61st Annual Meeting of the California Forest Pest Council - 2012
Invasive Species and Illegal Activities
Threats to California Forest Health
Meeting Abstracts
November 7 - 8, 2012
Wildland Fire Training and Conference Center, McClellan, CA
About the California Forest Pest Council (CFPC)
The California Forest Pest Council (CFPC) fosters education concerning forest pests and forest
health, and advises the California Board of Forestry and Fire Protection on forest health
protection issues. It comprises a diverse group of forestry professionals and others interested
in the prevention of damage to forests from insects, pathogens, animals, weeds, and pollution.
Meetings are held throughout the State to discuss and evaluate current forest pest conditions.
The annual meeting is the most important, providing the membership a chance to review what
has happened in the last year, to formulate and vote on resolutions, and to address topics of
special concern. Membership in the CFPC is granted to anyone attending. The CFPC is a 501(c)3
non-profit corporation (Tax-ID 94-3248518).
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2012 Conference Organizers
Kim Camilli, Council Secretary and Southern California Committee Chairperson, California
Department of Forestry and Fire Protection, Paso Robles, CA, kim.camilli@fire.ca.gov
Danny Cluck, Insect Committee Chairperson, USDA Forest Service, Forest Health Protection,
Susanville, CA, dcluck@fs.fed.us
Susan Frankel, At-Large Director, USDA Forest Service, Pacific Southwest Research Station,
Albany, CA, sfrankel@fs.fed.us
Greg Giusti, Animal Damage Committee Chairperson, University of California Cooperative
Extension, Mendocino County, Lakeport, CA, gagiusti@ucdavis.edu
Stephen Jones, Council Treasurer, California Department of Forestry and Fire Protection
Sacramento, CA, stephen.jones@fire.ca.gov
Martin MacKenzie, At-Large Director, Stanislaus National Forest, Sonora, CA,
mmackenzie@fs.fed.us
Patricia Maloney, Disease Committee Secretary, Department of Plant Pathology, Davis, CA,
pemaloney@ucdavis.edu
Brent Oblinger, At-large Director, USDA Forest Service, Forest Health Protection,
boblinger@fs.fed.us
Don Owen, Firewood Task Force Chairperson, California Department of Forestry and Fire
Protection, Redding, CA, Don.Owen@fire.ca.gov
Katie Palmieri, Conference Committee Chairperson, California Firewood Task Force and Oak
Mortality Task Force/UC Berkeley, Berkeley, CA, kpalmieri@berkeley.edu
Bob Rynearson, Council Chairperson, W.M. Beaty & Associates, McArthur, CA,
bobr@wmbeaty.com
Tom Smith, Disease and Editorial Committee Chairperson, California Department of Forestry
and Fire Protection, Davis, CA, tom.smith@fire.ca.gov
Meeting Sponsors
The USDA Forest Service, Pacific Southwest Region, State and Private Forestry, Forest Health
Protection
The USDA Forest Service, Pacific Southwest Research Station
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Invasive Species and Illegal Activities - Threats to California Forest Health
Program of Events Summary
Wednesday, November 7, 2012
12:00
12:45
12:50
1:05
2:30
2:45
4:15
4:30
5:30
6:30
pm
pm
pm
pm
pm
pm
pm
pm
pm
pm
Registration
Welcome
2012 Forest Conditions and Aerial Survey
Insect Committee Meeting (All are welcome)
Break
Disease Committee Meeting (All are welcome)
Break
Pesticide Laws and Regulations
Poster Session and Social
Adjourn
Thursday, November 8, 2012
8:00 am
Registration
8:30 am
Welcome
8:35 am
New and Noteworthy
10:10 am
BREAK
10:30 am
New and Noteworthy, continued
11:20 am
Ongoing California Forest Health Issues
12:30 pm
LUNCH (included)
1:30 pm
The Impact of Illegal Activities on California Forest Health, In Cooperation with
the Jere Melo Foundation
2:35 pm
BREAK
3:00 pm
Managing Forest Pathogens, Insects, and Weeds During Complex Construction
Projects
3:40 pm
Forest Issues Related to Vertebrate Management
4:45 pm
Adjourn
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4
Oral Presentation Abstracts
(In Agenda Order)
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6
Ecological Assessment of Jeffrey Pine Beetle-Caused Mortality from
1991-1996 near Spooner Junction, Lake Tahoe Basin
Joel M Egan, USDA Forest Service, Northern Region Forest Health Protection, 200 E
Broadway, Missoula, MT 59801; jegan@fs.fed.us; J. McLean Sloughter, Seattle University,
Seattle, WA; Tamre Cardoso, TerraStat Consulting Group, Seattle, WA; Patrick Trainor,
University of Louisville, Louisville, KY; David Fournier, USDA Forest Service, Lake Tahoe
Basin Management Unit, South Lake Tahoe, CA; Hugh Safford, USDA Forest Service, Pacific
Southwest Region, Vallejo, CA; John Wenz, USDA Forest Service, Retired
A Jeffrey pine beetle (Dendroctonus jeffreyi Hopkins) (JPB) epidemic caused Jeffrey pine (Pinus jeffreyi
Grev. and Balf.) mortality throughout the Lake Tahoe Basin from 1991-1996 following multiple years of
below average precipitation. Census data, including geospatial location and tree attribute data for 10,721
stems, were obtained from a continuous, 60-acre study area near Spooner Junction that was established to
assess JPB activity without management intervention. This epidemic is considered to be at the high end
of potential outbreak scenarios based on prior outbreaks documented within the Lake Tahoe Basin.
