California oaks
Factors affecting blue
oak recruitment and regeneration
Client: California Department of Forestry
and Fire Protection, Strategic and Resources Planning Program
We studied how management practices, stand characteristics,
and site factors interact to affect blue oak (
Quercus douglasii)
sapling establishment. We assessed regeneration and associated variables
in a total of 1500 plots distributed among fifteen 150-acre study locations
which were dispersed across the range of blue oak in California. We also
compiled and mapped historical fire, rainfall, and grazing records over
a 30-year interval for use in the analysis of management history. We used
logistic regression to analyze the effects of history and environmental
variables on sapling recruitment. The final project report is
online.
Diseases
and insect pests of California oaks
Client: California Department of Forestry
and Fire Protection, Forest and Rangeland Resources Assessment Program
In this 2.5 year project, we evaluated the impacts
of diseases and insects on the health and regeneration of native oaks in
California. Based on our review of the literature and field observations,
we produced a PC-based host index database (CODA) listing reported associations
between oak species and their diseases and insect pests in California.
We also conducted a focused study on the impacts of diseases, arthropods,
and other factors on the survival of natural blue oak (
Quercus douglasii)
seedlings. We established field plots and surveyed native oak stands to
determine the types and degree of disease and insect impacts on all oak
life stages. Field plot data was organized into a geographically-linked
database that was delivered to CDF at the conclusion of the project.
California
Oak Disease and Arthropod Database
Clients: California Department of Forestry and Fire
Protection, Forest and Rangeland Resources Assessment Program ,
USDA
Forest Service
We provided distribution and support services for the
California Oak Disease and Arthropod (CODA) host index database, which we developed
under CDF Contract 8CA74545. In addition, we updated and refined the database
using information from the literature, unpublished sources, and feedback from
CODA users. In 2003, we received a grant from the
USDA Forest Service to create a web-based interface for the database and add
hyperlinked images of agents and symptoms. We programmed the web interface and
uploaded many photos from our collection to the CalPhotos database, which is
used as the main image server for CODA. CODA is available
online.
Field guide to common pests
and diseases of oaks in California
Client: USDA Forest Service
We have developed a field guide to common diseases and insect pests of California
oaks which was published by the USDA Forest Service Pacific Southwest Research
Station. Using data in CODA and other sources, we developed a list of species
to be included and wrote descriptive summaries on the geographic distribution,
symptoms, life cycle, and impacts associated with each pest or disease. We also
selected photographs for use from our own image collection and obtained images
from other sources. We distributed draft versions for review to specialists
and incorporated input from these sources in the final version. This publication is distributed free of charge by the USDA Forest Service. Downloading and ordering information is available
online.
Techniques
for restocking valley oak
Client: California Department of Forestry
and Fire Protection, Forest and Rangeland Resources Assessment Program
This was a two-year project to develop minimum
input techniques for valley oak (
Quercus lobata) restocking on hardwood
rangeland. We reviewed the existing literature on natural and assisted
regeneration in valley oak and evaluated past valley oak restocking projects.
We then established demonstration projects at four sites in northern California
to demonstrate and compare methods for restocking valley oaks in rangeland.
The results of the demonstration projects, evaluations of previous valley
oak restocking projects, and information in the literature were incorporated
into a model to predict the cultural inputs necessary to restock valley
oaks based on site characteristics.
Oak
woodland restoration planting and monitoring
Volunteer public service for the Vacaville
Tree Foundation and City of Vacaville
We have organized and conducted seed collection,
planting, and monitoring of oak woodland restoration projects on several
City of Vacaville open space lands on an annual basis since 1992. Through
1997, hundreds of community volunteers have helped plant over 2,000 sites
with seeds of locally-collected oaks (
Quercus lobata, Q. wislizeni,
and
Q. douglasii) and California buckeye (
Aesculus californica).
We have also conducted pilot-scale plantings of native grasses. In grazed
sites, we continue to monitor and maintain over 300 individual planting
site exclosures. In nongrazed areas, we use sample monitoring plots to
assess growth and survival.
