Welsh Assembly minister for rural affairs Elin Jones is to issue orders to fell larch trees infected by a new outbreak of the sudden oak death disease.

The news follows the discovery of the pathogen among larches in forests in South Wales and the subsequent implementation of biosecurity measures by the Forestry Commission.

Ms Jones said the scale of the infection had resulted in an assessment of Forestry Commission Wales’ programme priorities to enable an effective response and to manage possible long-term impacts.

She revealed that infected trees have been reported on around 6,251ha, of which 464ha have been identified as being infected with the disease.

Most of the larch in Wales is on the Assembly government woodland estate and the species accounts for about 10% of the Assembly government woodland estate.

Ms Jones’ instructions will initiate a clearance programme on the estate and the Forestry Commission will use its regulatory powers to compel owners to fell infected trees. But he said it was not possible to compensate owners for loss of timber income.

“The financial impact of the disease cannot yet be quantified because Forestry Commission Wales is still assessing how widespread the infection is and do not, as yet, know how marketable the infected material will be.”

The clearance programme represents 13.8% of the annual harvesting total on the estate.

Mr Jones said there could be an impact on the delivery of current woodland programmes if further significant funding was required to deal with the disease.

Sudden oak death has caused significant damage to US oak trees, but to date only one British oak has been infected.