The Earth As Modified By Human Action Part 20

If we may credit late reports, the growth of the eucalyptus is so rapid in California, that the child is perhaps now born who will see the tallest sequoia overtopped by this new vegetable emigrant from Australia.]

European and American Trees compared.

The woods of North America are strikingly distinguished from those of Europe by the vastly greater variety of species they contain. According to Clave, there are in "France and in most parts of Europe only about twenty forest-trees, five or six of which are spike-leaved and resinous, the remainder broad-leaved." [Footnote: Etudes Forestieres, p. 7.] Our author, however, doubtless means genera, though he uses the word especes. Rossma.s.sler enumerates fifty-seven species of forest-trees as found in Germany, but some of these are mere shrubs, some are fruit and properly garden trees, and some others are only varieties of familiar species. The valuable manual of Parade describes about the same number, including, however, two of American origin--the locust, Robinia pseudacacia, and the Weymouth or white pine, Pinus Strobus--and the cedar of Lebanon from Asia, which, or at least a very closely allied species, is indigenous in Algeria also. We may then safely say that Europe does not possess above forty or fifty native trees of such economical value as to be worth the special care of the forester, while the oak alone numbers more than thirty species in the United States, [Footnote: For full catalogues of American forest-trees, and remarks on their geographical distribution, consult papers on the subject by Dr. J. G. Cooper, in the Report of the Smithsonian Inst.i.tution for 1858, and the Report of the United States Patent Office, Agricultural Division, for 1860.] and some other North American genera are almost equally diversified. [Footnote: Although Spenser's catalogue of trees occurs in the first canto of the first book of the "Faery Queene"--the only canto of that exquisite poem actually read by most students of English literature--it is not so generally familiar as to make the quotation of it altogether superfluous:

VII.

Enforst to seeke some covert nigh at hand, A shadic grove not farr away they spide, That promist ayde the tempest to withstand; Whose loftie trees, yclad with sommers pride, Did spred so broad, that heavens light did hide, Not perceable with power of any starr: And all within were pathes and alleies wide, With footing worne, and leading inward farr; Faire harbour that them seems; so in they entered ar.

VIII.

And foorth they pa.s.se, with pleasure forward led, Joying to heare the birdes sweete harmony.

Which therein shrouded from the tempest dred, Seemd in their song to scorne the cruell sky.

Much can they praise the trees so straight and hy, The sayling pine; the cedar stout and tall; The vine-propp elm; the poplar never dry; The builder oake, sole king of forrests all; The aspine good for staves; the cypresse funerall;

IX.

The laurell, meed of mightie conquerours And poets sage; the firre that weepeth still; The willow, worne of forlorn paramours; The eugh, obedient to the benders will; The birch for shaftes; the sallow for the mill; The mirrhe sweete-bleeding in the bitter wound; The warlike beech; the ash for nothing ill; The fruitfull olive; and the platane round; The carver holme; the maple seeldom inward sound.

Although the number of SPECIES of American forest-trees is much larger than of European, yet the distinguishable VARIETIES are relatively more numerous in the Old World, even in the case of trees not generally receiving special care. This multiplication of varieties is no doubt a result, though not a foreseen or intended one, of human action; for the ordinary operations of European forest economy expose young trees to different conditions from those presented by nature, and new conditions produce new forms. All European woods, except in the remote North, even if not technically artificial forests, acquire a more or less artificial character from the governing hand of man, and the effect of this interference is seen in the constant deviation of trees from the original type. The holly, for example, even when growing as absolutely wild as any tree can ever grow in countries long occupied by man, produces numerous varieties, and twenty or thirty such, not to mention intermediate shades, are described and named as recognizably different, in treatises on the forest-trees of Europe.]

