When Should You Arrange A Professional Tree Assessment?

Trees add significant value to any property, but they also carry a level of inherent risk that property owners have a legal responsibility to manage.

A tree risk assessment is the process by which that risk is identified, evaluated and addressed. Whether you own a single garden tree or manage a site with many mature specimens, understanding what a tree risk assessment involves and when you need one is an important part of being a responsible property owner.

What Is A Tree Risk Assessment?

A tree risk assessment is a structured inspection carried out by a qualified tree surgeon or arborist to evaluate the likelihood of a tree or part of a tree failing and the potential consequences of that failure.

The assessment considers the structural condition of the tree, any signs of disease or decay, the tree's growing environment and its proximity to people, property, roads and other areas that could be affected if failure occurred.

The outcome of the assessment is a judgement about the level of risk the tree presents and a recommendation for how that risk should be managed. This might range from no action required through to monitoring, remedial pruning or, in cases where the risk cannot be adequately managed, removal.

What Does A Tree Risk Assessment Involve?

Visual Inspection

The assessment begins with a thorough visual inspection of the tree from the ground, examining the crown, trunk, root zone and surrounding environment.

The arborist looks for signs of structural weakness, including deadwood in the canopy, cracks or splits in the trunk or main branches, fungal growth at the base or on the trunk, changes in the lean of the tree, and any disruption to the ground surface around the roots that might indicate root damage or decay.

Closer Examination Where Required

Where the visual inspection identifies areas of concern that require closer examination, the arborist may use specialist tools to assess the internal condition of the tree. Resistance drilling and decay detection equipment can help to identify areas of internal rot or decay that are not visible from the outside, providing a more accurate picture of the tree's structural integrity.

Assessing The Surrounding Areas

An important part of any tree risk assessment is evaluating what lies within the tree's potential failure zone. A tree in an isolated location where failure would affect no one and nothing presents a very different level of risk from an identical tree growing over a footpath, a car park or adjacent to a building. The proximity and vulnerability of potential targets is a key factor in determining the overall risk rating of the tree.

Recommendations / Documentation

Once the inspection is complete, the arborist will provide a written report setting out the findings of the assessment, the risk rating assigned to the tree and the recommended course of action. This documentation is important for property owners, as it provides a clear record of due diligence and demonstrates that the risk presented by the tree has been properly considered and managed.

When Do You Need A Tree Risk Assessment?

As A Routine Precaution

For property owners with mature trees in locations where failure could affect people or property, a periodic risk assessment is good practice regardless of whether any obvious problems are apparent.

Many tree defects develop gradually and are not visible to the untrained eye until they have reached an advanced stage. Regular, professional inspection allows issues to be identified and addressed early, before they become serious.

After A Storm / Significant Weather Event

High winds, heavy snowfall and lightning strikes can all cause damage to trees that is not immediately visible from the ground. Following any significant weather event, having trees that are close to buildings, paths or roads assessed by a qualified tree surgeon is a sensible precaution.

When You Notice A Change In The Tree

If you notice any change in a tree that concerns you, whether a new lean, fungal growth at the base, deadwood appearing in the canopy or cracks in the trunk, arranging a professional assessment promptly is the right course of action.

Changes in a tree's appearance or structure can be an indication of developing problems that require attention.

Before Construction / Development Work

Where building work, excavation or changes in ground levels are planned near existing trees, a tree risk assessment carried out in advance will identify any trees that may be affected by the works and allow appropriate protection measures to be put in place.

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