We quantified conditions within the study area that supported this outbreak, mortality levels, effect of
JPBs on forest attributes, and conditions that were resilient to JPB-caused mortality. The study area was
located on south-facing slopes that ranged from 5-20%. Forest conditions averaged 15" quadratic mean
diameter, 302 stand density index (SDI), 37% canopy cover, and 95% Jeffrey pine host species
composition. JPBs caused mortality in 44% of all available Jeffrey pines within the study area at a rate of
74 trees per acre. The JPB-caused mortality (trees per acre) response had a strong positive, linear
relationship with stand density index in a best-fit, mixed regression model that adjusted for significant
spatial autocorrelation. Tree mortality occurred in proportion to available hosts in stems < 30" diameter
at 4.5 feet in height (DBH); however, mortality was disproportionally less in stems > 30" DBH. Portions
of the study area with < 210 SDI or 125 square feet of basal area per acre were resilient to extensive tree
mortality even after exposure to high levels of JPB population pressure.
Additionally, for each year of the outbreak, probability of infestation for individual trees was modeled
using probit regression. We examined several models, each with a single tree-level or neighborhood
predictor variable to assess which had the greatest influence on the probability of JPB-caused tree
mortality. Tree-level predictors that had highest influence included DBH and distance to nearest brood
tree. Two neighborhood-based predictors also highly influenced the probability of mortality. These were
total basal area of infected trees, a proxy for localized bark beetle population pressure, and total SDI
within half-acre neighborhoods.
Model runs using DBH showed that, for initial attacks during an incipient population stage (1991), there
was a negative relationship between DBH and probability of mortality. That is, trees with smaller stems
had greater probability of attack while larger stems had relatively less probability of infestation. The
following year (1992) appeared to be a transition, incipient-epidemic year with no significant DBH effect.
A switch towards enhanced probability of mortality in larger diameter stems occurred during the epidemic
population stage (1993 – 1994). During post-epidemic years (1995 – 1996) when the levels of tree
mortality declined, the DBH effect switched and probability of mortality was reduced with increasing
stem diameter, which was similar to the incipient stage. Model runs using distance to nearest brood tree
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were restricted to within 164 feet of the nearest brood tree to capture a negative linear response with this
variable. Distances greater than 164 feet showed no obvious relationship with probability of tree
mortality. The nearest brood tree predictor was significant in all years, with higher mortality associated
with closer proximity to a brood tree. There were no obvious changes in the distance to brood tree effect
from year to year. Model runs using total basal area of infected trees within half-acre neighborhoods
showed significant positive effects on mortality in transition incipient-epidemic and epidemic years (1992
– 1994). The effect was not significant during the post-epidemic period from 1995 – 1996. Model runs
using total live SDI within half-acre neighborhoods had significant, positive linear effects on mortality for
all years of the outbreak except for the peak of the epidemic in 1994. During this year, it appeared that
distance to nearest brood tree, infested basal area within half-acre neighborhoods, and DBH were most
influential for predicting mortality. Additional work will create best-fit models that incorporate multiple
predictor variables.
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Tree Diseases in Southern California
James Downer, University of California Cooperative Extension, 669 County Square Drive,
Suite 100, Ventura, CA 93003; ajdowner@ucanr.edu
Because of a mild climate, Southern Californians enjoy a diverse urban forest with well over a thousand
species of ornamental trees. Southern California is also home to several international airports, harbors,
and ports of entry. With a burgeoning population of over 15 million people, there is constant pest
movement into California. For this reason, there was an upsurge in plant pathogens over the last 20 years.
Pest-free genera such as Eucalyptus collected an array of new insect pests. Shade tree diseases became
more numerous, and host ranges have been extended as new insect vectors and new fungal pathogens
entered Southern California. Native pathogens such as Armillaria mellea and Botryosphaeria dothidea
also make extensive use of ornamental/non-native tree hosts.
Nurseries continue to propagate plant pathogens and sell them with nursery stock. Root rot diseases
caused by Phytophthora spp. are common nursery inhabitants and are often sold with trees and other
ornamental plants into otherwise “clean” landscape settings. Phytophthora-caused root rots are common
in landscapes killing both monocotyledon (palms) and dicotyledon trees. Diagnosis and treatment of root
rots involves not only symptom recognition but also sampling and in-vitro culture of the pathogen.
Management of root rots is bet attained with integrated approaches involving cultural, biological and
fungicidal controls.
Palms are iconic trees in the Southern California urban forest. Twenty five years ago there were a
handful of palm diseases mostly affecting Washingtonia filifera, the California Fan palm. Palms are
extensively planted in new landscapes and the species diversity of landscape palms has increased. The
number of new diseases and insect pests of palms is also increasing. Curiously, unlike dicotyledon trees,
new insects of palms have not increased to the extent of new pathogenic fungi. Several new blight fungi
have been discovered as well as new wilt fungi. We have also begun to clarify the roles of fungi in
causing palms to decay and observed various rot fungi on their stems. Current research is focused on
Fusarium wilt of Canary Island Date Palm.
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Forest Health and Mortality Trends Across Elevation Zones in the
Lake Tahoe Basin
Camille Jensen, University of California, Davis, Tahoe Environmental Research Center, 291
Country Club Drive, TCES 3rd Floor, Incline Village, NV 89451; jensencamille@gmail.com;
Patricia Maloney, University of California, Davis, CA; Detlev Vogler, USDA Forest Service,
Institute of Forest Genetics, Placerville, CA
Biotic (e.g., pathogens, insects) and abiotic (e.g., fire, drought) disturbance agents are important
influences in Sierran conifer forests. Many of the pathogens and insects present are endemic and play a
vital role in forest dynamics. However, anthropogenic disturbances such as the introduction of exotic
organisms, historical land-use (e.g., logging, fire suppression policies), and human-induced climatic
warming can influence the activity, spread, and frequency of biotic and abiotic stressors.
The Lake Tahoe Basin serves as a model system to study forest health and mortality trends in Sierran
conifer forests across elevation zones. Lower elevation mixed-conifer forests vary in composition but are
generally a mix of Jeffrey pine, white fir, sugar pine, incense cedar, ponderosa pine, and lodgepole pine.
