Request for ID – Fungus or egg mass?

Brown woody mass on side of (poplar?) snag

I have great faith in the power of the nature blogging community to help others with identifications for mystery organisms and objects. Sometimes there are things you come across that you just can’t seem to find the right combination of search terms to produce a result and an ID on the web. You all came through on the comfrey I posted back in the summer. Now I’m asking for your help again; admittedly, this challenge is probably a little more difficult than the wildflower.

Brown woody mass on side of (poplar?) snag

I found this stuff in our cedar woods at the back of the property. The woods border on a bog/poor-fen, and are themselves rather wet. It’s nearly uniformly cedar, but there seem to be one or two tall poplars in the middle. Also mixed in are a few small snags that looked like they were maybe once upon a time also poplars, but were in any case not cedars. I found half a dozen of these small snags, and every single one of them had these brown cakey masses on the sides of the main trunk. I didn’t spot any small trees with this bark pattern that were still alive.

Brown woody mass on side of (poplar?) snag

They ranged in size from a few inches long to as much as seven or eight. Some were a rich brown, while others were nearly the same colour as the bark. All of them were covered, to some degree, with algae. And all of them had these tiny holes, about 2-3mm in diameter, clustered mostly around the edges and sparingly across the middle. I tried to peel it up to look underneath or assess its texture, but it was woody and firmly attached.

Brown woody mass on side of (poplar?) snag

My hypothesis was that these were egg masses of some sort of insect. I also considered fungal growths, but then what are the holes? I’m reminded of a post I did in the first couple of weeks of writing this blog, about the bracket fungus Cerrena unicolor, which has a symbiotic relationship with a horntail wasp, whose larvae feed on the fungus’ mycelium in exchange for carrying the fungus’ spores to its next host. The fungus then also uses pheromones to attract an ichneumon wasp that parasitizes the horntail larvae, presumably helping keep the horntails from going crazy and decimating the fungus’ root system. Maybe it is a fungus and there was something like that going on here?

Any thoughts?

Wet (in summer) cedar woods

Speaking of trees and stuff, the January edition of Festival of the Trees is up at Xenogere. Jason takes us on a walk through the Celebration Tree Grove in Dallas, Texas. I encourage you to head over and join him.