Safety inspection of trees

Inspections should be carried out by persons who are competent to spot the warning signs. Some may prefer to employ a specialist contractor to carry out inspections. Judgment is needed and the opinion of more than one experienced person may be beneficial in decision-making.  Binoculars may be helpful during inspection of trees.

Location of individual trees

On sites where there are lots of trees, a sketch map should be made which shows the location of individual trees or groups of trees, e.g., with reference to assigned orienteering co-ordinates.   Ideally, each tree should be uniquely identified, e.g., have an identification tag on its trunk.  This should not be a problem where there are few trees to be inspected.  However, often it may be practicable only to identify uniquely those trees that are in the high risk zone or which are considered to be an increased risk, e.g. trees which are more likely to shed limbs, e.g., beech trees.  

Type and frequency of inspection

The type of inspection should be in accordance with its target zone classification, roughly as follows:

• Informal – a quick scan during a “walk by” of a small group of trees to pick out a tree with obvious warning signs.
  
  
• Routine – spending more time on each tree to pick out obvious warning signs during a “walk by”.
  
  
• Detailed – systematic and thorough visual examination of each tree taking into account whether warning signs exist.

A good time to carry out inspections is during clear weather at the beginning of autumn when it should be relatively easy to spot premature colouration, premature shedding of foliage or fungal growth associated with decay.

A schedule of inspections should be carried out with reference to the premises’ range of target zones. Inspection of trees in high risk target zones should be more frequent than those of trees in low risk target zones. Trees in high risk target zones should be inspected after high winds. Knowledge of local conditions will be needed to schedule inspection intervals appropriately.

Suggested minimum inspection intervals are: