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Removal and disposal of Chalara-infected ash trees


This advice on the removal of infected young ash trees is for landowners and land managers.

There is value in removing as many recently planted ash trees (i.e. trees planted within about the plast five years) as possible and replanting with alternative species. This is a precautionary approach based on the probability that some of these younger ash trees are already infected, and the possibility that more will become infected within the next few years.

This is general advice. Landowners and managers might decide for themselves the best way of dealing with infected trees which is most suitable to their circumstances. 

If you are served with a Statutory Plant Health Notice (SPHN) the notice will specify the method of plant or tree disposal, and might provide more detail. 

Different methods of plant or tree disposal might be a condition of any grant, which will be specified separately. Owners and managers should acquaint themselves with the requirements of the country they are operating in.

Grants are available for replacing ash trees in England which have been affected by Chalara ash dieback.

This advice supports the wider Chalara Management Plan and biosecurity measures to slow the spread of the disease. It will be kept under review and revised as necessary in light of emerging scientific evidence. Any requirements in Statutory Plant Health Notices take precedence over this general advice.

Removing recently planted young plants less than 1.3m in height

Recommendation: Herbicide treatment

Treat individual plants with herbicide (NB: this is only a safe and practical option for young trees less than 1.3m in height).

Treatment: Make an overall application of a 360 g/l glyphosate or similar product. Follow the application rates detailed on the product label. (Further guidance is provided in Field Book 8 – The use of herbicides in the forest.)

Timing: June – August, when trees are in full leaf for optimal control, but application from March – October can give some control if trees have flushed and are in active growth.

Application: Ensure good coverage of foliage spaying to just before the point of runoff. Plants can be left in situ to desiccate and naturally fall over and decompose. In terms of biosecurity this has the disadvantage that treated infected leaf and shoot material will eventually come into contact with the ground and could produce fruiting bodies. If this is a concern you should follow the guidance below for older trees, or cut and burn the trees when they have died, ideally within one week after treatment.  

Monitoring: Check for signs of re-growth and be prepared to make a repeat treatment if necessary.

Product: Examples of suitable effective herbicides for overall foliar sprays include Montsanto Roundup (Pro Biactive, 360 g/l glyphosate); and Dow AgroSciences Triclopyr (Timbrel, 480 g/l triclopyr;).

Older trees, greater than 1.3 m in height

Recommendation: Cut, treat stumps and, optionally, burn.

Cutting and immediately treating cut stumps is likely to be the most cost-effective option for older plants greater than 1.3m in height. All stumps should be cut below the lowest live branch, but left tall enough to be visible.

Treatment: Cut trees and apply a 10% solution of a 360 g/l glyphosate or similar product to the cut stumps. Ensure you follow the application rates detailed on the product label. (Further guidance is provided in FC Field Book 8 – The use of herbicides in the forest.)

Disposal: Cut stems and branches can be left in situ, or be disposed of by burning on site for improved biosecurity. This is the preferred option, where allowed, under legislation on smoke control areas and subject to minimising smoke nuisance. Chipping of whole trees or branches and leaving the chipped material on site is not currently a recommended treatment for infected sites because of uncertainties over the risk that this might help to spread the disease. However, chipping and removal for use as biofuel is safe, as long as the material is removed quickly from the site, and stored under cover, or dried to less than 20% moisture content, before burning.

Timing: Cut and spray in November – mid-March for optimal control, avoiding the period of spring sap flow. Applications at other times are also possible, but are likely to be somewhat less effective, particularly during April to early June. Where it is intended to immediately burn the arisings, treatment from July to September/October is preferable to waiting until November, because it will destroy the current season’s leaves before autumn fall.

Application: Applications should be made to saturate the stump surface, paying particular attention to the outer circumference of the stump containing the phloem. Avoid run off to surrounding ground. Applications should not be made to frozen stumps. Ideally, for optimum control, spraying should take place within 1 hour of cutting, although a reduced level of control might still be possible if applications are made within 24 hours of cutting. If spraying cannot take place within these time frames, the stems should be re cut before application. The use of a dye marker such as Dysol Turquoise (50% Acid Blue 9) at 2% of final spray volume can help to ensuring that all cut stumps are properly treated.

Monitoring: Signs of re-growth from the stumps should be monitored and a repeat treatment made if necessary.

Product: Examples of suitable effective herbicides for cut stump treatments include Montsanto Roundup (Pro Biactive, 360 g/l glyphosate); and Dow AgroSciences Triclopyr (Timbrel, 480 g/l triclopyr;).

Further information

The Pesticides Codes of Practice - the approved Pesticides Codes of Practice for England and Wales and Scotland provide guidance on the safe use of pesticides.

Regardless of any other advice, always read and comply with the instructions on the relevant product label, e.g. - Roundup Pro Biactive Product label and Timbrel product label

Additional guidance on the use of herbicides in the forest is available in: Willoughby, I. and Dewar, J. (1995). The use of herbicides in the forest. Forestry Commission Field Book 8. HMSO, London.

Disposing of waste material

Burning is the preferred option where it is allowed under smoke control area legislation, and is subject to minising the risk of smoke nuisance. Please  consider neighbours by advising them before lighting a bonfire, so that they can be prepared for any minor inconveniences which might arise.

Where it is not possible to deal on site with plants or plant material from affected areas, the waste should be securely contained. This should be by either bagging it or placing it in enclosed containers and transporting it the minimum distance necessary for incineration (including energy recovery) or non-hazardous landfill at existing permitted facilities. Off-site composting and other biological treatments remain less-preferred options because of some uncertainty over the destruction of the fungus. Using the compost locally would mitigate any possible residual risk.

As with any waste, its movement should be accompanied by a written description of the waste, which will enable others to comply with the Duty of Care under s.34 of the Environmental Protection Act 1990. The waste must only be transported to a facility which is authorised to receive it. Where a consignment of waste comes from a source which is highly likely to contain waste infected with H. fraxineus, that fact should be recorded on any waste transfer note to assist others handling or processing the waste.

The Environment Agency has published a regulatory position statement which will allow the disposal of infected trees and plants without an environment permit.

The Scottish Environment Protection Agency (SEPA) has published guidance to assist those managing trees and plants infected with plant diseases, including Chalara ash dieback. The guidance note, ‘Disposal of trees and plants infected with specific plant diseases’ is available from its website.

Biosecurity procedures

Biosecurity advice for operations under Option 1 and 2.

Replanting options

Tree species advice - what to use to replace ash trees, and best methods of replanting.


The Forestry Commission accepts no liability whatsoever for any loss or damage arising from the interpretation or use of the guidance on the use of herbicide. All applications are made at users' own risk. The product label remains the primary source of information for the safe use of a pesticide. Any list of products is not comprehensive: other manufacturers may be able to provide products with equivalent characteristics. Reference to a particular manufacturer or product does not imply endorsement or recommendation of that product or manufacturer by the Forestry Commission.

Last updated: 16th December 2017