Phytophthora ramorum (P. ramorum) is a fungus-like disease mainly affecting larch trees. It is currently the biggest threat to trees in Scotland today.

The main visible symptom of infection is needles turning orangey-brown in spring and summer. Larch trees are the only conifer trees that shed their needles in winter, so this can be a difficult disease to identify and requires close monitoring. The disease can cause the infected branches - and then whole trees - to die.

There is no cure for P. ramorum and it is nearly impossible to remove from an area once it takes hold. The only thing we can do is to try to slow the spread of the disease by felling the infected trees and those around them.

How we deal with infected trees

Scottish Forestry, the regulator for forestry in Scotland, conducts bi-annual helicopter surveillance along with ground surveys of larch to monitor the spread of Phytophthora ramorum.

Once the disease has been confirmed, we are issued with Statutory Plant Health Notices (SPHNs). These come from Scottish Forestry and let us know which trees need to come down and when. After being issued with an SPHN, we then start work on the removal of infected larch trees. This is usually done quickly, to reduce the spread.

The diseased larch can still be sold as timber, if felled early enough. This means there shouldn’t be a loss to the carbon store.

We will continue to remove additional larch to reduce the potential spread across Scotland. Scottish Forestry has recently launched a revised policy for dealing with Phytophthora ramorum.

Phytophthora ramorum in central Scotland

P. ramorum has hit central Scotland particularly hard and we are having to fell a lot of larch in the area. This will change the shape of Cowal and Argyll Forest Park for the next 40-50 years.

The animation below shows how the disease is already impacting the hillside above Kilmun.

How you can help stop the spread of pests and diseases

Phytophthora ramorum can be spread in many ways, including mud or needles stuck to footwear and tyres on bicycles, buggies, machines and vehicles. It can also be spread by taking home an acorn or stick from the forest.

Please follow our Keep It Clean advice to ensure footwear, bikes, kit and dogs’ paws are always clean before and after a visit to any woodland.

Learn more about how you can help protect our forests