Davey Tree Flipbooks

22 THE DAVEY BULLETIN | July/August 2019 EXPERTISE HOLISTIC APPROACH NEEDED FOR OAK DECLINE Chelsi Rooney, technical advisor, Davey Institute, facilitated a webinar with the Maryland Arborist Association on the topic of oak decline, a complex issue that's difficult to diagnose and even harder to manage. "Oaks are just dying in dramatic fashion all over the place," Rooney said. "We have it in our minds that oaks are the hardiest of all the trees, long-living, and here forever. Now they are starting to decline and die." Oak decline is not just a disease, an abiotic issue, or an insect. It's a combination of these three elements, Rooney said. It can be confused with oak wilt, which is a devastating fungal disease, because oak decline looks extremely similar in trees that belong in the white oak family. In order to understand oak decline, there needs to be a holistic approach, not just for diagnosis, but also for management, Rooney said. The start of the decline often correlates to an environmental factor, and then problems like two-lined chestnut borer and root rot opportunistically take hold. "It's difficult to treat and identify the environmental factor(s), but it's imperative to managing oak decline," Rooney said. "The earlier you can start battling oak decline, the better. When it gets infested with the two-lined chestnut borer or infected with root rot, you are getting into stages of decline Left: The early stages of decline are often linked to environmental factors. It can sometimes be difficult to treat and identify environmental elements but it's imperative to managing oak decline. A way to tell oak decline is happening is if the canopy of the tree starts defoliating from the outside and moves in, as if the tree is making itself smaller and more manageable. Chelsi Rooney's advice is when you start to see the first signs of decline that you run through the steps of diagnosis and question why it's having these symptoms. Right: Here is an example of what advanced oak decline looks like. Once the advanced stages of decline have been reached, you've likely moved past the point where you can bring that tree back, Rooney said. ASH TREE SAFETY Safety is essential for arborists working with trees infested with emerald ash borer. In a new YouTube presentation with arborists for EAB University, Davey's Tim Walsh, director of corporate safety, discussed new research from the Davey Institute showing EAB-infested trees becoming like Styrofoam: easily breakable with rapid strength loss. Such brittle conditions pose an immediate hazard risk for climbing and working. "Ash trees weaken so quickly it's often hard to tell – they might look healthy; they might still be green and have live leaves on them – but they are structurally unsound," Walsh said. You can find the presentation on YouTube under the title, "Dealing with Ash Trees: When to Climb, and What to Do If You Can't." Tim Walsh will present findings from Davey Institute's Anand Persad about EAB and tree safety at the annual International Society of Arboriculture conference on Aug. 14 in Knoxville, Tennessee. where you may not be able to bring that tree back." Her biggest piece of advice is looking at the whole picture, not just what's on the surface. Arborists need to look at the inciting, predisposing, and contributing factors to be able to manage the decline. "Decline's a natural process," Rooney said. "All trees die eventually. All we can do is prolong their lives." E A R LY S T A G E A D VA N C E D S TA G E

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