Название: The Wood for the Trees: The Long View of Nature from a Small Wood
Автор: Richard Fortey
Издательство: HarperCollins
Жанр: Прочая образовательная литература
isbn: 9780008104672
isbn:
Kalm recorded precisely how, after felling, every part of the tree had a value; almost nothing went to waste. Farmers used to say of pigs that everything is used except the squeak; the beech woodsmen’s equivalent might be: everything has a use except the bark. They ‘sold the smooth part, or sawn it up into boards, but those of which the stem had been knotty or uneven was cut up for firewood and piled up in cords. When the beeches … were cut down and felled to the ground they were cut off close to the earth. Two or three years after that, the stump that had been left, together with all the roots proceeding from it … was dug up, cut into small pieces and arranged in four sided oblong heaps to dry … In digging up the roots they had been so careful that among those heaps there lay a great many fibres of the roots, whose length was not over 6 inches, and thickness not greater than a quill pen. These roots thus arranged were sold as fuel to those who lived some English miles around.’ Dry twigs bound into bundles of faggots were fuel for bread ovens. Some observers even regarded the beeches in the way that we now look at factory farming. The pioneering landscape architect Humphrey Repton remarked in 1803 that ‘these woods are evidently considered rather as objects of profit than of picturesque beauty’. He preferred specimen trees carrying full crowns of branches adorning a grand park, the whole designed for effect. He would not have stooped to grub up roots.
Kalm also made calculations, and his observations show a clear, scientific mind at work. ‘A beech trunk was measured which had at the large end fifty four sap rings. The diameter was just two feet. The sap rings which were found nearest the heart were narrowest and smallest, from which they grew larger the further they lay from the heart out towards the surface.’ A cross-section cut from the trunk of a tree could not have been better described. The ‘sap rings’ are the record of the new wood lain down by each year’s growth beneath the bark: fifty-four rings is fifty-four years, the age of the tree. Our own wood needs just such a chronology.
The neighbouring wood has had some recent felling, and I can record the cleanly cut log-ends on display in a stack by the entrance to Grim’s Dyke Wood. Beech chronology turns out to be not quite as simple to measure as I might have thought. The good thing about our trees is that such straight trunks provide a reliable, nearly circular section. Nearer the ground the trunks are all buttressed and irregular, and no two diameters are the same; these undulations record the profiles of the ‘props’ that hold the trunks aloft. So the upper part of the tree – waist-height and above – provides the best experiment. Since all tree trunks do taper gently, different sections of the same tree will have decreasing diameter upwards. The difficulty is that the ‘narrowest and smallest’ rings in the centre of the tree are not so easy to read. Some years added no more than a millimetre of new wood.
I have to take a felled piece of heartwood home to see if I can tease out some figures. I laboriously buff it with fine sandpaper for hours, and as the distracting irregularities are polished away, so the early growth rings become clearer as darker lines. It is like seeing a diagnostic thumbprint slowly developing from obscurity. The wood almost shines pink-brown when I finally make out twenty-seven rings in thirty-five millimetres diameter. It evidently took a long time for this particular tree to get going, after which it sped up mightily. Even in the mature part of the tree not every ring announces itself clearly. There are good years and bad: the summers of 1974 and 1975 were droughts, and the growth rings would have been minimal. Skilled dendrochronologists can ‘read’ tree rings as a diary of climatic variation extending over centuries, but my skills do not extend that far. However, in older trees most of the rings add about three to four millimetres to the radius every year, and these can be counted easily enough. I eventually reach a consensus with my own scientific conscience. Several trees come out with eighty rings, more or less, possibly as many as eighty-five. Jackie provides a second pair of unbiased and independent eyes and tots up a similar figure. These are from trunks ranging in diameter from twenty-seven to fifty centimetres; and another trunk of forty-three-centimetre diameter has just under sixty rings. I cannot prove that the former come from higher in a tree that might have had a more impressive base. What I can say, with confidence, is that a number of beeches in Lambridge Wood grew from seedlings around 1930, and are now fine, big trees.
It is easy enough to convert diameters into circumferences, and with my very own trees the latter is what I record at shoulder-height with my tape measure. I can prove that many of the standing beeches are of similar size to those sitting on the log pile. It is actually rather easy to show this without wielding the tape, by using that alternative, hippy measurement – ‘the hug’. Trees with a fifty-centimetre diameter can be comfortably hugged, with hands meeting around their girth. There are an equal number of trees that are just too big to hug, although they do decrease in diameter to become huggable towards the canopy. And then there are the real giant trees, like the King Tree and the Queen Tree, and one I call the Elephant, with circumferences up to 250 centimetres. Surely these are much older than eighty years. If I assume that they continue to grow by adding a three-to-four-millimetre ring every year, it is not unreasonable to arrive at an age of 140 to 180 years. There are perhaps a dozen of these trees scattered through our wood. Their bark eventually loses the smoothness of the younger trees to become lightly scarred, as if daubed with vertical stretch-marks. Since there are certainly no trees still more antique, I conclude that these fine examples have been responsible for seeding some of their younger companions. They have been left alone. A great felling must have occurred about eighty years ago – and selective felling probably continued for another twenty years or so until Sir Thomas Barlow’s ownership, when we know that little happened in our part of the wood. The somewhat ‘unhuggables’ may well record regrowth after another, earlier phase of beech harvesting. There is no doubt at all that the whole wood has been replaced, thinned, sawn and regenerated. Its history is written in the tree rings. This is the same wood that John Stuart Mill walked through in 1828. Only the trees have changed.
Like those of many wind-pollinated species, beech flowers are unspectacular. I already noticed brown bunches of fallen stamens from the male flowers in May, while the separate female components now sit above, waiting to mature into three-sided beechnuts, which will eventually fall to the ground in October. The most beautiful and accurate drawings I know of living twigs are by Sarah Simblet in The New Sylva,2 which is a large, luxurious, even sumptuous tribute to John Evelyn’s original, and about as appropriate for taking into a real wood as The Oxford English Dictionary. Last year’s beechnuts germinate as early as April, and the seedlings can be told from all others by their pale-green seed leaves (cotyledons), which resemble the blades of two inch-wide ping-pong bats placed side by side. Before the canopy has opened out, optimistic seedlings can come up almost anywhere in the beech litter, and are not short of light. A tender shoot then appears between the two seed leaves and starts to put out regular leaves. By now in June it is already clear that most of these young plants are doomed; they lack enough light to make further progress, as the canopy sucks it all up to feed the crowns of the trees. The babies yellow and fade. Only those seedlings close to a clearing can put on the vital first inches of growth that will give them a chance to mature into a giant. That is where a dozen or so small beech trees not much taller than I am vie to be first to fill the gap in the sky. At some stage I will have to pick a winner and thin out the rest. If I fail to do so the surviving trees will become too crowded and grow all spindly.
Squirrels
I am sitting in contemplative mood on a beech log left behind by cousin John when the bombardment begins. I cannot work it out at first. Bits of hard stuff are falling from the sky, and some of them are hitting me. Then I catch a piece as it lands: it’s a fragment of beech bark, more than a quarter of an inch thick. I am being pelted with beech bark! Protecting my eyes with spread fingers I look СКАЧАТЬ