Ants have been plotted on hi-tech maps to protect them during forestry operations

Nests made by the formidable hairy northern wood ant - the UK's biggest - have been given a unique GPS address and plotted on hi-tech maps to protect them during forestry operations.

The amazing conical structures - some up to 7ft (2.1m) high and made of millions of conifer needles - have grown progressively taller over the years on the Forestry Commission estate in 375-acre (150-hectare) Holystone Wood, near Rothbury, Northumberland.

Now the next phase in a project to restore part of the site to its ancient roots as an oak wood is under way - and the ants will stay snug in their nests.

Jonathan Farries, from the Forestry Commission, said: "Holystone is one of the most important ancient woods in Northumberland and also a Site of Special Scientific Interest.

"This long-term project will see many of the conifers planted in the 20th century removed to allow native species like oak and birch to regenerate. But we are tweaking our plans to ensure that the wood ant nests continue to thrive."

More than 10,000 tonnes of timber are due to be felled and rangers have identified 69 ant nests in the areas affected by the work.

The co-ordinates of each have been recorded using GPS devices and then plotted on to a computerised mapping system.

This will allow foresters to take them into account when planning forest operations. Some conifers will be left in situ as the ants like to build their amazing structures in sun traps, with trees providing sheltered alcoves and also needles for building materials.

The northern, or hairy, wood ant is Britain's biggest and has become so rare that it merits its own species action plan.

Red and black in colour, it is found at only two other Forestry Commission locations in the North East.