After the last ice age, pine forest spread across Scotland from coast to coast. Centuries of clearance reduced it to fragments, and Glenmore is one of the largest. Around half the trees here regenerated naturally; the rest were planted from local seed, a careful effort to keep the genetics of this particular forest intact. The result is something rare: a working woodland that still functions as a Caledonian forest, with all its associated species. Scottish crossbills - found nowhere else on Earth, prying open pine cones with their crossed mandibles - work the canopy. Crested tits flick through lower branches. Capercaillie, the turkey-sized grouse whose males perform an elaborate spring courtship, breed here in numbers that, in 2006, made Glenmore the most productive monitored site in Scotland. The forest park, established in 1948, is also a national nature reserve and a Site of Special Scientific Interest. The designations are the modern equivalent of fencing off something sacred.

During the Second World War, this forest became a training ground for Norwegian resistance fighters. Selected men of Kompani Linge and other special units trained in the pines and on the surrounding moors, learning to ski cross-country, survive in cold weather, and conduct sabotage operations they would later carry out behind German lines in occupied Norway. The terrain was the closest thing in Britain to the country they had left behind. A memorial near the visitor centre commemorates them. Some did not survive the operations they trained for. The most famous of those operations - the destruction of the heavy water plant at Vemork - struck a critical blow against the German atomic programme, and several of the men who carried it out had trained in these woods. The pines that shelter capercaillie today sheltered men preparing to do something that mattered very much.

Above the canopy, the sky belongs to predators. Ospreys hunt the loch of Morlich, plunging feet-first for trout. Golden eagles ride the thermals above the higher ground, occasionally crossing the forest in long, deliberate glides. Peregrine falcons and merlins hunt smaller prey, and both occasionally breed in the area. On the open plateau above the tree line, dotterel - small wading birds that migrate from Africa - sometimes show themselves. Down in the rivers and lochs, otters fish, and Atlantic salmon return each year to spawn in the gravel beds. Red squirrels, almost extinct elsewhere in Britain thanks to the introduced grey, still flourish in the pines. Red deer drift through at dawn. The narrow-headed ant - one of Britain's rarest insects - builds its mounds among the heather. It is a working ecosystem of the kind that has become exceedingly hard to find.

Folklore clings to Glenmore the way moss clings to its trees. The Ly Erg - a small soldierly figure said to appear in the forest with a single bloody hand - is a portent of death; meet him on the path, the legend goes, and someone close to you will not see the year out. An Lochan Uaine, the small green lake, is the more cheerful story: the fairies wash their green clothes here, and the dye has tinted the water permanently. The real cause is more mundane - light scattering through suspended particles and the dark peat-stained bed - but the fairy version is the one that gets told. The lochan sits at the head of the Ryvoan Pass, reached by a short walk from the visitor centre, and on a still day the green is genuinely startling. The forest has been telling stories about itself for as long as there have been people in it to listen.