Will tanoak die out – is it worth saving? Tanoak (Lithocarpus densiflorus) is a California native hardwood tree common in the forest of Northern California and susceptible to Sudden Oak Death (SOD). Since tanoak is not a commercial tree should we just let it die? Tanoak has stumped manufacturers and researches alike trying to find a place for it in the market. It has many first-rate material properties but it has a reputation of being very difficult to dry without creating serious drying defects. The Fifth Sudden Oak Death Science Symposium was held in Petaluma, CA from June 19-22 to address the current knowledge of SOD and devoted a day to shed light on tanoak’s worth. The conference brought together scientists, researchers, and other experts to share information and solutions. More information on the conference presentations can be found at the conference website.
Friday’s session focused on tanoak’s importance and value. Its history and background were discussed first, summarizing its uses, advantages vs. disadvantages and economic viability. This was followed by a discussion of the efforts and studies being done to prevent tanoak trees from succumbing to SOD. The conference did an excellent job of connecting people, bringing people from different fields together to share knowledge and expertise on how to use and protect tanoak.
A presentation, titled “Tanoak as a Forest Product Recourse: Past, Present, and Future”, by John Shelly and Steve Quarles, two University of California forest products experts was presented by Steve, currently employed at the Insurance Institute for Business & Home. This presentation looked at tanoak as a potential lumber resource and compared it to more traditional hardwood species. Tanoak has a rich history as an acorn food source for Native Americans, a source of tannin—a natural chemical used to produce leather from animal hides, firewood, lumber, and pulp for paper. Compared to Northern red oak (a benchmark species), tanoak is stronger and harder, however it is more difficult to dry and exhibits greater tangential and radial shrinkage. More information is available at the UC Woody Biomass Hardwood Utilization webpage. An accumulation of experience from various researches and practitioners has led to core knowledge of best practices. These include avoiding the dark-colored core zone as it cannot be dried without defects, quarter-sawing lumber to improve dimensional stability, and using a drying schedule of air drying to 30% MC followed by a mild kiln-drying schedule. Additionally restraining the movement of wood as it dries by placing a uniform weight of about 150 lbs/ft2 on top of the lumber stack as it dries is known to be beneficial in reducing warp.
Some people are concerned that removing trees that are inflicted with the SOD tree disease pathogen will increase the risk of spreading the disease. Research reported by Shelly however, indicated that the very low risk of spreading the disease when fresh cut wood is transported to different locations disappears entirely once the wood is processed and dried. In fact, using diseased wood my even have some positive benefits. Further information is presented at: http://ucanr.org/sites/WoodyBiomass/HardwoodUtilization/SOD/ .
One such potential benefit is the presence of spalted wood –an early stage of decay—often found in SOD diseased trees. This, combined with the insect tunnels often associated with SOD infected trees creates an appealing aesthetic appearance, often called character wood. This character has the potential to set it apart from other woods. However, it was noted that spalted wood should not be used for flooring because the hardness of the wood with incipient decay is greatly reduced making it too soft for flooring. The interesting appearance of spalted wood can be very attractive in furniture, art, and craft uses. This could create a niche market for SOD-diseased tanoak that is unique, appealing to select buyers.
The participants in the tanoak session also had the opportunity to view an exhibit of a display of pictures, a slide show, and examples of tanoak lumber and finished products (e.g. flooring and furniture). The pictures and slide show depicted tanoak lumber being cut and quartered, then dried. Here the audience could see the preparation process—from forest to flooring—as well as examples of drying effects. Many people’s questions revolved around the option of using tanoak for flooring and its expected durability. Another common topic was the amount of unutilized tanoak in California forests. It is clear that there is continuing interest in finding uses for this tree. The UC experts concluded that with expansion of the market and improvements in the processing we could see a dramatic increase in the use of tanoak across California.
For almost 20 years now, UC Forest Advisors and Specialists, along with a dedicated group of volunteers, have been leading summer training opportunities to inspire K-12 teachers to teach about environmental issues.
Living in an urbanized state, few Californians recognize how much they depend on the forest for water, wood products and wildlife habitat, as well as their responsibility for its proper management. Through environmental learning integrated into the educational system, students can discover how to make critical choices about issues such as forest health, ecosystem management, consumerism and local economies.
