Oak Wilt in Texas
and the
Texas Oak Wilt
Suppression Project
Oak Wilt
Veinal necrosis
on live oak
• Caused by the fungal pathogen Ceratocystis fagacearum.
• This native pathogen affects oaks in some 20 eastern and
mid-western states (worst outbreak is in Texas).
• Fungal spores vectored by insects, primarily nitidulid beetles.
• Red oaks and live oaks are most susceptible.
• Veinal necrosis is a diagnostic symptom on live oak leaves.
Oak Wilt in Texas
• First identified in Texas in Dallas in 1961.
• Live oaks and red (Spanish) oaks are most
severely affected.
• Only red oaks produce fungal mats.
• Most tree losses occur from pathogen spread
through connected root systems
(common in live oaks).
Fungal mat
on red oak
Distribution of Oak Wilt in Texas
• 55 counties in Central Texas
Fort Worth
Austin
San Antonio
Dallas
• 6 counties in West Texas
College Station
Houston
Counties in Texas with oak wilt
cover an area larger than VT, NH,
MA, CT, NJ, RI and MD combined.
Impact of Oak Wilt in Texas
Rural Areas
Thousands of acres of live oaks
have become victims of oak wilt
in rural areas of Central Texas.
Impact of Oak Wilt in Texas
Rural
Residential
Areas
Loss of live oaks to oak wilt
has greater economic impact
around ranch houses.
Impact of Oak Wilt in Texas
Suburban
Areas
(1-10 acres)
The many new “ranchettes”
(<10 ac) in Central Texas
have increased incidence
and impact of oak wilt.
Impact of Oak Wilt in Texas
Urban Areas
(< 1 acre)
Oak wilt may reduce urban
property values by 15-20%.
Texas
Oak Wilt
Suppression Project
1988 - 2001
Cooperators
• USDA Forest Service/ Forest Health Protection
• Texas Forest Service
• Cities, neighborhoods, private landowners
• Texas Cooperative Extension
• Texas Agricultural Experiment Station
• Lower Colorado River Authority
TFS Oak Wilt Staff
• Project director (10%)* + support staff
• Administrative coordinator (30%) + support staff
• Oak wilt technical coordinator (100%)
• Oak wilt field coordinator (35%)
• 6 staff foresters (45 - 80%)
• 5 urban foresters (10 - 15%)
* percent of time devoted to Oak Wilt Project
Oak Wilt Technical Advisory Board
• Dr. Dave Appel, TAMU
• Emsud Horosovic, City of
• Dr. Brad Barber, TFS
•Billy Kniffen, Hays County Extension
• Dr. Ron Billings, TFS
• Jon Long,
• Carrie Burns, City of Lakeway
• Dr. Forrest Oliveria, USDA Forest Service
• Kim Camilli, TFS
• Curt Randa, City of Cedar Park
• Jay Culver, City of Austin
• Dale Starkey, USDA Forest Service
• Eugene Gehring, Arborist
• Damon Waitt, Johnson Wildflower Center
Round Rock
Oak Wilt Specialists of Texas
• Jordy Hagen, Bartlett Tree Services • Dr. Dan Wilson, USDA Forest Service
= New Members in 2001
Project Objectives
• Public awareness
• Detection and evaluation
• Technical assistance to landowners
• Cost shares for oak wilt control
• Special projects
• Implement long-range management of oak wilt
Increase
Public
Awareness
of Oak Wilt
Public Awareness
• Circulars and publications
• Internet web pages, public fairs
• Training sessions, tours and demonstrations
• Responding to phone calls, e-mail inquiries
• News articles, videos, posters, displays, etc.
• One-on-one site visits
150 Participants
Oak Wilt Hot Line
For answers to most often asked questions
Call
512 - 473 - 3517
Courtesy of Lower Colorado River Authority
Cost Share Procedures
• Initial contact
• Treatment installation
• Field inspection
• Completion report
• Cultural resource survey • Reimbursement (50%)
• Treatment plan
• Landowner agreement
• Post-suppression
evaluation
Barrier Treatments
• Trenching (at least 4 feet deep) to halt oak wilt
spread through connected root systems
• Roguing (removal of diseased trees within
trenched area)
Most Common
Trenching Equipment in Texas
Ripper Bar
Back Hoe
52-Inch Rock Saw
Used in Recent Years
Trenching Accomplishments
1988 - 2001
• To date, the Project has installed a total of 2,655,900 feet
(503 miles) of trenches in 35 counties since 1988 to halt the
spread of 1,903 oak wilt centers.
• Equivalent to a trench extending from Houston to Lubbock.
• Of this total, ca. 8% have been installed in urban sites, 14% in
suburban sites, 35% in rural residential sites, and 43% in rural
non-residential sites.
• Two of every 3 trenches have held without breakouts.
Cost/foot and number of trenches
vary with land use category
• Rural Non-residential: More than 10 acre ranch
without a residence in vicinity of trench
• Rural Residential: Home site on ranch of
more than 10 acres
• Suburban: 1-10 acre home sites in transition
area between rural and urban areas
• Urban: Urban residential setting (< 1 acre)
Percent of Total Trenches by Land Use
FY 89-93
Percent
FY 94-98
FY 01
60
U = Urban
S = Suburban
50
40
30
R. R. = Rural
Residential
20
10
R. N. = Rural
Non-residential
0
U.
