October - December 2013
White Oak Decline
White oak is important in Missouri due to its longevity, mast production for wildlife and saw timber value (2 billion dollars). Increased decline and mortality is a concern for this resource. Beginning in August 2011 and continuing through fall 2013, the MDC Forest Health staff received many reports of rapid white oak decline and mortality, often occurring within one growing sea-son. In 2013 a majority of reports came from east central and southeast Missouri.
This syndrome is different from other oak decline patterns reported in Missouri, which typically include red oak species on ridge tops and upper slopes of SW facing aspects and is often attributed to the combined effects of advanced tree age, high stem density, and drought. In many recent white oak reports, pockets of white oak decline in mixed oak stands have been located on lower slopes. Other oak species are rarely affected. Biscogniauxia (Hypoxylon) canker, twolined chestnut borer and other native borers are frequently observed. Some trees have evidence of Armillaria root rot. Depending on the location, white oak has been subjected to many stressors in recent years including multiple extreme weather events and severe jumping oak gall infestation in 2010. Funding has been secured through a USDA Forest Service Evaluation Monitoring grant for a white oak decline research project at the University of Missouri with cooperation and additional funding from MDC. Further investigations will look in greater detail at associated insect and fungal pathogens as well as site characteristics.