The goal of the Forestry Institute for Teachers (FIT) is to provide California's K-12 teachers with knowledge, skills and tools to more effectively teach forest ecology and forest resource management practices. The program is co-sponsored by UCCE, the Northern California Society of American Foresters, US Forest Service and many other organizations. FIT brings natural resource specialists together with teachers from both rural and urban schools for one week, working side by side to explore the intricate interrelationship of forest ecosystems and human use of natural resources. The science-based curricula explore many subject areas, including environmental science, physical science, social science, biology, forestry and history. At each session, more than 40 local resource professionals representing many disciplines are invited to teach components of the course. UCCE advisors and specialists serve as co-directors and teachers. FIT offers annual institutes in three Northern California locations: Humboldt, Shasta and Plumas Counties. Back at their schools, FIT participants conduct in-service training for colleagues, and develop forestry education projects with their students.
Since 1993, over 1,300 K-12th grade teachers, evenly spread among grades, have participated in FIT. About one-third of the teachers come from Southern California, one-third from central and rural California and one-third from the Bay Area and Sacramento. Their responses to the course emphasize (1) new insight into the complexity of forest management and (2) activities and lessons that prove valuable in the classroom. Because teachers have utilized the activities and information gained from FIT in the classroom, students are improving their knowledge and decision-making skills. FIT has received a number of environmental education awards.
A graduate from the 2011 program shared, “I came up here expecting more of a science based workshop but left with so much more. Yes, science based but more of an understanding of our forest, the timber industry and ways to implement this information into the classroom- even when we don’t live near a “forest” environment. The web of involvement (people, agencies, policies, environmental groups, landowners) to most people is not known. I have gained a greater appreciation for those who are involved. Taking this back to the classroom will be much different than just teaching “the surface” (leaves, water, habitats). Now I will have the “meat” to all these lessons I have been teaching for years. Thank you for a wonderfully organized and extensive week! I will be taking what I have learned not only to my students but to the staff of my school, my friends and my family.”
While another stated; “Awesome! I really appreciate this opportunity. The FIT program is one of the BEST training courses I’ve ever participated in- great mix of perspectives & activities. It’s obvious that you’ve been offering the program for many years- it’s fine-tuned & perfect. Thank you!”
Four week-long sessions are offered in California. To learn more about FIT visit: www.forestryinstitute.org.
Learning how to read a tree core.
FIT teachers busy learning to identify amphibians.
Learning to measure the diameter of a redwood tree.
Sampling gravel to learn if conditions can support fish spawning.
- Editor: Sophie Kolding
- Author: Susie Kocher
Most people planning home improvement projects take into account how improvements will affect the home’s ability to withstand rain and weathering. In California we should also consider the threat of wildfire when planning home improvement projects this spring
Most homes that burn during wildfires are ignited by flying embers landing on combustible material on or near homes. A wildfire passes by a home quickly, usually in a few minutes, while the exposure to flying embers can last for an hour or more. Therefore, activities homeowners undertake to make their home less ignitable from embers do the most to ensure its survival.
The most important home upgrade homeowners can do to reduce wildfire risk is to replace wood shake roofs with Class A roofs. Single-paned windows should also be replaced with dual-pane windows (with at least one pane being tempered). Combustible siding can also be vulnerable, but replacing it with non-combustible siding is less important if you have done a good job of locating and maintaining vegetation near your home. Replacing combustible decks with noncombustible decking products will also reduce risk.
Even though these upgrades are expensive, they reduce the likelihood that you will experience the cost and trauma of losing a home in a wildfire. If you cannot afford to undertake these projects this year, there are less expensive projects you can take on to reduce wildfire risk. These center on maintaining your home in good condition by replacing worn boards , sealing cracks in locations where embers can enter the home, and protecting vulnerable areas with non-combustible materials and coverings.
Even if you have already upgraded your home to resist fire by installing a new roof, windows, or deck, it is important to maintain those home components in their proper condition so embers cannot gain entrance to the home. Creating defensible space by clearning flammable vegetation and debris is also crucial to reducing your wildfire risk. For more information on the performance of building materials in a wildfire, please see http://firecenter.berkeley.edu/ or www.extension.org/surviving_wildfire. For more on creation of defensible space, contact your local fire agency.
Homeowner installing screens under a deck to reduce the likelihood of ember intrusion
during a wildfire. Photo by Steve Quarles.
Suggested home maintenance projects to reduce wildfire risk
- Plug roof openings: Install end-stops (bird-stops) at the edge of your roof if it has a gap between the roof and the sheathing (as with a clay barrel tile roof).
- Protect roof edges: Install metal angle flashing at the roof edge to protect the roof sheathing and fascia board, especially if there are gutters attached that can hold combustible pine needles. Even a Class A roof cannot protect the wood sheathing under it if the roof edge is unprotected.
