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New Leaves on Trees: Will They or Won’t They Show?

Posted: May 17, 2016

Driving around Pennsylvania this time of year, we’ve seen or are starting to see leaf bud break on many trees. Leaf out gives a good idea of what should be happening, but maybe isn’t.

As I pass through various regions, I’m paying close attention to what’s happening with the trees. Bud break and leaf out vary between species and are quite often influenced by weather. This year is an interesting year due to the early warmth and dryness, and now cool and wet – it appears many trees may be confused. Or maybe there is something wrong... Leaf out gives a good idea of what should be happening, but maybe isn’t. The inner monologue as I see trees not quite fully leafed-out goes something like this, “Is that one a black walnut? Yes! Okay, it’s not bad that that one doesn’t have leaves yet. Wait, where are Thousand Cankers Disease outbreaks? How close am I to those? Okay, fingers crossed for that one. An oak? Maybe I can start to see some green. Whew, I see flowers expanding which look like tassels below the small young leaves. That one’s good too. What about that one? That’s an ash. It is gone. That one won’t be leafing out this year or ever again… So sad.”

Since its first Pennsylvania detection in the middle 2000s, the extent of the emerald ash borer impact is significant, in both the area and the speed of the damage done. It seems this year that a lot of ash that previously were hanging on are no longer. Fence rows have standing dead trees. Yard trees are dead. This component of the forest has been decimated, in the literal sense of the word.

When the emerald ash borer was identified in the Midwest and the first infestations were discovered in western PA, many wrote the species off. At that time, ash only comprised 11% of the state’s forest trees, and by the time we discovered the borer’s presence, its extent was beyond the initial discovery area. It’s hard to determine where those little guys are until ash start dying. Despite marketing campaigns to “stop moving firewood,” these pests were considered unstoppable, and major eradication or control efforts were not implemented because there weren’t any feasible options for large scale treatment.

We live in a time of global commerce with unfortunately limited resources for inspection of imports to stop new threats from entering our forests. As a result, battles have to be chosen wisely and all too often there are few options for mounting an offensive. The emerald ash borer has taken or is taking a tenth of the forest trees. Combine that with dead and dying elm (Dutch elm disease and elm yellows) and hemlock (hemlock woolly adelgid), gypsy moth infestations, both current and from several years ago, impacting the oaks, and thousand cankers disease now threatening the black walnuts, we see lots of dead trees. Now, as things green up, it’s easy to find the absence of green where it should be. And once you see, you can’t stop seeing.

As you begin to see what’s missing from the landscape where you travel or visit, pay attention to other species having trouble. Seemingly, there are always known and unknown threats challenging trees and forests. If we find them early, there are sometimes control options, even if it means removing affected trees. Recently in nearby states, keen-eyed and curious woodland owners were some of the first to identify the Asian long horned beetle and in Pennsylvania the spotted lanternfly. These early detections are key to control these pests.

So what happens now with all the ash? Dead ash are messy decomposers. They tend to decay quickly and often snap up high in windy weather. Now is the time to pay attention to the dead ash in your yards, next to your buildings, along your trails. These dead trees will quickly become hazard trees and may pose a safety concern for you and yours.

Removing dead trees is always a risky activity. Use all of your personal protective equipment and tremendous caution in getting these trees down. Don’t hesitate to call on a professional if the trees are big, numerous, or in settings where property or personal injury are concerns

Going forward, pay attention to all the trees around you. Watch for crowns of trees that were once lush and full, but now are looking sparse or thin. Watch for increased woodpecker and other insect-eating bird activity, as they strip bark to get at the insects just underneath. Inform yourself about what’s going on in your area so you know what to watch for in your woods and the woods around you.

The PA DCNR Bureau of Forestry has a useful website where they post advisories, information about forest pests, fact sheets, and how to identify what is killing your tree. Check it out. Keep yourself informed. And keep your eyes open!

Contact Information

Allyson Brownlee Muth, Ed.D.
  • Forest Stewardship Program Associate
Phone: 814-865-3208