Part 10

Trees do not change their clothes, and they do not move away. Day after day, if we use our eyes and notice what is going on in the tree tops, as the seasons follow each other, we come to know our trees by name; we recognise them in winter by their bark, and by the framework of their tops, in summer by leaves and flowers, in autumn by their changing colour and by their fruits. It is not hard work for those who love trees. It is like getting acquainted with other neighbours whom we are glad to count among our friends.

TREES WE KNOW BY THEIR SHAPES

The life of every tree depends upon its success in holding its leaves out into the sunlight. The tree which exposes the greatest amount of leaf surface to the sun makes the greatest growth. The shape of their tops is a character in which trees differ widely. We shall come to know many of them in winter time better than in summer, by the distinct shapes revealed when the foliage is gone. In any bare tree, the purpose of all of the branching and branching again, is plainly seen. Each twig and branch reaches out toward the outer surface of the dome, or pyramid. Here the buds in winter are waiting to open, when spring comes, into leafy shoots. These will cover the tree top with a dome of green greater than the one of the previous summer. Their work through the growing season will lengthen every branch and every root, and add a layer of wood under the bark of trunks and branches and roots.

The most remarkable tree shape is that of the Lombardy poplar. The tall trunk is clothed with many short, close-branched limbs, which do not spread, as in ordinary tree forms, but grow upright, so as to lie almost against the main trunk. The upper branches are overlapped and crowded by those below them, and so on down the trunk. The result is a tree shaped like a capital I. In summer time, the heart-shaped leaves cover the twigs on the outside of this spire, but the beauty of the tree top is marred by the dead branches which have been smothered by the crowding.

A young Lombardy poplar is handsome as it stands covered with its twinkling leaves. It grows rapidly, and is especially striking and effective in clumps of round-headed trees. It is like an exclamation point. Architects always like to have a few of these trees dotted about the grounds to keep company with tall chimneys and distant church spires. There is no shade under trees of this form, though miles of them are planted along roadsides where they stand like tin soldiers, all alike. The older trees look very ragged, for they are unable to shed their dead limbs, and as old age comes on they send up suckers from the roots that form a little forest around the parent tree.

Scattered over fallow fields of worthless ground, the red cedars are allowed to grow. They are the evergreen counterparts of the slim Lombardy poplars. Sometimes the red cedar broadens into a pyramid, wide at the base, but we are all familiar with the green exclamation points, dotted over the hillsides, wherever birds have dropped the blue berries full of seeds.

The pointed firs with their horizontal branches becoming longer and longer towards the ground, are good examples of the pyramid form so common among evergreens. This is the shape of the spruces, and the pines, and the hemlocks, until storms have broken their branches, and taken away the symmetry of the top. The pin oak and the honey locust send out horizontal branches of graduated lengths from the central shaft, imitating the evergreens in shape.

The evergreen magnolia of the South has a dome like an old-fashioned beehive, pyramidal, and regular when it grows in sheltered places. Such a dome is the hard maple’s in the North.

Some trees branch low, and their short trunks break into great limbs whose ample spread forms a dome much broader than its height. The white oak in the North and its evergreen counterpart, the live oak of the South, illustrate this noble form. Somewhat like them, but with its dome elevated upon a tall trunk, is the American elm with the fan top. The lines of the elm branches are all curves from the arching limbs that rise out of the trunk to the flexible twigs which droop at the extremities of the branches. The dome of a white oak is made of angular limbs. Even the twigs are likely to be crooked. No one would confuse the elm with an oak.

Round-headed trees are many. Go from the apple tree in the orchard to the red and Norway maples along our streets. A great many trees find this form best adapted to spreading their leaves out towards the sun. Many oaks and ash trees, the hickories and birches, and the beeches have widely spreading limbs forming tops that are oblong in shape. There are trees so irregular in habits of growth that we shall never know them by their forms alone.

The winter is the best time to study tree shapes, for then the framework is revealed. The trees to study are those which stand apart from others, so that they have been able to take their natural shapes. These we shall find growing on the streets, and in yards, and parks, and in open spaces in the woods. Where trees crowd each other in growing, their branches chafe and clash in storms, destroying the buds and leaves, and bruising the tender bark. Such limbs die of these injuries, and the whole shape of the tree top is changed by its losses.

It is hopeless for lower limbs to live in a dense pine forest. The top branches form so thick a wall of shade that lower branches die from lack of sun. It is the same with broad-leaved trees. In any dense woods, the trees stand bare as telegraph poles, lifting small heads of foliage at the top, and competing there with their neighbour trees for sun and air. It is only when set apart from other trees that a trunk can keep its lower branches hale and strong as those at the top.

