Wonderful instructions, Ken. They do root pretty firmly into the bark if it is rough, and porous enough. Fasten them firmly enough (so they don't move) to a branch or piece of bark and they will be rooted to it in few months.
I've been gradually thinning this clump in the crutch of an oak tree, and believe me, they are really rooted in there! It takes some determined prying to get them loose.
