Part 9

It is good fun to lie under a maple tree, and watch the seeds as they fall. If the wind is strong, they shower down like rain. Each key separates from its mate, and as it lets go its hold on the twig, the wind catches its thin wing, and sends it whirling round and round. The heavy seed makes for the earth, while the flat blade above it acts as a parachute, or a sail, to keep it in the air.

How far does a silver maple send its seeds in these summer days, when they are falling? It is easy to answer this question by pacing the distance from the tree trunk in a straight line to the point where the farthest key falls. Go in the direction towards which the wind is blowing, in determining this distance. It will be interesting to run out another line from the tree trunk to find out how far the seeds are thrown on the side that is against the wind.

From the silver maple go to a red maple, and watch the harvest of these small-winged keys. Do a little measuring here, and find out if their smaller size and weight enables these seeds to sail further in the same breeze than those of the silver maple.

The sugar maple is known also as the rock or hard maple, because its wood is harder, and therefore slower to grow, than the two quick-growing soft maples just described. This is the one whose trunk is tapped in spring, and the sap boiled down in great kettles over an open fire in the woods. When the water is all evaporated, solid cakes of maple sugar remain. If you are walking in the woods in winter, and come upon any trees bored with small auger holes, several near the base of each trunk, you may suspect that this is a grove of hard maples which the New England farmer calls his “sugar bush.”

Look at the twigs, and you will see that the plump round buds are set opposite, and the twigs are opposite on the branch. This is the way with all maple trees. Are the branches many, and do they shoot upward rather than outward, and form an oval head? This is the typical habit of young hard maple trees. As they grow older the heavy lower limbs become horizontal. They are clean, hardy, vigorous trees, long-lived, dependable, able to meet the storms, and to suffer the theft of their rich sap every spring without apparent loss of strength and vitality.

The leaves come out later than those of the soft maples. They are firm, and broad, with five pointed lobes between wide fissures that reach half-way to the stem. Margins of these lobes are wavy, never saw-toothed, like those of the silver maple. They are dark green above, with paler linings. In autumn they turn to yellow, orange, and red.

The flowers open in May, shortly after the leaves appear. They are in thick, hairy, yellowish clusters. Some are pistillate, some staminate, in the same cluster. Those with the forked pistils remain and grow into smooth fruits towards the end of summer. The keys of sugar maples are short-winged, like those of the red maple, but have stouter, thicker seeds. They are shed in late autumn and early winter.

Hard maples are among the best of shade trees, and the glory of their autumn colouring makes them one of the most to be desired among trees planted merely for ornament. A street planted to hard maples is well planted always. But people are impatient for trees to grow up. The slow growth of the sugar maple is discouraging. It is a good plan to plant the quick-growing soft maples, and alternate with them the slow-growing species. For a few years the soft maples are pretty, and with each year’s growth they give more abundant shade. By the time the wind has crippled their long arms, and made the trees unsightly, the hard maples are coming on to take their places, and they need the room which is given them by the removal of their neighbours on to the left and right.

When I went into the woods of Oregon, I found the vine maple trees, which seems not to have sufficient backbone to stand upright. These trees start to grow erect, but their weight soon overcomes their strength, and they droop, but keep on growing, with their limbs prostrate on the ground. The wet land in many places was covered with a network of the interfering branches of these serpentine maple trees.

The leaf is about the size of the palm of my hand, and almost circular. The border is cut into many shallow lobes. The seeds are characteristic keys, smooth, and the wings of each pair are spread almost opposite each other.

The Norway maple is a most popular street tree. Its foliage is very dense, and the tree forms a round, symmetrical head. The broad, five-lobed leaves are remotely toothed, smooth, thin, and dark green on both sides. Break a leaf stem, and a milky juice appears. The seeds are very flat, and have broad, flaring wings. The flowers are yellowish. Great clusters of them come out with the leaves. The seeds are ripe in autumn.

We shall find that the foliage of the Norway maple stands the wear and tear better than that of many shade trees. The crown of a Norway maple turns to bright gold in autumn, and most of the leaves are still unmarred when they fall.

The box elder is the one native maple which has compound leaves. The leaf blade is cleft quite to the stem, and the thirds form separate leaflets, each mounted on its own stalk. These leaves are set opposite on the twigs, like those of other maples.

In spring pink fringes like corn silk decorate the branches of certain box elder trees. Other trees of the same kind hide little green flowers among the opening leaves. The pink fringes are the pollen-bearing flowers, which fall when ripe. Staminate trees never bear fruit. All through the summer the trees which bore the greenish flower are dangling clusters of pale green seeds, each with the peculiar wing, which proves it a maple. When the ragged, yellowing foliage falls, these seed clusters remain on the branches, and all through the winter the wind is plucking and carrying them away.

