- Posted By: Sophie Kolding
- Written by: Tom Scott
RIVERSIDE, Calif. – A catastrophic infestation of the goldspotted oak borer, which has killed more than 80,000 oak trees in San Diego County in the last decade, might be contained by controlling the movement of oak firewood from that region, according to researchers at the University of California, Riverside.
“This may be the biggest oak mortality event since the Pleistocene (12,000 years ago),” said Tom Scott, a natural resource specialist. “If we can keep firewood from moving out of the region, we may be able to stop one of the biggest invasive pests to reach California in a long time.”
A cadre of UC researchers is leading the effort to assess and control the unprecedented infestation, in partnership with the U.S. Forest Service. Scott and others are working to identify where the infestation began, how it is spreading through southern California’s oak woodlands, and what trees might be resistant. In October 2010 Scott and other UCR researchers received $635,000 of a $1.5 million grant of federal stimulus money awarded to study the goldspotted oak borer and sudden oak death.
The goldspotted oak borer (Agrilus auroguttatus), which is native to Arizona but not California, likely traveled across the desert in a load of infested firewood, possibly as early as the mid-1990s, Scott said. Researchers have confirmed the presence of the beetle as early as 2000 near the towns of Descanso and Guatay, where nearly every oak tree is infested.
The half-inch-long beetle attacks mature coast live oaks (Quercus agrifolia), California black oaks (Quercus kelloggii) and canyon live oaks (Quercus chrysolepis). Female beetles lay eggs in cracks and crevices of oak bark, and the larvae burrow into the cambium of the tree to feed, irreparably damaging the water- and food-conducting tissues and ultimately killing the tree. Adult beetles bore out through the bark, leaving a D-shaped hole when they exit.
Scott and Kevin Turner, goldspotted oak borer coordinator for UC Agricultural and Natural Resources (ANR) at UCR, said that field studies in San Diego County in the last six months point strongly to the transportation of infested oak firewood as the source of the invasion that threatens 10 million acres of red oak woodlands in California.
Outbreaks have been found 20 miles from the infestation area, implicating firewood as the most likely reason for the beetle infestation leap-frogging miles of healthy oak woodlands to end up in places like La Jolla. In contrast, communities that harvest their own trees for firewood have remained relatively beetle-free, even as adjacent areas suffer unprecedented rates of oak mortality. Both examples support the growing conviction that the movement of infested firewood is the primary means by which the beetles are spreading, Scott said.
California’s coast live oaks, black oaks and canyon live oaks seem to have no resistance to the goldspotted oak borer and, so far, no natural enemies of the beetle have been found in the state.
The devastation can be measured in costs to communities and property owners for tree removal, the loss of recreation areas and wildlife habitat, lower property values and greater risk of wildfires. The three oaks under attack may be the single most important trees used by wildlife for food and cover in California forests and rangelands.
Most of the dead and dying trees are massive, with trunks 5 and 6 feet in diameter, and are 150 to 250 years old. The cost of removing one infested tree next to a home or in a campground can range from $700 to $10,000. The cost of removing dead and dying trees in San Diego County alone could run into the tens of millions of dollars. In Ohio, which has experienced similar losses from the emerald ash borer, several small cities went bankrupt because of tree removal costs associated with that beetle, Scott said.
So many oaks have died in the Burnt Rancheria campground on the Cleveland National Forest – a favorite spot for campers who favored the shade of a dense canopy of coast live oaks – that the Forest Service has had to erect shade structures. Other state and county parks in the region have suffered equally devastating losses.
Turner said an Early Warning System of community volunteers launched in San Diego County now includes representatives from every southern California county as far north as Ventura. Those volunteers are trained to monitor the health of oak trees in their communities and report any unusual changes.
At the same time, a network of UC Cooperative Extension, ANR, U.S. Forest Service and other agencies in the region is working with woodcutters, arborists and consumers to discourage the sale and transportation of infested wood. Wood that is bark-free or that has dried and cured for at least one year is generally safe to transport, Scott said. This relatively small change in firewood-handling methods could save a statewide resource without jeopardizing the firewood industry, he said.
