Читать книгу Trees, Shown to the Children - C. E. Smith - Страница 13

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“Sweet bird of the meadow, soft be thy nest,

Thy mother will wake thee at morn from thy rest:

She has made a soft nest, little redbreast, for thee,

Of the leaves of the birch, and the moss of the tree.”

—Leyden.

The Birch tree is the daintiest and most fairy-like of all our forest trees, and, strange to say, it is one of the hardiest. Who would believe that the delicate tracery of purple twigs and branches, which looks like fairy fretwork against the grey wintry sky, could thrive in places where the sturdy Oak tree dies?

In the far, far north, in Lapland, where the ground is snow-covered all the year, the Birch tree flourishes, and many are the uses to which it is put in that dreary land.

Look at the Birch tree (1) early in the year before the sun has awakened the trees, and flowers, and seeds from their long winter sleep. It is easy to recognise, because no other tree has such delicate twigs and branches, and the colour of the trunk is peculiarly its own. Most tree trunks are grey, or grey-green, or brown, but the trunk of the Birch is covered with a silvery white bark that glistens like satin. In many places this bark is marked with dark bands which crack across the tree trunk on the silvery surface.

This silver bark is a wonderful thing. It peels off readily in large flakes which resemble tissue paper, and which look very easy to destroy, but are wonderfully tough and lasting. It burns readily, but in almost no other way can it be destroyed. If a Birch tree is blown down and left lying on the damp ground for many years, all the wood inside the silvery bark will decay, but the outside of the trunk remains unchanged. Stand on it, and you find that what you took to be a solid tree is nothing but a hollow tube of bark.

In North America the Indians cover their canoes with Birch bark, and in some snow-covered countries the people use it for tiles with which to roof their houses. Some time ago, when men were digging in the peat-bogs of Lancashire, they found the remains of Birch trees which must have been there for a thousand years. The wood had turned into stone, but the bark was still the same as when it grew on the tree.

In April the young leaves (2) cover the tree like a green mist. They are very tiny, the smallest and most fairy-like of all our tree leaves. Each leaf is oval in shape, with a glossy surface, and has a double row of teeth, first a large tooth, then a smaller one, cut unequally all round the edge. The leaf stalk is very slender and wiry, and the twig to which it is attached is very little stouter, so that the leaves dance and rustle in the slightest breath of wind. Sometimes the back of a Birch leaf is covered with fine yellow powder. This powder is really a tiny plant which has made its home on the Birch tree leaf and feeds on it, just as the ivy and mistletoe do on larger trees. In autumn these leaves turn pale yellow, and the moss and heather are strewn with their flakes of gold.

There is another stranger makes its home on some of the Birch trees. In spring, before the leaves come, you may often notice curious bunches of twigs that look like crows’ nests high up among the branches. These are caused by a tiny insect which has come to stay on the Birch tree, and, in some way which we do not understand, it makes all the twigs crowd together in that curious manner. “Witches’ Knots” they are called in Scotland.

In May the Birch tree is in flower. You know that tree flowers are not so easy to see as meadow flowers: they require to be sought for and looked at carefully if you wish to know about them. The Birch tree has two kinds of flowers, and both are needed if the seed from which new trees may grow is to be made ready. It takes the tree a whole year to prepare one kind of flower. During summer look at the foot of a leaf stalk, where it joins the twig, and you will find two tiny green stamen catkins (4) with all their soft scales tightly closed together. In autumn these little catkins become dark purple, and they hang on the tree all winter. Early in the following spring they change entirely. The scales unclose and the catkins grow longer till they look like a pair of caterpillars loosely shaking in the wind. Behind the scales in these reddy-brown caterpillars you find a mass of flowers, each made up of one tiny sepal, also two slender stamens with small yellow heads.

Now look at the other kind of flower, the seed catkin (3). These also are small and green, but they grow singly and are fatter and rounder than the stamen catkins. Their scales never open very wide, but if you look closely you will see behind each scale three little pear-shaped seed-vessels with two slender horns standing up from the top of each.

When the seeds in this catkin are ripe they resemble tiny nuts with wings on each side (5): and on windy days you can see clouds of these little winged seeds (5a) fluttering to the ground like small flies. Birds are very fond of Birch tree seeds, and one kind of finch, the siskin, is usually found hovering among the Birch trees.

The Birch tree lives till it is about a hundred years old. It is not grown up till it is twenty-five, so you will find no seeds on the young birches. It is a tree with many useful qualities. The bark is sometimes twisted into torches, as it contains a good deal of oil, and it is also used in tanning leather. The delicious scent of Russian leather is due to Birch bark oil. And there is sugar in the sap which may be made into wine. Furniture is largely made from the prettily grained Birch wood.