Not sure why this is in the lawn forum but I looked at the ISA website. I'm filing that information under my garden humor folder. According to the website there are less than a dozen ISA certified arborists in Texas. One of them is Davey. Davey hires hundreds if not thousands of people to hack on trees all over the country. They must have had to send someone to the ISA school so they could get government contracts. All I've ever seen them do is "dehorn" trees. The result is a tree that looks like this...
There is a name for such a method (Pollarding) but it results in a goofed up looking tree. What kind of arborist would do this to an oak tree?