studying oak tree genetics, said, “I'm of the mind that you shouldn't ever name an oak.”

Even the tan oak, long thought to be misnamed, is coming under new scrutiny.

“It's not an oak,” Barnhart said. “It has acorns, male and female flowers on the same stalk, but tan oaks are insect pollinated. True oaks are wind pollinated. Tan oaks are closer to chestnuts.”

But Papper raised his hand. “Genetically, it might be an oak,” he said.

Barnhart laughed. “So tan oak is up in the air. That's why it's so much fun to be in science,” he said. “I learned something today.”

Doctoral student Phrahlada Papper discusses oak tree genetics.

In popular culture, oaks are thought to be majestic, towering trees, with wide spreading branches. However, Barnhart said, most California oaks are shrubs, including the leather oak.

Leather oaks grow in serpentine soils and have the ability to produce two types of flowers, one in the spring and another quite different in the fall. Leather oaks are monoecious, they have both male and female flowers on the same plant. On a particular leather oak at Pepperwood, Papper was surprised to find male and female flower parts in one bract and surmised that weather patterns may be responsible.

“California has weird weather and with climate change, it's getting even more weird,” Papper said.

Leather oak details.

Papper believes tracking phenology, the cyclic and seasonal changes in plants, is an ideal citizen science project for California Naturalists. One such project underway at Pepperwood is led by Wendy Herniman. A University of Edinburgh, Scotland, master's student, Heniman is documenting the phenology of 10 Pepperwood oak trees: 2 blue oaks, 3 coast live oaks, 2 black oaks and 3 Oregon oaks.

“Pepperwood is looking at climate change. It's a designated sentinel site. We're monitoring fog, we have soil probes, and we're collecting all weather and climate information. We can tie that to phenology,” she said. “We're trying to find out if phenophases are changing.”

Understanding the changing phenophases is important, Barnhart said.

“Everything is connected,” he said. “If acorns are produced early, animals species that depend on the food source will be disrupted. You have imbalances in the timing of the natural world. With climate change, what are the effects we'll be seeing?”

Wendy Heniman talks about her research near a hybrid Oregon-blue oak.
 
The acorn shape is Oregon oak-like. The leaf contours are blue oak-like. The specimen is evidence of hybridization in oaks.
 
California native poison oak is also found on the Pepperwood Preserve. It is unpopular with humans, but birds like the golden berries.
A 15-year-old Douglas fir was mechanically removed to stop it from crowding a 50- to 60-year-old oak tree, Steve Barnhart said. Fire suppression is giving oak competitors like firs a greater foothold in oak woodlands. "Fire suppression was an unhealthy thing to do," Barnhart said.
Posted on Monday, October 16, 2017 at 1:30 PM
Tags: California Naturalist (26), oaks (11)

The Amazing Bee-Parasite Research of Leslie Saul-Gershenz

Leslie Saul-Gershenz in the Channel Island National Park conducting a native bee survey.

Evolutionary ecologist Leslie Saul-Gershenz goes places where many have been but few have ever really seen.  Bees and blister beetles, yes. We remember writing about her work in April of 2013 when she addressed the Nor Cal Entomology Society (now...

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