Local, state and federal agencies recognize that firewood production is one of the least-regulated industries in California, and view UC Cooperative Extension education as the best means of stopping goldspotted oak borer movement in firewood.
“Quarantines don’t work, but enlightened self-interest can keep oak woodland residents from importing GSOB-infested firewood,” Scott said. “This is a situation where the university can play a critical role in changing behavior through research and education rather than regulation.”
A cross-section of an oak infested by the goldspotted oak borer shows the damage done by the non-native beetle.
To view original article, Click Here.
Related Links:
Goldspotted Oak Borer Information
GSOB Research at UCR
UC Cooperative Extension
- Posted By: Jaime Adler
- Written by: Michael Hamilton, Director of the Blue Oak Ranch Reserve and Rulon Clark, Assistant Professor at CSU San Diego
One would think that in the oak woodlands, the most important predators would be mammals such as mountain lion, coyote and bobcat. But new field research is discovering that the most important predator may be rattlesnakes in terms of overall biomass. Rulon Clark, an assistant professor at California State University at San Diego, and his team of eight graduate and undergraduate students, are studying rattlesnakes and their prey at one of the newest University of California Natural Reserves, Blue Oak Ranch Reserve. The 3,300 acre reserve is situated on the west slope of Mount Hamilton, only 10 miles from San Jose.
Clark and his students have documented densities of rattlesnakes on the reserve that far exceed any they have previously encountered throughout California, including the remote Mojave Desert. Rattlesnakes have likely been left alone by humans at Blue Oak Ranch Reserve for many decades. Given the local abundance of wild prey, the snakes have reached population levels that may have been typical prior to centuries of persecution by ranchers and hunters, according to Clark.
The rattlesnake researchers, dubbed “Team Crotalus,” have just completed nearly two months of detailed studies of the interactions between the northern Pacific rattlesnake, Crotalus oreganus, and its preferred prey species the California ground squirrel, Spermophilus beecheyi. When confronted by predators, many animals engage in lengthy, conspicuous interactions involving stereotyped signals and displays. These antipredator signals have been studied mainly as warning signals directed toward conspecifics, even though they may also serve to communicate with predators. Studies of how these signals affect predators have been rare because predation is infrequent and difficult to observe in the field.
Team Crotalus has begun assembling a one-of-a-kind database of natural antipredator signaling interactions and predator responses. To do so, they are using a high tech assortment of tools. These range from radio telemetry transmitters surgically implanted in the rattlesnakes, to miniature, battery-powered webcams. The webcams transmit live video of snake/squirrel interactions several miles away to the reserve headquarters for recording and observation. The team also confronts snakes with a mechanical, taxidermied rodent affectionately named “Robosquirrel.” The Robosquirrel is programmed to make antipredator sounds and movements to snakes in experimental encounters. The bouts allow the scientists to test predictions of how predators and prey communicate in controlled experiments. (Watch a video of a robosquirrel being struck by a rattlesnake).
Team Crotalus research has focused on the behavior of rattlesnakes confronted by two prey species, ground squirrels and kangaroo rats. These two distantly related rodents have evolved sophisticated anti-snake behavior independently. Comparing the two rodents’ interactions will allow the scientists to examine the role of various ecological and organismic factors that shape predator-prey signaling interactions. Their unique approach combines these methods in studies that simultaneously consider both prey signaling behavior and predator responses in an experimental context. This system promises to provide novel insights into such areas as honesty in animal communication, antagonistic coevolution, and the role of animal sensory systems in shaping signaling behavior.
For more information:
Bree Putman’s Blog: Strike, Rattle and Roll http://strikerattleroll.blogspot.com/
Rulon Clark Lab http://www.bio.sdsu.edu/pub/clark/Site/Home.html
Blue Oak Ranch Reserve http://www.blueoakranchreserve.org
Contact information:
Rulon Clark <rclark@sciences.sdsu.edu
Hamilton Michael <mphamilton@berkeley.edu
- Posted By: Jaime Adler
- Written by: Greg Giusti, UCCE Forest Advisor
Understanding the Role of History on California’s Oak Forests
In his book The Destruction of California, Ray Dassmann (1965) chronicled the dramatic impact land-use practices have had on wildlife populations throughout California during the past 150 years. He articulates the impacts from the loss of wetlands, forest conversion and urban expansion on a number of economically important wildlife species. In his book, he quotes an early California pioneer, A. B. Clark (1852) who recorded the abundance of vertebrate diversity that was so apparent in the early days of exploration. Mr. Clark wrote, “ I have no where seen game as plenty as in the (central) valley. We killed an antelope in the morning. We could frequently see herds of deer and elk in different directions around us, as well as wild horses”. Today, concentrations of deer, elk and waterfowl populations can be found in remnant habitats distributed in small, isolated patches throughout the valley.