S.
R. R.
Land Use Classification
R. N.
Cost of Oak Wilt Trenching by Land Use
Total Cost/Foot
10
U = Urban
S = Suburban
FY 89-93
Y 94-98
FY 01
8
6
4
R
.N
.
R
.R
.
0
SU
B.
R. N. = Rural
Non-residential
2
U
R
B.
R. R. = Rural
Residential
What are Economic Benefits
of 500 miles of trenches?
• The 500 miles of trenches effectively protect a total
of 15,000 acres from oak wilt spread over 5 years.
• These 15,000 acres include 20,000 urban trees, valued
at $70 million, 150,000 suburban trees ($47
million), 110,000 trees ($78 million) on rural
residential sites, and 210,000 trees ($5 million) on
rural non-residential sites.
• The total value saved is ca. $200 million for an
investment of $10 million.
Prevention
Prevention of Oak Wilt
• Avoid pruning between January and June
• Paint wounds and pruning cuts
• Remove and dispose of diseased trees
• Treat threatened oaks with fungicide Alamo®
• Proper management of oak firewood
• Plant resistant trees, diversify landscapes
Other Special Projects
• Aerial sketch mapping and ground verification
of oak wilt centers
• Development of computerized data management
system
• Economic analysis of Project activities
• Partnerships with cities of Austin and Lakeway
• National Oak Wilt Symposium;
North American Forest Insect Work Conference
Aerial Detection Surveys
• Sketch map surveys conducted over 13 million acres
(319 USGS quadrangles or 19 counties).
• Total of 8,002 mortality centers detected on 13 million
acres; of 5,714 centers (71%) ground
checked to date, 4,989 (87%) are oak wilt.
• An estimated 6,962 oak wilt centers occur on the 13
million acres of land surveyed to date.
• Assuming 20% of land in oaks, this represents 2.7
oak wilt centers/1000 acres of host type.
Economic Analysis
FY 1990 - 1996
Objective: To determine the economic efficiency
of the Texas Oak Wilt Suppression Project.
Benefits: Infected tree removal and tree replanting
costs avoided by cooperators due to Projectinstalled trenches to halt oak wilt spread for 5 years
(although many additional benefits are involved).
Costs: Total Project costs, including cost shares
and administrative costs ($5,491,468 for FY 1990-1996).
Results of Benefit : Cost Analysis
Urban
Suburban
6:1
14 : 1
Rural Residential
8:1
Rural Non-residential
4:1
Project Accomplishments
• Network of TFS foresters established throughout
Central Texas to provide technical assistance.
• Aerial detection surveys conducted over 13 million
acres (ca. 19 counties); ca. 8,000 oak wilt centers
detected and 5,000 confirmed on ground to date.
• Public awareness of oak wilt greatly increased and
$1.6 million of cost shares distributed in 35 counties.
• More than 2.6 million feet (503 miles) of trenches
installed to control 1,900 oak wilt centers.
• Several thousand infected red oaks removed and live
oaks injected with fungicide.
Highlights in FY 2000-2001
• Oak wilt technical coordinator position filled (Kim Camilli);
10 new members added to Technical Advisory Board.
• New office opened in Johnson City (Robert Edmonson);
Lampasas position filled (Jay Hein).
• City of Lakeway adopted as newest city partner and oak
wilt forester hired by city (Carrie Burns).
• Oak wilt “how to” brochure translated into Spanish.
• Computerized Operations Information System revamped.
• Office facilities in Austin expanded to better serve public.
The Texas
Oak Wilt Program
is integrated with
other federal programs.
Coordination with other Programs
Oak Wilt
Program
Stewardship
Program
Urban Forestry
Program
Fire Prevention
Program
What is the Impact of the Suppression
Project on a Landscape Scale?
• Assume 8,000 - 10,000 oak wilt centers in Texas
• Only 150 - 200 centers controlled per year with
Project assistance
• New centers develop each year as Texas’
population expands
• Without additional federal and state support, the
Project is unlikely to substantially reduce the
incidence of oak wilt on a landscape scale.
Oak wilt
in Texas
Does this mean that
suppression efforts
are futile?
Suppression Project
Are Suppression
Efforts Futile?
Oak wilt is analogous to auto accidents
• Both will increase as the human population in
Central Texas increases.
• Frequency and severity can be reduced through
public education (= defensive driving class).
• With oak wilt, trenching reduces potential losses, as
do seat belts and air bags in autos.
• Prevention is preferred and most effective approach.
Long-range Strategic Plan
• Apply integrated approach to pest management
• Identify priority areas for education, prevention &
suppression
• Empower communities to address oak wilt
• Increase state funding; technical assistance staff
• Seek federal funds from federal Cooperative
Forest Health Program
• Plant resistant trees; diversify landscapes
When it comes to oak wilt,
Texans are learning to:
Make the best
of a bad situation
Thank you
for your attention!