This week’s extra bit of botanising was a walk along the route of the old Stainmore railway line, which once joined Darlington to Tebay, through Smardale Gill NNR near Kirkby Stephen. This is a special place for both its industrial heritage and its current plants, butterflies, moths and bird life. Scandal Beck flows north-east through the valley, cut deep into the limestone fells, before it joins the River Eden. My geologist friend speculates that the valley is too deep and wide to have been cut by this little beck and must have been carved out by glacial flow during the last ice age.
Despite the valley’s bucolic appearance nowadays you don’t have to look hard to discover the area’s industrial heritage. There is plenty of evidence of quarrying of both limestone and some sandstone and a pair of well-preserved limekilns on the west side of the old railway line, which was built in the 19th Century to transport iron ore from the west coast towards the steel works at Consett. It must have been a lucrative business to make building viaducts like Smardale Gill worthwhile and apparently also made economic sense to produce the lime needed for the Consett blast furnaces along the way. By the early 20th Century there were two or three passenger trains a day on the line too – passengers would have enjoyed similarly spectacular views to those you still get from the Settle to Carlisle trains. The new(er) Smardale viaduct is the highest on the Settle-Carlisle route, crossing Scandal Beck at a height of 40 m, just a kilometre or so north of the old viaduct.
The steep slopes of Demesne Wood, on either side of the railway path at the north end of the valley are now being managed by Cumbria Wildlife Trust, who are removing planted non-native species to encourage natural biodiversity. Immediately around the path the trees are cut back every few years and log piles built to encourage fungi and decomposing invertebrates. Letting some light in has allowed Broad-leaved helleborines and Common fragrant orchids to flourish, along with the wild raspberries we snack on as we walk. Stone bramble, Rubus saxatilis, was a new plant to me – if I’d known these tempting looking fruits were edible I’d have been tried them too but their luminosity made me wary! Wikipedia tells me they are widely used in Russian jams, syrups and compotes, much as we might use ‘ordinary’ brambles Rubus fruticosus agg.
It’s not just the woodland that is flourishing. Beside the track on the more open ground on the far side of the viaduct is limestone grassland where a riot of native wildflowers provides nectar for the real stars of the show, the butterflies. The mixture is slightly different to what I find on the Magnesian limestone, closer to home but Knapweed, Great burnet, Small and Devil’s-bit scabious, Bloody cranesbill and Sneezewort are all popular with bees, hoverflies and butterflies.
We see plenty of Peacock, Painted lady, Meadow brown, Common blue and Small skipper butterflies, to name the most obvious, and masses of Scotch Argus butterflies, which were new to us both. This is one of the two places they are found south of the border.
Where there are abundant insects, birds and reptiles will follow. Leaving some dead trees standing has made life easier for woodpeckers and, though we didn’t see them, Green woodpeckers laughed at us from the safety of the woods. We did see a Redstart in the quarry above the limekilns but there was no sign though of the lizard Steve had seen on a springtime visit – I suspect there were just too many people out enjoying the flowers and butterflies for any self-respecting lizard to risk basking in public!