- Protect roof eaves: “Box in” your open eaves with sheathing, such as a fiber cement soffit or higher grade plywood.
- Skylights: Particularly on steep or flat roofs, replace plastic skylights with skylights that use tempered glass in the outer pane.
- Maintain siding: Fill gaps in siding and trim materials with a qood quality caulk help keep out embers. Replace warped or degraded siding.
- Protect vents: Inspect the vents into your attic and crawl space. Make sure the screens are in good condition. Replace ¼ inch mesh screen with 1/8 inch mesh screening.
- Maintain decks: Replace deck boards that are less than an inch thick with two inch thick boards. Remove combustible materials from under the deck.
- Protect combustible siding: Install metal flashing between a deck and combustible siding to protect it from accumulated debris that can ignite during ember attack.
- Remove flammable material from under decks: If your deck is made from wood or wood-plastic lumber decking, remove combustibles (firewood, lumber, etc.) from under the deck.
- Replace gates: Replace combustible gates and sections of wooden fences within five feet of the house with noncombustible materials and components.
- Adjust garage doors: Your garage door can be very “leaky” to embers. Since most people store combustibles in their garage, make sure your garage door is well sealed at the edges.
- Editor: Sophie Kolding
- Author: Yana Valachovic
- Author: Pamela Kan-Rice
University of California Cooperative Extension employees, who coordinate most of the sudden oak death-related research and monitoring in Northern California, got a surprise in the spring of 2010, when samples from a monitoring station near the mouth of Redwood Creek near Orick in Humboldt County tested positive for the pathogen. This meant that trees were infected somewhere in the 200,000-acre watershed – more than 50 miles from the nearest known infestation, and farther north than the pathogen had ever been detected in California.
Federal and state agencies, including the USDA Forest Service, CAL FIRE and the Natural Resources Conservation Service, joined forces with UC Cooperative Extension and quickly mobilized resources to control the pathogen in Redwood Valley and halt its spread to neighboring forests. Local landowners have also played a key role.
Yana Valachovic, UC Cooperative Extension advisor in Humboldt County and forestry expert, explained that she and her agency partners had been preparing for this moment.
“We’ve been closely monitoring the disease for years and anticipating a scenario like Redwood Valley, so we were ready to take action and respond quickly,” Valachovic said.
Figure 1. Yana Valachovic sampling vegetation
The UCCE staff leads an extensive sudden oak death monitoring program on the North Coast, and one of their detection strategies involves "leaf-baiting" in streams. Using this technique, they “bait” Phytophthora ramorum, the non-native pathogen that causes sudden oak death, by placing susceptible leaves in strategic locations in North Coast streams. If the leaf baits become infected with SOD, the scientists know that the pathogen is present in the watershed without having to comb the landscape for symptoms.
After they detected the pathogen in Redwood Creek, UCCE acted quickly to pinpoint the source of the waterborne spores, scouring the watershed for the very inconspicuous symptoms of SOD with the help and permission of public and private landowners. By November 2010, the scientists had narrowed the location to Redwood Valley, where they found dead tanoaks and several other infected host plants.
Given its proximity to extensive public, private and tribal lands, the infestation in Redwood Valley was a serious concern. The disease, which was discovered in the Bay Area in the mid-1990s, is found in 14 coastal counties in California, from Monterey to Humboldt, and has infested 10 percent of the at-risk areas in the state. P. ramorum thrives in the coastal climate, and has killed over 5 million tanoaks and true oaks over the past 15 years. It’s still not clear how the pathogen got to Redwood Valley, but it could threaten the dense tanoak forests of the surrounding area, resulting in widespread tree mortality and increased fire hazard.
Much of the on-the-ground effort has been completed by contractors and CAL FIRE handcrews, who have created 100-meter buffers around infected trees by removing California bay laurel (pepperwood) and tanoak, the two hosts that most readily support P. ramorum spore production and spread. Infected plant material has been trucked offsite and donated to the nearby DG Fairhaven Power Company, piled and burned, or lopped and scattered onsite.
Funding from the American Recovery and Reinvestment Act, the USDA Forest Service and NRCS enabled the swift response in Redwood Valley. UCCE used ARRA funds, also known as federal stimulus funds, to hire four people to work on the project, lending stability to the effort.
Landowner support has been critical to the success of the project, according to Valachovic. More than 20 landowners in the valley have allowed monitoring and treatment activities on their properties, recognizing that their cooperation may keep the disease from spreading to other areas.