Jeffrey pine dwarf mistletoe was observed in these forests on 35% of host trees present. Upper montane
forests are dominated by red fir, western white pine, and lodgepole pine. In the upper montane forests we
observed the highest levels of mountain pine beetle activity, with a mean incidence of 11% (range: 030%). Subalpine forests of the Lake Tahoe Basin are dominated by whitebark pine with some mountain
hemlock, lodgepole pine, red fir, western white pine, and occasional Jeffrey pine. White pine blister rust
is the largest biotic threat to whitebark pine in the Lake Tahoe Basin with a mean incidence of 35%
(range: 1-65%). Average percent mortality observed in the lower mixed-conifer, upper montane, and
subalpine forests was 9.4, 10.8 and 2.6%, respectively. The cause of death was most often attributed to
multiple biotic and abiotic stressors rather than having a single causal agent.
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Arbuscular Mycorrhizal Colonization of Giant Sequoia
(Sequoiadendron giganteum) in Response to Canopy Gap
Restoration
Robert A. York, Research Station, UC Berkeley UC Center for Forestry, 4501 Blodgett Forest
Road, Georgetown, CA 95634; ryork@berkeley.edu
Natural regeneration of giant sequoia (Sequoiadendron giganteum) is threatened by the absence of
moderate and local high-severity fires that create canopy gaps. The creation of artificial canopy gaps is a
potential tool for giant sequoia restoration. However, little is known about how these practices affect
giant sequoia mycorrhizae. Mycorrhizal fungi colonize the roots of most terrestrial plants and improve
plant mineral nutrient uptake in exchange for plant-assimilated carbon. A better understanding of the role
that mycorrhizal associations play in the regeneration of giant sequoia seedlings within canopy gaps will
assist restoration efforts. In this study, conducted within a native giant sequoia grove, we investigated the
impact of: (1) sapling location within gaps, (2) gap size, and (3) soil substrate on arbuscular mycorrhizal
(AM) fungal colonization of giant sequoia sapling roots. We correlated the levels of AM colonization
with sapling height growth. Furthermore, we examined community composition of AM fungi in giant
sequoia roots. Gap size and the within gap position of saplings had a significant effect on AM root
colonization. Saplings located at the southern edges of gaps had less AM colonization than the centers
and north edges. Saplings in small gaps were more likely to support AM fungal storage vesicles in their
roots than saplings in large gaps. Soil substrate (ash versus bare mineral soil) had no effect on the extent
of root colonization. When considering patterns in above and below-ground resource availability, our
findings suggest that AM colonization is controlled by availability of plant-assimilated carbon to the
fungus rather than by the AM fungal supply of nutrients to the tree roots, in turn suggesting that light, not
belowground nutrients are limiting in this system. Additionally, AM fungal colonization exhibited a
negative correlation with other non-AM fungal species, indicating a potential protective function of AM
against pathogens. Giant sequoia is an iconic species that can be used to drive restoration of entire
habitats and the role of mycorrhizae in these practices should be carefully considered. Our study suggests
that practices that affect light availability and carbon assimilation alter feedbacks between sapling growth
and activity of AM fungi in the roots, and may affect root colonization by other potentially pathogenic
fungi.
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Wildfire Influences Forest Disease Dynamics Through Selective
Host Mortality and Pathogen Suppression: Sudden Oak Death in
Big Sur, CA
Margaret R. Metz, Kerri M. Frangioso, and David M. Rizzo, University of California, Davis,
CA 95616; mrmetz@ucdavis.edu; Maia M. Beh, University of California Cooperative
Extension-Humboldt County, Eureka, CA 95503; Ross K.Meentemeyer, University of North
Carolina, Charlotte, NC 28223
Most disease ecology in natural plant communities has focused on shifts to community composition due
to disease without consideration of the role of endemic or interacting disturbances. Sudden oak death
(SOD), caused by the exotic pathogen Phytophthora ramorum, is an emerging forest disease associated
with extensive tree mortality in coastal California forests. Wildfire is an important endemic disturbance
in these forests, also influencing community composition in the absence of SOD. Fire may impact SOD
directly through suppression of P. ramorum or indirectly through mortality of important hosts for the
epidemiology of the disease. Using surveys of burn severity, tree mortality, and regeneration following
wildfires in SOD-impacted forests, we ask (1) how wildfire affected the survival of the pathogen; and (2)
how the impacts of the fire for dominant tree species differed under the separate or joint influences of
SOD and wildfire. Both disturbances cause selective patterns of mortality because trees differ in their
susceptibility to mortality from SOD and fire. In two habitat types, the dominant hosts for pathogen
sporulation suffered greater fire-caused mortality than other species, which should lead to disease
suppression in burned, infested areas relative to unburned, infested areas. We observed such suppression
because only 20% of sampled, previously infested burned areas were found to contain the pathogen
immediately following the fire. In many sites where P. ramorum was no longer recovered, we found
other non-native Phytophthora species that we previously detected only in areas without P. ramorum,
indicating the possibility that fire affected the competitive dynamics of the pathogen. There were also
synergistic interactions of the fire and disease as mortality from the co-occurrence of the disturbances was
not always predictable from the impacts of either disturbance alone. For example, coast redwood is
resilient to either disturbance alone, but had greatly elevated mortality in areas experiencing both SOD
and fire. Outside of burned areas, forest composition has been shifting to dominance by sporulating
species that do not die from pathogen infection, leading to positive feedbacks on disease prevalence in
these areas and continued mortality of hosts suffering lethal infections. The trajectory of post-disturbance
recovery thus differs greatly among sites depending on the separate or joint influences of SOD and fire
because of changes to host abundance by each disturbance.
