While many trees have a long lifespan, they are still living organisms and will, at some point, structurally fail. However, the decision to remove a tree that adds value to a landscape should not be taken lightly. Property owners can make an informed decision by discussing their trees with an experienced arborist who has an understanding of how and why trees fail and which ones pose the greatest risk.
When an arborist inspects a tree, he/she looks for defects and conditions that could contribute to premature tree failure. This assessment may be a visual inspection or may include drilling or other equipment to determine if there is excessive internal decay. In addition to looking at the tree, arborists also look at the site and people or structures that could be injured or damaged by the tree’s failure.
Industry standards on tree risk assessment lead arborists to focus on the risk trees pose as a whole, rather than looking only at the extent of tree defects. The factors reviewed in a tree risk assessment are: the likelihood of failure, the likelihood of the failed tree or branch impacting a person or structure, and the consequences of tree failure and impact. These factors are combined to define risk.
With this in mind, a tree with defects that is well away from people or structures would pose less risk than the same tree positioned near a home or building.
Winter is a good time to have the trees on your property inspected. Based on the level of risk, removal may not be the only option. Options like cabling, bracing, or pruning can address some defects and help mitigate the risk of failure depending on the situation.