The Forestry Commission has provided information about the incidence of new cases of ramorum disease of larch trees detected in England this year. The disease is caused by the Phytophthora ramorum pathogen.
Aerial surveying of high-risk areas of England has detected up to 525 hectares of larch woodland as possibly infected, representing an increase in known infected area of up to 26 per cent. There are 44,000ha of larch woodland in England, and Andrew Smith, Head of Sustainable Forest Management for Forestry Commission England, said,
"These figures are positive insofar as they do not show the level of progression being experienced in other parts of the UK, and the great majority of larch in England remains healthy.
"They are still subject to checking from the ground, and the exact figure, based on previous years' experience, could be as much as 30 per cent lower than this, as other causes are confirmed for some of the symptoms seen from the air.
"However, there is no room for complacency. These data show regional variations in spread and, overall, a moderately greater degree of spread than we've found at this stage in previous years. This is not surprising given last year's exceptionally wet weather, which was conducive to spread of the disease."
Mr Smith added that Forestry Commission England would continue with its current approach to controlling the disease. This requires the felling of infected trees, and the felling of neighbouring trees out to a radius of 100m from infected trees. Evidence shows that this is the most effective way of reducing the risks of spreading the disease further and minimising wider environmental impacts.
Mr Smith cited the example of Devon, where, "despite having some of the first cases four years ago, about 80 per cent of larch trees remain healthy, which indicates that the current strategy and prompt action by the sector is helping to abate spread of the disease".
There has been a greater increase of disease in North West England compared to previous years, with the new findings split almost equally between North West and South West England. The Commission is working closely with stakeholders to minimise the impacts of the disease and associated control measures in that part of the country.
He thanked woodland owners for their co-operation with the policy, saying that compliance with statutory notices to fell infected trees had been "extremely good", with more than 90 per cent of owners complying.
Further information about ramorum disease, including a map of confirmed cases, is available from www.forestry.gov.uk/pramorum .