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1.1
Risk Assessment and Mapping
(From
Ross Meentemeyer,
Sonoma State University – Geographic
Information Center [as of 10/14/02]).
Completed:
Preliminary SOD risk model for areas of California covered by CALVEG vegetation
mapping, based on:
Vegetation
- Relational
database of species presence and abundance for each CALVEG
vegetation alliance, compiled from text descriptions
of the alliances; species which are known SOD hosts are
coded as such and assigned a risk ranking score in the
database;
- SOD
host vegetation scores for each CALVEG alliance, calculated
as the sum of host species abundance score times host
risk ranking score for all SOD hosts within each alliance;
- Distribution
map of SOD CALVEG host vegetation scores; maps show relative
risk of SOD due to presence, abundance, and importance
of SOD host species in the landscape
Climate
-
Climate
maps of 30 year averages of total annual precipitation, July maximum
temperature, January minimum temperature, spring relative humidity, and
total annual snowfall;
-
Climate
variables scored and weighted to map environmental suitability for the
SOD pathogen;
Proximity
(From
Maggi Kelly, CAMFER,
UC Berkeley)
1.
Mapping of water-stressed trees using ADAR imagery
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Reseach
has been completed, and a paper has been submitted for review in GeoCarto.
-
Summary:
We investigated the ability of high spatial-resolution 4-band
imagery (Airborne Digital Acquisition and Registration - ADAR)
to discern moisture
stress in trees affected by Sudden Oak Death (SOD). We wanted
to test if the imagery could be used to distinguish between
green oak trees
with advanced SOD trunk symptoms, and green oaks with no SOD
trunk symptoms. ADAR imagery of China Camp State Park in Marin
County, California
was flown in spring 2000 and 2001. Training samples from the
field consisting of the locations green healthy oaks and green symptomatic
oaks were used to derive spectral signatures for the two classes. Both
hierarchical unsupervised classification (HUC) and maximum likelihood
classification (MLC) were used to classify the imagery. Accuracy
assessment and other spectral measurements were performed to analyze
the separability of the two signatures. Poor overall
accuracy 55.17% was obtained by the HUC method. A better overall
accuracy 74.19%
was obtained by MLC method, but the low transformed divergence
(1448) indicated poor separability of the training samples.
The poor accuracy
results can be explained by the fact that ADAR image has relatively
broad spectral bands that combine narrow moisture- stress-sensitive
regions with broader stress-insensitive regions; such combination
could decrease the capability of ADAR to detect moisture stress.
In addition,
healthy oaks in the area display a marked variability in canopy
condition, making it difficult to separate healthy trees from
those experiencing
some stress. In conclusion, this research indicated the inability
to automate mapping of moisture stress in oaks using ADAR imagery,
and
limited success in using methods that require extensive field
data. From Kelly and Liu, in Review.
2.
Mapping of dead and dying oaks in Marin Co.
-
-
Imagery
(2000, 2001) classified using standard methods.
-
New classifiers
evaluated for 2000, 2001, and 2002 imagery.
-
Summary:
Sudden Oak Death is caused by a newly discovered virulent pathogen
(Phytophthora ramorum) that is killing thousands of native
oak trees in California. We present a landscape-scale study
on the spatio-temporal
dynamics of the disease. Second order spatial point pattern
analysis techniques (Ripley's K) were applied to the distribution
of dead tree
crowns (derived from high-resolution imagery) in Marin County,
CA to determine the existence and scale of mortality clustering
in two years
(2000 and 2001). Both years showed clustering patterns between
100 and 300 m. A classification tree model was developed to
predict spatial
patterns in disease risk based on several landscape-scale variables. Proximity
to forest edge was the most important explanatory factor, followed
by topographic moisture index, proximity to trails, abundance
of Umbellularia californica, and potential summer solar radiation.
This research demonstrates
the utility of integrating remotely sensed imagery analysis
with geographic information systems and spatial modeling for
understanding the dynamics
of exotic species invasions. From Kelly and Meentemeyer, 2001.
3.
Use of hyperspectral imagery to map oaks with SOD
-
-
Water
content of leaves correlated with portions of spectrum.
-
Discrimination
between healthy and stressed not found, work continues.
