Discoloured larch needles are the most visible symptom of infection by the destructive, fungus-like Phytophthora ramorum pathogen, so it is difficult to identify infected larch trees once they have shed their needles in the autumn.
Dr John Morgan, head of the Forestry Commission's Plant Health Service, said:
"Without knowing whether the trees are infected, we would risk inadvertently spreading the disease during harvesting, transporting and processing operations if infected trees were felled and moved in winter without biosecurity precautions being taken.
"We also do not want to impose the burden of biosecurity precautions on owners, hauliers and processors handling timber that might be disease-free.
"We have agreed with the forestry and timber processing sectors that we should postpone new permissions to fell larch until next spring, when we can be more confident about identifying infected and uninfected trees, before allowing felling to resume in the high-risk areas.
"We fully understand the disruption that this will cause to some forest managers' plans, but we feel that it is a necessary part of our strategy to bring this highly destructive disease under control.
"I would like to thank all of those forest owners who have co-operated with our control strategy, despite sometimes significant disruption and losses. It is very much appreciated."
Dr Morgan added that the Commission would process licence applications as quickly as possible once larch felling can resume. The exact date when that can happen will depend on the timing of needle flush next Spring, and is likely to be different in different parts of Britain, but is expected to be no later than 31 May 2012.