While the American forest flora has made large contributions to that of Europe, comparatively few European trees have been naturalized in the United States, and as a general rule the indigenous trees of Europe do not succeed well in our climate. The European mountain-ash--which in beauty, dimensions, and healthfulness of growth is superior to our own [Footnote: In the Northern Tyrol mountain-ashes fifteen inches in diameter are not uncommon. The berries are distilled with grain to flavor the spirit.]--the horse-chestnut, and the abele, or silver poplar, are valuable additions to the ornamental trees of North America.

The Swiss arve or zirbelkiefer, Pinus cembra, which yields a well-flavored edible seed and furnishes excellent wood for carving, the umbrella-pine, [Footnote: The mountain ranges of our extreme West produce a pine closely resembling the European umbrella-pine.] which also bears a seed agreeable to the taste, and which, from the color of its foliage and the beautiful form of its dome-like crown, is among the most elegant of trees, the white birch of Central Europe, with its pendulous branches almost rivalling those of the weeping willow in length, flexibility, and gracefulness of fall, and, especially, the "cypresse funerall," might be introduced into the United States with great advantage to the landscape. The European beech and chestnut furnish timber of far better quality than that of their American congeners. The fruit of the European chestnut, though inferior to the American in sweetness and flavor, is larger, and is an important article of diet among the French and Italian peasantry. The walnut of Europe, though not equal to some of the American species in beauty of growth or of wood, or to others in strength and elasticity of fibre, is valuable for its timber and its oil. [Footnote: The walnut is a more valuable tree than is generally supposed. It yields one-third of the oil produced in France, and in this respect occupies an intermediate position between the olive of the south and the oleaginous seeds of the north. A hectare (about two and a half acres) will produce nuts to the value of five hundred francs a year, which cost nothing but the gathering.

Unfortunately, its maturity must be long waited for, and more nut-trees are felled than planted. The demand for its wood in cabinet-work is the princ.i.p.al cause of its destruction. See Lavergne, Economie Rurale de la France, p. 253.

According to Cosimo Ridolfi (Lezioni Orali, ii., p. 424), France obtains three times as much oil from the walnut as from the olive, and nearly as much as from all oleaginous seeds together. He states that the walnut bears nuts at the age of twenty years, and yields its maximum product at seventy, and that a hectare of ground, with thirty trees, or twelve to the acre, is equal to a capital of twenty-five hundred francs.

The nut of this tree is known in the United States as the "English walnut." The fruit and the wood much resemble those of the American black walnut, Juglans nigra, but for cabinet-work the American is the more beautiful material, especially when the large knots are employed.

The timber or the European species, when straight-grained, and clear, or free from knots, is, for ordinary purposes, better than that of the American black walnut, but bears no comparison with the wood of the hickory, when strength combined with elasticity is required, and its nut is very inferior in taste to that of the s.h.a.gbark, as well as to the b.u.t.ternut, which it somewhat resembles.

"The chestnut is more valuable still, for it produces on a sterile soil, which, without it, would yield only ferns and heaths, an abundant nutriment for man."--Lavergne, Economie Rurale de la France, p. 253.

I believe the varieties developed by cultivation are less numerous in the walnut than is the chestnut, which latter tree is often grafted in Southern Europe.

The chestnut crop of France was estimated in 1848 at 3,478,000 hectolitres, or 9,877,520 Winchester bushels, and valued at 13,528,000 francs, or more than two million and a half dollars. In Tuscany the annual yield is computed at about 550,000 bushels.

