Feb 04 2014

Schenley’s Oak Wilt Trees Are Coming Down

Published by at 7:20 am under Schenley Park,Trees

Oak stump upended to prevent the spread of oak wilt (Joseph O'Brien, USDA Forest Service, Bugwood.org)

Don't be surprised when you see trees being felled this month at Prospect Drive in Schenley Park.  An acre of diseased trees must be clear-cut to protect the park's healthy oaks.

Councilman Corey O'Connor held an informational meeting last night where we learned about the project from City Forester Lisa Ceoffe and Pittsburgh Parks Conservancy's Erin Copeland.  They described oak wilt, its treatment, and the affected area in Schenley Park which I've drawn on the tiny map below.  Click on the map for a better view in Google.

Location of the Oak Wilt zone in Schenley Park, February 2014 (screenshot of shared Google map)

Here are some of the 55-60 trees that will come down, marked with blue logging paint last summer. Many of them are 100 years old.
Oak wilt trees marked for removal from Schenley Pak (photo by Kate St. John)

Why is the area so large and why must it be clear cut?

Oak wilt is caused by a fungus that doesn’t spread easily but can kill a tree in 30 days.  The fungus travels in the oak’s vascular system and when the tree detects it it blocks those vessels -- the arboreal equivalent of a stroke.  Watch the 13 minute video here to see how this happens.  You know the oaks are sick when you see browning leaves in mid-summer.  This is the only sign.

Oak leaves showing oak wilt (Joseph O'Brien, USDA Forest Service, Bugwood.org)

The infection travels through an entire stand because the oaks are joined underground.  When their roots touch, they graft to share nutrients and, sadly, disease.  We only see the symptoms in summer so a large area can become infected before anyone notices.

Oak root graft (photo by Ronald F. Billings, Texas Forest Service, Bugwood.org)


Once the fungus has taken hold, an infected tree is doomed.  The only way to save nearby healthy trees is to trench the perimeter of the infection(*) and remove all the trees inside the circle.  Sap beetles can carry the infection so the logging must be done in winter when the sap isn't running.  (Note!  Don't prune your oaks in spring and summer.  This opens them to oak wilt.)

When the logging begins in about 10 days, Prospect Drive will be closed each morning when the equipment arrives and reopened when Davey Tree is done for the day.  Signs will be posted explaining what's going on and Davey Tree will have brochures for those who want to know more.  The site is easily visible from the Boulevard so the City expects a lot of questions.  Now that you know what's going on, spread the word.

By the end of February the area will be empty, but not for long.  Site restoration begins March 22 with a tree planting conducted by the Pittsburgh Parks Conservancy.  Who's going to plant the trees?  Volunteers!

Schenley Park needs you on Sunday March 22, 10:00am to 2:00pm, rain or shine.  Click here or call 412-682-7275 to learn more about signing up.


(photos from Bugwood.org by Joseph O'Brien, USDA Forest Service, Bugwood.org and Ronald F. Billings, Texas Forest Service. Screenshot of shared Google map. Click on the map to see details on Google.)

(* Trenching prevents healthy roots from growing into the infected zone.)

UPDATE 2 June 2014: Click here for the most recent update.

12 responses so far

12 Responses to “Schenley’s Oak Wilt Trees Are Coming Down”

  1. Marcy Con 04 Feb 2014 at 10:27 am

    I am assuming they will not be using oak trees to replant? How long does this stay in the soil or old roots? so sad to see this happen…but necessary to save the rest…will they use the logs to make something for the park?

  2. Kate St. Johnon 04 Feb 2014 at 10:49 am

    Marcy, no they won’t be using oaks to replant. It will be a mix of native trees including aspens (quick growing), birches, maples, hickories. The fungus does stay in the soil so they have to be careful.
    Not sure what’s going to happen to the wood.

  3. bhanceyon 04 Feb 2014 at 5:15 pm

    Thanks for this wonderfully informative write-up. We are dealing with a somewhat similar situation in California, but with an infection in the citrus trees. It is the same disease that caused some of the groves in Florida to have to destroy over 40% of their trees. We haven’t been largely impacted yet – but those who monitor such things here are working to protect our groves from devastation. The trees aren’t as old, or as beautiful, but they are crucial to the nation’s citrus industry, and our economy out here.

  4. Dani Mon 07 Feb 2014 at 11:00 am

    Kate, I appreciate your blog. I am a forest pathologist working with oak wilt detection. I encourage you to contact me.

  5. A.J. Tarnason 09 Feb 2014 at 6:07 pm

    That would be a lot of very valuable timber, every tree worth well over $1k. I hope they don’t just chip and dump it all, as usually happens in this city.

  6. Joeon 25 Feb 2014 at 2:00 pm

    Great write up. Hope they can stop the spread of this fungus before it kills too many trees. Not the same for the Ash trees. Over 300 million in Pennsylvania will die as a result of the emerald ash borer. Over 57,000 in the City parks.


  7. anonymouson 02 May 2014 at 7:42 pm

    this is so stupid and unnecessary killing.this city still isnt using chemical injections to save fungal growths..*rolls eyes.but what would city forresters do with all that free time not cutting and wondering what to do with deadwood

  8. Kate St. Johnon 02 May 2014 at 8:44 pm

    Dear anonymous, There is no way to save an oak that is already infected with oak wilt. Even if it is still alive it cannot be saved with chemicals. USDA instructions on control of the disease are: “To suppress overland spread of the fungus, control must be aimed at destroying the source of inoculum – the diseased tree – at the proper time. All trees that die in any given year should be checked carefully for fungus mats and oak bark beetle colonization by April 1 of the following year. If the mats or beetles are present, the entire tree should be burned, chipped, or covered with plastic for 60 days.”
    Please read more information at this link at USDA: http://www.na.fs.fed.us/spfo/pubs/fidls/oakwilt/oakwilt.htm

  9. Stella McMurrayon 05 Jun 2014 at 12:02 am

    I’d like to know why Prospect Drive IS STILL CLOSED TO CARS. It appears the tree removal is not complete and the replanting was not done in the affected area. Why is there a large dumpster sitting along the edge when it does not have to be? This lovely roadway is unnecessarily closed off when it does not have to be! I love to sit in my car and enjoy the birds singing while I do my crossword puzzles. I’m 84 and it is too difficult for me to walk in there and sit in the shelter. Please give us older folks our lovely park back.

  10. Kate St. Johnon 05 Jun 2014 at 4:54 am

    Stella, I did walk back there and there are still many branches, trunks and pieces of trees lying around which must be removed.

  11. Kate St. Johnon 06 Jun 2014 at 9:25 am

    More news for Stella: They are still cutting down trees at Prospect Circle. That’s why it’s closed.

  12. Stella McMurrayon 11 Jun 2014 at 10:16 pm

    Thank you Kate for your reply. I hope they finish soon. I parked at the opening the other day and walked down the drive. It is still so lovely there. I hope they finish soon. Maybe in time for the car show in July???

    Stella 🙂

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