TREES WE KNOW BY THEIR SHAPES The life of every tree depends upon its suc cess in holding its leaves out into the sun light. 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 bet ter than in summer, by the distinct shapes re vealed 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 pre vious summer. Their work through the grow ing 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 up right, 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 ef fective 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 chim neys 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 Lom bardy poplars. Sometimes the red cedar broad ens 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 com mon among evergreens. This is the shape of the spruces, and the pines, and the hemlocks, un til 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, imi tating 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 irregu lar 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.