A dying pine, oak or ash in Oklahoma City

A pine that goes from green to dead within a season fits pine wilt, and Oklahoma County has seen it. An oak dying back from the top in a hot, dry stretch may have the canker that OSU says is common across much of the state. A website cannot diagnose your tree, so use this to know what to ask. We connect homeowners with tree companies and are not tree doctors.

Pine wilt

An Oklahoma State University update from June 30, 2010 describes a trek with the Oklahoma County Extension educator through parts of the county with severe pine losses. It is an old notice, and we did not find a newer count for the county. The details still help:

• It hits non-native pines hardest, naming Austrian, Scots and Japanese black pine. Native pines usually resist it unless drought and heat have stressed them.
• The cause is a nematode carried by long-horned beetles.
• Death can come as little as 1 to 2 months after the nematode arrives. Needles yellow or brown, droop, and often stay on the tree.
• The wood goes dry and lacks resin, so branches tend to snap clean instead of bending. Cut wood may show blue stain, which the update says is not proof by itself.

The update also says storm damage does not cause that kind of fast death, so a pine that dies quickly after a storm may not be a storm story at all.

What it advises: cut dead trees down and burn them in spring, before May 1, before the beetles emerge. Where burning is not allowed, chip them as small as possible and do not use the chips for mulch, since transmission from infested chips has been shown. Burying often fails. Do not move the wood. Ask the fire department or the city whether burning is allowed at your address, since we did not confirm that, and ask any company exactly where the wood will go. Injections exist, but the update calls them preventative, not a cure.

When replacing a pine, the city's tree guide says loblolly is highly resistant to pine wilt. Its 2016 plant list still includes Japanese black pine, so a tree being on a city list does not settle the question.

Oak canker and dieback

OSU's fact sheet on Biscogniauxia, formerly Hypoxylon, canker says the fungus lives quietly in the bark and sapwood of healthy trees until stress lets it take over. It says "The most common stress factor in Oklahoma is drought and heat", and that the disease is now common throughout much of the state. All oaks can get it, more often the red oak group, and it can turn up on maple, hickory, pecan and sycamore.

• Early on, leaves yellow and wilt, and branch tops die back.
• Later the bark sloughs off and shows a mat under it, white to brown at first, then gray to black.
• The whole tree can seem to brown overnight, though the sheet says the girdling takes weeks to months.

There is no cure. The sheet, dated 2012, says no chemicals are registered to treat it, and that in a home setting a tree with more than 15 percent of its crown infected should be cut to ground level and burned, with the wood destroyed soon because it keeps producing spores. Less damaged trees get extra care, like water in a drought and protection from trunk and root injury. Burning is again a question for your city. Chemical rules may have changed since 2012, so check that before you rely on it.

Emerald ash borer

A state notice from April 28, 2026 confirms the beetle in Wagoner County and lists Carter, Choctaw, Delaware, Love, McCurtain, Murray and Pushmataha as well, for eight counties. Oklahoma County is not on that list. That is what the notice says as of its date, and the insect can travel on firewood, so the state's advice is to buy and burn local firewood. If you think you have seen it, it asks you to email OKForest@ag.ok.gov with photos.

This matters here because ash is on the city's 2016 street tree list. Green ash is also on the state's native list for the county. Since Oklahoma County is not on the notice, do not assume the borer is why an ash here is failing, and do not rule it out either. Have it looked at before it comes down.

The local tree mix

The state's native tree list for Oklahoma County includes eastern redcedar, eastern cottonwood, pecan, black walnut, post oak, blackjack oak, bur oak and American elm, among others. Oklahoma Forestry Services describes the Cross Timbers forest as a central Oklahoma feature, and its forest plan says those forests are drought stressed and dominated by post oak and blackjack oak. That lines up with OSU's point about stress.

The plan also says redcedar is encroaching on range and forest land where fire has been kept out, and that most people consider it an aggressive pest. If you have a young cedar coming up in a fence line, it is native and common here, and taking it out is a plain removal job, not a disease question.

Other things it could be

The state's tree insects and diseases page links fact sheets on anthracnose, bagworms and webworms, conifer diseases, Japanese beetles, pecan scab and common oak defoliators. Many of these look bad and do not call for removal. The city's guide also says most central Oklahoma soils are alkaline, and that some plants will not tolerate that, so a slow decline may be a soil problem. Before paying to remove a tree over a guess, have it examined. The trim or remove page says who can do that. We could not open OSU Extension's current pages to confirm its county office details, so search for OSU Extension in Oklahoma County.