Though rare, incidents caused by falling trees do occur and clearly, trees deemed to be a danger must be made safe. At the same time, other trees are protected because of their importance.
For responsible landowners, a tree survey plan would be a sensible route to take. This would enable them to identify risk areas and highlight trees that are eligible for protection, thus allowing for resources to be targeted appropriately.
Initially, a simple visual assessment of the trees which considers their position, structural stability and general health would suffice – particularly for those deemed to be low risk. However, such an assessment would also highlight any trees which may require specialist advice. In this case, a formal and complete inspection would be an appropriate course of action.
If a detailed inspection is deemed necessary, then it should be carried out by a qualified specialist. The inspection is likely to include a detailed visual assessment to highlight signs of structural failure, plus root and soil assessments, as well as diagnostic tools (such as a resistograph) and possibly, aerial surveys.
A resistograph provides specific details of problems in the tree such as cracks, cavities, and stages of decay. This makes it an important tool in the accurate analysis of a tree’s stability and general health. For some trees it can also be used to measure bark diameter and growth rings.
A resistograph works by inserting a micro drill into the tree (which does not cause damage) and the wood’s resistance affects the drill’s rotation speed. The information is translated into a graph which provides details required for professional analysis.
The inspection details should always be recorded and kept as they provide evidence of due care and attention, that action has been taken, and any subsequent recommendations.