More recently, Walter (1998) provides a complete overview of how past land-use practices have changed the landscape of California so dramatically that in some cases counties “have lost their natural heritage” and are mere remnants of their past biological richness. Brown et. al. (1994) and Marchetti and Moyle (1995) have outlined the once abundant numbers of salmon and how historical land-use practices directly impacted anadromous fisheries and how the legacy of these practices continues to impact these species. They specifically identify water diversions and related watershed degradation caused by past and on-going human activities as the direct cause of these declines. Moyle et. al. (1994) has identified as many as 10 anadromous species (including salmon, steelhead trout, lamprey, sturgeon, smelt) that meet the scientific criteria necessary for special protective status.
The common thread binding the terrestrial and aquatic inhabitants of pre-settlement California is the fact that many of these species were found in areas that we commonly referred to as oak (Quercus) woodlands. In many cases, the abundance that has been chronicled illustrates the importance of oak habitats to many of the species which spent a significant portion of their life history living in, or migrating through, oak woodlands. Because of their ubiquitous distribution oaks have been impacted throughout California during the past century. An early account written by Willis Linn Jepson (1909) states; “In some regions where the horticultural development has been rapid or the needs of an increasing population urgent, extensive areas have been cleared to make room for orchards or gardens, and scarcely a [valley oak] tree remains to tell the story of the old time monarchs of the soil, in other regions the destruction has not been so complete” (Pavlik et. al. 1991). Modern day land-use impacts on oak woodlands continue through urbanization and the conversion of oak woodlands to intensive agriculture.
California’s History of Forest Policy toward Oaks
In 1885, the Governor of California approved an act that authorized the appointment of a three-man State Board of Forestry, the first such body in the nation. Because of a lack of clear statutory authority and minimal budgeting, the original Board was only able to act in an educational and advisory capacity. By 1905, the Board of Forestry was supplemented by creation of the post of State Forester and in 1927 the Division of Forestry was organized.
In 1947, the original Forest Practice Act was passed by the State Legislature. Although the responsibilities and powers of the Board under the old act were less than they are today, the 1947 Act laid important foundations of experience and procedure which led to further development for the Board.
Throughout the period of the 1950s and 1960s, the Board of Forestry functioned under the mandate of the 1947 Act by formulating forest policy for the state. When the Division of Forestry was elevated to departmental status in 1977, the organizational relationship between the Department and the Board was retained. This reorganization of the Department had no effect upon the Board's mandated duties and responsibilities. With the passage of the Z'berg-Nejedly Forestry Practice Act of 1973, the Legislature reorganized the Board and concomitantly expanded its powers and responsibilities. To achieve a balanced approach to forest land policy, the Public Resources Code delineates the character of the Board by designating that five members will be from the general public, three are chosen from the forest products industry, and one member is from the range-livestock industry.
The Board is recognized as having the legislative authority to regulate both privately owned conifer and oak woodland forest types. Historically, the Board has focused its regulatory authority on those lands capable of producing commercial lumber products choosing to support an educationally based program for oak woodlands. The educational path was established with the creation of the University of California’s Integrated Hardwood Management Program (IHRMP) in the mid-1980s. In 1993 the Board delegated to the IHRMP the responsibility of assisting counties in the development of locally based conservation strategies for oak woodlands. In response to this directive, counties have developed a wide array of resolutions, ordinances and monitoring efforts through a variety of committees, Board of Supervisor actions and local initiatives.
