Thursday, July 10, 2008

Watch Your Ash

The other day I found myself taking a cross country walk through suburban Doylestown Township. From Cross Keys to Delaware Valley College, if you know the territory. I was trying to stay out of the sun so I stuck to the side streets, looking for shade. I found a lot of shade but as I proceeded though one particular development I noticed something disturbing. Almost every tree I walked under was ash. Green Ash is a great tree -tough as nails and well adapted to our region. Not much for flowers or fruit but it's a good choice for shade. Or it was.

As you may have heard, there's a new pest in Pennsylvania called Emerald Ash Borer. Just about one year ago the pest was found on the western Pennsylvania border. It traveled east from Ohio. The original infestation in the United States was found in Michigan in 2002 where it has devastated more than 30 million ash trees. Who knows how long it will take for this boring beetle to reach our end of the state but experts agree, it is just a matter of time. The larval stage of this insect destroys the water and nutrient conducting tissue just beneath the bark, causing trees to die. Symptoms include back cracking, woodpecker activity, crown die-back, and ultimately , tree death. Several other borers attach ash. Check symptoms to distinguish between them.

So, as I enjoyed the shade of these fine trees I could not help but think that some day they are likely to be wiped out by a new invasive pest. Forget about eradication. This cat is out of the bag. Individual ash trees will be candidates for insecticide treatment but wholesale protection of woodland trees and most landscape trees is just not feasible. Don't panic now and call the arborist. We'll have more specific instructions when it finally gets here. No sense in treating trees before the bug is here.

For now, enjoy the shade. Think twice before planting ash (we're talking the genus Fraxinus not mountain ash, Sorbus). Be glad that Pennsylvania has only a modest amount of ash in it's forests and landscapes. It may be many years before eastern Pennsylvania deals with this pest. Regulatory agencies are monitoring throughout Pennsylvania to track it's progress. If you happen to see a big purple box hanging in an ash tree, this is one of the monitoring stations.

Click on the Emerald Ash Borer link above to get the full story. You can follow the progress of this insect and read it's history from this site. And watch your ash.

1 comment:

Anonymous said...

HI Scott

Great blog, I always learn so much from you.
We have a property full of Pin Oaks which are all dying, I believe from Sudden Oak Death Disease. Any comments on this disease?
Makes one appriceate why diversity in the landscape is so imortant.