The wood of box elder is very soft. The tree is planted because it grows so quickly and surely, and its seeds are so easily obtained. But broken branches give the older trees a crippled, unhappy look, and the ragged clusters of seeds give them a disheveled appearance all winter. Fortunate is the man who has planted elms or hard maples along the road, so that he may take out the decrepit box elders, and have the better trees coming on to take their places.

The striped maple is a little tree, which hides in the woods, and only a few people know the tree, and love it as it deserves. The stripes are on its smooth green bark, which breaks into a network of furrows as the stems increase in diameter. These furrows expose a very pale under-bark, so that at a short distance the trunk seems to be delicately traced with white lines.

In its blossoming season the striped maple has a loose, drooping cluster of yellow, bell-like flowers. The leaves that surround them are broad and shallowly three-lobed, and saw-toothed all around. The seeds are little maple keys, smaller than those of the red maple.

The mountain maple is another little tree quite as modest and retiring as its striped cousin. It has longer, more taper-pointed leaves. The flower clusters are much smaller than those of the striped maple, and they stand erect. The fruits hang late in the winter, on the grey downy twigs, which are brightened by red buds.

THE WILLOW FAMILY

One of the first tree families whose name we learn is the willow family. The members are numerous, and the botanists find great difficulty in distinguishing certain species, which closely resemble each other; but these troubles we shall leave to the scientist. The point for us to consider is this: When we see a tree which we know to be a willow, _how_ do we know it? “It looks like a willow,” some one says. But who knows, and can tell _how_ willows look—how they differ from other trees?

First, willows have slender, flexible twigs that give the tree tops grace and lightness. Second, willow leaves are nearly always long and slim to match the supple twigs. They are always simple, and short-stemmed. The wood is light and soft, so the trees break easily in storms of wind and ice. An old willow tree is likely to be crippled, but its scars and wounds are covered in summer by the arching branches and the abundant foliage.

The first trees to blossom in spring are the shrubby pussy willows, a distinct kind whose catkins are so eager to push out of their scales that their grey, silky noses are often seen in November. Frequently, they are out and the scales dropped in February; but the yellow stamens and the long-tongued pistils do not rise above the grey fur until March, at least. The most attractive stage of these catkins is the earlier one, when the flower buds are concealed by the grey silk.

By cutting pussy willow twigs in the late fall, or any time during the winter, and putting them into a jar of water, we may see the blossoming, quite out of season. Sufficient food is stored in the twig to force out the blossoms, even to the shedding of the pollen. It is a charming thing in the winter to have a vase of these twigs in full bloom on a window sill when snow banks are piled high just outside.

Willows are lovers of wet ground, and we shall see groves of them scattered along streams and on the margins of ponds and swamps. A few species thrive in dry soil, and seem to prefer it. Some grow at sea level, others are found on high mountains. From small shrubs they vary to mighty trees. There is no climate and no soil that does not have its native willows. The family is distributed from the Equator to the Arctic Circle.

It is very common in many places for farmers to plant a grove of willows for a windbreak, to protect their houses and barns. This is especially seen in prairie states and other treeless regions. Willows are quick-growing trees, and sure to grow. All one needs do is to cut limbs from a growing tree, chop these limbs into pieces the length of stove wood, and drive them into the ground. Each one takes root, and grows into a tree, if the soil is at all moist.

Another plan is to cut fence posts from the willow grove, and drive them into the ground. Each of these posts forms the trunk of a willow tree, which soon has a great head of branches.

In Holland and other countries, willows are thickly planted to form hedges and for their roots to hold the soil along the banks of streams and ditches. The same trees may perform a double service. Willow wood makes good summer fuel, where a quick, hot fire is desired. The twigs make the best charcoal used in the manufacture of gunpowder. The long, flexible twigs of a low-growing willow are used in the manufacture of wicker chairs, tables, and other furniture. These trees are grown on a large scale in France and other European countries, and the industry is being introduced in some parts of America.

When spring comes on, we may notice a peculiar change in the colour of the bare willows that line the stream borders. The twigs turn gradually green, and the long, pointed buds prepare to cast off their single scales. These are shaped like the long, knitted caps which children wear in winter time, although there is no tassel at the end. The cap fits snugly over the long bud, and is fastened in a circle at the joint. The swelling bud simply pushes it off.

Under these trees, we shall find a good many fresh twigs. Reaching up to break one, we find that it snaps off short at the base. It is not brittle along its whole length. Try a dozen twigs, and off they snap, almost at a touch. The wind has broken off those that fell to the ground. Some that fall in the water, float away down stream. They catch on sandbars, and strike root. Some swing in to the shore, and grow on the banks.