Current Forest Policy and Oaks
Under the direction of the Z'berg-Nejedly Forestry Practice Act of 1973 the Legislature identified the timberlands of the State to be “among the most valuable of natural resources….are of great concern ….relating to their utilization, restoration and protection”. The legislature further recognized the need to “encourage prudent and responsible forest resource management while giving consideration to the public’s need for watershed protection, fisheries and wildlife, and recreational opportunities…”. The Act further defined timberlands as, “[non-federal] lands available for, and capable of, growing a crop of trees of any commercial species…..”. The Board further defined “commercial species” to include most economically important conifers and some hardwood species, when growing on timberland.
The impact of the Z'berg-Nejedly Act has continually evolved, since its inception. The Act, through a separate set of Forest Practice Rules, recognizes the need for the protection of watershed elements by establishing minimum standards for streams zone protective widths (by stream class), archaeological sites, soil stability and cumulative effects. These requirements are mandatory for any landowner who wishes to engage in timber harvesting. The Act in combination with the Rules is designed to identify and mitigate any potential negative impacts from the harvesting of timber as a requirement of the California Environmental Quality Act (CEQA). As a result of the Act, a landowner is required to secure the services of a Registered Professional Forester (RPF) to submit a Timber Harvest Plan (THP) for review and approval by the California Department of Forestry and Fire Protection (CDF) prior to the harvesting of commercial tree species. The THP, only one of several vehicles used by CDF and RPFs, is viewed by the State as serving as the functional equivalent of an Environmental Impact Report (EIR) under CEQA..
By definition, most species of Quercus are currently not recognized as commercial species. Only under specific circumstances are pre-determined oak species (Q. Kelloggi and Q. Garryana) recognized by the Forest Practice Rules. In all other situations, if any oak species, including the two identified, occur on lands not designated as timberlands they are not afforded protection under the Forest Practice Act, thereby, not given statewide considerations under CEQA. However, many of these oak woodland species occur as a continuum of forest canopy in many watersheds of California. In many situations throughout the State a common vegetative pattern exists with conifer dominated coastal and mountainous forests transforming into oak dominated types in drier or lower elevation sites.
Inconsistency is in the Policy not the Forests
An obvious inherent conflict with current land-use forest policy is the recognition of tree species (and thereby habitats) afforded protections under CEQA relative to their economic values and not their ecological values thereby creating an artificial delineation of forest types. A glaring example of the inherent inconsistency with this current policy situation is best exemplified by the State’s role in providing protection to salmonid species in northwestern California under CEQA. Under the current Forest Practice Rules, salmon and steelhead, are afforded some level of protection (though a recent independent scientific panel determined the level of protection was inadequate to protect salmonid resources: Ligon et. al. 1999) when they enter freshwater habitat located in a conifer forest setting. However, in many cases, those same fish will continue their upstream migration passing through the conifer belt and ultimately complete their journey in a predominately, oak woodland habitat type. This scenario is true for fish in the Russian, Navarro, Eel, Klamath, Smith and Sacramento and San Joaquin River systems. Under these scenarios, the stream and the forest cover represent an ecological continuum for the fish as it moves through the system from the marine environment to its natal spawning grounds in order to complete its life history. Furthermore, once spawned and hatched, many of the juvenile fish will spend a significant portion of their early life stages in the oak dominated portions of the watershed. However, as the fish move from one forest type to another, the level of protection is not contiguous thereby providing only a minimal level of protection for a small portion of the overall habitat.
This inconsistent application of standardized protective measures is most apparent in those counties with the absence of local requirements to mitigate land-use impacts on streams i.e. grading ordinance, stream zone buffers, etc. Under the existing statewide forest management policies the current statewide mechanism to protect forest streams (Forest Practice Rules) do not provide a continuous level of protection throughout a watershed based on the definition of commercial vs. non-commercial tree species.
The lack of a standardize statewide approach to oak conservation has promoted a variety of measures to be developed, modified and implemented throughout the oak region of California in an attempt to address both riparian and upland issues. A collection of resolutions (Tehema, Shasta, Madera Counties), ordinances (Sonoma, Napa, Santa Barbara), evaluation committees (Lake, Madera), monitoring efforts (El Dorado) and ballot measures (Santa Barbara) targeting an equally wide array of issues. In many instances, the adopted mechanisms have focused on a single resource issue such as water quality (Napa and Sonoma Counties) or heritage tree preservation (various county tree ordinances) and have not produced comprehensive measures with adequate monitoring mechanisms capable of evaluating their effectiveness or large landscapes or watersheds.
