Oak Wilt in Texas

and the

Texas Oak Wilt Suppression Project

Oak Wilt

• 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.

Veinal necrosison live oak

• 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).

Oak Wilt in Texas

Fungal maton red oak

Distribution of Oak Wilt in Texas

San Antonio

Dallas

Austin

Houston

College Station

Fort Worth

• 55 counties in Central Texas

• 6 counties in West Texas

Counties in Texas with oak wiltcover 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 ResidentialAreas

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 Project1988 - 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

• Dr. Brad Barber, TFS

• Dr. Ron Billings, TFS

• Carrie Burns, City of Lakeway

• Kim Camilli, TFS

• Jay Culver, City of Austin

• Eugene Gehring, Arborist

• Jordy Hagen, Bartlett Tree Services

• Emsud Horosovic, City of Round Rock

•Billy Kniffen, Hays County Extension

• Jon Long, Oak Wilt Specialists of Texas

• Dr. Forrest Oliveria, USDA Forest Service

• Curt Randa, City of Cedar Park

• Dale Starkey, USDA Forest Service

• Damon Waitt, Johnson Wildflower Center

• Dr. Dan Wilson, USDA Forest Service

= New Members in 2001

• Public awareness

• Detection and evaluation

• Technical assistance to landowners

• Cost shares for oak wilt control

• Special projects

• Implement long-range management of oak wilt

Project Objectives

Increase Public

Awarenessof 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

• Field inspection

• Cultural resource survey

• Treatment plan

• Landowner agreement

• Treatment installation

• Completion report

• Reimbursement (50%)

• 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 CommonTrenching Equipment in Texas

Rock Saw

Ripper Bar

Back Hoe

52-Inch Rock SawUsed in Recent Years

Trenching Accomplishments1988 - 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

0

10

20

30

40

50

60

U. S. R. R. R. N.

Land Use Classification

FY 89-93 FY 94-98 FY 01Percent

U = Urban

S = Suburban

R. R. = Rural Residential

R. N. = Rural Non-residential

Cost of Oak Wilt Trenching by Land Use

0

2

4

6

8

10

FY 89-93 Y 94-98 FY 01Total Cost/Foot

U = Urban

S = Suburban

R. R. = Rural Residential

R. N. = Rural Non-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

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 Project-installed trenches to halt oak wilt spread for 5 years (although many additional benefits are involved).

Costs: Total Project costs, including cost sharesand administrative costs ($5,491,468 for FY 1990-1996).

FY 1990 - 1996

Results of Benefit : Cost Analysis

Urban 6 : 1

Suburban 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 ForestryProgram

Fire PreventionProgram

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 wiltin Texas

Suppression Project

Does this mean that suppression efforts

are futile?

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!