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Fusarium Dieback and the Polyphagous Shot Hole Borer: An
Invasive Disease/Pest Complex Threatening Agricultural and
Natural Landscapes in California
Akif Eskalen, Department of Plant Pathology and Microbiology, University of California,
Riverside, CA 92521; akif.eskalen@ucr.edu; R. Statouhamer, Department of Entomology,
University of California, Riverside, CA 92521; M. Twizeyimana, S.C. Lynch, D. H. Wang,
and J. S. Mayorquin, Department of Plant Pathology and Microbiology, University of
California, Riverside, CA 92521
The Polyphagous Shot Hole Borer (PSHB) is an ambrosia beetle that forms a symbiosis with a new, yet
undescribed Fusarium sp. and is a serious problem for the Israeli avocado industry. In California, PSHB
was first reported on black locust (Robinia pseudoacacia) in 2003, but there are no records of fungal
damage. In 2012, several backyard avocado trees and landscape trees in urban forest exhibiting branch
dieback were observed in Los Angeles and Orange Counties. Upon inspection, symptoms of white
powdery exudate, either dry or surrounded by wet discoloration of the outer bark in association with a
single beetle exit hole, were found on the trunk and main branches of the trees. Examination of the cortex
and wood under the exit hole revealed brown discolored necrosis. The PSHB was also found within
galleries that were 1 to 4 cm long going against the grain. Symptomatic cortex and sapwood tissues were
plated onto potato dextrose agar amended with 0.01% tetracycline (PDA-tet). After 5 days of incubation
at room temperature, regular fungal colonies with aerial mycelia and reddish brown margins were
produced. Fungal identification was determined by using the rDNA internal transcribed spacer (ITS), and
elongation factor (EF1-α) and primers. Pathogenicity tests were conducted by inoculating detached green
shoots of healthy avocado trees. Lesions were observed on all inoculated shoots except for the control.
Mean lesion lengths were 12.8 cm 3 weeks after inoculation. This is the first report of symbiotic
Euwallacea sp. and Fusarium sp. on avocado and landscape trees in California.
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Epic Devils Windstorm and Forest Blowdown in the Middle Fork of
San Joaquin River Valley
Deanna M. Dulen, DOI-National Park Service (NPS), Devils Postpile National Monument,
Mammoth Lakes, CA 93546; Deanna_Dulen@nps.gov
On November 30th to December 1st, 2011, an extreme wind event affected the central Sierra Nevada
mountain region of California, causing extensive windthrow of trees. The wind event was caused by an
extreme pressure gradient from north to south over Nevada and the Sierra. This was unusual for the
region in its duration, atypical wind direction, and high intensity wind. This combination of winds lasting
over 12 hours, at speeds from 100 and gusting to over 200mph, and from the north to the south, combined
factors creating a, “perfect storm.” The consequences altered the extensive homogeneous stand of old
growth forest into a patchwork of downed trees with openings for new growth. The ecological effects of
this disturbance provide a rich source of research opportunities.
A draft manuscript is in process called Attributes of Wind thrown Trees in a Sierra Nevada Mixed Conifer
Forest by Kathleen Hilimire, Devils Postpile National Monument, Mammoth Lakes, CA; Jonathan
Nesmith, Sierra Nevada Network Inventory and Monitoring Program, Three Rivers, CA; Rhett Milne,
National Weather Service, Reno, NV, and is anticipated to be in print in 2013. Findings from the research
will include forest species, direction, blowdown/snapping, and preliminary beetle activity. The
description of the event that will be published includes:
“Within Devils Postpile National Monument, there were approximately 118.5 windthrown trees/km.
Average diameter at 1.37 m of windthrown trees was 55.36 cm, 2.3 times greater than pre-windstorm
standing trees. Trees differed in damage type; 86% of trees were uprooted, while 14% were snapped.
Tree species was not a factor in likelihood of windthrow. This wind event is the most extensive on record
for California’s Sierra Nevada mountain range and may have long lasting impacts on forest composition.”
NPS staff; Beverly M. Bulaon, U.S. Forest Service Forest Entomologist, Forest Health Protection, South
Sierra Shared Service Area; and Johnny Nesmith, Forest Ecologist, Sierra Nevada Inventory and
Monitoring program, collaborated in gathering observations and data on beetle activity. Thus far, beetles
were active around the campgrounds early in the season as the fire crews were cleaning up the debris, but
as for the general forested areas where blowdown occurred not much has been happening. Monitoring
will continue through fall 2013. For more information about the blowdown, see the podcast, “A Look at
the November 2011 Wind Event,” an interview with Ecologist Jonathan Nesmith at
http://www.nps.gov/depo/photosmultimedia/videos.htm.
A significant challenge for the NPS was addressing the volume of downed trees and slash. Multiple
efforts included the gathering of slash in the visitor use and developed area, and transporting these green
loads to a local landfill to be used for chipping for local dust abatement. A serendipitous opportunity
coincided with providing split logs as firewood to campers, while increasing public awareness of the
importance of Keeping Fuelwood Local education efforts to prevent the transport of non-native bugs that
could disrupt the forest ecology. Efforts are underway to manage the fuel accumulation with downed
trees and slash through stacking piles for a prescribed burn in fall 2013.
In closing, I wish to invite interested researchers to consider the rich source of research opportunities.
Please see the attached list of suggested research topics. The staff provides hospitality and appreciation to
researchers, and the setting provides an area that is “Large enough to be meaningful, small enough to be
manageable.”
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Suggested Research Topics
1) Quantify extent and severity of windthrow using images from the Annual Detection Mortality Survey
or other aerial image data.
a) Describe patch size and develop a severity metric.
b) Record species of windthrown trees.
c) Investigate relationship between landscape factors (e.g., topographic features, forest composition,
demography, and juxtaposition) and severity and location of blowdown patches.
