Hardwood Silviculture Notes
Oak decline is a slow-acting disease complex that involves the interaction of predisposing factors such as climate, site quality and advancing tree age. No single cause is responsible for the decline. Trees that are greater than 70 years of age and that occur on drier sites such as shallow, rocky soils on ridgetops and south- to west-facing upper slopes are most affected. Mortality of rootlets in the upper 12 inches of the soil initiates dieback in severe droughts. Secondary insects and diseases (red oak borers, twolined chestnut borers, armillaria root rot, defoliating insects, hypoxylon cankers) are contributing factors that cause further stress and damage to the trees.
"SP675 Managing Oak Decline," The University of Tennessee Agricultural Extension Service, R12-4910-026-001-06 SP675-1.5M-6/06 06-0323, http://trace.tennessee.edu/utk_agexfores/21