AT least 23 sites in Scotland have been identified as having the deadly Chalara ash dieback disease that threatens to devastate the UK's 80 million ash trees.

Environment minister Paul Wheelhouse confirmed the rise, which includes mature trees and the wider environment.

He said the disease has been found at one nursery, 18 recently-planted sites and in four further areas north of the Border, but it is affecting 241 sites across the UK.

There are only 12,355 acres of pure ash woodland in Scotland, compared to the 1.63 million acres of largely conifer woodland managed by Forestry Commission Scotland (FCS) – which accounts for 35% of Scotland's total woodland cover.

The species is a significant component of Scotland's 153,205 acres of mixed broad-leaved woodland.

Mr Wheelhouse, who revealed the rise as he appeared before the Scottish Parliament's environment committee, said significant work was being done to combat the fungal disease.

He said: "We have been working very closely with the UK Government and other devolved administrations on this problem.

"Although our native ash is not a major component of woods and forests in Scotland, it is an important feature of our landscape, has considerable biodiversity value and is also one of the most productive broad-leaf species in terms of timber and firewood."

An FCS spokesman said the sites currently affected in Scotland are: a nursery in the north-east; a planting site at Knockmountain, near Kilmacolm; a mature tree site at Eyemouth; in the natural environment at Kinghorn in Fife, Coldstream in the Borders and near Buckie on the Moray Firth.

The affected new planting sites are near Carrbridge, Blairgowrie, Montrose, Dalbeattie Wood near Castle Douglas, Hamilton, south of Lesmahagow, Scone, Leadhills, Cowdenbeath, Burnfoot, Croy in North Lanarkshire, East Kilbride, Alyth, Cleish in Kinross, Duntocher, Largoward and Kennoway.

Rory Syme, from the Woodland Trust Scotland, said: "Given the scale of the rapid search undertaken by the Forestry Commission, it's not surprising that more cases of Chalara ash dieback have been confirmed.

"It's important to remember that Chalara ash dieback is just one of many pests and diseases that are threatening trees."