The Fate of a Tree Seed

The ripened seeds of trees are sent forth with many strange devices and at random for the unoccupied and fertile places of the earth. There are six hundred kinds of trees in North America, and each of these equips its seeds in a peculiar way, that they may take advantage of wind, gravity, water, birds, or beasts to transport them on their home-seeking journey.

The whole seed-sowing story is a fascinating one. Blindly, often thick as snow, the seeds go forth to seek their fortune,—to find a rooting-place. All are in danger, many are limited as to time, and the majority are restricted to a single effort. A few, however, have a complex and novel equipment and with this make a long, romantic, and sometimes an adventurous journey, colonizing at last some strange land far from the place of their birth. Commonly, however, this journey is brief, and usually after one short fall or flight the seed comes to rest where it will sprout or perish. Generally it dies.

One autumn afternoon in southeastern Missouri, seated upon some driftwood on the shallow margin of the Mississippi, I discovered a primitive craft that was carrying a colony of adventurous tree seeds down the mighty river. As I watched and listened, the nuts pattered upon the fallen leaves and the Father of Waters purled and whispered as he slipped his broad yellow-gray current almost silently to the sea. Here and there a few broad-backed sandbars showed themselves above the surface, as though preparing to rise up and inquire what had become of the water.

This primitive craft was a log that drifted low and heavy, end on with the current. It was going somewhere with a small cargo of tree seeds. Upon a broken upraised limb of the log sat a kingfisher. As it drifted with the current, breezes upon the wooded hill-tops decorated the autumn air with deliberately falling leaves and floating winged seeds. The floating log pointed straight for a sand-bar upon which other logs and snags were stranded. I determined, when it should come aground, to see the character of the cargo that it carried.

Now and then, as I sat there, the heavy round nuts like merry boys came bounding and rattling down the hillside, which rose from the water's edge. Occasionally as a nut dropped from the tree-top he struck a limb spring board and from this made a long leap outward for a roll down the hillside. These nuts were walnut and hickory; and like most heavy nuts they traveled by rolling, floating, and squirrel carriage.

One nut dropped upon a low limb, glanced far outward, and landed upon a log, from which it bounced outward and went bouncing down the hillside aplunk into the river. Slowly it rolled this way and that in the almost currentless water. At last it made up its mind, and, with the almost invisible swells, commenced to float slowly toward the floating log out in the river. By and by the current caught it, carried it toward and round the sand-bar, to float away with the onsweep toward the sea. This nut may have been carried a few miles or a few hundred before it went ashore on the bank of the river or landed upon some romantic island to sprout and grow. Seeds often are carried by rivers and then successfully planted, after many stops and advances, far from the parent tree.

The log hesitated as it approached the sand-bar, as if cautiously smelling with its big, rooty nose; but at last it swung round broadside, and sleepily allowed the current to put it to bed upon the sand. As a tree, this log had lived on the banks of the Mississippi or one of its tributaries, in Minnesota. While standing it had for a time served as a woodpecker home. In one of the larger excavations made by these birds, I found some white pine cones and other seeds from the north that had been stored by bird or squirrel. A long voyage these seeds had taken; they may have continued the journey, landing at last to grow in sunny Tennessee; or they may have sunk to the bottom of the river or even have perished in the salt waters of the Gulf.

In climbing up the steep hillside above the river, I found many nests of hickory and walnuts against the upper side of fallen logs. Upon the level hill-top the ground beneath the tree was thickly covered with fallen nuts; only a few of these had got a tree's length away from the parent. Occasionally, however, a wind-gust used a long, slender limb as a sling, and flung the attached nuts afar.

The squirrels were active, laying up a hoard of nuts for winter. Many a walnut, hickory, or butternut tree at some distant place may have grown from an uneaten or forgotten nut which the squirrels carried away.

The winged seeds are the ones that are most widely scattered. These are grown by many kinds of trees. From May until midwinter trees of this kind are giving their little atoms of life to the great seed-sower, the wind. Most winged seeds have one wing for each seed and commonly each makes but one flight. Generally the lighter the seed and the higher the wind, the farther the seed will fly or be blown.