The Tuscan peasants think the flour of the dried chestnut not less nutritious than Indian cornmeal, and it sells at the same price, or about three cents per English pound, in the mountains, and four cents in the towns.] The maritime pine, which has proved of such immense use in fixing drifting sands in France, may perhaps be better adapted to this purpose than any of the pines of the New World, and it is of great importance for its turpentine, resin, and tar. The epicea, or common fir, Abies picea, Abies excelsa, Picea excelsa, abundant in the mountains of France and the contiguous country, is known for its product, Burgundy pitch, and, as it flourishes in a greater variety of soil and climate than almost any other spike-leaved tree, it might be well worth transplantation. [Footnote: This fir is remarkable for its tendency to cicatrize or heal over its stumps, a property which it possesses in common with some other firs, the maritime pine, and the European larch. When these trees grow in thick clumps, their roots are apt to unite by a species of natural grafting, and if one of them be felled, although its own proper rootlets die, the stump may continue, sometimes for a century, to receive nourishment from the radicles of the surrounding trees, and a dome of wood and bark of considerable thickness be formed over it. The healing is, however, only apparent, for the entire stump, except the outside ring of annual growth, soon dies, and even decays within its covering, without sending out new shoots. See Monthly Report, Department of Agriculture, for October, 1872.] The cork oak has been introduced into California and some other parts of the United States, I believe, and would undoubtedly thrive in the Southern section of the Union. [Footnote: At the age of twelve or fifteen years, the cork-tree is stripped of its outer bark for the first time. This first yield is of inferior quality, and it employed for floats for nets and buoys, or burnt for lampblack. After this, a new layer of cork, an inch or an inch and a quarter in thickness, is formed about one in ten years, and is removed in large sheets without injury to the tree, which lives a hundred and fifty years or more. According to Clave (p. 252), the annual product of a forest of cork oaks is calculated at about 660 kilogrammes, worth 150 frances, to the hectare, which, deducting expenses, leaves a profit of 100 francs. This is about equal to 250 pound weight, and eight dollars profit to the acre. The cork oaks of the national domain in Algeria cover about 500,000 acres, and are let to individuals at rates which are expected, when the whole is rented, to yield to the state revenue of about $2,000,000.

George Sand, in the Histoire de ma Vie, speaks of the cork-forests in Southern France as among the most profitable of rural possessions, and states, what I do not remember to have seen noticed elsewhere, that Russia is the best customer for cork. The large sheets taken from the trees are slit into thin plates, and used to line the walls of apartments in that cold climate. On the cultivation and management of the cork oak, see Des Incendies et de la culture du Chene-liege, in Revue das Eaux et Forets for February, 1869.] the walnut, the chestnut, the cork oak, the mulberry, the olive, the orange, the lemon, the fig, and the mult.i.tude of other trees which, by their fruit, or by other products, yield an annual revenue, nature has provided Southern Europe with a partial compensation for the loss of the native forest. It is true that these trees, planted as most of them are at such distances as to admit of cultivation, or of the growth of gra.s.s among them, are but an inadequate subst.i.tute for the thick and shady wood; but they perform to a certain extent the same offices of absorption and transpiration, they shade the surface of the ground, they serve to break the force of the wind, and on many a steep declivity, many a bleak and barren hillside, the chestnut binds the soil together with its roots, and prevents tons of earth and gravel from was.h.i.+ng down upon the fields and the gardens. Fruit-trees are not wanting, certainly, north of the Alps.

The apple, the pear, and the prune are important in the economy both of man and of nature, but they are far less numerous in Switzerland and Northern France than are the trees I have mentioned in Southern Europe, both because they are in general less remunerative, and because the climate, in higher lat.i.tudes, does not permit the free introduction of shade trees into grounds occupied for agricultural purposes. [Footnote: The walnut, the chestnut, the apple, and the pear are common to the border between the countries I have mentioned, but the range of the other trees is bounded by the Alps, and by a well-defined and sharply drawn line to the west of those mountains. From some peculiarity in the sky of Europe, cultivated plants will thrive, in Northern Italy, in Southern France, and even in Switzerland, under a depth of shade where no crop, not even gra.s.s, worth harvesting, would grow in the United States with an equally high summer temperature. Hence the cultivation of all these trees is practicable in Europe to a greater extent than would be supposed reconcilable with the interests of agriculture. Some idea of the importance of the olive orchards may be formed from the fact that Sicily alone, an island scarcely exceeding 10,000 square miles in area, of which one-third at least is absolutely barren, has exported to the single port of Ma.r.s.eilles more than 2,000,000 pounds weight olive-oil per year, for the last thirty years.

