On an overcast, drizzly afternoon at Durham Wildlife Trust’s Low Barns nature reserve, alder (Alnus glutinosa) provided the brightest splash of colour in the landscape.
A tree had been felled and sawn into logs. Chainsaw wounds on this species can look like a massacre, because soon after the timber is cut, it turns a lurid shade of red, almost like blood, in stark contrast to the battleship-grey bark. Eventually those wounds, which briefly resemble raw meat, fade to orange and finally to chestnut brown.
When this reserve was established half a century ago, around old gravel pits, some moisture-loving alders were planted to help revegetate a bare, windswept site. Alder wood is one of the finest sources of charcoal, and the plantation trees are old enough now to be coppiced, to produce barbecue fuel.
There is also an important natural alder wood here, created by a cataclysm almost two and a half centuries ago, which led to the designation of the reserve as a site of special scientific interest.
The Great Flood of 1771 swept through Weardale, washing away bridges all the way to the coast. When the water subsided, the course of the River Wear had shifted half a mile south, and the old riverbed became what is now the reserve’s Long Alder Wood, the finest example of its kind in the region.
In winter, when it sometimes floods, this tangle of gnarled trees has a hint of the Florida Everglades about it, with mossy, fallen trunks sinking back into the ooze. Year round, there are wonderful opportunities to watch birds from an embankment level with the tree canopy. This afternoon an acrobatic flock of about 30 goldfinches bounced and chattered through the twigs, feeding on tiny seeds that fall from the woody cones.
Sadly, since the mid-1990s, another catastrophe has befallen this locally unique woodland: alder dieback disease has killed around half the mature trees. Coppicing is leading to some regeneration, though in this precious habitat dead timber is allowed to lay where it falls, reserved for the needs of a diverse community of fungi, invertebrates and woodpeckers, rather than back-garden burger-flippers on summer evenings.
• This article was corrected on 6 December 2018 from Alnus incana, the non-native grey alder, to Alnus glutinosa, the native common alder that is common to Witton-le-Wear.
