Tree Safety and Risk Assessment

The Occupier’s Liability Acts 1957 and 1984 and the Occupiers’ Liability (Scotland) Act 1960, place a duty of care on property owners and/or occupiers to ensure, as far as is reasonably practicable, that people entering onto, or passing by, the property do not suffer injury or damage as a result of any act or omission which could reasonably have been foreseen.

The owner/occupier may be held liable for physical harm or damage to property arising from an accident to a third party, where the cause of the accident was both reasonably foreseeable and reasonably preventable, bearing in mind all the circumstances of the situation.

Regular inspection of all trees growing on a property should therefore be undertaken by a competent person to identify any visible defects and assess the risk of those trees causing harm or damage. Recommendations for appropriate remedial works can then be made to control or eliminate the risk and thereby reduce the liability of the tree owner.

We are licensed users of the Quantified Tree Risk Assessment system (QTRA), which applies established and accepted risk control principles to tree safety in accordance with ISO 31000: 2009 “Risk Management - Principles and Guidelines”. The system provides a legally defensible framework for controlling the risks posed by trees. It quantifies the risk of significant harm from tree failure in a statistical way that corresponds to the Tolerability of Risk (ToR) Framework developed and promoted by the Health and Safety Executive. This allows tree owners or managers to discharge their duty of care while balancing safety with tree value, and operating to a predetermined limit of reasonable or acceptable risk (as advised by the HSE).

QTRA is a probabilistic system that:  

  • is repeatable, and leaves a clear paper trail showing that risks were identified and considered.
  • moves away from predictive assessment - we do not need to state that a tree is either safe or unsafe or that it will not fail.
  • provides robust protection for both the tree inspector and owner/manager in the event of litigation.
  • reduces the need for hazard remediation (i.e. tree surgery or felling) particularly in low usage areas.
  • conforms to standards accepted in the UK as best practice in the management of industrial and workplace risk.

Using the system, we can assess the level of risk posed by trees with a high degree of confidence. This means we only specify such works, if any, that are actually necessary to ensure our clients' compliance with their legal obligations. As we do not carry out tree work ourselves, we have no interest in specifying unnecessary, and costly, work which is out of proportion to the level of risk involved.

What this means in simple terms is that you are better protected if anything should go wrong, and it costs you less.

Further information on tree risk management, including practical and comprehensive advice for tree owners, can be found in The National Tree Safety Group (NTSG) guidance document "Common Sense Risk Management of Trees" published by The Forestry Commission. The document is available for free download at

Please contact us for more information


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