Alex Shigo was a singular fellow, a noted tree pathologist, and he really knew his trees. TPP was a postdoc on a project collaborating with Alex, not to mention working with befriending his son-in-law, Dr. Chips, and his daughter along the way. At any rate just a few blogs ago, the topic dealt with tree injury and TPP provided a link to Shigo and Trees Associates as a source for information on pruning and tree injury. So not only do they have highly informative books and pamphlets written by Alex, but mention The Phytophactor and get a discount! TPP doesn't get anything, so this blog remains unsullied by money, the deal is for readers, not TPP. You can even get a Touch Tree bumper sticker.