Trees Worth Knowing Part 10

leaves twinkle and dance and catch the sunlight like ripples on the surface of a stream, while the foliage of oaks and other trees near by may be practically motionless.

=The Balsam Poplar=

_P. balsamifera_, Linn.

The balsam poplar is the balm of Gilead of the early settlers, the Tacamahac of the Northern Indians. They squeezed the fragrant wax from the winter buds and used it to seal up the seams in their birch-bark canoes. The bees taught the Indian the uses of this glutinous secretion, which the tree used to seal the bud-scales and thus keep out water. When growth starts with the stirring of the sap, this wax softens; then the bees collect and store it against a day of need.

Whether their homes be hollow trees or patent hives, weather-cracks are carefully sealed up with this waterproof gum, which the bee-keeper knows as "_propolis_."

Forests of balm of Gilead cover much of the vast British possessions north of the United States, and reach to the ultimate islands of the Aleutian group. They dip down into the states as far as Nebraska and Nevada. In cultivation, the species has proved itself a tree of excellent habit, easily propagated and transplanted, and of rapid growth. It has all the good points of the Carolina poplar and lacks its besetting sin of becoming so soon an unsightly cripple.

=Narrow-leaved Cottonwood=

_P. angustifolia_, James.

=Lance-leaved Cottonwood=

_P. ac.u.minata_, Rydb.

=Mexican Cottonwood=

_P. Mexicana_, Wesm.

These three cottonwoods line the banks of mountain streams at high elevations in the great system of mountain chains that stretch from British Columbia southward. The dancing foliage, bright green in summer, golden in autumn, lends a charming color note to the dun stretches of arid plain and the sombre green of pine forests. These trees furnish the settler fuel, shade, and wind-breaks while he is converting his "homestead" into a home.

=Black Cottonwood=

_P. trichocarpa_, Hook.

Farther west, covering the mountain slopes from Alaska to Mexico, and liking even better the moist, rich lowlands, is the black cottonwood, the giant of the genus, reaching two hundred feet in height, and seven to eight feet in trunk diameter. Tall and stately, it lifts its broad rounded crown upon heavy upright limbs. In the Yosemite the dark, rich green of these poplar groves along the Merced River makes a rich, velvet margin, glorious when it turns to gold in autumn.

=Swamp Cottonwood=

_P. heterophylla_, Linn.

The swamp cottonwood of the South has leaves of variable but distinctly poplar form, always large, broadly ovate, with slim round petioles. The white down of the unfolding leaves often persists into midsummer. On account of the fluttering leaves the trees were called, by the early Acadians, "_Langues de femmes_" a mild calumny traceable to the herbalist, Gerarde, who compares them to "women's tongues, which seldom cease wagging."

The wood of poplars, soft, weak, and of slight value for fuel or lumber, has within two decades come into a position of great economic importance. Wood pulp is made of it, and out of wood pulp a thousand articles, from toys to wheels of locomotives, are made. A state forester declared: "If I could replace the maples in the state forest by poplars to-day, I would do it gladly. It would be worth thousands of dollars to the state."

THE WILLOWS

Along the watercourses the willow family finds its most congenial habitat. It is a very large family, numbering more than one hundred and seventy species, which are, however, mostly shrubs rather than trees. America has seventy species of willows, and new forms are constantly being discovered, which are the results of the crossing of closely related species. These "natural hybrids" have greatly confused the botany of the willow family.

Not more than half a dozen American willows ever attain the height of good-sized trees, and many of these are more commonly found in the tangled shrubbery of river banks, or covering long semi-arid strips of ground far to the north, or on mountain sides where their growth is stunted. Little trees, six inches high, bearing the characteristic catkins and narrow leaves of the willow, are found on the arctic tundras.

The wood of willows is pale in color, soft in texture, and of very little use as lumber or fuel, except in localities where trees are scarce. The Indian depended upon the inner bark of the withy willow for material for his fish nets and lines, and farmers in the pioneer days took the tough, supple stems, when spring made the sap run freely, for the binding together of the rails of their fences. Knotted tight and seasoned, these twigs hardened and lasted for years.

In Europe the white willow has long been used for the making of wooden shoes, artificial limbs, and carriage bodies. Its wood makes the finest charcoal for gunpowder. Willow wares, such as baskets and wicker furniture, are as old as civilization, and that in its primitive stages. It is a common sight in Europe to see groves of trees from which the long twigs have been taken yearly for these uses.

The stumps are called "pollards" and the trees "pollarded willows"

whose discouraging task has been to grow a yearly crop of withes for the basket-makers; yet each spring finds them bristling with the new growth.

