This is the bark of a tulip tree, along with its resident lichens and molds. The tulip tree (Liriodendron tulipifera) has the most intricate bark tread of any tree I know, and I find them quite majestic. Their bark is the really expensive brand name winter tire of trees. We have many tall old tulip trees around the lake. I even have a fine specimen standing right outside my apartment window. The old oaks, maples, and sycamores can't hold a candle to the intricacy of these bark patterns. Even the grand old elm tree by the lake with its beautifully venerable bark is outpaced. And yes, consider this a challenge: if you know of any tree with a more intricate bark tread, then please post pics--I would love to see them.
I like the composition of the first pic better, but this one is a better photo for clarity.
I will post lots more pics of tulip tree bark tread so you can get a better idea of just how intricate it can be, along with some other barkish beauties. I really do love me some fine tree bark quite a lot.
Also posted at http://lavendertook.dreamwidth.org/1484