In May the silver maple starts the flight of winged seeds. This tree has a seed about the size of a peanut, provided with a one-sided wing as large as one's thumb. It sails away from the tree, settling rapidly toward the earth with heavy end downward, whirling round and round as it falls. Red maple seeds ripen in June, but not until autumn does the hard maple send its winged ones forth from amid the painted leaves.

The seed of an ash tree is like a dart. In the different ashes these are of different lengths, but all have two-edged wings which in calm weather dart the seed to the snowy earth; but in a lively wind they are tumbled and whirled about while being unceremoniously carried afar; this they do not mind, for at the first lull they right themselves and drop in good form to the earth.

Cottonwoods and willows send forth their seeds inclosed in a dainty puff or ball of silky cotton that is so light that the wind often carries it long distances. With the willow this device is so airy and dainty that it is easily entangled on twigs or grass and may never reach the earth. The willow seed, too, is so feeble that it will often perish inside twenty-four hours if it does not find a most favorable germinating-place. This makes but little difference to the willows, for they do not depend upon seeds for extension but upon the breaking off of roots or twigs by various agencies; these pieces of roots or twigs often are carried miles by streams, and take root perhaps at the first place where they go around.

The seeds of the sycamore are in balls attached to the limbs by a slender twiglet. The winter winds beat and thump these balls against the limbs, thus causing the seeds to loosen and to drop a few at a time to the earth. Each seed is a light little pencil which at one end is equipped with a whorl of hairs,—a parachute which delays its fall and thus enables the wind to carry it away from the parent tree.

The conifers—the pines, firs, and spruces—have ingeniously devised and developed their winged seeds for wind distribution. Most of these seeds are light, and each is attached to a dainty feather or wing which is used on its commencement day. These wings are as handsome as insects' wings, dainty enough for fairies; they are purple, plain brown, and spotted, and so balanced that they revolve or whirl, glinting in the autumn sun as they go on their adventurous wind-blown flight to the earth. A high wind may carry them miles.

With the pines and spruces the cones open one or a few scales at a time, so that the seeds from each cone are distributed through many days. The firs, however, carry cones that when ripe often collapse in the wind. The entire filling of seeds are thus dropped at once and fill the air with flocks of merry, diving, glinting wings. A heavy seed-crop in a coniferous forest gives a touch of poetry to the viewless air.

The lodge-pole pine is one of the most patient and philosophical seed-sowers in the forest. It is a prolific seed-producer and has a remarkable hoarding characteristic,—that of keeping its cones closed and holding on to them for years. Commonly a forest fire kills trees without consuming them. With the lodge-pole the fire frequently burns off the needles, leaving the tree standing, but it melts the sealing-wax on the cones. Thus the fire releases these seeds and they fall upon a freshly fire-cleaned soil,—a condition for them most favorable.

Although the cherry is without wings or a flying-machine of its own, it is rich enough to employ the rarest transportation in the world. With attractively colored and luscious pulp it hires many beautiful birds to carry it to new scenes. On the wings of the mockingbird and the hermit thrush,—what a happy and romantic way in which to seek the promised land!

Many kinds of pulp-covered seeds that are attractive and delicious when ripe are unpleasant to the taste while green; this protective measure guards them against being sown before they are ready or ripe. The instant persimmons are ripe, the trees are full of opossums which disseminate the ready-to-grow seeds; but Mr. 'Possum avoids the green and puckery persimmons!

The big tree is one of the most fruitful of seed-bearers. In a single year one of these may produce some millions of fertile seeds. These mature in comparatively small cones and, each seed being light as air, they are sometimes carried by high winds across ridges and ravines before being dropped to the earth.

The honey locust uses a peculiar device to secure wind assistance in pushing afar its long, purplish pods with their heavy beanlike seeds. This pod is not only flattened but crooked and slightly twisted. Dropping from the tree in midwinter, it often lands upon crusted snow. Here on windy days it becomes a kind of crude ice-boat and goes skimming along before the wind; with its flattened, twisted surface it ever presents a boosting-surface to the breeze.

The ironwood tree launches its seeds each seated in the prow of a tiny boat, which floats or careers away upon the invisible ocean of air, sinking, after a rudderless voyage, to the earth. The attachment to some seeds is bladder- or balloon-like; tied helplessly to this, the seed is cast forth briefly to wander with the wandering winds.

