Nature Notes

Jenny Dixon

Wharfedale Naturalists Society

wharfedale-nats.org.uk

I DON’T get out much at present owing to arthritis. Stuck at home, it’s amazing how you notice ordinary things near at hand. This Autumn I’ve been very aware of leaf-fall. The large oak on the edge of our garden, so heavily foliaged this summer, now sports a few ragged leaves. Of the rest, some were sent to Municipal recycle in the brown bin, others collected in our home-made wire-netting container to form rich leaf mould for future compost. Lots are still lying in drifts around the edges of lawn and pathways – a home for overwintering invertebrates, frogs or even, if we’re lucky, a hibernating hedgehog. I was fascinated by how many leaves, caught by the wind, flew right over the house to collect in a damp heap by the garage. It made me realize how a mature tree can scatter leaves, potential nutrients, over a wide area.

All this was very predictable. What surprised me was that a sapling oak, no doubt a descendant of the big tree, that is about 5m tall and grows about 12m from its parent, is still fully clothed in leaves, many brown but some a rather shabby green. It will only lose this foliage when Spring starts. This is apparently the case with most saplings – but why? Protected by its parent, it is not in danger of being caught and blown over in winter gales; it may be glad of the slightly warmer microclimate formed by its leafy coat or perhaps it needs to hang onto the nutrients in its leaves as long as possible. It’s an interesting conundrum.

It’s also interesting to notice the order in which familiar trees defoliate. The horsechestnut near the Health Centre always begins to brown and shed first. A relatively new incomer from the south, horsechestnuts have developed their own ways of dealing with our northerly climate. As well as species, other factors are at work: altitude and, more importantly position. Is the tree directly open to equinoctial gales or protected by the lie of the land, buildings or by its comrades? Many beeches seem to hang on to their glowing leaves well into November. I remember walking through great crackling drifts of them near Virginia Water very late in the year. They’re so waxy that it’s another of Nature’s wonders how they ever break down.

In any wood, winter is the time of intense underground activity. Myriads of tiny creatures are working amid the bounty, and the mycelium of fungi – great webs of hairlike filaments – penetrate fallen leaves, branches and even whole fallen trees, breaking them down to basic elements and then carrying these through their network to nourish all the woodland flora. Scientists have called this “the wood-wide web.”