Diagnosis
of valley oak decline
Client: CalMat, Fresno
We investigated the causes of mortality in a
riparian/floodplain stand of valley oak (
Quercus lobata). We conducted
site investigations to observe symptoms and identify pathogens present
at the site and reviewed historical aerial photos, water table and precipitation
records, and management history to determine the contribution of various
biotic and abiotic factors to the decline. Our report included recommendations
for sustainable stand management.
Oak
survey and vegetation assessment
Client: Riverbrook Partners, Stockton
We assessed native oaks and other vegetation
for potential impacts from a planned community development project on a
760 acre site near Riverbank. We mapped and rated the condition of 468
individual oaks, and assessed levels of natural regeneration in existing
oak stands. We recommended measures to minimize development impacts on
individual trees, oak stands, and other existing vegetation resources.
Habitat
assessment following firewood harvest
Client: Bruce and Donna Jensen, Windswept Ranch, Tehama
County
We evaluated stand quality, density, and general wildlife
habitat value in a partially-logged oak woodland and made recommendations for
canopy retention within different portions of the site.
Evaluation
of literature on effects of fire and grazing on blue oaks
Client: California Native Plant Society.
We conducted a critical review of published research relating to the effects
of fire and grazing on blue oak (
Quercus douglasii) ecosystems, primarily
focusing on the Sierra Nevada foothills. We analyzed each study's design, methodology,
and statistical data analyses to assess the validity and applicability of published
findings and assertions.
Phytophthora ramorum canker (sudden oak death): Factors affecting
disease risk, disease progress, and failure potential
Client: USDA Forest Service
We initiated this
ongoing case-control study in 2000 to examine the role of water stress and various
other factors on the development of
Phytophthora ramorum cankers
(aka "sudden oak death") in coast live oak (
Quercus agrifolia)
and tanoak
(Lithocarpus densiflorus). The study compares subject trees
that exhibited symptoms of
Phytophthora infection (case trees) with symptomless
(control) trees. Data are collected from permanent plots established at 10 locations
in Marin County, and one location each in Sonoma and Napa Counties. With additional
funding provided by the USDA-FS Pacific Southwest Research Station, additional
observations on the plots have been made in annually through 2004. These repeated
observations allow us to study disease progress, mortality, and tree failure
in these plots. Project reports that present the results from this to date study are available
online.
Monitoring
effects of Phytophthora-related mortality (Sudden Oak Death) in Sonoma
County
Client: Sonoma County Fish
and Wildlife Advisory Board/USDA Forest Service/University of California
We established permanent research/monitoring
plots in woodland and forest types at risk from
Phytophthora-related
mortality to monitor disease progression and assess impacts of disease over
time. We also assessed the impacts of other agents to develop an overall picture
of forest health for the target species. We analyzed the plot data to determine
how disease impacts vary across the landscape within a forest type and how different
forest associations within the county are impacted. The final report from the
original project is available
online.
As part of a cooperative project with Dr. David Rizzo (Department of Plant Pathology,
UC Davis) with funding from the USDA Forest Service, we resurveyed these plots
in 2004 to assess disease spread and disease progress since the original 2001
survey.
The final report from this follow-up project is also available
online.
Relationships between tree
failure potential and Phytophthora ramorum canker (sudden oak death)
Client: USDA Forest Service, Pacific
Southwest Research Station
This study was designed to help resolve questions related
to the relationship between
Phytophthora ramorum canker (sudden oak death)
and tree failure. This study uses a case-control design at six study locations
to assess tree, disease, and site factors that may influence failure potential
in coast live oak (
Quercus agrifolia). From the data, we also estimated
overall rates of tree failure within the study areas over several time intervals.
The results of the study are presented in a report that is available
online.
