Poultry Talk Ontario (pto.ca)

We are not sure what is causing this tree to be attacked, and by what, although we suspect it's ash borer, since it's an ash tree. Is this what ash borers do; i.e., do they drill holes into the tree and throw off big chunks of bark all the way up the the tree? It seems like it's only on the SE side of the tree, too.
We have other ash trees n the property that do not appear to be affected. The tree that's affected is about 70 feet tall and it looks like it's affected all the way to the top.
Anybody have any ideas what it could be?[
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Woodpecker? Most likely tree is infected with the borer, and the woodpeckers have discovered the tasty larvae inside.

100% emerald ash borer.
D shaped holes. My bush is probably 60 percent ash and every ash tree looks just like yours. Later this year i want to scout for living ash and start getting seeds from the survivors...its just awful down here how much of the bush is standing dead. Sorry jaye....but that is ash borer. :-(

Poor old tree, so sad. That's what my husband says too, an ash borer due to the D shaped holed.

Most likely emerald ash borer. The holes are from adult beetles exiting the tree, and the bark damage is from birds and rodents trying to get at the larvae to eat them.

EAB all the way. Be advised that it is safer to take it down now before it can cause any damage. Trees that have died as early as two years ago can fall over unexpectedly, causing both property damage and personal injury if they are in proximity of buildings and roads.

Got some dead ash around my place. Seems to be sending up shoots from the base. Wondering if that will thrive, or if the borer will just kill that too or does it have a chance of being some how immune?

The dead ones, if I can find a fairly straight branch the right size I have make a couple of hoe handles from them. Good hard wood for that.

so your tree was probably hit about 3 years ago, and now the bark is weakening and sloughing off. these trees are very weak now, you should get it taken down as soon as you can. it makes nice firewood....we were hit 5 years ago, and now it's downright dangerous to be in the woods in the wind. we just lost another 2 trees on our access road to the river flats, and it hasn't even been that windy. while out deer hunting this year i witnessed 2 trees blowing down, and one just fell on a perfect calm morning. thankfully it cracked first, so i could get away from it!

if you have new shoots coming up i would clip some and root them and get them under cover-all ours were killed as well, and then if it is resistant to the bugs you will have something very special to take clippings and grafts from.

I'm am in agreement with the woodpecker -ash borer story. The bark is torn off.

Thanks all. The consensus has confirmed our fears that it is ash borer :-( Such a nice big tree too. Since the tree is near the edge of our property and fairly close to our neighbour's house (and in front of the coop), we'll be taking it down as soon we can. Right now there are no new shoots that I can see, but maybe in the spring we will get some coming out of the stump.