I was looking for self-grafts such as on this fused beech stem. Grafts "take" better the closer the genetic relationship is of the two parts. Oaks and beeches are difficult to graft because of tannins that enter into the cuts. I wonder if this graft has taken or if there is a layer of cells that are dividing the merged stems?

Here is a cross-section of a birch polypore or tinder conk I found in the Arboretum. Five thousand years ago, humans carried this fungus with them as either a medicine or as a fire starter (or both). The material above the pores was used to carry smoldering embers or was shaved into fine filaments as a fire starter.