Usually in this country when we think about important trees, we focus on height, girth, age, visual impact – in short, their material properties. Few therefore would probably name willow as a number one British species.
Willows often have no central trunk as in our archetypal tree model, and few specimens are more than 7 metres tall. Yet there is a sphere in which willows are pre‑eminent: more invertebrates live on them (452 species) than any other trees, including oaks, their closest contenders (423). In his glorious guide Trees of Britain and Ireland, Jon Stokes points out that 160 lichens thrive on willows too.
