Julles, those carvings are something else, I love the heron one!
Mikey, its physical damage to the tree. A lot of logging is done around here for hardwood trees. A good veneer tree goes for big bucks.
We have a very dear friend that does carvings. He is in his 80's and in a wheelchair, paralyzed when he was in his early 40's. He decided he wanted to do some tree carvings, so we supplied the trees. He kept the first one and gave us #2. It is white oak, sixteen inch diameter. I would love to have it outside, but hubby insists we keep it inside so it doesn't crack and discolor. Most of our guests come in our backdoor, so this greats them. It's not exactly my "cup of tea" but it means a lot to us.