DOZENS of hectares of diseased larch along Dartmoor's southern fringes have been felled to try to contain a disease known as the foot-and-mouth of the forestry world.

Phytophthora ramorum is a fungal disease which is attacking Japanese larch trees, a favourite among commercial timber growers.

Deborah Elton, the Forestry Commission's policy implementation officer, said 110 felling notices have been issued on forestry commission land and private forest estates, with much of the work already carried out and more due to take place over the next few weeks.

The south west is by far the worst affected region in the country, as the disease thrives in warm wet conditions. Wales is also badly affected.

Nationwide 829 hectares are being felled, the bulk of it in the south west. Of that 71 per cent is in private hands.

Around 12 acres of diseased larch on Forestry land at Brimpts is due to be felled and more trees are being cut down at Canonteign.

The Forestry Commission declined to give a list of affected sites but a map of the region updated last month suggests that about a dozen of them are in Teignbridge.

Infected trees develop lesions known as bleeding cankers. Black fluid seeps from the bark and later dries to a crust on the trunk.  The inner bark is usually discoloured and the tree dies when lesions become extensive.

Biosecurity measures to minimise the risk of spread from felling operations include washing down vehicles and footwear to remove mud and infected needles. 

There is no risk to human or animal health.

Ms Elton said: 'We don't think we've seen all the infections yet. We anticipate new sites will be found in the spring once the larch needles flush again.'

She said that it can take a couple of years before an infected tree shows symptoms.

'Our hope is that the strategy to contain the disease by felling diseased larch will begin to have an impact and by the end of this year we will see a slowing down in the disease.

'A lot of it is weather dependent. We need dry weather. probably the cold winter may have helped a bit as well.'

Japanese larch is a widely planted commercial tree species, occupying almost ten per cent of all woodland in Cornwall, Devon and Somerset. Some 76 per cent is growing in privately owned plantations and private owners have been urged to report any suspicious signs promptly.

Descriptions and photographs of the disease are available at http://www.forestry.gov.uk/pramorum">www.forestry.gov.uk/pramorum.