Oak Decline and Red Oak Borer

Background

• Oak decline is a complex phenomenon with no single cause. Stands are predisposed to decline by such factors as relatively old age, shallow, rocky soils, ridge-top and upper slope locations, heavy stocking, and previous droughts (e.g., 1950's, 1980's). Decline is incited or triggered by factors such as short-term, acute drought (1998-2000) or repeated insect defoliation (e.g. gypsy moth in the east). Secondary insects and diseases are contributing factors that further stress trees and ultimately lead to mortality. Common contributing factors are: red oak borer, 2-lined chestnut borer, armillaria root disease, defoliating insects like walkingsticks, and hypoxylon canker. Red oaks are more severely affected than white oaks.
• Ozark Highlands forests are experiencing an episode of oak decline that was incited by 3 years of drought resulting in high levels of mortality by 1999. The abundance of old age forest as well as shallow, rocky soils and, perhaps, overstocking has predisposed the area to this event.
  
• Red oak borer is the contributing factor that is particularly noticeable. Populations have exploded to unprecedented levels.
  
• Ozark Highlands forests have experienced episodes of oak decline in the past, although not this severe.

Project Highlights

• FHP personnel participated with the Ozark NF, Ouachita NF, NA-FHP, Mark Twain NF, Arkansas Forestry Commission (AFC) and Missouri Department of Conservation (MDC) to develop action plans.
  
• A single funded/action plan did not materialize, but cooperation/collaboration continued.
  
• Responses were concentrated on public safety, public awareness, inventory and assessment, management strategies (prevention, suppression and restoration), and research.
  
• Public awareness brochure published by FHP - "Why Are the Oaks Dying".
  
• FHP participated in several public meetings and field tours.
  
• Assisted with web-based Q&A for AFC for landowner education.
  
• Participated in training sessions for AFC foresters.
  
• A Forest Health Evaluation (FHE) implemented by FHP on the Pleasant Hill RD in 1999 with monitoring of decline/mortality through 2004 (data presented orally).
  
• NA-FHP implemented a similar FHE on the Mark Twain in 2000.
  
• FHM-EM project was funded with Jim Guldin, SRS for a regional evaluation.
  
• Training/assistance by FHP to Ozark and Mark Twain on hazard tree identification criteria, primarily for roadway hazard mitigation.
  
• FHP has funded suppression and prevention activities on the Ozark and Ouachita NF.
  
• FHP has funded other STDP and FHM-EM projects aimed at documenting ROB populations, attack behavior, hazard rating, and silvicultural responses such as prescribed burning.

Conclusions/Future direction

• This event and the red oak borer epidemic are running their course. Mortality levels have begun to taper off and the red oak borer population may well be declining in some areas due to weather conditions, exhaustion of suitable host material and other factors.
  
• Many stands have been severely damaged and all cannot be treated in a timely manner to silviculturally address the current conditions.

FHP Contact:

Dale A. Starkey
Forest Service-USDA
2500 Shreveport Hwy.
Pineville, LA 71360
Phone: 318-473-7293
Email: dstarkey@fs.fed.

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USDA Forest Service - Forest Health Protection, Southern Region
Last Modified: Monday, 14 January 2013 at 09:38:29 EST