Science, Tech, Math › Animals & Nature Problems with Included Tree Bark Bark Inclusions Make for Weak and Unsafe Trees Share Flipboard Email Print An included bark junction formed in a wild cherry tree (Prunus avium). (Duncan R Slater/Wikimedia Commons/CC BY-SA 3.0) Animals & Nature Forestry Tree Structure & Physiology Tree Identification Basics Arboriculture The Science Of Growing Trees Conifer Species Individual Hardwood Species Pests, Diseases, and Wildfires Tree Planting and Reforestation Amphibians Birds Habitat Profiles Mammals Reptiles Insects Marine Life Dinosaurs Evolution View More By Steve Nix Forestry Expert B.S., Forest Resource Management, University of Georgia Steve Nix is a natural resources consultant and a former forest resources analyst for the state of Alabama. He is a member of the Society of American Foresters. our editorial process Steve Nix Updated April 16, 2017 Included bark or "ingrown" bark tissues often develop where two or more stems grow closely together causing weak, under-supported branch angles. Bark often grows around the branching stem attachment and into the union between the two stems. Bark has no strong supportive fiber strength as wood does so the connection is much weaker than a union without included bark. Pruning All maturing trees are subject to having bark inclusions and need pruning while limbs are smaller and easier to remove. Any signs of a cracked weak branch angle (shaped like a V) with included bark that occurs on the main stem or any included bark areas on larger, lower limbs should be considered a defect. Connected stems with a supported U or Y shape are desirable. Proper pruning will help prevent included bark and encourage the proper shape. Don't Automatically Worry about Decay The presence of decay by itself does not make the tree a hazard tree. All trees have some rot and decay with advancing age. Decay is a problem where the wood is soft and hollowed out along with the presence of mushrooms/conks. Take immediate action if advanced decay is present or associated with weak branches or included bark. Signs for Concern A weak branch union occurs on the main stem.A weak branch union is associated with a crack, cavity, or another defect.