The hosts of Caesar invading England in the First Century found the Britons defending themselves behind willow-woven s.h.i.+elds, and living in huts of wattled willows, smeared with mud. From that time to the present the uses of these long shoots have multiplied.

The roots of willows are fibrous and tough as the shoots. For this reason they serve a useful purpose in binding the banks of streams, especially where these are liable to flood. Nature seems to have designed these trees for just this purpose, for a twig lying upon the ground strikes root at every joint if the soil it falls on is sufficiently moist. The wind breaks off twigs and the water carries them down stream where they lodge on banks and sand bars, and these are soon covered with billows of green.

Willows start growth early in spring, putting out their catkins, the two s.e.xes on different trees, before the opening of the leaves. Before the foliage is full grown, the light seeds, each a minute speck, floats away in a wisp of silky down. Its vitality lasts but a day, so it must fall on wet ground at once in order to grow. But the willow family is quite independent of its seeds in the matter of propagation.

Chop the roots and twigs into bits and each will grow. Chop a young willow tree into sticks and fence posts and each one, if it is stuck green into the ground, covers itself with a head of leafy twigs before the season is over.

=Weeping Willow=

_Salix Babylonica_

The weeping willow, much planted in cemeteries and parks, came originally from Asia and is remarkable for its narrow leaves that seem fairly to drip from the pendulous twigs. (_See ill.u.s.tration, page 55._) The foliage has a wonderful lightness and cheerfulness of expression, despite its weeping habit.

=The p.u.s.s.y Willow=

_S. discolor_, Muehl.

The p.u.s.s.y willow is the familiar bog willow, whose gray, silky catkins appear in earliest spring. A walk in the woods in late February often brings us the charming surprise of a meeting with this little tree, just when its gray p.u.s.s.ies are pus.h.i.+ng out from their brown scales. We cut the twigs and bring them home and watch the wonderful color changes that mark the full development of the flowers. Turning them in the light, one sees under the sheen of silky hairs the varied and evanescent hues that glow in a Hungarian opal. In midsummer a p.u.s.s.y willow tree is lost among the shrubby growth in any woods. It is only because it leads the procession of the spring flowers that every one knows and loves it. (_See ill.u.s.trations, pages 86-87._)

THE HORNBEAMS

Two genera of little trees in the same family with the birches are frequently met in the woods, often modestly hiding under the larger trees. One is the solitary representative of its genus: the other has a sister species.

The hornbeams grow very slowly and their wood is close-grained, heavy, and hard. In flexibility, strength, and ability to stand strain, it rivals steel. Before metals so generally became compet.i.tors of woods in construction work, hornbeam was the only wood for rake teeth, levers, mallets, and especially for the beams of ox yokes. It outwore the stoutest oak, the toughest elm. Springiness adapted it for fork handles and the like. Bowls and dishes of hornbeam lasted forever, and would never leak nor crack. "Ironwood" is the name used wherever the wood was worked.

=American Hornbeam=

_Carpinus Carolinianum_, Walt.

The American hornbeam has bluish gray bark, very fine in texture, from which the name "blue beech," is common in some localities. "Water beech" points out the tree's preference for rich swamp land.

The trunk and limbs are strangely swollen, sometimes like a fluted column, oftener irregularly, the swelling under the bark suggesting the muscular development of a gymnast's arm.

In favorable places the hornbeams grow into regular oval heads, their branches dividing into a mult.i.tude of wiry, supple twigs. Crowded under oaks and other forest growth, they crouch and writhe; and their heads flatten into tangled ma.s.ses of foliage.

The delicate leaves, strong-ribbed, oval, pointed, turn to red and orange in autumn. (_See ill.u.s.tration, page 87._) The paired nutlets are provided with a parachute each, so that the wind can sow them broadcast. This wing is leafy in texture, shaped like a maple leaf, and curved into the shape of a boat. After they have broken apart, the nutlets hang by threads, tough as hornbeam fibres always are. At last, away they sail, to start new trees if they fall in moist soil.

The European hornbeam was a favorite tree for making the "pleached alleys," of which old-world garden-lovers were proud. A row of trees on each side of a promenade were pruned and trained to cover an arching framework, and to interlace their supple branches so that at length no other framework was needed, and one walked through a tunnel of green so closely interlaced as to make walls and roof that shut out light and wind and rain! Hedges, fences, and many fancies of the gardener were worked out with this hornbeam, so willingly did it lend itself to cutting and moulding into curious forms.