Searching for the identity of these loud tree-infesting pests

[birdgirl]

I went camping last weekend in central Virginia, at Bear Creek Lake State Park, about 60 miles west of Richmond. After we set up camp, we explored the woods immediately surrounding our site. There were two large fallen trees about 20-30 yards behind our site that were in our path. So just as I was about to duck under the first tree, I stopped and noticed it more closely…

There was a layer of “sawdust” (for lack of a better word) on the ground beneath the tree. All over the surface of the fallen tree were tiny holes surrounded by piles of sawdust (similar to ant holes, but with wood dust instead of dirt.) Then as I was examining the tree, I noticed this noise, this kind of rhythmic, crunching or chomping noise, eminanting from the tree…

So basically there were some sort of tiny creatures infesting this tree, and I suppose there were so many of them that they were making this low, loud crunching noise. My friend and I stood there in utter amazement, trying to figure out the mystery of what these creatures were. First of all, we didn’t think they were termites, because termites don’t eat live trees, do they? This tree was clearly alive when it fell because it still had green leaves all over it, and the break looked very fresh.

There were tiny holes all over the trunk of the tree, maybe a millimeter in diameter. If you looked closely, you could see a steady stream of sawdust being pushed out of the holes. But as hard as you looked you could never see the actual creature.

What also became apparent is that this tree was probably infested long before it fell, and the infestation probably made it so weak that it fell. We could see no other evidence for why the tree fell. No other trees in the vicinity were infested, so that made me think it was an infestation that was particular to this species of tree (I don’t know what type of tree it was, but it was decidious, not coniferous).

Anyway I am wondering if anyone knows what was eating this poor tree. I know that when trees fall, they eventually get eaten by all sorts of creatures, but this was different. I have never seen anything like this before. And the most striking part of it was the noise, the loud chomping noise that never stopped. It was so loud we could hear it in our tent back at the campsite!

[jamie1928]

Termites?

[birdgirl]

Like I said, I don’t think they are termites. The tree was alive. Termites don’t infest live trees, do they?

[Mangetout]

Going only on the size of the bore-holes, I would suggest some kind of beetle larvae.

[yabob]

I would agree with beetles. There are many beetle species whose larva are wood borers. Ambrosia beetles, for instance:

http://fhpr8.srs.fs.fed.us/idotis/insects/ambrosia.html

Look at the picture of the sawdust beneath the tree.

[Duck_Duck_Goose]

http://cecalaveras.ucdavis.edu/wood.htm

Borer larvae are slender, white, segmented grubs with brownish heads and rather prominent jaws. These larvae produce the chewing noises and piles of wood-colored sawdust that frequently cause alarm. This sawdust material may be relatively fine or coarse and fibrous.

These borers also are responsible for the wide zigzag or meandering tunnels seen beneath the bark and deep in the wood. The tunnels of both groups are oval in cross-section, not perfectly round. Wood borers are primarily a nuisance. The noise and sawdust they produce is suggestive of termites and thus, disconcerting.

[Doctor_Jackson]

What kind of trees? The pine beetle is currently a scourge in the southern US.

[yabob]

The OP said “decidious”, and mentioned the tree having leaves all over it (not needles), so I didn’t mention pine bark beetles, and used an example beetle that attacks hardwoods.

There’s still a fairly long list of beetles whose larva bore into trees. And I’m not sure the pine beetle is exclusive to pines, either.

The caterpillars of some moth species are wood borers, too, but I think they leave larger holes.