Phytophthora ramorum is a tree disease that affects larch trees. It has been prevalent in south west Scotland for many years with sporadic outbreaks elsewhere in the country. It can’t be eradicated. The only way to slow the rate of spread is to fell the infected trees and those surrounding them.

Felling operations and site closures are ongoing in order to remove affected trees and reduce the risk of spread to other woodlands in Cowal and Argyll. Felling operations mean certain areas and paths throughout Corlarach Forest, Benmore Forest, Puck's Glen and Kilmun Arboretum will be closed to the public for safety reasons. Areas that are closed change frequently throughout the works and we often need to close multiple areas at the same time. If you are planning to visit, we recommend checking the relevant forest webpage first to ensure it is open.

Felled areas will be replanted. Although, depending on the species chosen, there is a recommended fallow period of three years. Our response to Phytophthora ramorum will not result in long term deforestation.

How we find out what trees are affected

Scottish Forestry, the regulator for forestry in Scotland, conducts bi-annual helicopter surveillance and associated ground surveys of larch to monitor the spread of Phytophthora ramorum. The disease was confirmed at 24 sites in 2020, and a further 60 suspected cases were identified in 2021. We are currently working to fell infected areas and survey suspected sites. This map shows the confirmed SPHNs:

Map - Phytophthora ramorum sites in Cowal (PDF)

Statutory Plant Health Notices (SPHNs) are issued requiring the felling of infected larch stands and susceptible hosts within a 250 metre buffer zone, usually within a 2–4 month period. Felling of larch and other trees affected by the Statutory Plant Health Notices has been approved by Scottish Forestry. If you have any questions about this approval, they should be addressed to: Scottish Forestry, Perth & Argyll Conservancy, Upper Battleby, Redgorton, Perth PH1 3EN, or sent by email to This email address is being protected from spambots. You need JavaScript enabled to view it.. 

Scottish Forestry has recently launched a revised policy for dealing with Phytophthora ramorum.

After being issued an SPHN, we then start work on the removal of infected larch trees. We also aim to fell additional larch areas over the next four years to reduce the potential for infection in this area and therefore reduce the spread across Scotland. To achieve this increased felling, new forest roads will have to be built, existing forest roads upgraded and harvesting facilities constructed. We appreciate this will have a big impact on the landscape and our visitor trails and facilities. However, we are already working on replanting plans which will reduce the visual impact as much as possible. Visitor trails will only be closed when there is no other option and will be reopened as soon as is practically possible.

Latest stakeholder update on Phytophthora ramorum in Cowal (PDF)

Confirmed Statutory Plant Health Notices in Cowal and their current status

Biosecurity

Phytophthora ramorum can be spread in mud or needles stuck to footwear and tyres on bicycles, buggies, machines and vehicles. Please follow our Keep it clean advice to ensure footwear, bikes, kit and dogs’ paws are always clean before and after visiting any woodland.

Why this work is necessary (PDF)

Larch disease in Argyll Forest Park (PDF)

Phytophthora ramorum in Scotland (Scottish Forestry website)