On a crisp winter morning, when a dazzling white sun hangs just above the tree line, and the sky to the north is eggshell blue, I slip through deep sunken lanes, worn away over centuries by generations of carts and oxen, to come upon a thicket of silver birch standing by a patch of ancient heathland. The air is damp and resinous from nearby pines, but as the lane rises up into the sun, there comes a warmth with the light, even though we are only a few days into January. And as the hill climbs up past oaks still brown with autumn’s clinging leaves, away from a pair of pheasants that leap and clutch at the air with a rattle of wings, here are the birch. The sunlight sparkles on the bark, and the white paper against the blue sky brings an elemental simplicity unlike anything else in the landscape.