A Guide to Tree Safety Surveys and Reports

Do I need a tree safety survey?

The law requires that those responsible for trees "take reasonable care to avoid acts or omissions which cause a reasonably foreseeable risk of injury to persons or property". To better understand what this means for you, you must ask yourself two main questions;

In regard to resource, the courts seem to consider that the extent of any tree inspection is proportional to the size and resource availability of the tree owner or manger. For homeowners it may be considered enough for them to informally 'keep an eye on' their trees during the course of their usual activities and call in specialists only when they felt it necessary. If those responsible were a large business or public body, regular formal inspections conducted by a specialist would be more appropriate given the resources available.





Are my trees safe?

To answer this question, we must first understand how dangerous trees are generally. Statistics show that in the UK about six people are killed by tree failures every year. As for non-fatal injuries you are about 40 times more likely to be hospitalised by a wheelie bin than by a tree. So, in regard to individual trees, they are unlikely to pose a significant risk unless they meet the three following criteria;





What is a significant target?

If a tree stands in a seldom frequented location, such as in a field or at the bottom of a large garden, it is very unlikely to cause harm to anyone or anything. People may pass under it from time to time but as this is infrequent, especially in bad weather when trees usually fail, these do not represent significant targets.

If a tree stands next to a busy road, or overhangs the entrance or buildings of a busy public site like a school, the chances of the tree causing harm are much higher. This is especially the case as such areas would be busy even in poor weather. These cases represent very significant targets.





What is a significant structural issue?

Where the defective tree or branch is large enough to cause harm, significant structural issues might include;

  • Deadwood in the canopy
  • Larger cavities and areas of decayed wood
  • Cracks or splits
  • Weak branch or stem junctions (typified by 'V' shaped rather than 'U' shaped profiles on the upper side of the junction)
  • Rooting instability (typified by crack or movement in the ground level, or in some cases by leaning trees)

There are also two other symptoms that may indicate underlying structural issues. These are;

  • Very poor tree health (typified by severe leaf loss or large areas of deadwood)
  • Significant fungal infections (typified by fungi growing on the tree or close to its base)





If I need a specialist should I employ a Tree Surgeon or an Arboricultural Consultant?

Tree surgeons have a wealth of practical experience with tree faults and are often best placed to remedy them. They also frequently assess the condition of trees free of charge and provide a quote for any work. For tree owners with a small number of trees and limited resources a tree surgeon might be the best option.

Arboricultural consultants usually charge to inspect trees but will provide a written arboricultural report. This can be useful or indeed necessary in some cases. Also, consultants are usually trained to a greater level in areas such as structural and physiological analysis, and tree risk assessment. This extra knowledge often helps consultants detect tree faults that are less obvious. More frequently it gives them the confidence to recommend less tree work. Minimising tree work not only saves the client money, but also prevent the unnecessary loss of, or harm to, trees. Arboricultural consultants are perhaps better suited to sites with larger numbers of trees and potential targets, or where the preservation of the trees involved is more important.





Do I need a written tree safety report?

The keeping of reports or inspection records comes into its own if an incident occurs and those responsible are required to prove they have taken reasonable care of their trees. The courts tend to consider what is 'reasonable care' in proportion to the size and resource availability of the tree owner. For a home owner it is likely enough that they keep invoices for any tree works completed by their tree surgeon. For larger land owners and organisations formal record keeping is considered more appropriate.

Other instances where a written arboricultural report might be necessary include;