We have discovered a habit of certain kinds of willow trees. The shedding of their twigs at the season when they are fullest of life is the tree’s method of colonising new territory. These twigs float away, and blow away, and those which lodge in wet ground before they dry are almost sure to grow. The billowy acres of green which cover sandbars and stream borders are willow trees, children of parents that grow far up stream.

Along roadsides in this country a large willow is much planted, whose leaves are pale beneath, so that they look very cheerful and cool in midsummer. The most striking thing about these willows is that their twigs are yellow as ducks’ feet, and particularly bright in early spring. The older trees grow very stout, and great branches leave the trunk close to the ground. This is the golden osier willow, one form of the white willow of Europe, which does not grow vigorously in this country.

The weeping willows, whose long, supple branches sweep out and downward, sometimes yards in length, from the tree top, came originally from Babylon. Who were they in that far country who “hung their harps on the willow trees”? A great many weeping willows in the Eastern states are said to be sprung from the parent tree, which grew on the Island of St. Helena. What famous prisoner probably sat under the shadows of this willow tree, and dreamed again of conquering the world? The weeping willow has the habit of snapping its twigs off, short, at the base. One of these long withes, cut into bits with one or two buds on each cutting, will start as many weeping willow trees, if the bits are stuck into wet sand and kept wet until rooted, and then set out and given plenty of water until they become established in the ground.

The black willow is named for the black bark of the old tree. It is the only one of the narrow-leaved willows whose leaves are uniformly green on both sides. These leaves are often curved like a sickle. At the base of each leaf is a pair of heart-shaped, leafy blades, called stipules. Many trees have stipules that come out with the leaves, and are dropped off, but these persist, as a rule, all summer. The black willow is one of those with the twigs that snap. It takes possession of stream borders, and its offspring may cover miles of new territory in a single season.

The balsam willow we shall know by the fragrant coating of wax, or balsam, on its young shoots and buds. Its broad leaves are blunt at the tip, and look scarcely willow-like, but the tree is known by its buds and its catkins. To find it we shall have to go into the boggy regions in the Northern tier of states, where it is numerous, but never more than a shrubby tree.

One use is served by no tree as well as a willow. When the sap rises in spring, the willow branches are in prime condition to make whistles. I wonder if there is a boy, in town or country, who does not know how to make a willow whistle that will “go”? Surely not, unless his supply of uncles and grandfathers is short. You cannot make a willow whistle by following printed directions. Some skilful person, who has been a boy, must show you, and one lesson is enough.

WHY TREES NEED LEAVES

Spring or early summer is the best time to study the leaves of trees. They are clean, and fresh, and new. Every tree is a great mound of green. The broad-leaved trees seem to be thatched or shingled with overlapping blades so that no sunlight can get into the darkened room, which is empty except for the bare branches that support this outer dome of leaves. A sugar maple, or a linden tree, shows best this outer thatch, which is so thick that the sun is unable to look through. The bird flying overhead sees only a solid mass of leaves. The one on its nest in a forked limb looks up and sees the inside of this leafy tree cover. She is glad for the twilight that surrounds her, and for the coolness of this shady place; but more glad that her nest is hidden from sight of hawks that sail overhead, while she keeps a close watch for sly, thieving red squirrels that may come to steal her eggs, by climbing up the branches.

What are the leaves for? Why does the tree put out in spring young shoots with rows of leaves along their sides? Why does the tree hold these branches out as far as possible from the trunk, and bend the leaf stems and the twigs so as to face the leaf blades towards the sun?

The reason is this: the life of the trees is in the green layer which we see on the surface of all green shoots, and which we can discover under the older bark of twigs, which has turned brown. Following the twig back from its tip, all of the leafy part is green. Behind it the smooth twig is no longer green, but a thumb nail easily strips off the layer of brown, and reveals the green under bark. Go a little further back, and gradually the outer bark thickens, and it is more difficult to get at the soft under layer. After a while, we shall need a knife to reach it, for old bark is hard and tough.

When the bark gets so thick that the sun cannot reach the green layer, the colour fades out. The living part of the trunk of the tree is the soft, juicy layer between the bark and wood. Through this portion of the tree the sap rises from the roots, and finally reaches the leaves. This sap needs to be changed before it can be useful to the tree as food.

The leaves are the places where these changes take place. Through little doorways in the under sides of the leaf air passes in. With it goes carbonic acid gas, an important food element. The soft green leaf pulp, which is the green juice of a bruised leaf, has a wonderful work to do. It cannot do this work unless the sun is shining upon it. On a bright day every leaf is making starch, and sending it down through the twigs and branches as food. This starch is contained in the sugary sap that flows back constantly from the leaves to the farthest root tips. It is made in the leaves out of the sap brought up from the roots and the carbonic acid gas which the leaves absorb from the air.

