Oaks dying in Jarrettsville

Asked September 26, 2019, 11:32 AM EDT

I’ve had quite a few oaks die off very rapidly in the past two years on my heavily wooded property in Jarrettsville. I’m getting a bit worried. Are there resources to assess the problem and find solutions?

Harford County Maryland

1 Response

Oak trees are in decline all over our region, unfortunately — both red and white oaks. There is no single cause. To occur over many oak species and a wide area points to environmental and cultural causes. Higher summer temperatures are a factor.

White oaks are intolerant of saturated soil, so last year’s excessive rain is believed to play a role. Red oaks are especially affected by years of drought. Drowning and drought both kill roots, and the first symptom is dieback of foliage in the canopy. Then trees stressed by unfavorable environmental conditions become more susceptible to secondary disease issues and pests such as ambrosia beetles and borers.

Some oaks are dying of bacterial leaf scorch, but this is not common on white oaks. Oak wilt is not active in Maryland generally. Here is more about those diseases: https://extension.umd.edu/hgic/why-oak-trees-are-declining

Take a look at this publication about oak decline. https://extension.tennessee.edu/publications/Documents/SP675.pdf

Most declining oaks are 50-70 years old. Bigger trees need more resources than smaller trees and are less resilient. Many trees are surrounded by turf that intercepts rain and nutrients. Whereas a forest tree’s fallen leaves are entirely recycled into nutrients to feed the tree, homeowners rarely leave those leaves on the ground for trees. Lawn mowing itself can compact soil, so rain and oxygen can’t penetrate.

There isn’t really much you can do to reverse decline in mature oak trees. A certified arborist can evaluate the tree for pests and diseases and structural integrity. Find one near you at the International Society of Arboriculture website: treesaregood.org. Since oaks are premier trees, it’s good to replant oaks. Be sure to protect saplings from deer.