Management of Phytophthora ramorum canker (sudden oak death) in tanoak
Client: Kashia Band of Pomo Indians of Stewart's Point Rancheria/USDA Forest Service
We designed and established a pilot study to determine whether bark-banding treatments with phosphite (a low-risk fungicidal material) can be used to effectively prevent stem cankers caused by
Phytophthora ramorum in native tanoak
(Lithocarpus densiflorus) stands in Sonoma County, CA. In addition, we coordinated a related study to determine whether phosphite application affects the nutritional or phytochemical composition of acorns on treated tanoaks. Because tanoak acorns are used by the Kashia and other native tribes as a traditional food, the quality of the acorns from phosphite treated trees is a key factor in determining whether use of this material will be acceptable.
Management of Phytophthora ramorum canker (sudden oak death) in tanoak and oak stands
Clients: USDA Forest Service, Pacific
Southwest Research Station, USDA Forest Service Forest Health Protection, Midpeninsula Regional Open Space District, San Francisco Public Utilities Commission
We are conducting several related projects designed to test the efficacy of the most promising techniques for managing
P. ramorum canker (sudden oak death) in forests containing tanoak, coast live oak, Shreve oak, and California black oak. In these collaborative projects, we have established a network of long-term disease management plots ranging for plots around individual trees to multi-acre plots. Because disease epidemiology differs between different canker hosts, we are testing different control strategies in tanoaks and susceptible oaks, including the use of potassium phosphite (as a topical stem application or injection) and local or area wide bay removal. Results of this project will be used to improve disease management recommendations and will provide additional information on the epidemiology of the disease in treated and untreated stands.
Horticultural and Agricultural Consulting
Tree
assessment prior to highway widening
Client: California Department of Transportation
We assessed native and introduced trees potentially
impacted by a highway construction project on State Route 29 in the Napa
Valley. We recommended specific measures to reduce construction impacts
on individual trees.
Street
and landscape tree problem diagnosis
Clients: City of Vacaville, Alza Corporation,
Marriott Facilities Management, Chalk Hill Winery, and others
We have identified agents and conditions responsible
for problems in a variety of street and landscape tree plantings, including
Raywood ash, zelkova, chinese pistache, interior live oak, cork oak, Norway
maple, and coast redwood. We made recommendations for short and long term
remediation, including lists of species to use or avoid in replanting,
and modified irrigation regimes.
Diagnosis of
walnut decline
Client: Pacific Gas and Electric Company
We investigated the causes of plant decline in a walnut orchard located around
a natural gas dehydrator facility. We found that poor plant condition was due
to a combination of a viral disease (blackline), soil salinity problems, and
inadequate irrigation.
Decline
of landscape shrubs
Clients: City of Vacaville and others
In various projects, we have identified soil factors and
biotic agents associated with decline of various woody perennial shrubs used
in the landscape. We made recommendations for corrective cultural actions.
Diagnosis
of ground cover failures in urban landscapes
Clients: City of Fairfield and others
We investigated the cause of repeated failures
of perennial ground cover species in median islands and street landscape
bed plantings in several different locations. We described several options
for improving the plantings.
Integrated
pest management guidelines for commercial landscape plantings
Client: Jepson Parkway Associates
We identified pests and beneficials present on
landscaping in a shopping plaza, and identified cultural practices that
had increased pest and disease problems. We provided guidelines for implementing
an integrated pest management program at the site, including a list of
pest-resistant plant species to be used to increase habitat for beneficial
insects.
Natural Resources
Effects
of thinning on a riparian mitigation planting
Client: Santa Clara Valley Water District
We designed and conducted a study to determine how plant
water status and condition are affected by thinning in a densely planted riparian
mitigation planting along the Guadalupe River in San Jose. We monitored
soil moisture, stomatal resistance, plant growth, and condition in three riparian
species (
Populus fremontii,
Salix laevigata, and
Acer negundo)
to determine whether plant competition can be reduced to improve plant condition
at this site.
Mitigation planting of
willows and cottonwoods in an urban floodwater detention basin
Client: City of Vacaville
We conducted investigations on soil conditions and hydrology and developed a
mitigation plan to grow willows and cottonwoods in an urban floodwater detention
basin using locally-collected cuttings. We also developed a plan to mitigate
for the loss of mature valley oaks (
Quercus lobata) at the site by conserving
and recruiting existing native valley oak seedlings in the project area. A summary of the project is available
online.