The current inconsistencies in oak management policies and strategies will certainly continue to fuel the intense debates currently underway throughout the oak region of California as land-use practices increase in scope and magnitude. A need exists to evaluate current local policies and develop comprehensive strategies that promote, protect and enhance oak woodlands and all of their inherent resources.
Literature Cited
Brown, L. R., P. B. Moyle and R. M. Yoshiyama. 1994. Historical Decline and Current Status of Coho Salmon in California. No. Am. J. of Fisheries Mngt. 14: 237-261.
Dassman, R. F. 1965. The Destruction of California. MacMillan Co. New York. 247pp.
Marchetti, M. P. and P. B. Moyle. The decline of sea-run fishes in California: An ongoing tragedy. Cal Ag. 49 (6): 74.
Moyle. P. B. 1994. The Decline of Anadromous Fishes in California. Consv. Biol. 8 (3) 869-867.
Walter, H.S. 1998. Land Use Conflicts in California. Eco. Studies 136:108-125.
- Author: Jaime Adler
To Register Click Here by June 24th!
When: Thursday, June 30, 2011 9:00am-2:30pm. Please register by Friday, June 24th.
Where: Avenales Ranch Road, Pozo, CA 93453, San Luis Obispo County . We will meet at the American Canyon Forest Service Campground
Who: Anyone interested in research, education, management and conservation of oak woodland ecosystems. This includes landowners and managers, consulting range managers and registered professional foresters, community and conservation groups, land trusts and policy makers.
What: Agenda for the day
9:00 am - Arrive for coffee and registration
10:00 am - Brief Introduction to Avenales Ranch
10:15 am - Oak woodland management concerns
10:30 am - Oak regeneration, seeding, stump-sprouting
11:15 am - Oak thinning, measuring, management
12:00 pm - Lunch*
12:45 pm - Forest production and management
1:15 pm - Wildlife in Oak woodlands
1:45 pm -Sycamore regeneration study
2:15 pm - Alternative Review Program
2:30 pm - Adjourn
*Please remember to bring your own bag lunch.
In addition, appropriate clothing and footwear are recommended. There will be some off-trail hiking.
Please register by June 24th by Clicking Here!
For more detailed information, including directions, please Click Here! Please note: you do not need to be an Oak Webinar participant to attend this field trip.
Questions? Email Rick Standiford: standifo@berkeley.edu
Pictures from one of our field trips to the Sierra Foothills Research and Extension Center:
- Posted By: Jaime Adler
- Written by: Bill Tietje and Royce Larsen, UC Cooperative Extension
California residents who want to plant an oak tree or two on their property, often find it challenging, given our climate with irregular winter rains and no summer rainfall, to keep the newly-planted trees green and growing. A devise that has come onto the market recently is dubbed the “Groasis Waterboxx”. According to the website (Groasis.com) the Waterboxx has proven effective at “self-watering” new plantings, even in a truly desert climate.
Recently, we started a trial to test the Waterboxx by planting some oak seedlings and elderberry plants in a remote area. The Waterboxx is a round plastic “box” that fits around the tree trunk. The inward-slanting corrugated top cools during the night and channels condensed dew and heavy fog that collects on the top to the base of the tree. The Waterboxx also provides some protection for the newly planted tree and reduces the evaporation of water from the soil around the base of the tree, important additional benefits for new plantings. Once the tree is established, the Waterboxx can be removed and reused for another plant. Placing a collar around a tree that collects moisture and at the same time provides some protection can be a big incentive and a boost to getting that tree started.
As you can understand, the Waterboxx can be a big help as an alternative to carrying water to distant areas or setting up a drip system. For more information about the Waterboxx, contact your local UC Cooperative Extension Office or go to the Groasis Waterboxx website: Groasis.com. On the website you will notice that the inventor of the Waterboxx is providing users the opportunity to provide information on the growth and survival of their plantings. You may want to check it out.
