While I was exploring the woods behind my boyfriends house, we discovered this strange looking substance on the tree trunk of a small sapling? The tree trunk was about an inch or two around. It looked like it was made up of white strands that turned powdery when I scraped it with a stick. The substance wasn't on the leaves just the trunk and I noticed another small tree nearby that had the same stuff on it. I have "googled" powdery white substance, tree fungus, mildew but I still can't find anything that doesn't look like a mushroom.