Figure 2. Chris Lee (UCCE Staff Research Associate) and David Casey
(NRCS Forester) inspecting a treated area
“We couldn’t just stand back and let the disease roll through the forests that we manage, and the landowners understood that,” said Dan Cohoon, who works for Eureka-based Able Forestry, which manages many of the private forestlands in the watershed.
Brandon LaPorte, manager of Cookson Ranch and one of the key landowner collaborators in Redwood Valley, has supported the project from the beginning. LaPorte explained, “We’ve learned a lot about the disease through this project, and we certainly don’t want it getting worse here on the ranch or spreading beyond the valley.”
The first phase of treatment is currently wrapping up, and UCCE is beginning to monitor project efficacy and watch for spread of the pathogen beyond project boundaries. The Yurok and Hoopa tribes will be paying close attention to this effort, as they are only a ridge away from the infestation.
Ron Reed, a Yurok tribal forester, commented, “Oaks are an important part of our culture and history, and we will do what we can to keep sudden oak death out of our forests.
The Redwood Valley project highlights the value of stream monitoring as a detection tool for SOD, but it also demonstrates the ability of agencies and landowners to collaborate swiftly and effectively to protect the region’s forest resources. Maybe most important – regardless of the future course that sudden oak death takes in the North Coast – is what the project shows about the ability of proactive communities concerned about the health of their landscapes to come together, attract the support of state and national authorities, and work to make things better.
The community collaboration is being honored with the Two Chiefs’ Award. The award, which is given jointly by the NRCS and the Forest Service, highlights projects from across the country each year, recognizing exemplary partners who have worked collaboratively to support conservation and forest stewardship. Valachovic will accept the award on behalf of the federal, state, tribal and private partners involved the project at an event in Davis on Wednesday, May 16.
For more information about sudden oak death disease, visit the California Oak Mortality Task Force website at www.suddenoakdeath.org.
For more ANR news, visit
University of California Division of Agriculture and Natural Resources
- Editor: Sophie Kolding
- Contributor: Max Moritz
Although wildland fires are a natural part of forest ecosystems, they can interefere with the planning of land-management activities and may have an array of anthropogenic factors. The article, Spatial variability in wildfire probability across the western United States from the International Journal of Wildland Fire, uses fire obsertvations to produce detailed estimates of wildfire probability, of both natural and anthropogenic factors. The International Journal of Wildland Fire publishes papers that advance basic and applied research concerning wildland fire. The Journal wishes to attract papers on a broad range of wildland fire issues that may include subjects beyond the range of papers published in recent issues. The Journal has an international perspective, since wildland fire plays a major social, economic and ecological role around the globe. The authors of the article, Spatial variability in wildfire probability across the western United States, include Marc-Andre Parisien, Susan Snetsinger, Jonathan A. Greenberg, Cara R. Nelson, Tania Schoennagel, Solomon Z. Dobrowski and Max Moritz.
Here is the article's abstract, along with figures and their descriptions:
'Despite growing knowledge of fire-environment linkages in the western USA, obtaining reliable estimates of relative wildfire likelihood remains a work in progress. The purpose of this study is to use updated fire observations during a 25-year period and a wide array of environmental variables in a statistical framework to produce high-resolution estimates of wildfire probability. Using the MaxEnt modeling technique, point-source fire observations that were sampled from area burned during the 1984-2008 time period were related to explanatory variables representing ignitions, flammable vegetation (i.e. fuels), climate and topography. Model results were used to produce spatially explicit predictions of wildfire probability. To assess the effect of humans on the spatial patterns of wildfire likelihood, we built an alternative model that excluded all variables having a strong anthropogenic imprint. Results showed that wildfire probability in the western USA is far from uniform, with different areas responding to different environmental drivers. The effect of anthropogenic factors on wildfire probability varied by region but, on the whole, humans appear to inhibit fire activity in the western USA. Our results not only provide what appear to be robust predictions of wildfire likelihood, but also enhance understanding of long-term controls on wildfire activity. In addition, our wildfire probability maps provide better information for strategic planning of land-management activities, especially where fire regime knowledge is sparse.'
Figure 1. The study area showing the 11 western USA states, elevation, road density (computed using a 1000-hacircular window), mean annual precipitation, mean annual temperature and land cover that was generalized from the National Gap Analysis.
Figure 2. Mean predicted wildfire probability (based on 25 model replicates) for the Full model (a); the Non-anthropogenic model (b); the absolute change (c); and the relative change (d) from the Full model to the Non-anthropogenic model, whereby green indicates an increase and blue represents a decrease in wildfire probability as a result of human-influenced variables.
To view the entire article, please visit the website: