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Tree Health Diagnostic and Advisory Service

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Home Services Tree Health Diagnostic and Advisory Service

The Tree Health Diagnostic and Advisory Service provide advice and where possible diagnosis and identification of tree pests and pathogens.

Range of services:

  • Reporting tree pests and diseases
  • Diagnostic & advisory service

Reporting tree pests and diseases

If you are reporting a tree pest or disease, please use TreeAlert

Diagnosticians will view your enquiry and, if necessary, will investigate your case further. Please note that not all enquiries will be followed up directly. However, every enquiry will be used and will contribute to our understanding of tree health issues across Great Britain.

What is TreeAlert?

TreeAlert is the online tool managed by Forest Research. It is a valuable aid for forestry and tree professionals or people with knowledge of trees and woods, allowing them to quickly report any suspect findings of tree pests and diseases which are of concern in Britain. TreeAlert was created following the arrival of Chalara (ash dieback) as an easy method that encouraged rapid reporting. It is the only online tool in the country created for the purpose of flagging up potentially new tree pest and disease threats and can act as an early warning system to protect out trees.

What happens to TreeAlert reports?

The management of pests and diseases is greatly helped by early detection and prompt action. The effectiveness of TreeAlert depends completely on the reports submitted by users. Apart from the rapid detection of new threats, the reports also give us an indication of the most common disorders currently affecting trees as well as gathering information about the general health of the nation’s trees, woodlands and forests. We use the data obtained through TreeAlert to follow up findings, to identify trends of spread, to direct surveys looking for regulated or quarantine pests and pathogens and to support pest and disease management. In addition to the reports submitted to TreeAlert, the Forestry Commission and Forest Research carry out various surveillance activities for the detection of a range of tree pests and diseases.

THDAS service scientist

Reporting suspected cases of Chalara die back of ash

Chalara dieback of ash is a disease of ash trees caused by the fungus Hymenoscyphus fraxineus. The disease causes leaf loss and crown dieback in affected trees, and is usually fatal.

We would encourage you only to report suspected cases of Chalara dieback of ash in new (unshaded) areas on the following map

Please use TreeAlert to report your finding

There is no fee associated with this service.

Further information on Hymenoscyphus fraxineus and details on symptoms guidance

Diagnostic & Advisory Service

This is a chargeable service offering the diagnosis of pests and diseases on trees using conventional and molecular methods, identify fungal fruiting bodies and supply general information and advice on all aspects of tree diseases and disorders

There is no charge for this service if the enquiry concerns a regulated pest or disease


We deal with samples from the following:

  • Woodlands in both public and private ownership
  • Trees on farmland, in hedgerows, shelterbelts and screens
  • Christmas tree plantations
  • Trees in forest and horticultural nurseries
  • Publicly and privately owned amenity trees

If you own or manage trees please use TreeAlert

Please note that you will need to include your TreeAlert reference number recevied after submission of your report.

For further information on how to take and package samples please visit Advice on how to take and package samples

CG lab

Diagnostic service charges

There is a flat rate charge for the initial investigation which in many cases may be all that is needed to resolve the problem. Additional work, which may involve culturing from specimens or a site visit, will incur additional charges but will not be undertaken without the prior agreement of the customer.

In the event that you are unable to use TreeAlert to submit your enquiry, please contact us