Weed monitoring program
for Jepson Prairie Preserve
Client: Solano Land Trust (formerly Solano
County Farmlands and Open Space Foundation)
We designed, tested, and initiated a program for monitoring
selected invasive weeds and desirable native species at the Jepson Prairie Preserve,
a vernal pool / grassland ecosystem in Solano County, California. We
produced reports which present the monitoring results
for
2001 and
2002
and discuss the results of our data analyses. We provided training for Solano
Land Trust (SLT) staff and volunteers and delivered GIS files, databases, method
documentation, and other materials needed to allow SLT to continue monitoring
efforts.
Effects of grazing on
native and exotic vegetation at Jepson Prairie Preserve
Client: Solano Land Trust
Grazing and prescribed burning have been used to control undesirable vegetation
at the Jepson Prairie Preserve, a vernal pool / grassland ecosystem in Solano
County, California. As prescribed burning becomes increasingly difficult to
implement, interest has turned to optimizing grazing to achieve the maximum
benefit. We designed and conducted a study to determine the effectiveness
of different grazing regimes at Jepson Prairie. The
study addressed the degree to which different grazing regimes can reduce the
cover of various target weeds, decrease thatch, and increase the cover of native
species.
Effects of different grazing regimes on Viola pedunculata cover
Client: Solano Land Trust
Viola pedunculata or California golden violet is the sole food plant of the larvae of the Callippe silverspot butterfly (
Speyeria callippe callippe), a federally-listed endangered species. We designed an experiment to test whether variations in the grazing regime could be used to promote the growth and cover of
V. pedunculata to improve habitat quality for Callippe silverspot. We established study plots and collected pretreatment data on variation in
V. pedunculata cover for two years before initiating cattle exclosure treatments in 2009.
Impacts of diseases
affecting native stands of Ione manzanita (Arctostaphylos myrtifolia)
Client: California Dept. of Fish and Game /
San Francisco State University
We evaluated the role of diseases in the of decline of
native stands of the endangered species Ione manzanita (
Arctostaphylos myrtifolia).
We described symptomatology and disease progression, and identified pathogens
associated with symptoms of dieback and decline of entire plants. We also investigated
whether water stress was associated with differences in disease severity. As
part of this study, we identified and described a new disease of both
A.
myrtifolia and
A. viscida (whiteleaf manzanita) that has major implications
for developing a conservation strategy for Ione manzanita. The report describing
our study and findings is available
online.
Distribution of Phytophthora
cinnamomi in native stands of Ione manzanita (Arctostaphylos myrtifolia)
Client: Dr. Matteo Garbelotto, University
of California, Berkeley/
California Dept. of Fish and Game
In our initial project on Ione manzanita (
Arctostaphylos myrtifolia), we determined that
Phytophthora cinnamomi
was the cause of a root and crown rot that results in large patches of
plant mortality in stands of this rare species. In
this follow-up study, we delineated the geographic extent of
P. cinnamomi
within the natural range of Ione manzanita and investigated the local distribution
of
P. cinnamomi in soils around root disease centers. Information developed
in this project is critical for developing a strategy to conserve the endangered
Ione manzanita.
Distribution of Marin manzanita (Arctostaphylos virgata) at Point Reyes National Seashore
Client: Point Reyes National Seashore
We conducted field surveys to verify and remap the distribution of the rare (CNPS 1B) Marin manzanita (Arctostaphylos virgata) within Point Reyes National Seashore. Using the existing GIS coverage as a starting point, we updated GIS layers to show the current distribution of Marin manzanita. We also collected data on stand density, health, and degree of tree canopy overtopping for mapped polygons of this species and provided field observations and digital images for all mapped polygons.
Baseline
documentation of agricultural property and riparian corridor for conservation
easement
Client: Solano County Farmlands and Open Space Foundation
We prepared an archival baseline document for a 149 acre
agricultural parcel used for row crops and an adjoining riparian corridor. The
report documents existing conditions of the natural resources and various improvements
at the site through the use of descriptions, vegetation survey data, and both
aerial and ground-level photography. The document establishes a baseline for
monitoring compliance with separate conservation easements on the agricultural
parcel and the riparian corridor.
