Project portfolio

Highway Tree Survey Strategy


Cumbria County Council Highway Tree Survey Strategy


Cumbria County Council / Tetra Tech



Highway authorities are required to ensure trees do not present an unreasonable risk to road users. They have statutory powers to manage trees alongside the highway, including their own assets and those owned by third parties.

The rise and spread of ash dieback disease is of concern in the UK. Not least for local authorities concerned about their liability for trees alongside highways and public open spaces. Ash dieback disease is now prevalent in the county and trees suffering from the disease are likely to represent greater risk to road users.

We were commissioned to review Cumbria County Council’s current programme for tree survey and inspection, and provide advice on its improvement. The study was driven by the increased risk arising from ash dieback disease.

In order to meet their duty of care and demonstrate compliance with health and safety legislation local authorities are incorporating ash dieback checks into routine inspections.

How we helped

We reviewed the current tree inspection programme undertaken by the Council, and compared it to Best Practise for the management of highway trees. This considered the approaches adopted by other local authorities, statutory advice, and published recommendations.

The second stage in the strategy was to work out the size of the tree resource. Enviroscope carried out a desk-based assessment of the county’s roads, using GIS and remote imagery to assess randomly assigned road sections. Google Earth Street View was used to provide an estimate of the frequency of highway trees in different districts and road types. From this an estimate was made of the total number of trees under public and private ownership, and the number of ash trees. Further work is recommended to increase the accuracy of this estimate.

The Council have identified additional resources to expand their tree inspection programme with survey of additional roads and purchase of tree inspection and management software. The report reviews current tree inspection procedures and provides advice for an expansion of the programme to allow the Council to meet their duty of care and comply with current best practice.

The strategy included advice on the targeting of the survey programme to ensure that roads and tree populations of greater risk were prioritised. Factors considered included road speed and use, total tree population, and the frequency of ash trees.

Ash dieback disease is now prevalent in the county and trees suffering from the disease are likely to represent greater risk to road users. It is proposed to address this by prioritising tree inspection in areas with the highest density of ash trees, monitoring the development of the disease in these trees, and to set a reinspection period appropriate to their condition once surveyed.

This report contains a draft NEC3 Professional Service Contract Scope and Schedule of Rates to assist in the tendering of the survey work.

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In The News

Cumberland Council, who have inherited responsibilities for highway management have taken the advice in the study to implement a routine highway tree inspection programme, focussing on ash dieback disease as a threat.

Read more about this work we supported with our specialist tree advice Infected trees alongside major road to be cut down

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What our clients say


Guy, you are a prince among men!
Thanks for taking time out to look at the tree and for your incredibly helpful advice!


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