SQUIRRELS and pine martens are being tracked through GPS technology to see how they are dealing with trees being torn out of their woodland environment by giant machines during forestry operations.

The work is being carried out by Forestry Commission Scotland, whose land is home to many animals including the two protected wildlife species but is also there to provide a product to be harvested.

As part of a pilot project, squirrels have been tagged with GPS collars and monitored for their behaviour.

The initial study launched in Strathspey appears to suggest that squirrels and pine martens adapt to the impact of commercial forestry and now more work will be carried out to establish how they respond to work being carried out in their habitat.

Kenny Kortland species ecologist for FCS, said the commission was looking to see how forestry operations can impact on habitat use of red squirrels and pine martens and to find out the locations and sorts of places these animals use for breeding and shelter in our productive forests.

He said both are heavily protected and are a major constraint on forestry operations.

He said: "We have to avoid disturbing pine martens and red squirrels and causing damage to their dreys and dens during our forest management and felling work.

"But not that much has been known about how they respond to our forestry operations. So we have done a small trial study in Glenmore in Strathspey where we tagged 10 squirrels with GPS collars in an area where we had some tree harvesting going on.

"We got good data from five or six. Basically this showed that the squirrels did not desert the area altogether. They stayed around just changing their home ranges slightly, while the harvester machine was in operation.

"We did not know they would react in this way, so it is very useful. But now we have to do further studies using more sophisticated GPS tags."

In previous generations the timber was felled by two man cross-cut saws and extracted by horses. They were replaced by teams with chainsaws and winches.

But now four or six-wheeled articulated machines, 'harvesters', fell the coniferous trees, remove branches and cut the trees to prescribed lengths.

These are then collected by 'forwarders', also articulated machines, which can weigh up to 18 tonnes. They come into the woods to load timber on to a trailer and stack the timber at the side of the forest roads for collection by huge timber wagons.

Red squirrels, in comparison, have a body length, not including their tail, of just nine inches or less, and pine martens are rarely over 22 inches.

Mr Kortland said the tags used only lasted 12 days so next year they would be using GPS collars that would give information for several months to get the bigger picture of the habitat occupation before during and after the forestry operations.

"It will be a proper scientific study," he said. "The pilot was to see if we could get GPS collars to work in a forest environment and we did.

"Pine marten have the same protection as squirrels. So when we are going into the forest for felling operations, we have to protect their breeding sites. But we know very little about their breeding sites and have hardly ever found any.

"By doing this radio tracking, again in Glenmore, it has given us our first real insights. We have had great success in locating the places where they are breeding - in standing dead trees, in rock piles, some of them a close as 10ft from the ski roads."