2) Monitor regeneration in blowdown patches and compare to controls.
a) Assess forest (species and community) diversity changes at plot-scale and landscape-scale.
b) Compare regeneration in various disturbances from Rainbow Fire, mechanical treatment for
hazard fuel reduction, and sites of multiple disturbances.
3) Monitor beetle dynamics in and around windthrow patches.
a) Compare dynamics of beetles that typically infest standing live trees versus those that infest slash.
4) Model fire severity and probability related to the blowdown.
a) Monitor dead and down trees for drying.
b) Describe connectivity (or lack thereof) between blowdown patches.
5) Study wildlife and trophic relationships (e.g., birds, mammals, and plant species) as they relate to the
blowdown.
a) Describe changes to habitat resulting from windthrow.
6) Assess the relationship of the blowdown to invasive plant incidence.
a) Monitor root pits for invasive species.
7) Investigate root structure of trees and whether it contributed to vulnerability of trees to windthrow.
a) Calculate density of root wood.
b) Describe substrate and rooting depth.
8) Research watershed and hydrology impacts related to blowdown.
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Forest Health Survey of Northeastern California Aspen
Danny Cluck, USDA Forest Service, Pacific Southwest Region Forest Health Protection, 2550
Riverside Drive, Susanville, CA 96130; dcluck@fs.fed.us
In 2009, Forest Health Protection established ninety-one long-term monitoring plots throughout NE
California on the Modoc, Lassen, Plumas, and Tahoe National Forests (USFS) and the Surprise, Alturas,
and Eagle Lake Resources Areas (BLM). These plots were designed to describe aspen stand tree species
composition, size class, condition, and to document insect, disease, animal, and abiotic damage.
Brief summary of results:






Many aspen stands in NE California have two distinct layers; a decadent overstory (60% of trees
dead or with moderate to severe dieback) and an understory with adequate sprouts (3450
sprouts/acre average).
The bronze poplar borer was the most documented woodborer in NE California.
The large aspen tortrix was the most documented foliage feeder.
Sooty-bark canker was the most frequently recorded disease in NE California.
Browsing of aspen regeneration by wild and domestic ungulates was high in NE California,
recorded as the primary damaging agent on 43.2% of sprouts on 47.3% of plots. At the stand
level, 70.3% had evidence of browsing.
The overall percentage of aspen tree mortality was 10.1% in NE California.
Discussion
Many common insect and disease agents of aspen that are found throughout the west were also found in
NE California. Despite the presence of these common insect and disease agents, they are impacting aspen
health far less than other biotic factors such as animal browsing and conifer encroachment and abiotic
factors such as drought.
A decline, characterized by the dieback and mortality of large diameter aspen stems, in many NE
California aspen stands is occurring. However, most of the stands where this is occurring appear to have
adequate regeneration. This type of decline does not fit the definition of Sudden Aspen Decline nor does
it necessarily indicate that these stands are at a high risk of disappearing from the landscape in the near
future.
The full document is available at the Pacific Southwest Region, (Region 5) Forest Health Protection
website: http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5365578.pdf.
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2012 Update of Balsam Woolly Adelgid, Adelges piceae, in
Northwest California
Jack Marshall, California Department of Forestry and Fire Protection, Ukiah, CA;
Jack.Marshall@fire.ca.gov
BALSAM WOOLLY ADELGID – Adelges piceae
Balsam wooly adelgid (BWA) was first reported in California in a 1928 publication, wherein the author
reports BWA collected from Abies pectinata, A. nobilis, A. nobilis var. glauca, and A. grandis in Golden
Gate Park (San Francisco Co.) and from A. grandis in Hillsborough (San Mateo Co.). No dates were
given for the CA collections, but the assumption is that they were made before 1928. The author also
indicated that it was quite likely that BWA was more widely distributed.
Damage in Oregon (grand fir near Salem) noticed in 1930 indicated BWA was also likely in Oregon in
the 1920s. In the Pacific Northwest (OR, WA, ID, BC), BWA primarily attacks subalpine fir and Pacific
silver fir in mountainous areas, and grand fir in lowland valleys (old FPL #118). BWA may now be in
NW Montana.
BWA was later found in Palo Alto (Santa Clara Co.) (host unknown) in 1934 and at UC Berkeley
(Alameda Co.) (host unknown) in 1958.
Nothing was reported again until 1986 when a very light infestation on A. nordmanniana was found in
Capitol Park in Sacramento (Sacramento Co.) and an extremely heavy infestation was found on a true fir
in Los Altos (Santa Clara Co.).
In 2012, BWA populations have been found on grand fir along a 20-mile stretch of coastal Mendocino
County from the mouth of Ten Mile River, south to Dark Gulch. Woolly stem infestations were found at
all 14 sites, but grand fir in the Ten Mile River locations had the most pronounced gouting of branches.
Where gouting occurs, crowns seem most affected on leeward sides and at mid-crown locations. Fir
engraver beetle-killed trees were found at Ten Mile River and Inglenook, but a close association between
these attacks and BWA infestation is not known. One property near Cleone had over half of its 70 grand
fir infested, with heavily infested stems showing lots of pitching. No trees there have yet died from these
infestations.
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iPhone® Mobile Application for Citrus Disease Reporting
Larry Hawkins, USDA Animal and Plant Health Inspection Service, Regional Legislative and
Public Affairs Office, 650 Capitol Mall, Suite 6-400, Sacramento, CA 95814;
lawrence.e.hawkins@aphis.usda.gov
USDA’s Animal and Plant Health Inspection Service (APHIS) is engaged in public education and
outreach to prevent the introduction and spread of invasive plant pest and diseases. APHIS developed the
HungryPests (www.hungrypests.com) campaign to provide plant pest information and education
resources to stakeholders and the public in an effort to generate discussion about this serious problem and
help provide firm actions the public can take to preserve agricultural and natural resources impacted by
invasive plant pests and diseases.
