Bubbles on Gabriola treesBubbles on Gabriola trees

Just when I think I’ve figured out what all the strange stuff is in the Gabriola forest, I find another weird thing. This time it’s bubbles on trees. It looks as if somebody’s gone out with some dishwashing liquid, squirted it on trees, and added enough liquid to make bubbles.

I’ve seen these bubbles on all kinds of coniferous trees – these ones were spotted during the downpour a few days ago, while we were hiking through the Elder Cedar Nature Reserve. What on earth makes them?