The linden, or basswood, tree uses a monoplane for buoyancy. The basswood attaches or suspends a number of seeds by slender threads to the centre of a leaf; in autumn when this falls it resists gravity for a time and ofttimes with its clinging cargo alights far from the tree which sent it forth.

Burr- or hook-covered seeds may become attached to the backs of animals and thus be transported afar. One day in Colorado I disturbed a black bear in some willows more than a mile from the woods; as he ran over a grassy ridge three or four pine cones that had been hooked and entangled in his hair went spinning off. Seeds sometimes are internationally distributed by becoming attached by some sticky substance—pitch or dried mud—to the legs or feathers of birds. Cottonwood seed often has a long ride, though generally a fruitless one, by alighting in the hair of some animal. Sometimes a cone or nut becomes wedged between the hoofs of an animal and is carried about for days; taken miles before it is dropped, it grows a lone tree far from the nearest grove.

Though the witch-hazel is no longer invested with eerie charms, it still has its own peculiar way of doing things. It chooses to bloom alone in the autumn, just at the time its seeds are ripe and scattering. Assisted by the frost and the sun, it scatters its shotlike seeds with a series of snappy little explosions which fling them twelve to twenty feet from the capsule in which they ripen.

The mangrove trees of Florida germinate their seeds upon the tree and then drop little plants off into the water; here winds and currents may move them hither and yon as they blindly explore for a rooting-place.

The cocoanut tree covers its nuts with a kind of "excelsior" which prevents their breaking upon the rocks. This also facilitates the floating and transportation of the nut in the sea. When the breakers have flung it upon rocks or broken reefs, here its fibrous covering helps it cling until the young roots grow and anchor it securely.

Thus endlessly during all the seasons of the year the trees are sowing their ripened seed and sending them forth, variously equipped, blindly to seek a place in which they may live, perpetuate the species, and extend the forest.

It is well that nature sows seeds like a spendthrift. So many are the chances against the seed, so numerous are the destroying agencies, so few are the places in reach that are unoccupied, that perhaps not more than one seed in a million ever germinates, and hardly one tree in a thousand that starts to grow ever attains maturity. Through sheer force of numbers and continuous seed-scattering, the necessarily random methods of nature produce results; and where opportunity opens, trees promptly extend their holdings or reclaim a territory from which they have been driven.

Many times I have wandered through the coniferous forests in the mountains when the seeds were ripe and fluttering thick as snowflakes to the earth. Visiting ridges, slopes, and caÑons, I have watched the pines, firs, and spruces closing a year's busy, invisible activity by merrily strewing the air and the earth with their fruits,—seeding for the centuries to come. One breathless autumn day I looked up into the blue sky from the bottom of a caÑon. The golden air was as thickly filled with winged seeds as a perfect night with stars. A light local air-current made a milky way across this sky. Myriads of becalmed and suspended seeds were fixed stars. Some of the seeds, each with a filmy wing, hurried through elliptical orbits like comets as they settled to the earth; while innumerable others, as they came rotating down, were revolving through planetary orbits in this seed-sown field of space. Now and then a number of cones on a fir tree collapsed and precipitated into space a meteoric shower of slow-descending seeds and a hurried zigzag fall of heavier scales. Occasionally on a ridge-top a few of the lighter seeds would come floating upward through an air-chimney as though carried in an invisible smoke-column.

One windy day I crossed the mountains when a gale was driving millions of low-flying seeds before it. Away they swept down the slope, to whirl widely and flutter over the gulch where the wind-current dashed against the uprising mountain beyond. Most of the seeds were flung to the earth along the way or dropped in the bottom of the gulch; a few, however, were carried by the swift uprushing current up and across the mountain and at last scattered on the opposite side.

When the last seed of the year has fallen, how thickly the woodland regions are sown broadcast with seeds! Only a few of these will have landed in a hospitable place. The overwhelmingly majority fell in the water to drown or on rock ledges or other places to starve or wither. The few fortunate enough to find unoccupied and fertile places will still have to reckon with devouring insects and animals. How different may be the environment of two seedlings sprung from seeds grown on the selfsame tree! On their commencement day two little atoms of life may be separated by the wind: one finds shelter and fertile earth; the other roots in a barely livable place on the cold, stormbeaten heights of timber-line. Both use their inherent energy and effort to the utmost. One becomes a forest monarch; the other a dwarf, uncouth and ugly.