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Summary: A
total of 139 reflectance spectra (between 350 and 2500 nm) from coast
live oak (Quercus Agrifolia) leaves were measured in the laboratory
with a spectrometer FieldSpec®Pro FR. Correlation analysis was
conducted between absorption features, three-band ratio indices derived
from the spectra and corresponding relative water content (RWC, %)
of oak leaves. The experimental results indicate that there exist
linear relationships between the RWC of oak leaves and absorption feature
parameters: wavelength position (WAVE), absorption feature depth (DEP),
width (WID) and the multiplication of DEP and WID (AREA) at the 975
nm, 1200 nm and 1750 nm positions and two three-band ratio indices:
RATIO975 and RATIO1200, derived at 975 nm and 1200 nm. AREA has a higher
and more stable correlation with RWC compared to other features. It
is worthy of noting that the two three-band ratio indices,
RATIO975 and RATIO1200, may have potential application in assessing
water status
in vegetation. From Pu et al. in Press.
4.
Other imagery analysis
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USFS,
Cal Poly SLO, & UC Berkeley collectively involved in planning/implementing
aerial surveys to detect/monitor SOD May-July 2002.
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Survey
area included 12 infested & 31 uninfested counties totaling
60 M acres, within which 20 M acres of potential host habitat
prioritized for survey
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Over 14,500
miles flown, mapping approx 150,000 acres (gross polygon area) hardwood
mortality, over 450 polygons recorded using Digital Aerial Sketch-mapping
System.
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Ground
visits just completed by USFS contract crews/near completion
or completed by Cal
Poly crews for approximately 100 priority polygons (some additional
sites are being visited by counties interested in participating
on ground effort).
-
Information
received to date by USFS has been summarized (as of 1-03):
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Total sites
visited (polygons, multiple points within, or points outside) = 103
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Total number
of samples submitted for testing = 63
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Total number
of results positive = 9 (2 contra costa, 2 monterey, 1 santa cruz by
nursery)
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Total
number of results pending = 3
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2.1
Forest Inventory and Analysis (FIA) Plots
(Report
from Joseph Donnegan, USDA-FS, presented at the 2003 National
Forest Health Monitoring Conference)
Program
•
PNW-FIA Program visits and collects data on nearly 10,000
permanently located forest inventory
plots across CA.
• Two studies were initiated to monitor SOD on FIA plots
• In 2002, all off-panel, CA periodic inventory plots (on and off
national forests) visited in 12 counties
Results
• 212 plots
• 10% access denied
• ~70 leaf samples taken, ~25 ooze samples taken
• ~12 samples positive for P. ramorum on 10 plots
• both PCR/Culture
• all on Bay, no positives on National Forest land
• 3-12% of samples area is positive (several results are still pending,
the picture could change)
2.2
Systematic ground-based surveys for distribution of P. ramorum on
leaf spot or twig dieback hosts
Summary:
A statewide survey for Phytophthora ramorum, the causal
agent for Sudden Oak Death (SOD) has been completed. Host
plants in 99 nurseries (approximately 8,500 acres) and a quarter-mile
buffer area around them were
inspected for symptoms of Phytophthora ramorum, between February
25 and March 28, 2002. California Department of Food and Agriculture Nursery
Program biologists and staff members of 23 affected County Departments of Agriculture
jointly performed the survey. The survey was risk-based and biologically
biased in that it focused on nurseries 1) located in areas where known
SOD host plants naturally occur and 2) that ship known hosts of Phytophthora
ramorum. Additional focus was placed on nurseries shipping to Canada. No
survey activities were performed in the 25 counties where these criteria were
not met. Fifty-seven samples were collected during the survey and submitted
to the California Department of Food and Agriculture’s Plant Pest Diagnostics
Center for analysis. All samples have been tested and found to be
negative for the presence of Phytophthora ramorum.
