Oak processionary moth: how it is regulated in Great Britain, zone by zone
What the Forestry Commission and Forest Research say about oak processionary moth: its quarantine status, the management zones in England, and what each zone means for moving oak trees.
Checked against the sources at the bottom of this page on October 8, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the official source says. It is not legal advice: ask the office named here. Oak processionary moth is a caterpillar whose hairs cause itchy rashes and eye and throat irritation, and whose nests sit in the trunks and branches of oak trees. Most of the official material is written for England, so the zone table below is England's. The guide to tree pests and diseases gives the wider list of pests agencies track.
Status by country
| Country | Status and what is covered | Agency and date on its page |
|---|---|---|
| England | Regulated as a quarantine pest known to be present in Great Britain. It cannot be introduced, moved, multiplied or released without prior authorisation. Oak tree imports and movements are restricted by zone. | Forestry Commission, on GOV.UK. Page last updated August 13, 2026. |
| United Kingdom, whole | Notifiable. The established area is most of Greater London and some surrounding counties. The rest of the United Kingdom is designated an area free from the pest, with special restrictions on moving oak plants. | Forest Research. Page data shows modified September 23, 2026. |
| Scotland, Wales, Northern Ireland | The GOV.UK page applies to England and links separate guidance for each of the three. | Forestry Commission, on GOV.UK. Page last updated August 13, 2026. |
| United States | No official status page found on October 8, 2026. | Not stated. |
| Canada | No official status page found on October 8, 2026. | Not stated. |
| Ireland | No official status page found on October 8, 2026. | Not stated. |
| Australia | No official status page found on October 8, 2026. | Not stated. |
| New Zealand | No official status page found on October 8, 2026. | Not stated. |
The management zones in England
The Forestry Commission's guidance on managing oak processionary moth in England divides the country into zones, shown on a management zones map with a postcode list and a list of local authorities and wards. Some wards sit inside a zone even when the whole local authority does not.
| Zone | What the page says |
|---|---|
| Area free from the pest | Officially designated free from the pest and covering most of the country. Government funds an extensive surveillance programme, and says it will take robust action to eradicate the moth if it is found here. |
| Buffer zone | An annual surveillance and control programme led by the Forestry Commission, which treats infested oak trees and trees close by. An owner of an infested oak may be issued a Statutory Plant Health Notice asking for action. |
| Exclusion zone | A 10 km wide strip on the outer ring of the buffer zone, where additional movement restrictions apply. |
| Established area | The south east of England, where the moth is known to be present. Landowners are responsible for managing it on their land. |
Moving and importing oak trees
The same page says no oak trees may be imported from outside the European Union. Imports from EU countries are allowed only for oak trees grown throughout their life in a place of production in a country where the moth is not known to occur, in a pest free area set up under the international standard, or in a site with complete physical protection that was inspected at suitable times and found free. The rule applies to oak (Quercus) trees with a girth of 8 cm or more measured at 1.2 m above the root collar.
For movement inside Great Britain the page says large oak trees in the area free from the pest can move anywhere in Great Britain. Moving large oak from the buffer zone or established area into the area free from the pest is prohibited unless the trees were grown throughout their life in a fully protected site and found free of the moth. Legislation in force from May 24, 2023 set up a demarcated area and a risk-based approach to moving large oak within the buffer zone and the established area. The separate GOV.UK publication on moving large oak trees within the management zones, published July 11, 2024, says movement and trade there are permitted when certain biosecurity requirements and movement restrictions are met.
Who the rules reach
Forest Research says on its oak processionary moth page that forestry workers, tree surgeons, landscapers, nursery staff and anyone else growing, moving, managing or importing oak trees must comply with the regulations. It also says owners and managers of oak in affected areas should know the regulations on handling and moving oak material that arises from felling, forestry operations and tree surgery.
Both agencies say sightings go through the TreeAlert reporting tool. The GOV.UK page says removing nests and caterpillars is a hazardous operation, recommends that a professional does it, and points to the Arboricultural Association to find an OPM management professional. For the other protective measures aimed at tree workers see the guide to health hazards in tree work.