Caledonian pinewoods threatened by spread of tree disease

The disease thrives in humid conditions and was originally an issue affecting the southern hemisphere

Scientists are working to reduce the spread of a tree disease which could threaten Scotland's native Caledonian pinewoods.

Dothistroma Needle Blight is affecting large areas of commercial forestry.

It is expected to have the greatest impact in the north and north-east of Scotland, where pine accounts for almost half of the woodland area.

The Scottish government has said it is working closely with the industry to monitor the spread of the disease.

Scientists believe its spread northwards may be at least partly linked to climate change.

Based on the experience of New Zealand foresters, field-scale trials of aerial spraying are due to begin next year.

The work will help establish if fungicides can help reduce the impact of the disease without adversely affecting the wider environment.

It thrives in relatively warm and humid conditions and was originally a southern hemisphere disease.

Hugh Clayden, Forestry Commission Scotland, said: "What we most need to do right now is buy time by reducing those areas that are most heavily infected, to reduce overall spore production.

The Scottish Green Party called for images to be distributed showing what diseased trees look like

"We can look at other techniques too, like heavy thinning and pruning to increase the air flow and reduce humidity.

"And we also need to start thinking what has become the unthinkable to Scottish foresters over the last 20 years and consider aerial spraying."

In the north of Scotland, the spread of needle blight has already resulted in the felling of large areas of commercial woodland.

Neil Crookston of Scottish Woodlands said: "The forestry industry in Scotland is very important for the rural economy.

"It is vital that we are aware of the pests and diseases that we face in order to remain one step ahead of them."

Biodiversity impact

The Scottish government is also concerned about the impact the disease could have on biodiversity.

Minister for the Environment and Climate Change Paul Wheelhouse said: "We are very aware that Dothistroma has the potential to impact severely on Scotland's forests and on the forestry sector and the arrival of new, exotic pests coupled with potential climate interactions are a major concern.

"That is why the Scottish government, through Forestry Commission Scotland, has been working very closely with the industry to raise awareness of the disease, not only to help forest managers identify it and assess its local severity but also to highlight the measures that can be taken to slow it's spread and limit the damage that it can cause."

Some of the woodland which has already been felled was home to the endangered capercaillie and it is thought other species could be affected by habitat loss.

The Scottish Green Party has called for a campaign to alert the public, as Dothistroma Needle Blight can be spread from infected to uninfected areas on shoes and clothing.

Alison Johnstone MSP said: "We would like the Scottish government to raise awareness of the disease, and distribute pictures of what the trees actually look like when they have been affected.

"Perhaps there should also be a hotline which people can use to access information about how to stop this disease spreading."