The Wood for the Trees: The Long View of Nature from a Small Wood. Richard Fortey

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      There are always grey squirrels somewhere in the wood. They skitter acrobatically along branches and leap effortlessly through the canopy; it is their realm. They build untidy drays high in the trees in which they can raise two litters a year. They have abundantly fluffy tails. They are, of course, invaders from North America. They were released on a few English estates in the nineteenth century for aesthetic reasons, and then stayed on and prospered. They pushed out the red squirrels from most of England, and continue to expand their range northwards into Scotland today: they are bolder animals, faster breeders and generally more robust. They carry a lethal pox virus to which their red cousin has not yet acquired immunity. There is nothing new about worrying about the invader. A wartime Surrey Mirror exclaimed in 1942 that to eradicate this pest ‘all possible steps such as shooting and trapping must be taken. The national interest demands it.’ Never mind Hitler: the nation might be brought down by a climbing rodent! When I was a youngster there was a bounty of sixpence on every grey-squirrel tail. Neither threats nor inducements have worked: the cheeky grey squirrel dances nimbly onwards.

      It has been claimed that red squirrels are better adapted to conifer woods and that greys outcompete them only elsewhere – though I know plenty of conifer plantations with greys in command. I try very hard to banish Beatrix Potter’s charming Tale of Squirrel Nutkin from my mind, since her drawings provide such effective propaganda for the red species. Some ecologists even challenge the notion of ‘native’ species at all, when so much British wildlife has come from elsewhere. They are probably right that it is foolish to think of restoring some notional Eden, a prelapsarian paradise labelled ‘Natives Only’. In this argument I am obliged to take the part of my precious beech trees. Although I can find some records of tree damage by red squirrels, it does not seem to be as extensive as that caused by the grey interloper. A proven continuity of fine beech woods in our patch points to the red squirrel as no more than an occasional nuisance. Maybe they were once popular enough as food to keep the numbers down. Most damage happens in years when lots of squirrels have come through a mild winter following a good year for beech mast: overpopulation is part of the problem. One of my woody neighbours shoots as many greys as he can; another believes nature will correct the numbers in her own good time.

      I have found a bleached squirrel skull to add to the collection, manner of death uncertain. I simply want to believe that there will still be tall, healthy beech woods here in the century to come, so that some future J.S. Mill may glory in their abundance. In the end, global warming might be more important than any kind of squirrel. The New Sylva warns that if summer drought increases, beech ‘may disappear from the Chiltern Hills except on northern slopes with moist soils’. To survive at all, the woods will have to move northwards, alongside the delinquent greys. They will become partners in a human crime. I shudder at the thought.

      Two ghosts and a Dutchman’s pipe

      When the beech canopy captures the sun the forest floor becomes a darker place. The bluebells have faded, and only faint greasy traces reveal the wraiths of their dead leaves. The grasses that made a brief, bright sward are muted now; nodding wood melick has set its seed for the year and will soon aspire to invisibility. Taller, elegant wood millet (Milium effusum) raises its flowering spike in wispy tiers making a brief show of green flowers that dangle from the ends of spread branchlets like tiny beads. Only sedges by the wayside are more obdurate. Their tufts and clumps of coarse, dark-green leaves see out the seasons, though few passers-by would notice them if there was the bright promise of bluebells in the woods beyond. Wood sedge (Carex sylvatica) briefly dangles little rods dotted with yellow stamens in spring, and then might even be described as pretty.

      Its broader-leaved companion, thin-spiked wood sedge (Carex strigosa), is a recherché plant for botanical enthusiasts, with flower spikes so discreet that I can only identify the species with a lens in one hand and a book in the other. It is something of a rarity, though it seems to grow enthusiastically enough in ruts left by tractors. Distant sedge (Carex remota), with the thinnest leaves of all our sedges, lurks inconspicuously by the damp seep, and has its greenish fruits tucked into its leaf bases, so that anyone giving it a casual glance would think it a grass. Toughness in sedges is evidently inversely proportional to their showiness. But even they cannot grow under the largest beeches. Apparently, nothing can. The deepest leaf litter is inimical to living things. It is a place fit only for ghosts.