Preventing the spread of tree disease
It is important that you take care when visiting forests, and act appropriately to prevent the spread of tree disease.
Ash dieback disease
Ash dieback is a disease of ash trees caused by the fungus Chalara fraxinea. The disease causes leaf loss and crown dieback in affected trees and can cause tree death.
Ash dieback has been identified in young ash saplings at several sites in Northern Ireland. You can read more information about Ash dieback disease on the Department of Agriculture and Rural Development (DARD) website:
Phytophthora lateralis (P. lateralis)
Phytophthora lateralis infects tree roots which come into contact with spores in the soil or water, and it kills most Lawson cypress trees it infects.
Public forests affected
P. lateralis is present in a number of locations, including:
- Tollymore Forest
- Mourne Forest
- Somerset Forest
A very small number of affected trees have also been identified in Castlewellan and Belvoir Forests.
The implementation of measures to control the spread of P. lateralis is ongoing. Public access to certain areas of these forests is restricted to prevent soil movement, and users of the forests are asked to observe signage and remain on the way marked paths.
How can I identify Lawson cypress trees and P. lateralis?
Anyone concerned about Lawson cypress trees are asked to access the guide below where information on the identification of Lawson cypress and P. lateralis symptoms is available.
- Guide to identification of Lawson cypress and Symptoms of Phytophthora lateralis (PDF 532 KB)
- Help with PDF files
If landowners are concerned about the disease, they should send their name, address, telephone number and a photograph of the tree to the email below.
Phytophthora ramorum (P. ramorum)
P. ramorum has the potential to cause serious damage to woodlands and plants in the wider environment.
How can you identify Japanese larch trees and P. ramorum?
The first indication of the disease on Japanese larch trees is a visible wilting of young shoots and foliage. Later in the growing season, signs of the disease include withered shoot tips with yellowing needles, which then become blackened. The infected shoots shed their needles prematurely. Trees may also have bleeding cankers on their upper trunks.
All woodland owners and managers are asked to look out for symptoms of the disease in Japanese larch and report suspicious symptoms to Forest Service
- telephone: 028 9052 4480
Further information on the disease is available from the Forestry Commission website:
Public forests affected
Forests in Northern Ireland affected by P. ramorum disease are shown on the outbreak map:
Tree disease can be spread in many ways, including:
- on footwear
- on vehicle wheels
- on tools and machinery
- by the movement of infected plants
- in rain, mists and air currents
If you’re visiting a forest, pay attention to signs showing what you should do to prevent the spread of tree disease.
In forests you should:
- avoid any action which could move infected soil or plant parts to uninfected areas
- stay on forest roads
- keep dogs on leads
- remove soil and mud from shoes and boots before leaving the woodland