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Information on Sirhowy forest work

Coronavirus update

We're continuing with our harvesting operations to assist the supply of wood products. Helping to sustain essential services in the health, food and energy sectors.

All of our forestry sites are subject to strict checks to ensure that we are operating within current Government guidelines on coronavirus and social distancing measures.

We remain in close contact with Public Health Wales and will be reviewing our procedures daily in order to keep our staff, contractors, customers and partners safe.


Find out more in our response to the coronavirus pandemic

Removal of larch trees

From April 2020 work will begin to remove approximately 70 hectares of diseased larch trees from the Sirhowy Valley. The trees are infected with phytopthera Ramorum, which is more commonly known as larch disease.

There are approximately 30 hectares of diseased larch trees on the Sirhowy Country Park side of the valley, and approximately 40 hectares on the Cwmfelinfach side.

We anticipate that the work will be finished in December 2020.

Larch disease

Larch disease, or Phytophthora ramorum, is a fungus-like disease which can cause extensive damage and mortality to a wide range of trees and other plants. Larch disease spreads through airborne spores from tree to tree. It poses no threat to human or animal health. Approximately 30ha hectares of trees at Sirhowy are larch and while not infected are part of the Welsh Government “Larch reduction Policy”. Whilst we cannot stop the spread of larch disease, we can take action to slow it down.

The first location to be infected was the Afan valley in south Wales. Parts of the site that were felled in 2010/11 are already starting to regenerate.

In 2013, surveys identified that larch disease was spreading rapidly across forestry in Wales, sparking a nationwide strategy to remove diseased trees to stop it spreading further.

Since 2014 we have been tracking the spread of the disease by conducting helicopter surveys of public and private forests across Wales.

The disease has infected approximately 6.7 million larch trees across the whole of Wales and has had a dramatic impact on our forestry. 

We are legally required to remove infected larch trees under the Statutory Plant Health Notice - Movement (SPHNm) which is issued by Welsh Government. 

Forest access

We do not like to close off access to our forests, which are enjoyed by many, but this is the safest way to allow the work to be undertaken quickly and safely.

We’ve been granted an application to close the foot paths in and around the forestry and will reopen footpaths in certain areas as soon as it is safe to do so. We will keep you informed which section will be re-opened as early as possible via our website and social media channels.

Initially, we anticipate that the operation at Sirhowy Valley will be completed within nine months. 

The forest will become a live operational harvesting site, and areas where the work is being carried out will be clearly sign posted. It is vital that members of the public do not enter these areas for safety reasons.

We understand the short notice of the closure is frustrating, and we want to reassure you that we’ll do our best to limit the amount of disruption caused by the felling. 


We will be replanting over the next three planting seasons, which take place between November and April. The reason we plant in the winter is because we need the trees to become dormant before the nursery can lift and transport the trees for us to plant in our woodlands.

The Sirhowy valley is a Planted Ancient Woodland Site (PAWS) and we will be replanting it with native broadleaves which are more resilient and help secure the site for the future. You can read more about our restocking work in our news section.

Planted Ancient Woodland Sites (PAWS) are sites which are believed to have been continuously wooded for over 400 years and currently have a canopy cover of more than 50 percent non-native conifer tree species. From 2011 5,000ha of Ancient Woodland has been identified on the Welsh Government Woodland Estate that we manage.

Harvesting and haulage operations

We cannot use modern harvesting and forwarding machinery due to steep slopes. Timber has to be cut manually and then pulled to the processing and storage site on the road using a ‘Skyline’ winch system. The winch machinery and wire ropes (loaded with several tonnes of whole trees) are positioned upslope and will bring material up to the harvesting machinery for processing, storage in log piles and then loaded onto lorries.

The work will initially begin on the Cwmfelinfach side of the valley. The trees will be transported via our existing private haulage road and the public highway. Our teams are working closely with Caerphilly council to make the routes as low impact as possible

Harvesting machinery will be disinfected (steam-cleaned) before moving off site to minimise the risk of further spread of larch disease.

Proceeds from selling the timber

All income from timber sales goes towards the operating costs that NRW incurs through managing the Welsh Government woodland estate. Our costs exceed the revenue generated by timber sales so we also receive additional financial support from Welsh Government. This enables us to continue to provide many free facilities throughout Wales for the benefit of local communities and visitors.

The cost of harvesting larch is greater than other tree species due to the fact that larch was historically planted on steep sided valleys making extraction of timber more labour intensive. 


We welcome feedback from site users so that we can minimise inconvenience and improve our operations.

If you have any questions you feel are not answered here or would like to give us feedback on our communications, contact us:

General Enquiries:

Telephone: 0300 065 3000 (Mon-Fri, 9am - 5pm) Minicom service: 03702 422 549**

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