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.
Willows are also generous at key moments of wider seasonal hardship. Their March blossom is a lifesaver for spring insects, while the trees’ infestations with 23 aphid species makes them rich protein sources for birds summer-long. Willows are, in effect, ecosystems.
If we reframed nature as a tangled flux of relationships (instead of our view of life as a catalogue of separate “things”), then willow would symbolise it all. Of course, to speak of “willow” singular is problematic, as there are about 20 native species, not to mention 70 hybrids, 20 of which originate from just three family members. That promiscuity seems a further branch of their gift for generating abundance, but it also makes it difficult to fix them in our dominant nature-as-list schema.
Pure willow stands are rare, but I know of one nearby that I hold close to my heart, partly to share it only with the red deer that go to wallow in its muddy hollows. It’s so dense in this gloomy thicket that there is a sense of entry to a contained space: a cavern or sanctuary. Progress is wonderfully slow. You have to test the black bog ground while endlessly bowing under branches or skirting whole trees that are spherical redoubts of outward-facing limbs. On my last visit, the slow black trickle through its heart was edged silver with ice. Wind rattled the whole moss-lagged place and from one sludge patch came my only bird, a woodcock: silent, dark, wings brattling on branches as it rose, before it plumped down into the next willow entanglement.
• Under the Changing Skies: The Best of the Guardian’s Country Diary, 2018-2024 is published by Guardian Faber; order at guardianbookshop.com and get a 15% discount
