TWed o’clock on a cold December afternoon, and the sun is already sinking to the western horizon, casting long shadows across Flatts Wood. Forward, a blackbird lands along the footpath and begins tossing dead leaves aside, with the flustered air of a gardener discovering litter on their lawn. During short winter days, these birds use a lot of energy to dig out layers of decaying autumn leaves, looking for buried food. Head turned to one side, he seems to be listening, perhaps sensing something hidden here, and ignores us until we are a few steps away.
When he flies, we take a closer look: what lives under last summer’s discarded leaves? Beneath loose, wind-dried leaf litter lies several years’ accumulated dead foliage; a leafy lasagna welded together by fine fungal threads that proceed from a spreading delta of pure white mycelium and crawl out from under a fallen branch. For every mushroom that appears above the surface, there will be miles of this fine hyphaewhich eat their way through dead plants until they can store enough energy to organize themselves into another fungal fruiting body.
We find worms under the cavity the blackbird dug up, but not the kind he was looking for. Peeling apart layers of decomposing leaves, the oldest already picked-clean skeletons of their former selves, we find tiny white specks. They are nematodes – eelworms – which, suddenly exposed to daylight, roll out and squirm across the wet surface. There must be hundreds in every cold, damp handful of leaf mold. The largest, fully extended, is less than a centimeter long and not much thicker than a human hair.
Collectively, nematodes, hidden heroes of woodland nutrient recycling, are the most numerous animals on earth. In the fading light this winter woodland looks lifeless and dormant, but beneath the surface billions of them will be busy. Their slender, cylindrical bodies are translucent, so when we examine one under a hand lens, we can see small bundles of partially digested food progressing through its intestines.
Working with fungi, these ubiquitous critters turn fall’s detritus into crumbly humus, one microscopic mouthful at a time.
