Oak Trees Are Dying

Asked September 9, 2019, 2:16 PM EDT

There seems to be quite a large number of mature oak trees in the Catonsville area that have died this year. Are you aware of this, and if so, do you know why this is happening?

Baltimore County Maryland oak decline abiotic issues trees

1 Response

Oak trees are declining all over the region, unfortunately, and we have had many reports about them. There is no single cause. For such a situation to occur over many species of oaks and a wide area, it is probably an environmental problem -- multiple years of drought and higher summer temperatures are a possibility. Also, white oaks are intolerant of water-logged soils. Last year's excessively wet weather may have contributed to the problem. Root stress can lead to early fall coloration, browning, and/or early leaf drop. This year, we have had drought and excessive heat in many areas. When trees are stressed by unfavorable environmental conditions, they become more susceptible to pest and disease issues as well.

Some oaks are dying of bacterial leaf scorch, which is more common in red oaks and pin oaks in urban/suburban situations. 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

There isn't really much you can do to reverse decline in mature oak trees, unfortunately. Wait until next spring to see if the trees put out any new growth. If they do not, then they are finished. You could consult with a certified arborist if you would like to have any trees evaluated. You can find an arborist near you using this website from the International Society of Arboriculture. http://www.treesaregood.org/

Christa