Trunk Wounds, Decay and POTENTIAL HAZARDS

This is an excerpt from a great book on tree removal and tree care. Whether in Chicago, Naperville, Bolingbrooke, Plainfield, Downers Grove, or elsewhere, these are the things you can do to care for your trees so you won’t have to call a tree service company to come remove trees. Tree removal takes place because of poor maintenance of trees, diseases, or other things that in many cases can be prevented, providing your tree with a long life. This book, called “Tree Care Handbook” by The Morton Arboretum” is a worthwhile book to read, could save you a lot of money in tree removal and tree service costs in the future with some ongoing tree maintenance! Here is the excerpt:   TRUNK WOUNDS and DECAY When fresh wounds occur o n the trunk, the injured bark should be removed with a sharp utility knife or chisel, cutting back to healthy bark that it tight to the wood. A wound dressing is not necessary but may b applied for cosmetic purposes. If less than 25% of the bark around the trunk has been damaged the tree will probably recover in time. You will be able to observe the wound closing from the edges each year as the tree grows. When an older wound is discovered, remove the dried and loose bark back to this area where the new wood can be seen along the edges of the wound. Many of our urban and suburban trees are subject to decay because they are more likely to be wounded than trees in native stands. Most of the wounds are caused by people – lawn mowers, automobiles, construction, and improper pruning. Naturally occurring events such as storms, fires or damage by birds and animals may also cause wounds. Once a wound occurs, decay-causing fungi can enter heartwood, and the process begins. Trees have a unique defense. The wood around the wound begins to produce special compounds in the cells that set up a wall, or barrier, to isolate the infected area; this is called COMPARTMENTALIZATION. Once compartmentalized, discoloration and decay will spread no further unless one of the barriers is broken. Some trees can compartmentalized better than others. In a vigorous tree, the yearly new growth produced outside the compartment continues to form and add to the sound wood, while the diameter of the cylinder of decay in the trunk gets no longer, and the tree remains sounds even increases in strength. When compartmentalization is incomplete, or if the walls are disturbed, decay will spread, and the tree may become unsafe. Cleaning decayed wood from cavities is not recommended, since the compartment wall might be breached, and further decay of the trunk could result. Storm-damaged branches should be immediately and properly pruned (see pruning trees). Flush cuts can lead to extensive decay. HAZARD TREES When is a tree a hazard? – when an inspection reveals a structural weakness and when there is a “target”. A target is someone or something which could be hurt or damaged if the tree or limb falls. Where there are people or structures or other property that coul be hamred, trees with internal decay or poor branch structure pose a threat. WHAT TO LOOK FOR
  • LARGE DEAD OR DETACHED branches
  • Cavities or decayed wood
  • Sign of internal decay – mushrooms at the base of the tree or carpenter ants
  • Cracks or splits in the trunk where branches are attached
  • Many branches arising from one point on the trunk
  • Roots that have been cut or covered
  • Evidence that the tree was topped in the past
What to do about tree hazards
  • Remove the target
  • Prune tree
  • Cable the weak branches
  • Remove the tree
If the decay or structural problems are suspected, contact a professional arborist. Trees located in areas where people are frequently present should be inspected regularly.   Note: also distributed as the Morton arboretum plant clinic information leaflet no. 48   People have many questions about the trees and shrubs in their landscapes. The experience of our plant clinic at the Morton Arboretum tells us that the vast majority of questions are on plant selection and identification, plant culture, and pest problems. This tree care handbook is collection of information is unique, derived directly from the work of our research and collections programs. Many of the short phamplets and recommended plant lists were originally design as handouts for classes and for the plant clinic. Selecting and planting trees was produced for the twentieth anniversary of earth day in 1990, in cooperation with the office of the governor of Illinois. The large table in the center provides extensive information on the characteristics culture of more than 200 species of trees, but don’t overlook the information on planting procedures. The Tree Finders’ are authored by May Watts who was the Naturalist at te Morton Arboretum for many years. These are excellent aids to identifying plants for non-experts. This is the first time that the entire collections of these materials has been made available in a single, convenient binder. Everything is in an easy-to-read style and full of valuable practical information. In a very real sense, the variety of questions fielded at our Plant Clinic determined what is included, assuring that is the information people need most. This extensive collection of information has largely been used only in arboretum-related activities, but actually has a much wider application. The arboretum received a grant from the USDA forest service Urban Foresty Center for the Midwestern States to help transform this information into its present form so that it might be distributed more widely around the Midwest region. GARY WATSON, Ph.D., PLANT CLINIC MANAGER

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