Question
Hello! I hope you can help me. The oak tree in my front yard is about 12 years old. The bark of the tree, only where the trunk and branches meet, is dark black and possibly deteriorating. It almost looks like big knots have been make in these spots. Also, there are large indentations inwhich the bark located within the indentation is lighter, but not level with the rest of the branch around it. I don't see any holes. On the back of the leaves are circular raised spots. The tree is growing and full. Thank you for any information you can provide.  

Answer
There are several diseases and insects that cause galls and cankers on the trunk and/or leaves of oaks. They normally do not cause any real problems. If the folage is green and healthy and full do not worry about the galls and cankers. Sounds like you do not have any problems that will hurt the tree.