According to Cosimo Ridolfi, Lezioni Orali, vol. ii., p. 340, in a favorable soil and climate the average yield of oil from poorly manured trees, which compose the great majority, is six English pounds, while with the best cultivation it rises to twenty-three pounds. The annual production of olive-oil in the whole of Italy is estimated at upwards of 850,000,000 pounds, and if we allow twelve pounds to the tree, we have something more than 70,000,000 trees. The real number of trees is, however, much greater than this estimate, for in Tuscany and many other parts of Italy the average yield of oil per tree does not exceed two pounds, and there are many millions of young trees not yet in bearing.

Probably we shall not exaggerate if we estimate the olive trees of Italy at 100,000,000, and as there are about a hundred trees to the acre, the quant.i.ty of land devoted to the cultivation of the olive may be taken at a million acres. Although olive-oil is much used in cookery in Italy, lard is preferred as more nutritious. Much American lard is exported to South-eastern Italy, and olive-oil is imported in return.] The mult.i.tude of species, intermixed as they are in their spontaneous growth, gives the American forest landscape a variety of aspect not often seen in the woods of Europe, and the gorgeous tints, which nature repeats from the dying dolphin to paint the falling leaf of the American maples, oaks, and ash trees, clothe the hillsides and fringe the water-courses with a rainbow splendor of foliage, unsurpa.s.sed by the brightest groupings of the tropical flora. It must be confessed, however, that both the northern and the southern declivities of the Alps exhibit a nearer approximation to this rich and multifarious coloring of autumnal vegetation than most American travellers in Europe are willing to allow; and, besides, the small deciduous shrubs which often carpet the forest-glades of these mountains are dyed with a ruddy and orange glow, which, in the distant landscape, is no mean subst.i.tute for the scarlet and crimson and gold and amber of the transatlantic woodland.

[Footnote: The most gorgeous autumnal coloring I have observed in the vegetation of Europe has been in the valleys of the Durance and its tributaries in Dauphiny. I must admit that neither in variety nor in purity and brilliancy of tint, does this coloring fall much, if at all, short of that of the New England woods. But there is this difference: in Dauphiny, it is only in small shrubs that this rich painting is seen, while in North America the foliage of large trees is dyed in full splendor. Hence the American woodland has fewer broken lights and more of what painters call breadth of coloring. Besides this, the arrangement of the leaf.a.ge in large globular or conical ma.s.ses, affords a wider scale of light and shade, thus aiding now the gradation now the contrast of tints, and gives the American October landscape a softer and more harmonious tone than marks the humble shrubbery of the forest hillsides of Dauphiny.

Th.o.r.eau--who was not, like some very celebrated landscape critics of the present day, an outside spectator of the action and products of natural forces, but, in the old religious sense, an OBSERVER of organic nature, living, more than almost any other descriptive writer, among and with her children--had a very eloquent paper on the "Autumnal Tints" of the New England landscape.--See his Excursions, pp. 215 et seqq.

Few men have personally noticed so many facts in natural history accessible to unscientific observation as Th.o.r.eau, and yet he had never seen that very common and striking spectacle, the phosph.o.r.escence of decaying wood, until, in the latter years of his life, it caught his attention in a bivouac in the forests of Maine. He seems to have been more excited by this phenomenon than by any other described in his works. It must be a capacious eye that takes in all the visible facts in the history of the most familiar natural object.--The Maine Woods, p.

184.]

I admit, though not without reluctance, that the forest-trees of Central and Southern Europe have a great advantage over our own in the corresponding lat.i.tudes, in density of foliage as well as in depth of color and persistence of the leaves in deciduous species. An American, who, after a long absence from the United States, returns in the full height of summer, is painfully surprised at the thinness and poverty of the leaf.a.ge even of the trees which he had habitually regarded as specially umbrageous, and he must wait for the autumnal frosts before he can recover his partiality for the glories of his native woods.