Assessment
of native elderberry for transplanting
Client: Entomological Consulting Services
We identified factors associated with poor condition of
native elderberry (
Sambucus mexicana) and assessed suitability for transplanting
to satisfy mitigation requirements.
Diagnosis
of disease problems in elderberry mitigation plantings
Client: Pacific Gas and Electric Company
We identified plant pathogens and other factors responsible
for a rapid decline in condition of native elderberry (
Sambucus mexicana)
in several mitigation planting sites.
Ailanthus
control in an urban riparian corridor
Client: City of Vacaville
We produced visual aids and provided training and technical
input for a project to eliminate a dense stand of
Ailanthus altissima
from an urban riparian corridor. A major issue in the project was the protection
of native elderberry (
Sambucus mexicana), habitat of a federally-listed
threatened insect species.
Development
of dieback rating scales for Lupinus albifrons var. collinus
Client: Golden Gate National Parks Association
We developed rating scales and datasheets for evaluating
dieback in
Lupinus albifrons var.
collinus, host plant of the
endangered Mission Blue butterfly.
Soils and Irrigation
Evaluation
of riparian mitigation planting
Client: Santa Clara Valley Water District
We evaluated pest and disease impacts to plants
in a mitigation planting along the Guadalupe River in San Jose. We used
water use calculations and soil investigations to develop recommendations
for sustainable management of existing and planned plantings.
Water efficient landscape
documentation
Client: Elmon Development, Inc.
We provided the landscape water use summaries
and irrigation schedules for a residential development to satisfy the Yuba
County Water Efficient Landscape Ordinance.
Soil
water storage calculations
Client: Tire Farms
We calculated the potential effects of a proprietary
subsoil water reservoir system on total soil water storage and irrigation
water use. We produced a report that applied our findings to several soil
types and climates.
Soil
sampling and recommendations for proposed sports complexes
Clients: City of Fairfield, City of
Vacaville
We evaluated soil physical structure and sampled
soil for chemical analysis to identify soil factors that could affect the
suitability of proposed sports complex sites for establishment of turf
and landscaping.
Soil
sampling and recommendations for new landscaping
Clients: City of Vacaville and others
We evaluated soil physical structure and sampled
soil for chemical analysis to identify soil factors that could affect proposed
landscaping.
Urban Forestry
Urban Forest Management Plan Toolkit
Client: California Urban Forest Council / Inland Urban Forest Council
In this project, funded by a CalFire urban forestry grant, we developed the content for a website that helps users develop a management plan for their urban forest. We worked with a steering committee to help define the overall scope and structure of the website, conducted polls of prospective users to refine scope, developed the website's extensive content, and worked closely with the project manager and the website developers to help translate the concepts and structure into a unique website. We made several presentations on the Toolkit at professional meetings. The website has subsequently been revised by others. It is available
here.
Yolo County Oak Woodland Conservation and Enhancement Plan
Client: County of Yolo
We served as the oak woodlands specialist (Oak Woodlands Adviser) to provide technical direction and assistance to the County of Yolo, Planning, Resources and Public Works Department in its development of a county-wide Oak Woodland Conservation and Enhancement Plan. We provided advice on overall content and organization of the plan; reviewed data on resource conditions; assisted in the development of goals, policies, and programs for the plan; edited sections of the plan drafted by staff; and developed the plan section on establishing priorities for oak woodland conservation and enhancement projects.
Urban forest management
plan
Client: City of Rocklin
We developed an urban forest plan for the City of Rocklin, CA. To set the
context for the plan and identify needs we evaluated the current status of the
urban forest, including changes in canopy cover over the past 50 years; sample
surveys of trees in parks, along street, and in parking lots; and a review of
the city's current tree management procedures and policies. The plan includes
recommendations for urban forest management, including goals, objectives, and
specific actions, as well as technical recommendations for state-of-the-art
tree care. We worked closely with City staff to collect data on existing practices and conditions and to produce the plan document. Presentations related to the plan included a public workshop to solicit citizen input and a presentation of the final plan to the City Council for adoption.
