Next to the oak, the two hardwood trees which are most useful are the ash and the elm. Both these trees grow in the hedgerows as well as in the open fields, and they both blossom quite early in the year, before they put forth their leaves.
You may know Ash stems anywhere, even in winter, by two things. First by the tips of its branches, which are flat, as if they had been pressed under a weight. And secondly by its black buds shaped like little pyramids (see p. 65). No other tree has black buds like these. The trunk is an ash-grey colour, and the branches grow very gracefully, first dipping down from the boughs and then tilting up again like the horns of a deer.
In April the ash-buds on the side branches near to the tip begin to open out into clusters of purple-black flowers (2). Each flower is very small. It has no flower-leaves, nothing but a seed-box and two purple stamens. But these tiny flowers are so closely crowded that the whole tree is coloured by them.
Then, at the end of May, the leaf-buds begin to open. The leaves grow opposite to each other on the branches, and each leaf (1) is cut into seven or more leaflets, with an odd one at the end. Many leaves are cut up like this, and you might think each leaflet was a leaf. But if they were leaves, a bud would grow at the base of each, near the stem, and there would be a growing tip at the end. So when there are neither of these you may know that all the leaflets make up one leaf; and when it fades, the whole falls off together.
All through the summer the tree is very beautiful, and its bluish-grey leaves differ from those of any other tree. But early in the autumn they turn yellow and fall. Then you will know the tree by its curious long, flat, narrow fruits (3), which hang in groups from the branches like bunches of keys. In fact, they are called "keys." They hang on sometimes quite into the winter, till the rough winds tear them off.
You may often find a young ash-tree growing in your garden, for they are very hardy. But rabbits are fond of eating the young seedlings, so they have not much chance to grow. Young ash stems are often used for walking-sticks and hop-poles, and the wood, when full-grown, sells very well for coach-building and for making furniture.
We all know Elm-trees so well that perhaps you may think that there is nothing interesting to learn about them. But I wonder if you have noticed that the twigs of an elm grow on the trunk almost to the bottom of the tree unless they are lopped off. And I am almost sure that many of you do not know that the twigs are often covered with little lumps of cork, making the branch look as if it were diseased.
It is really quite healthy, but it tells a secret, namely, that the elm has a very corky bark. Even on the trunk the cork is thick and rugged, and on the small branches it has no room to spread, and has to lie in lumps. The inner part of the bark called the "liber" is very tough, and is used for making mats and ropes.
The common elm, which so often grows in rows between the fields, or is planted on the village green, was brought to England by the Romans. It is not quite at home even now, for its seeds do not ripen, except in very hot summers, and new trees have to be planted from suckers.
The real old elm of England is the Wych elm or Scotch elm. It has not such a tall trunk as the common elm, for its big branches grow out much lower down. Its leaves are bigger, and its seeds ripen and grow, when they are sown. But it is not very common in our country and grows chiefly in Scotland, Wales, and the West of England.
Even in winter you can count a great number of buds on the elm, and when April comes, if you look up through the boughs, you will see a purple tinge all over the top of the tree. This is caused by the tiny purple flowers which burst out on the twigs. Now watch the tree. At the end of April the fresh green leaves peep out of the leaf-buds. But already the seed-boxes are beginning to fall and are blown into heaps by the wind.
I am sure you must know these little, flat, green plates, with a lump in the middle where the seed lies. They are blown along the fields, and often down the village street, filling the gutters. If they fall from the Common elm it is very doubtful whether they will grow. But if you have a Wych elm on the green, you may know its seed-boxes, because the seed always lies quite in the middle of the plate, while in the common elm it lies nearer the point. These seeds are ripe and worth sowing.
There are a great many kinds of elm in England, very like each other, but it is easy to know the Cornish elm because it grows such a great deal of cork on its twigs. All the big forest elms are very useful for timber. They sometimes live for four or five hundred years, but the best time for cutting them down is when they are about one hundred and twenty years old.
A great many insects feed on the elm. The most destructive one is a beetle which eats its way down to the inner bark, and sucks the sap. Then the mother beetle works her way down about two inches and makes little galleries all along the tube on each side. In each gallery she lays an egg, and the grubs when they are hatched eat the wood. The trees of whole forests have been killed by this "elm-destroying beetle."
Bring an ash branch to look at the twigs and buds. Find a bunch of ash-keys. Find the corky twigs of the elm, and the green seed-plates in May. Look in decayed elms for the galleries of the elm-destroying beetle.