Coppiced since mediaeval times, people have found all sorts of uses for this member of the birch family, including charcoal, clogs and gunpowder, and someone once told me that Venice is built on Alder. This makes sense in that these trees are often found close to water, as on the banks of the Wharfe, and rather than rotting when wet the timber actually gets stronger. Alder roots help prevent riverbank erosion, and also make an ideal spot for an otter holt. Their location can help in identification, as do their flowers: the long, pendulous male catkins can be seen on the same tree as the small brown female cones. They are the only deciduous tree to have these, and they’re visible throughout the year. The twigs are a little unusual, featuring patches of purple, orange and red, with young ones feeling sticky. When the leaves come, they have a shape the reverse of your classic leaf.