Wednesday, April 14, 2010
End of Ash as We Know It?
Ash trees in North America are going the way of the American chestnut and American elm. A destructive invasive beetle called Emerald Ash Borer (EAB) is killing them. First found in Michigan in 2002, this Asian woodborer has spread to a dozen states. Millions of ash trees have already died – there are no ash survivors when EAB moves through. Unless something changes, our children and grandchildren won’t ever sit under the shade of an ash tree or swing an ash baseball bat.
So far quarantines and attempts to eradicate outlying EAB infestations in other states haven’t stopped the beetle. Eradication attempts typically involve cutting and chipping all the ash trees within 1/2 a mile of an infestation. These are very expensive projects that cause considerable disruption in the impacted neighborhoods.
EAB is capable of flying many miles on its own, but long distance dispersal is mainly via campers bringing ash firewood from home. You can’t blame them, ash burns well, and what else are you going to do with the dead ash trees in your yard?
Oregon faces a dilemma. It is quite possible that our ash trees will be the last survivors. Should we try to save them? Other states are spending millions and their trees keep dying. Cutting down the trees to save the trees doesn’t make any sense at all if our ash trees are the last ones standing.
Is there anything else we could do that might give us a better chance of success?
Here are some ideas for both the short-term and long-term.
1.) Support a ban on out-of-state firewood that isn’t kiln-dried or otherwise rendered pest free. This could buy us time. The OISC will be introducing a firewood bill in the next legislative session, let’s work together to get it passed.
2.) Educate as many people as possible about the symptoms of EAB infestation so if it does show up ahead of the leading edge, we might find it early enough to do something. If you see ash trees that are declining or attracting woodpeckers, report it ASAP to the OISC hotline (866-INVADER or oregoninvasiveshotline.org).
3.) Preserve an island(s) of high value ash trees. Does anyone know of a watershed or other natural boundary where we could draw a line and try to protect a refuge of Oregon ash trees in their native habitat?
4.) Encourage street tree diversity. Some towns and cities will suffer more from EAB because ash makes up a high percentage of their street trees.
5.) Encourage research on resistant varieties. Oregon is a leader in nursery production and nursery-related research. We have a progressive nursery industry that taxes itself to support research.
6.) Explore biological control. There may be parasitoids of EAB in its native range that could be introduced to reduce EAB populations. Biocontrol is never a sure thing and it takes many years of research to do it safely.
What do you think? How should Oregon prepare for EAB? We could use some fresh ideas.
Daniel J. Hilburn
Administrator, Plant Division
Oregon Department of Agriculture