Glasgow's Ash Dieback

Ash tree leaves grow in opposite pairs, with a single leaf at the end (See Figure 1).

Twigs have black buds, and the young bark is smooth (See Figure 2).

Mature trees have rough fissured bark (See Figure 3).

One of the first symptoms that an ash tree may be infected, is blackening, and wilting of leaves and shoots (Figure 1).

In some cases, the infection causes dark diamond shaped lesions to form (Figure 2) and would be visible at any time of year. Diamond lesion scarring (Figure 3)

Mushroom-like fruiting bodies (Figure 4) which grow on the stalks of the previous year’s fallen leaves. They release thousands of infective spores in summer, which are then spread by the wind.

The trees should ideally be assessed when in leaf (July to September) as seasonal changes in autumn may look similar.

The owner of the land is responsible for any trees on it and for taking reasonable steps to ensure that their tree(s) are maintained in a reasonably safe condition.

Firstly, have your tree examined by a suitably qualified and competent person, who can advise on what work may be required.

Always use a reputable contractor who is trained, equipped, and insured. Ask to see references, their Public Liability Insurance, and their test certificates. We recommend that you get three estimates for the work from businesses with proper addresses where you can contact them if problems arise.

The industry standard that applies to tree work is the ‘British Standard for Tree Work Recommendations (BS 3998:2010)’.

Please note that Glasgow City Council recommends that all tree works should be carried out to British Standard 3998, as a minimum.

Glasgow City Council does not carry out works on privately owned trees, other than as part of its Roads Enforcement process and has no powers to make an owner carry out works to a tree unless it is likely to affect a public road or footway.

In such cases, where the Council are made aware, the owner will be notified of their responsibility and may be issued a Statutory Notice.

Ash dieback is recorded under one of the four Health Class categories.

The four Health Classes are:

• Ash Health Class 1 100%–75% remaining canopy (Figure 1)
• Ash Health Class 2 75%–50% remaining canopy (Figure 2)
• Ash Health Class 3 50%–25% remaining canopy (Figure 3)
• Ash Health Class 4 25%–0% remaining canopy (Figure 4)

Glasgow City Council treat ash dieback Class 3 and 4 as priorities, and if present within high-risk areas, will be dealt with urgently.

The trees are best assessed when in leaf during July – September.

A tree in my garden is showing signs of Ash Dieback. It is protected. Does this mean I cannot conduct the necessary work?

Firstly, have your tree examined by a suitably qualified and competent person who can advise on what work may be required.

Then you should apply to the Council for permission to conduct the work. We will inspect the tree as soon as possible and give consent for any appropriate work required.

You can check if a tree is protected by using the the Council’s Environment and Conservation mapping application which can be found on the right for Conservation Areas, Listed Buildings and other statutory heritage designations.

 Tree Preservation Orders (TPO)  and other environmental legal designations can be found using the link below.

Alternatively, you can contact the Council regarding protected trees by :

Emailing:  Tree Enquiry  or In writing to:

Planning and Building Standards Neighbourhoods, Regeneration and Sustainability Glasgow City Council 231 George Street GLASGOW G1 1RX

The  Tree Council  provide an Ash Dieback guide for tree owners in Scotland.

Neighbourhoods, Regeneration and Sustainability (NRS) Tree Officers will continue to assess areas, prioritise inspections and recommend works to be conducted as part of an ongoing delivery plan of remedial works.

You may see trees being removed in your area; if a large volume of trees, or inconvenience with removals is caused by necessary works, we will notify Elected members, and local community groups in advance. Signage will also be erected.

NRS Tree Officers continue to carry out assessments of ash trees, with areas of high footfall prioritised.

To allow NRS to quantify and grade affected trees, an additional tree survey is being commissioned. This will capture the areas not included in the survey of July 2022 and will be prioritised via the risk categories.

Supporting inspections will also be conducted by NRS Tree Officers. This in turn will inform the resources required to address Ash Dieback.

NRS have established a project team.

The priorities of the team are to:

• Achieve an accurate assessment of the scale of ash dieback.
• Undertake a full appraisal of the project requirements, including revenue support.
• Refine a risk-based decision-making methodology regarding the need for, and prioritised timing of, monitoring/removal or remedial works.
• Develop an appropriate programme for ongoing inspection of all ash trees, including those on private land that may impact on our assets or their users.
• Introduce an appropriate process for addressing trees on private land where the landowner is not known.
• Commence a recovery/replanting programme planting three trees for every mature ash tree removed.
• Prepare a communications plan to inform and raise awareness amongst internal and external stakeholders. This will also include multi member ward updates where significant removal works are scheduled to take place.     
• Explore opportunities relating to external funding and potential partnerships.

The diseased trees that present the greatest risk are those of sufficient size to cause harm, should they fall in areas where members of the public access and egress from on a regular basis.

In general, these areas are:

• Road network and streets
• Education and Social Work properties
• Sport and leisure properties (including Glasgow Life facilities)
• Parks and open spaces
• Event spaces
• High use areas within cemeteries
• High use areas within woodlands
• High use areas within allotments

It is estimated that Glasgow contains approximately 2 million trees, and the ash tree composition is projected to be 12.5%. This equates to around 250,000 ash trees across Glasgow, under both Council and private ownership.

It is anticipated that approximately 125,000 (50%) are on council land, potentially 35,000 (28%) of the 125,000 council ash trees could pose a high risk.

All timber is currently recycled on site, or via our partner organisations; however, NRS are assessing opportunities to generate income, such as repurposing timber or offsetting the value of the timber against the cost of removal.

Yes, the intention is to replace every mature ash tree, which is removed, with three new trees.

Further information can be found on the Glasgow Tree Plan.

If you are looking for independent professional advice, then you should contact either the  Institute of Chartered Foresters  (ICF) or the  Arboricultural Association  (AA) as these organisations maintain registers of practicing members.

 The Tree Council Science and Research on Ash Dieback .

For more on biodiversity visit  Glasgow City Council Biodiversity .