When lightening hits a tree, sometimes it scars it, sometimes it blows the bark off and sometimes it blows it up. What accound for those varying effects?
The severity of the damage depends on the amount of moisture on and in the tree. If there is enough water on the surface of the tree, will conduct the lightening down into the ground. But if the tree is not that wet, the lightening will penetrate the bark, turn the water inside the trunk into steam and cause it to explode.