APHIS’s Save Our Citrus (www.saveourcitrus.org) campaign, coordinated with the HungryPests theme,
works to prevent the further spread of citrus pests and diseases. The primary goal of the campaign is to
increase public awareness (particularly among travelers and online consumers) of the potential risks
associated with moving citrus plants and products. Several diseases of citrus – citrus canker, citrus
greening, citrus black spot, and sweet orange scab – are already here in the United States. And other
citrus pests and diseases are just offshore waiting for an opportunity to enter the country. Each day U.S.
citizens and visitors to this country unknowingly and often unintentionally put U.S. citrus at risk by
moving citrus plants and products. From buying an orange jasmine plant online for their garden or asking
a relative in another country to mail specialty items like curry leaves for a favorite recipe, U.S. citizens
are unwittingly helping citrus pests and diseases enter and move around the country.
In 2012, APHIS developed and launched a Save Our Citrus native iOS mobile device application and a
web administrative tool. The iOS application allows users to link to the saveourcitrus.org website and
PSA video, create and save a unique profile, view a diagnostic library of citrus disease symptoms, report a
citrus disease, and view other public outreach information such as links to social media and the
hungrypests.com website.
18
Trends and Causes of Severity, Size, and Number of Fires in
Northwestern California
Carl Skinner, USDA Forest Service, Pacific Southwest Research Station, Redding, CA;
cskinner@fs.fed.us; Jay Miller, USDA Forest Service, Region 5, Fire and Aviation
Management, McClellan, CA; Hugh Safford, USDA Forest Service, Region 5, Ecology
Program, Vallejo, CA.; Eric Knapp, USDA Forest Service, Pacific Southwest Research Station,
Redding, CA; Carlos Ramirez, USDA Forest Service, Region 5, Remote Sensing Lab,
McClellan, CA
Research in the last several years has indicated that the frequency of large fires is on the rise in western
US forests. Although fire size and frequency are important, they do not necessarily provide information
concerning the effects of fire on ecosystems, as ecosystems differ in ecological and evolutionary
relationships with fire. Our study focused on the four National Forests of NW California (Klamath,
Mendocino, Shasta-Trinity, and Six Rivers). We assessed: 1) trends and patterns in fire size and
frequency from 1910-2008 (all fires >40 ha), and 2) percentage of high-severity in fires from 1987-2008
(all fires >400 ha).
During 1910-2008 the mean and maximum fire size and total annual area burned increased, yet we found
no trend in percentage of high-severity during 1987-2008. The time series of severity data was strongly
influenced by four years (1987, 1999, 2006, 2008) with region-wide lightning events that burned huge
areas at primarily low to moderate severity. Following decades of fairly successful fire suppression, the
fire rotation across the four National Forests reached a high of 974 yrs in 1984. However, by 2008 the
fire rotation had fallen to 95 yrs due to the years of widespread lightning fires. Percentage of highseverity in conifer-dominated forests was generally higher in areas dominated by smaller diameter trees
than areas with larger diameter trees.
The years with region-wide lightning caused fires were characterized by less winter and spring
precipitation than years dominated by smaller human ignited fires. Overall percentage of high-severity
was generally less in years characterized by these region-wide lightning events. Our results suggest that
under certain conditions wildfires could be more extensively used to achieve ecological and management
objectives in NW California.
References
Miller, J.D.; Skinner, C.N.; Safford, H.D.; Knapp, E.E.; Ramirez, C.M. 2012. Trends and causes of
severity, size, and number of fires in northwestern California, USA. Ecological Applications 22: 184-203.
Miller, J.D.; Skinner, C.N.; Safford, H.D.; Knapp, E.E.; Ramirez, C.M. 2012. Northwestern California
National Forests fire severity monitoring. R5-TP-035. USDA Forest Service, Pacific Southwest Region,
Vallejo, CA. 87 p.
19
California Firewood Task Force (http://www.firewood.ca.gov)
Donald R. Owen, California Department of Forestry and Fire Protection, 6105 Airport Road,
Redding, CA; don.owen@fire.ca.gov
2011 was a year for building Task Force membership, establishing a website, and conducting a pilot
outreach campaign over a limited portion of the State. The campaign was expanded in 2012 to include
additional activities and the remainder of California. Highway billboards promoted the “Burn it Where
you Buy it” message at strategic locations from Shasta County in the north to Imperial County on the
border with Mexico. Firewood posters were placed in campgrounds and highway rest stops throughout
California. The Task Force also manned informational booths at the State Fair and other public and
professional events. Many Task Force member organizations, including the Goldspotted Oak Borer
Working Group, are conducting additional, complimentary outreach efforts.
Our current mission is to examine how well our message was received and determine how to improve and
expand its impact. Feedback and suggestions are welcomed.
20
Take Back Our Forests
Madeleine Melo, Jere Melo Foundation, Fort Bragg, California 95437; mmelo@mcn.org
Jere Melo, forester and Fort Bragg City Council member, was murdered while investigating an illegal
trespass marijuana grow on Hawthorne Timberlands property in Mendocino County. As a result of the
incident, it became evident that issues such as environmental degradation and the safety of those visiting
and working in areas where drugs are harvested need to be made known.
To that end, the Jere Melo Foundation was formed in October of 2011, with the main objective of
educating the public through presentations, social media, and outreach to organizations and agencies.
Our community is not okay with what is happening in our forests.
The Foundation is only a year old. There is still much for us to learn and lots of education to conduct.
In the coming year, we plan to extend the Foundation’s sphere of influence, scheduling forums and
presentations in other counties throughout California.
We are looking to partner with all agencies and organizations that share our interest in stopping illegal
drug activity in our forests, and welcome anyone interested in doing so to contact us.
