In recent years oaks in the white oak group, such as chestnut oak (Quercus montana) and white oak (Quercus alba), have started dying in significant numbers. Some reports indicate other oaks are affected as well. Reports came from urban foresters, state foresters, residents, and Virginia Tech Cooperative Extension.
The past decade has seen more significant changes in dry and wet seasons in Northern Virginia. Long hot spells and extreme storms have increased. This, along with historical and current changes in our stormwater network, from increases in impervious area to the undergrounding of streams, have caused long-term stress in trees that can take decades to show impacts.
Trees can be damaged by cutting roots and damaging bark or branches. Construction damage, either on your property or nearby, can cause significant dieback in trees and may be a cause of the decline.
Affected trees have shown symptoms from fungal pathogens, insect damage, and bacterial disease. Many of these sources of damage are what is called a secondary factor, or something that comes after a tree is already weakened.
Our general recommendation is: do not treat for diseases or insects without knowing the cause of decline, and only when it will help your tree survive. Treating for diseases that are not present or treating when it will not help the tree’s likelihood of survival will waste your money and can cause negative impacts to our local ecosystems.
The following secondary factors have been reported, on stressed trees. Many of these are untreatable, or treating them may not improve your tree’s health:
Reports of Oak wilt or Sudden Oak death have been made, but not confirmed by lab tests, in Virginia.
The Virginia Department of Forestry has an in-depth analysis on broad-scale oak decline in Virginia, which can be helpful for further information.
This information was assembled by the City of Falls Church along with Arlington County, the City of Alexandria, the Virginia Cooperative Extension, Tree Stewards, and Arlington Regional Master Naturalists.