2.4
Statewide Urban Areas Survey
(Information
from Kathy Kosta, presented at the 2003 National Forest Health
Monitoring Conference)
Background
•
Approximately 14,500 gypsy moth traps are placed throughout
the State of California and are
routinely serviced
throughout the trapping season
by CDFA
Adding
SOD Inspections
• (GM) trap sites in the counties not currently
being regulated for Sudden Oak Death are being inspected for
evidence of SOD
• The traps that are located in the rural-residential, rural, and
remote locations were targeted for this survey
• California trappers were asked to look for dead oak or tanoak trees
within 20-30 feet of the GM trap site
Results
• Investigation of each site by the plant pathologist
is underway and will be continued into 2003
• To date, no sudden oak death has been found around the moth traps;
the trees that were noted all appear to have died from other causes
or, in a few cases,
were not known hosts of P. ramorum
2.5
Early detection survey for the Sierra Nevada
(Submitted
by Susan Frankel)
Program
•
The survey covered the Sierra, Sequoia, Stanislaus, Eldorado, Tahoe,
Plumas NF and Yosemite
and Sequoia/Kings Canyon NP
• The forests were risk-rated for P. ramorum and a random selection
of sections with each forest was performed
• A roadside survey was conducted along the road to sections
• Four contractors drove over 9,000 miles and checked P. ramorum
hosts for infection in a randomized fashion within chosen sections
• The project was a collaboration between Susan Frankel, Sylvia Mori,
Mike Srago and Don Triplat. (M. Srago and D. Triplat are contractors)
Results
•
181 sections surveyed
• All samples negative
Of Note
•
It was difficult to tell maple scorch from possible P. ramorum
infection.
The other accomplishment
was
with Garey Slaughter, confirmed that P. ramorum is present on
the Los padres NF near Big Sur. This is the first find of SOD on
NFS lands.
3.
DIAGNOSTIC, GIS DATABASE AND MAP SUPPORT
3.1
Field and laboratory diagnostic support
•
In progress.
• CDFA tests samples from infested areas, and UCB/UCD test samples from
uninfested areas.
3.2
GIS database and map support
Database
-
Database
completed, and updated as new confirmations come in from CDFA
and UC labs.
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22
batches of data have been sent out to cooperators statewide (14
collaborators, from PG&E, private organization, county regulators,
forest service, CDF, research).
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Confirmations
have gone from 196 on 9-20-01 to 277 on 10-14-02 (not including
Doug Fir and Redwood).
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Up-to-date
maintenance of GIS database of SOD distribution (from all sources:
hand-drawn maps, field notes, GPS data, etc.).
-
Maintained
metadata and projection for all data.
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Map
Support
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Created
on-demand customized user-specified county and zoomed-in maps,
both page poster size. Delivered via email, FTP downloading,
or by burned CD through mail. Used for variety of purposes:
personal use, presentation, reference, etc.
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Created
database to track map and data requests, with person and use
of maps and data.
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Maps
(~150) distributed to public (60%), government agencies (30%),
private organizations affiliated with SOD project (5%) and non-profit/regional
groups (5%).
-
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Total
hits to OakMapper website since 1/1/02: over 4000, with over
500 per month.
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Updated
the interactive OakMapper webGIS application to make it faster,
more user-friendly, and more useful for users from every discipline
(public, researchers, regulator). Added capabilities include
customized printouts, find-address function to locate specific
address or intersection of anywhere in California, hyperlink
function that links to pictures of area affected and/or symptoms
of affected trees. (Go
to OakMapper site)
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Created
a separate OakMapper webGIS application for Aerial Survey work,
to be used by CDF and other specialists for ground-truthing of
areas of mortality as found through aerial survey.
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Created
a separate OakMapper webGIS application for researchers to communicate
the location, purpose, and progress of individual SOD research
projects, to be used by UC Berkeley, UC Davis, CalPoly, independent
contractors and researchers, and others.
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Kept
each OakMapper website up-to-date as needed (as new data arrived).
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Kept
all metadata up-to-date, and created new table of contents to
allow easy access to metadata.
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Text
reports
In
progress:
1. Mapping SOD host species based on California
GAP Project vegetation coverage; integration of GAP data into risk mapping for
areas not covered by CALVEG;
2. Using USFS FIA plot data to validate the
application of CALVEG and GAP Analysis vegetation data in mapping distribution
and abundance of SOD host species;
3. Developing a statistical model of SOD
risk based on relationships
between predictor variables and confirmed infection sites (incorporating
FIA data, ground surveys, and COMTF reports).
4. Developing a dynamic model of SOD spread
through time and
simulations of potential habitat loss as consequence of disease.
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