Electrical
utility distribution line clearance study design
Client: Pacific Gas and Electric Company
We designed a multiyear field research project to compare
two different pruning methods for maintaining electrical distribution line clearances.
The study design included evaluations of tree regrowth rates and overall costs
associated with the two pruning methods. The design also included methods for
conducting all major evaluations and sample size estimates.
Electrical
utility distribution line clearance study
Client: Pacific Gas and Electric Company.
In this multi-year study, we compared two different pruning
methods for maintaining electrical distribution line clearances. Matched
pairs of London plane (
Platanus x
acerifolia) trees in urban street
tree plantings were pruned and monitored over four years. We collected and analyzed
detailed data on the pruning operations for each pruning method, including time
required to prune and the amount of waste produced. We also measured and analyzed
the rate of tree regrowth toward the primary power conductors. We developed
Monte Carlo computer simulations to model time usage by pruning crews and to
run an economic model that calculates the long-term costs for each pruning method.
Guidelines
for Developing and Evaluating Tree Ordinances on the web
Client: USDA Forest Service, National Urban
and Community Forest Advisory Committee.
This project was supported through the NUCFAC Challenge
Cost-Share Grant Program and matching contributions provided by the International
Society of Arboriculture, ESRI, Inc., Phytosphere Research, American Forests,
and other cooperating organizations. We established a comprehensive tree
ordinance web site based on our CDF publication
Guidelines for Developing
and Evaluating Tree Ordinances. Rather than using a “model ordinance”
approach, the Guidelines web site describes a process for developing and revising
tree ordinances as part of an overall urban forestry management strategy.
We updated and expanded site content and improved the web interface over the
two-year grant period, using input from site users and an advisory committee
comprised of representatives from major urban forestry-related organizations.
The Guidelines web site can be accessed through the
International
Society of Arboriculture’s web site and through our local
mirror
site.
Guidelines
for developing and evaluating tree ordinances
Client: California Department of Forestry and Fire
Protection, Urban Forest Program.
We collected, reviewed, and analyzed over 160 tree ordinances
from cities and counties throughout California. We incorporated information
from this analysis and from other sources into a report for local governments,
citizens, and organizations interested in tree ordinances. The report presents
guidelines for developing tree ordinances that are integrated with municipal
urban forest management strategies. Methods for evaluating the performance of
tree ordinances are also included. The report was prepared in-house as camera-ready
copy, and we had 5000 copies of the report printed and delivered to CDF.
In a follow-up project in 1999, we converted the original report into Adobe
Acrobat PDF format for posting at the CDF / UFEI web site. You can follow
this link to the
UFEI
site to download the report.
Review
of tree ordinance
Client: City of Mountain View
We provided a technical evaluation of the city's
existing heritage tree ordinance and provided comments and recommendations
on the ordinance and a proposed ordinance revision.
1992
California urban forestry survey and report
Client: California Department of Forestry
and Fire Protection, Urban Forest Program.
This project is a follow-up to the 1988 California
Urban Forestry Survey and report which we completed for CDF. We surveyed
all of California's incorporated cities and counties by mail to assess
the present status of urban forestry in California communities. We identified
recent trends by comparing the new survey data with data from the previous
survey. We prepared the final report as camera-ready copy and had 2000
copies of the report printed and delivered to CDF.
1988
California urban forestry survey and report
Client: California Department of Forestry
and Fire Protection, Urban Forest Program.
We surveyed all California cities and counties
by mail to determine the status of their urban forestry programs. The survey
questionnaire was based on a needs assessment conducted through interviews
with professionals involved in urban forestry from around the state. We
incorporated the results of the survey into a report for city and county
tree program managers and other urban forestry professionals. The report
was prepared in-house as camera-ready copy, and we arranged for the printing
and delivery of 1000 copies to CDF. The data gathered were incorporated
into a database, accessible by means of a customized interface.