To the north of the village of Bellingham, the Hareshaw Burn cuts a winding ravine deep into the land. The trees that grow in this sandstone gorge – pedunculate oak, elm, ash and hazel – are remnants of woodlands that were once more extensive. The moist air, the cycles of growth and rot, allow the survival of mosses, liverworts, ferns and more than 50 species of lichen. For this, and its rich flora, the area is designated as a site of special scientific interest. Linn is Northumbrian for waterfall, and the wood is called Hareshaw Linn after the dramatic cascade where the river descends from surrounding moorland.
It’s remarkable that this place feels so untouched. In the mid-19th century a massive stone dam was thrown across the lower end of the burn. It supplied water to an ironworks, sited here to exploit four key resources: water power, iron ore, limestone and coal. There were two blast furnaces, 70 coke ovens, 24 roasting kilns, a water-powered engine and a blacksmith’s shop. But the works lasted less than 20 years, failing from lack of a railway to transport the resulting pig iron, and part of the dam wall is all that remains.

Damp glistens on haws, elderberries and brambles as we enter the wood. The path is bordered by dog’s mercury, woodruff, wild raspberry and wood sage, indicators of the age of this plant community. Plump hazelnuts lie on cushions of emerald moss, and herringbone fronds of hard fern luxuriate in the wet air. Wood sorrel grows on decomposing logs, and lianas of honeysuckle droop from branches laden with epiphytic ferns, adding to the rainforest feel. Water is everywhere – crossing our path in stone channels, running in tiny streams among fallen rocks, thundering down the main river in coffee-brown swoops and curves.
Six bridges cross the Hareshaw Burn. We stop at each to watch bubbles and white foam spinning between boulders. As the cliffs rear taller, there’s a feeling of expectation and, round a bend, there is the Linn itself, powering down in creamy pulses into a large pool. Water drips from overhanging ledges on honey-coloured cliffs. I’ve seen the Linn iced up, all 30 feet of its restless movement frozen into candlewax accretions. Today, clouds of misty drizzle dampen my clothes but benefit the rare plants that flourish here.