This is a disaster unfolding. It is an environmental catastrophe - one with horrific consequences. My call
to all of us is to treat it with the same level of urgency and resources that would be dedicated to a raging
wildfire. Become a part of the solution by visiting our website at www.jeremelo.org.
21
Impacts on Natural Resources from Toxicants Associated with
Illegal Marijuana Cultivation on our Public and Tribal Lands
Mourad W. Gabriel, University of California Davis, School of Veterinary Medicine and
Integral Ecology Research Center, Blue Lake, CA; mwgabriel@ucdavis.edu; Greta M. Wengert,
University of California Davis, School of Veterinary Medicine and Integral Ecology Research
Center, Blue Lake, CA; J. Mark Higley, Hoopa Tribal Forestry, Wildlife Department, Hoopa,
CA
Wildlife species across the world have been impacted by pesticides used both legally and illegally across
the landscape. Typically, carnivores are exposed by consuming exposed prey in urban or agricultural
settings. However, in a long-term monitoring project on the population health of fishers, a mature forestdwelling mid-sized carnivore warranted for listing under the Endangered Species Act, we discovered that
over 80% of fishers throughout California were exposed to the highly toxic second-generation
rodenticides. In addition, we documented five fisher deaths with three more suspicious poisonings.
Interaction with law enforcement and first-hand documentation at marijuana grow sites on public and
tribal lands has revealed information on the pervasiveness of anticoagulant rodenticides throughout the
forests of California making it clear that toxicants used at these sites are the source of fisher exposure.
Other terrestrial and avian carnivores inhabiting forest lands are most likely at risk too, including the
federally threatened northern spotted owl, and species of concern like Sierra Nevada red fox, Humboldt
marten, great gray owl, and the California condor. Furthermore, much more acutely toxic pesticides are
regularly found at dismantled marijuana cultivation sites, including chemicals banned for use in the
United States, and are likely impacting many plants and animals and having effects throughout the foodweb. For example, at just one cultivation site visited in northern California, we discovered over 3500 lbs.
of high-nitrogen fertilizer, 13 lbs. of anticoagulant rodenticides, and over 25 lbs. of metaldehyde, carbaryl,
and malathion pesticides after visiting only half the cultivation complex.
Beyond the risk of toxicant exposure and poisoning at marijuana cultivation sites on our national parks,
forests, and tribal lands, a host of other detrimental impacts from this practice is evident. Riparian zones
and upland forests are being clear-cut, essential wildlife habitat is being lost to fires originating from
grow sites, animals including endangered species are being poached, and thousands of pounds of highnitrogen fertilizer are being distributed throughout concentrated grow areas with probable detrimental
ramifications at site and downstream. Finally, the costs to research, monitoring, and regulatory
compliance budgets have significantly increased because field personnel are now often required to access
remote sites in pairs rather than individually or completely abandon research sites that are integral to
wildlife conservation.
22
Forest Health Issues During Land Development
Jim Clark, HortScience, Inc., P.O. Box 754, Pleasanton, CA 94566; jim@hortscience.com
Trees that are retained during land development may be impacted in ways that increase their susceptibility
to insects, disease and decay. We describe impacts from construction as either direct or indirect. Direct
impacts include mechanical wounding, change of grade, and root severance. Indirect impacts include
changes in water table or drainage.
Species vary widely in their response to impacts from construction. Coast redwood and London plane are
very tolerant. In contrast, madrone and California black walnut are intolerant, generally dying as a result
of construction. Other species may tolerate some impacts, but not others. Coast live oak can be root
pruned without adverse effect but placing soil around the base of the trunk can lead to disease and decay
problems.
The presence of insect, disease, or decay influences both a decision to retain a particular tree as well as its
survival post-construction. Insects and diseases that might normally be considered a nuisance problem,
not requiring treatment, may be treated in order to enhance health. Examples include foliar diseases like
anthracnose and insects such as oak pit scale. Any insect or disease that is problematic on stressed trees
can be expected to appear post-construction and may require treatment. Where direct treatment is not
possible, one common treatment is to provide additional irrigation.
This presentation will discuss the general approach to forest health issues during land development, and
provide specific examples of tree species, their tolerance to construction, and the insect and disease issues
that may occur. The keys to successful management of trees before, during and post-development is
selecting good trees for preservation, minimizing impacts, and providing proper growing conditions postconstruction.
References
Dreistadt, S.; Clark, J.; and Flint, M. 2004. Pests of Landscape Trees and Shrubs: An integrated pest
management guide. 2nd edition. University of California Agriculture & Natural Resources Publication
3359.
Matheny, N. and Clark, J. 1998. Trees and Development: A technical guide to preservation of trees
during land development. International Society of Arboriculture. Champaign IL.
23
Examples of Tree Species and Relative Tolerance to Impacts Associated with Development.
Common name
Scientific name
Relative
Tolerance
Comments
White alder
Alnus rhombifolia
Moderate
Madrone
Arbutus menziesii
Poor
Calif. incense
cedar
Calocedrus decurrens
Moderate
Monterey cypress
Cupressus macrocarpa
Poor
Blue gum
Eucalyptus globulus
Poor
Modesto ash
Fraxinus velutina
'Modesto'
Calif. black walnut
Juglans hindsii
Monterey pine
Pinus radiata
London plane
Platanus x acerifolia
Good
Coast live oak
Quercus agrifolia
Good
Blue oak
Quercus douglasii
Poor
Short-lived. Alder borer
more problematic on
drought-stressed and/or
mechanical wounds.
Irrigation required.
Intolerant of root severance.
Dies.
Outside its range, may
require supplemental
irrigation.
Intolerant of root severance.
Dies. Fill soil may lead to
Armillaria.
Intolerant of root severance.
Develops decay, most
commonly Laetiporus
Tolerates root severance.
