This kind of injury causes the destruction of vascular tissue and interrupted flow of nutrients and photosynthate in the trunk regions of trees. Lawn mowers, string trimmers, synthetic bags, guy wires and ropes left on too long and rodents feeding are ways in which these injuries occur.
The lower trunk of a tree is a very crucial part of its anatomy. Such wounding requires the tree to use up energy reserves in order to perform wound response and initiate callus tissue. When a tree has reduced energy reserves it is more susceptible to infection by opportunistic pathogens. Lower trunk wounds are a good point of entry for those pathogens.
Girdling Roots are roots that are growing across the main trunk or root flares and are strangling the transport system of the tree. Where possible, these should be removed with caution.