An "American Oak" tree problem

[Charles T. Smith]

We bought and planted a tree that was called an "American Oak" about 3 years ago. It's currently about 3 - 4 cm (2 - 3 inches) in diameter.

A few days ago, I discovered a hole in the trunk, about 170 cm's from the ground (under 6 ft). The hole itself is about 1.5 cm's in diameter (just under an inch). A wire detected that it went about 15 cm up and 4 cms down (about a foot up and a few inches down).

After probing with the wire, I looked away for an instant, and then had the distinct impression that I saw something out of the corner of my eye pop its head out of the hole for a fraction of a second. I wasn't able to get it again. It looked like a huge worm or something. Or maybe it didn't happen. But something made that hole.

The hole occupies about 20% of the diameter of the trunk.

My question: will the tree grow in respect to the size of the hole, so that the hole becomes insignicant, or will the hole "grow" with the tree?

Should I cut it down now instead of pealing it off my house later?

Should I fill the hole with anything?

Any thoughts will be appreciated.

[David E. Ross]

I would be concerned that a hole that size would substantially weaken the trunk. Even as a small tree, it might easily break in the next wind storm. Thus, I would remove and replace it.

First, however, I would consult a local aborist or horticulturist to identify what pest made the hole. Then, you might be able to either plant something that does not attract such a pest or else be able to block it from damaging anything else.

The "World Book of Trees" and Sunset's "Western Garden Book" list many oaks (genus Quercus) with common names indicating European and Asian nations as well as states within the U.S. However, neither work lists an "American oak". Was it possibly an "Armenian oak" (Q. pontica)?

[Dave]

"American Oak" / centimeters?

Got Live oak, and Red oak around here. Our tape measure read inches and feet. Dave

[Charles T. Smith]

Yes? Ours doesn't.

[Charles T. Smith]

Yes, I guess you're right... unfortunately. I was hoping I could ignore it and it would go away. ;)

I actually hadn't intended to buy anything exotic ... we have oaks here in southern Germany ... but maybe it really was from a different clima. Your point makes me think that the garden shop did me a disservice.

Well, it was clearly presented as an American oak, but that could have just been sloppy naming.

[Amos Nomore]

[Sheldon]

Sounds like a tree borer. You probably did see it. I would try standing guard duty for a while and perchance it will emerge again and you can stab it with a barbed stick and yank it out. Also being such a young tree is in your favor becaue it can't be very deep as it could in a much larger tree, so there is probably just the one rather than a colony. If I had no luck in grasping the borer I would attempt to flush it out with a strong jet of water from a garden hose. Once it's out there is no reason you couldn't pack the hole completely, cement will work. The tree will heal and within 2-3 years you shouldn't even be able to find the remnants of that hole. But more importantly keep watch that more borers don't attack that tree or other trees as they are likely in your soil. You probably should adhere to a regimen of the proper insecticide applications.

[dr-solo]

the hole will not get any bigger as the tree grows and as long as water is not allowed to get into the hole it wont rot. Most of any tree is dead, in fact, 98% of a redwood is dead wood. the only part of the tree that is alive is right under the bark, the leaves, the roots. at this point I would be worried about that something eating or laying eggs in the hole, so I would flush with an insecticide. then tape the hole shut without encircling the whole trunk. as the tree grows the bark/growing layer will grow out until it meets and closes the entrance (more or less).

[Charles T. Smith]

Good news! Thank you.

[Charles T. Smith]

Thank you! The web site is a bit much to look at, but I'll get my wife to handle it - she's not as much of a chicken as I am. :)

[Charles T. Smith]

Cement? I was thinking along the lines of tar. I have an unused bag of cement, and I've seen trees with cement plugs, now that you mention it... But it seems extreme to me ... for example, cement gets warm when it hardens. That won't be a problem? Would cement be less of a chemical toxen to the tree than tar, for example?

[Sheldon]

Were it an old hollow tree or relatively large cavity then cement will cause problems. But yours is a very young tree, which in a few years will grow enough that it reduces that borer hole to mere insignificance. As to heat, trees easily tolerate far higher temperatures over much longer periods simply by growing in the sun. And that is why filling a void with tar is not a good idea, it's fine to "cauterize" a small surface wound in order to prevent entrance by insects and water. Whenever the sun strikes that tree the tar will reliquify to some degree and leach throughout the tree even into the living portions especially downwards (gravity) to the root area and that may interfere with sap flow... in a small tree that can have the same effect as a blood clot in your leg, death. Patching cement doesn't generate much heat, you can run a small test batch and check the temperature with an insta-read thermometer... I seriously doubt it will reach more than 90F during the curing, and only for a very short duration, not nearly as hot as the surface of a tree gets from the sun, and thats all day every every sunny summer day.

And if you're still tentative go to a plant nursery and ask if they can recommend an arborist's cement, calking compound or some such. Plumbers putty would work too, or spackle patching compound (probably easier to work with than cement, a small $2 can from The Depot will do, all you want to do is fill the void until the tree heals itself. Let us know if you get that borer out.

[Charles T. Smith]

No, I'll do the cement, I have it on hand.

But what do you mean, get the borer out? I was planning to just mash up and down with a heavy wire and then follow up with some insecticide - do you think it wise to actually have his carcass in hand (habeas corpus, so to speak)?

[dr-solo]

systemic works really well in trees that arent producing edible food. on my peach trees will occasionally get a borer, use the wire to spear it. but normally I have window screen wrapped around so they cant get close enough to lay and egg and get into the tree. Ingrid

You probably

[dr-solo]

[Charles T. Smith]

I bought a can of "acetamiprid". Does that qualify?

[Sheldon]

Unfilled that hole will definitely grow larger, no ifs, ands, or buts about it. Cambrium cannot grow over air or under tape, the hole must be properly filled to the correct level or that tree will develop internal dry rot and being so small a tree it will then probably die. For such a small tree that's a very serious wound, a bandaid can only hurt it by preventing air circulation and moisture will accumulate by condensation. If it's not going to be filled it should just be left alone and hope for the best. Window screen is no real protection from small egg laying insects... and often the smallest adult insects produce the most voracious and destructive larvae. Fill the hole... and rather than control insect infestation with poisonous chemicals attract birds, by attacting birds there is far less opportunity for insect infestation to begin with... if not for insect consuming birds forests would become wastelands. A few bird houses set about cost less than insecticides and are far easier to maintain. And don't ever feed birds during warm seasons, they find plenty to eat without your training them to not eat their regular normal diet.

[dr-solo]

[Treelady]

If the insecticide works why plug the hole with cement? No need, the tre will compartmentalise the wound. Oaks are great at sealing wounds, generally speaking. American White Oak= Quercus Alba

[Charles T. Smith]

Okay, I guess I'm back to the fill with concrete approach.