I have a cedar structure greenhouse attached to my garden shed. This past year I found "sawdust" where the greenhouse is attached, building up on the wall, floor and nearby rack. I could not imagine what it was. At one point this summer, I was stung by a bee that came from the inside of the shed, at the same position where the shreds of wood are falling on the other side. We sprayed heavily to kill the bees, and there seems to be no activity now. But is that what caused the damage you can see in my photos? Not sure if this is a Master Gardener question, and if not, I would be grateful if you could pass this along, or tell me where to send it. Thank you, Jan Haley Laporte, MN