Mulching has many benefits, but I have seen many people botch a mulch job. Have you ever heard the phrase “volcano mulching”. This is when too much mulch is placed around the collar of the tree. When mulch is built up too high on the stem of the tree, this can promote rot, and a place for diseases and insects to invade. This will ultimately stunt the tree, and can actually kill it eventually. When you are mulching around trees, all you need is an inch of mulch where the stem meets the first horizontal roots.