Knowledgebase

Red Oak Tree Decline/Death #725461

Asked September 20, 2020, 10:24 AM EDT

I have several Red Oaks that are showing die-back.  Several were removed this year after complete die-back. The White Oaks are doing fine.  The tree impacted this year looked OK until  a few weeks ago. 
Now its showing spotty but significant browning of canopy leaves, from the edges towards the middle of the leaf. It is also starting leaf drop of the completely brown leaves.  Other trees in the neighbor are showing similar but not as drastic signs. 

Anne Arundel County Maryland

Expert Response

We have received a lot of questions about decline of oak trees in recent years. For such a situation to occur over a wide area and in different species of oaks, it is likely due to a combination of environmental factors. The changing climate, higher summer temperatures, and multiple years of drought as well as the excessive rainfall in 2018 are all considered to be contributing factors in oak decline. When trees are stressed by unfavorable environmental conditions, they become more susceptible to pest and disease issues as well -- such as ambrosia beetles and borers.

Some oaks are also dying of bacterial leaf scorch, an issue that is more prevalent in red oaks located in urban and suburban areas. However, our plant pathologist does not see bacterial leaf scorch symptoms in your photos. A certified arborist would be able to take samples from your tree and submit them to a lab to determine if the the bacterial pathogen is actually present.

Here is an article from our plant pathologist on why oak trees are declining, https://extension.umd.edu/hgic/why-oak-trees-are-declining.

This publication goes into even more detail about the situation with oak

Residents of Anne Arundel County can report dying oaks to the county’s office of inspections and permits, https://www.chesapeakenetwork.org/2020/07/17/oak-decline-reporting-application-in-anne-arundel-county.

It does appear that there are new buds on the branches in your photo, so your tree may leaf out again next year, but overall this early fall coloration is not a good sign for the longer term.

Some steps you can take:

Water during drought periods in the fall to minimize stress on the tree.
https://extension.umd.edu/hgic/topics/watering-trees-and-shrubs

Consult with a certified arborist about options for care or safe removal.
Some trees in urban/suburban situations suffer from soil compaction (which limits oxygen to the roots) and a certified arborist would have the tools (air spade) to alleviate compaction if that is indeed an issue in this situation. This would be more useful for trees that are not already showing severe dieback.

You can find a certified arborist near you using this website from the International Society of Arboriculture, https://www.treesaregood.org/.

Finally, this article may be helpful in deciding when it is time to remove and replace the tree(s).
https://extension.umd.edu/hgic/topics/how-do-you-decide-when-remove-tree

Christa
Answered by the Home & Garden Information Center's Maryland Certified Professional Horticulturists Replied September 22, 2020, 11:49 AM EDT

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