As long as the leaves do their work, the tree is able to grow, and to blossom, and to ripen its seeds. When the leaves have done their work the summer has passed; the tree lets go the leaves, and rests without growing all winter.

It is not easy to explain the work of the leaves, nor even to understand the wonderful work accomplished there all through the summer. When we eat, our food must go into the stomach to be changed by the processes called digestion. It is hours before the digested food is poured into the blood and carried to all parts of the body. The tree takes its food from the air, and from the soil. Neither the dirty water that rises as sap to the leaves, nor the gas which enters the leaf doorways from the air, is useful as food to the growing tree until they have been combined and changed. The leaves are, then, in a sense, the stomachs of the trees, for in them the raw foods must be “digested” before they are ready to be poured into the life blood that flows down through all the live parts of the tree. Now they are fit to feed the growing cells, which are always hungry.

LEAVES OF ALL SHAPES AND SIZES

The leaf of the tree is its visiting card. We shall learn to know trees by their leaves, as easily as if the name were written across the face of the leaf. Some leaves have a single blade of green, and for this reason the botanist calls them _simple_ leaves. This blade has a stem that unites it with the twig. A _compound_ leaf is one whose stem bears more than one blade. These small blades are called _leaflets_. There are two types of compound leaves, one feather-like, having a main stem with leaflets arranged in two rows on opposite sides of this stem. Such a leaf is feather-like. The other type has a leaf stem with all the leaflets attached at one end. The horse chestnut is the best example of this type. The leaves spread from the end of the stalk somewhat as the fingers rise from the palm of your hand.

The biggest leaves with single blades to be found in our forests grow on trees of the magnolia family. The silver-lined leaves of the large-leaved cucumber tree are over a foot in length, sometimes two and one-half feet, down South. These great leaves are about one-fourth as wide as long, and at the base each one broadens and extends backward into two rounded ear-like lobes. This gives the tree the name, ear-leaved magnolia. The whole leaf flaps in the wind, like the ear of an elephant, and, of course, the wind lashes it into strings and soon robs it of its beauty.

The Northern cucumber tree is another magnolia whose leaves are tropical-looking. This is the hardiest of the magnolia family, and its heart-shaped leaves are six to ten inches long. They are not large for a magnolia of the South, but they look larger because they grow among the small-leaved trees of the Northern states.

The tulip tree has a large leaf of peculiar form. It is broad like a maple leaf at the base, but at the tip it is cut off square as if with a pair of shears, forming a right angle with its straight sides. Sometimes the leaf is notched, as if a V-shaped piece were cut out of the square tip. These leaves are long-stemmed, their blades polished, and they flutter on the twigs with the lightness of a poplar leaf. Once we have in mind the form of the leaf of the tulip tree, we shall never forget it, for it is different from all other leaves.

The catalpa tree, which lifts its great blossom clusters above the foliage in late June, is another of the few large-leaved trees of the North. The single blade is heart-shaped, six to eight inches long, and more than half as broad. These leaves usually have plain margins, but sometimes they are wavy and notched near the base so as to produce faint side lobes. The blades hang on long, stout stems.

Among the feather-leaved trees, the walnuts and butternuts, the sumachs, and the ailanthus, furnish examples. A black walnut leaf is often two feet long, with a dozen or more leaflets on the longest ones. These leaflets are always set opposite in pairs, with an odd one on the tip of the leaf stem. Butternut leaves have the same form, but the leaves are longer. They range from fifteen to thirty inches, and have from ten to twenty leaflets, but always an odd number. The peculiar gummy feeling of these hairy leaves, and their pungent butternut odour when bruised, make it easy to know the tree wherever we meet it, through the long summer.

The hickories are cousins of the walnuts, but their leaves, though of the feather form, have larger and fewer leaflets than any walnut tree. A shagbark hickory leaf has one or two pairs of little leaflets on the stem, and above them three of larger size. The pignut has the same habit of clustering its three largest leaves at the tip of the leaf stem, and tapering off at the base with one or two pairs of decreasing size.

The largest of all the compound leaves have branched stems to which leaflets are attached. The main leaf stem’s side branches may yet branch again, forming a twice-branched framework that is set with leaflets, not large, but so numerous as to make the whole leaf surprisingly large. The greatest of these twice-compound leaves is borne by that astonishing, spiny-stemmed Hercules’ club. A single leaf is often four feet long, and nearly a yard wide. There are no leaflets on the main stem; they are on the side branches.

How shall we tell a leaf stem from a twig? Leaf stems do not look like the twigs of the tree. A little practice in looking closely and comparing these leaf stems and twigs will obviate any confusion of the two. The leaf has a bud at its base, and it breaks off easily at this joint.