Foliar anthracnose seems to
be worse on impacted trees.
Intolerant of root severance.
Dies back everso slowly.
Irrigation required. Root
severance and mechanical
wounds increase
susceptability to red
turpentine beetle, 5-spined
engraver beetle and pitch
canker.
Tolerates root severance
with irrigation. No
particular pest problem.
Tolerates root severance.
Fill soil will lead to
Armillaria. Intolerant of
heavy summer irrigation.
Ambrosia beetles?
Intolerant of disturbance,
either severance or fill.
Moderate
Poor
Moderate
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Valley oak
Quercus lobata
Coast redwood
Sequoia sempervirens
Giant redwood
Sequoiadendron giganteum
Calif. bay
Umbellularia californica
Moderate
Good
Moderate
Poor
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Some tolerance to root
severance. Fill may lead to
Armillaria. Intolerant of
heavy summer irrigation.
Treat pit scale and
anthracnose on mature trees.
Tolerates root severance
with irrigation. No
particular pest problem.
May tolerate root severance.
Best with some irrigation
outside range.
Botryosphaeria under
drought stress.
Intolerant of root severance.
Develops decay, most
commonly Ganoderma.
Managing Invasive Species While Rebuilding the Historic Hetch
Hetchy Regional Water System
Ellen Natesan, San Francisco Public Utilities Commission, Natural Resources and Lands
Management Division, 525 Golden Gate Avenue, San Francisco, California 94102;
enatesan@sfwater.org
The San Francisco Public Utilities Commission (SFPUC) manages a complex water supply system
stretching from the Sierra to San Francisco that serves 2.6 million residential, commercial, and industrial
customers in the Bay Area. Built in the early to mid-1900s, many parts of the SFPUC water system are
nearing the end of their working life, with crucial portions crossing over or near to three major earthquake
faults. A $4.6 billion program was launched in 2002 to repair, replace, and seismically upgrade the
system’s deteriorating pipelines, tunnels, reservoirs, pump stations, storage tanks, and dams.
In addition to restoring sites that are temporarily disturbed during these system construction projects, the
SFPUC is also mitigating for impacts through protection and enhancement of approximately 1,800 acres
of tidal marsh, vernal pool, creek, sycamore and oak riparian woodland, oak woodland and savannah, and
serpentine and annual grassland. This mitigation program includes habitat restoration projects on 19
separate sites on property owned by the SFPUC in the East Bay and Peninsula.
The SFPUC is committed to preventing introduction of invasive species and has required contractors for
both construction and restoration projects to follow strict guidelines to minimize this risk. The SFPUC
enforces these requirements through regular inspections and frequent communication with contractors.
Examples include the following:




equipment, vehicles, and attire must arrive at each site clean and free of debris that might
carry weed seeds, plant pathogens, or other invasive species;
tree trunks with roots attached (“root wads”) imported to stabilize creek banks are heat
treated;
seed lots are added or rejected on a case by case basis based on purity analyses; and
nurseries growing plants to be used in restoration projects are held to specific sanitary
standards.
26
Anticoagulant Rodenticides: Secondary Poisoning of Wildlife in
California
Stella McMillin, California Department of Fish and Game, Wildlife Investigations Laboratory,
1701 Nimbus Road, Rancho Cordova, CA 95670; smcmillin@dfg.ca.gov
Anticoagulant rodenticides (ARs) have been widely detected in predators and scavengers in California.
In 1999, the Department of Fish and Game (DFG) requested that the Department of Pesticide Regulation
(DPR) place the second-generation anticoagulant rodenticide, brodifacoum, into reevaluation, based on 58
incidents of anticoagulant exposure and toxicosis in wildlife. As US EPA was considering the issue, no
action was taken by DPR. DFG has continued to monitor the issue and has now documented over 300
mortality incidents, including numerous raptor and wild canine species as well as mountain lion, bobcat,
bear, and fishers. Monitoring data show that the majority of predatory and scavenging wildlife tested in
California contain residues of anticoagulant rodenticides. Both first generation anticoagulant rodenticides
(FGARs) and second generation anticoagulant rodenticides (SGARs) have been detected, however the
more persistent and toxic SGARs have been found much more frequently. The anticoagulant rodenticides
of concern contain the active ingredients brodifacoum, bromadiolone, difethialone, and difenacoum. To
address this issue, USEPA has passed additional restrictions which limit the availability of secondgeneration anticoagulant rodenticides to consumers. While supporting USEPA’s action, DFG has
additional concerns about the availability of these materials in farm stores to the public, and has
recommended that DPR designate these materials as California Restricted Materials, which would limit
their availability to only certified applicators.
27
Porcupines: An Increasingly Rare Sight in California Mid-Elevation
Mixed Conifer Forests, and the Possible Consequences for the
Conservation of Pacific Fishers
Rick A. Sweitzer, Department of Environmental Science, Policy, and Management, Center for
Forestry, University of California, Berkeley, California 94720; rasweitzer@berkeley.edu
North American porcupines (Erethizon dorsatum) are widespread in the western United States, and until
approximately the 1970s were widespread and common in the mixed conifer forests of the Sierra Nevada.
Currently, however, there appear to be very few porcupines remaining in California’ mixed conifer forests,
even though they are regularly observed in the lower elevation oak woodlands in the high elevation alpine
zones of the Sierra Nevada. The decline and near disappearance of porcupines from mid elevation forests
in the Sierras has prompted efforts to determine their current range extent, and to understand why the
animals are so uncommon now compared to in the early 1900s. Herein, I will review historic information
on the range extent of porcupines in California, discuss several likely causes for their decline and
disappearance in several areas, and review what is currently known about their limited distribution.
Further, I will review the potential consequences of reduced numbers of porcupines for the conservation
of the Pacific fisher (Martes pennanti).
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