The weeping habit gives us some strange tree forms. The Camperdown elm forms a shady summer-house on many a lawn by arching limbs which droop to the ground on all sides of the main trunk. The weeping mulberry has the same habit. Weeping birches and willows have such light foliage, and such fine, flexible twigs, that they look like fountains of green as they stand among the other trees.

All weeping trees are made by grafting in the nursery rows. They are not grown from seeds, and it is not true that they “weep” because of being planted up-side-down! This preposterous notion is not uncommon.

TREES WE KNOW BY THEIR THORNS

In winter time, the bare limbs of trees reveal many strange secrets, which the leaves cover up in summer. Some trees we may know by the thorns they wear.

The honey locust scarcely conceals in summer the three-branched thorns, for which it is famous. These thorns are twigs, but they rarely bear leaves. Each is sharpened to a needle point, and highly polished. Sometimes it is single, oftener with a main thorn and two side branches; sometimes short, but often reaching over a foot in length, and growing stronger and more wicked-looking with age. Sometimes a honey locust has a crowded group of these thorns growing out of the trunk and large limbs. Once in a great while a honey locust is thornless, growing wild. From such trees a thornless variety has been developed. It is, therefore, possible to obtain from nurserymen trees of this variety.

The unbranched spines of the osage orange trees make it a formidable hedge plant, and no fences are needed where green barriers of these trees grow. Each shining leaf has a spike at its base, stout and sharp as a needle, and strong as steel.

Two spines stand guard at the base of each leaf of the yellow or black locust, and each leaflet has two little spines of the same type. The basal spines remain after the leaves fall, so that in winter we shall find these pairs of sentinels guarding the leaf scars up and down the ridged twigs. On the thicker stems the thorns are larger, and the tree is thus well-armed and able to do duty as a hedge plant, when thickly planted.

These thorns come off with the bark, hence they are more properly called prickles. They are not rooted in the wood of the branch as the thorns of the honey locust are, but they belong in the class with rose and raspberry prickles, which are mere outgrowths of the bark.

The hawthorn trees have single spines, some long and curved, some short, some branched. All are rooted in the pith of the twig that bears them; therefore, they are not prickles, but true thorns.

The wild plum trees have a strange habit of ending their shoots with thorny tips, as if the branches needed such defence against browsing cattle. Certainly these stunted, sharp-pointed twigs are useful as weapons of defence to the little trees that grow slowly in poor soil, and are sufferers from poverty and abuse. Perhaps it is their hard luck that makes them crabbed and thorny. Wild apple trees show the same tendency to have thorny twigs. The same little trees, transplanted to mellow soil, grow soft and leafy twigs, and abandon the carrying of weapons.

Hercules’ club is a tree which beats the ailanthus at its own game. Stems ten feet high and two inches in diameter at the base sometimes shoot up in a single season. These clubs of Hercules are covered with spines as thickly set as on a gooseberry bush, formidable and vicious, though only skin deep.

On account of its tropical growth, this tree is planted for ornament in gardens where there is room. Its leaves are wonderful. They come out with a rich, silky, bronze sheen in spring, and when they reach full size are often four feet long, and more than half as wide. Each one is branched and branched again, and ends in a multitude of small oval leaflets. These giant leaves sway in the summer winds, giving the tree the grace of a tree fern. In late summer a great pyramid of bloom rises above the foliage. Purplish berries, which succeed the flowers, make a fine showing in fall and winter, when the leaves have turned to red and gold.

We dare not touch this spiny tree, but we may come close and admire its wonderful crown of umbrella leaves, the biggest by far borne on any tree outside of the Tropics.

THE NEEDLE-LEAVED EVERGREENS

In our town and in our neighbourhood most of the trees drop their leaves before winter comes, and stand with bare limbs for several months. Here and there, however, a single tree stands, wearing the same green leaves it wore all summer. Everybody knows this tree as an evergreen. It belongs to a group of trees strangely different from those around it which have shed their leaves. Let us see how it differs from them.

Take the one that is nearest to you, and pull down one of its leafy, green branches. The leaves are like green needles, stiff, sharp-pointed, with waxy resin on the brown twigs, that makes your fingers sticky. Up in the tree tops strange oval, brown cones are hanging. Underfoot, a carpet of dead needles lies thick upon the grass, and cones, with their overlapping scales spread much wider than those upon the tree, lie about. Squirrels have gnawed some of these scales away, leaving a central spike like a cob from which the corn has been shelled. Little green cones, fat and waxy, no larger than your thumb, are seen near the tips of some branches. You can see the scales overlapping each other in these, even though they seem to be grown solidly together.