None of our north-eastern evergreens resemble the umbrella pine sufficiently to be a fair object of comparison with it. A cedar, very common above the Highlands on the Hudson, and elsewhere, is extremely like the cypress, straight, slender, with erect, compressed ramification, and feathered to the ground, but its foliage is neither so dark nor so dense, the tree does not attain the majestic height of the cypress, nor has it the lithe flexibility of that tree. [Footnote: The cold winter, or rather spring, of 1872 proved fatal to many cypresses as well as olive trees in the Val d'Arno. The cypress, therefore, could be introduced only into California and our Southern States.] In mere shape, the Lombardy poplar nearly resembles this latter, but it is almost a profanation to compare the two, especially when they are agitated by the wind; for under such circ.u.mstances, the one is the most majestic, the other the most ungraceful, or--if I may apply such an expression to anything but human affectation of movement--the most awkward of trees.

The poplar trembles before the blast, flutters, struggles wildly, dishevels its foliage, gropes around with its feeble branches, and hisses as in impotent pa.s.sion. The cypress gathers its limbs still more closely to its stem, bows a gracious salute rather than an humble obeisance to the tempest, bends to the wind with an elasticity that a.s.sures you of its prompt return to its regal att.i.tude, and sends from its thick leaflets a murmur like the roar of the far-off ocean.

The cypress and the umbrella-pine are not merely conventional types of the Italian landscape. They are essential elements in a field of rural beauty which can be seen in perfection only in the basin of the Mediterranean, and they are as characteristic of this cla.s.s of scenery as is the date-palm of the oases of the Eastern desert. There is however, this difference: a single cypress or pine is often enough to shed beauty over a wide area; the palm is a social tree, and its beauty is not so much that of the individual as of the group. [Footnote: European poets, whose knowledge of the date-palm is not founded on personal observation, often describe its trunk as not only slender, but particularly STRAIGHT. Nothing can be farther from the truth. When the Orientals compare the form of a beautiful girl to the stem of the palm, they do not represent it as rigidly straight, but on the contrary as made up of graceful curves, which seem less like permanent outlines than like flowing motion. In a palm grove, the trunks, so far from standing planted upright like the candles of a chandelier, bend in a vast variety of curves, now leaning towards, now diverging from, now crossing, each other, and among a hundred you will hardly see two whose axes are parallel.] The frequency of the cypress and the pine--combined with the fact that the other trees of Southern Europe which most interest a stranger from the north, the orange and the lemon, the cork oak, the ilex, the myrtle, and the laurel, are evergreens--goes far to explain the beauty of the winter scenery of Italy. Indeed, it is only in the winter that a tourist who confines himself to wheel-carriages and high roads can acquire any notion of the face of the earth, and form any proper geographical image of that country. At other seasons, not high walls only, but equally impervious hedges, and now, unhappily, acacias thickly planted along the railway routes, confine the view so completely, that the arch of a tunnel, or a night-cap over the traveller's eyes, is scarcely a more effectual obstacle to the gratification of his curiosity. [Footnote: Besides this, in a country so diversified in surface as Italy, with the exception of the champaign region drained by the Po, every new field of view requires either an extraordinary coup d'oeil in the spectator, or a long study, in order to master its relief, its plans, its salient and retreating angles. In summer, except of course in the bare mountains, the universal greenery confounds light and shade, distance and foreground; and though the impression upon a traveller, who journeys for the sake of "sensations,"

may be strengthened by the mysterious annihilation of all standards for the measurement of s.p.a.ce, yet the superior intelligibility of the winter scenery of Italy is more profitable to those who see with a view to a.n.a.lyze.]

The Forest does not furnish Food for Man.

In a region absolutely covered with trees, human life could not long be sustained, for want of animal and vegetable food. The depths of the forest seldom furnish either bulb or fruit suited to the nourishment of man; and the fowls and beasts on which he feeds are scarcely seen except upon the margin of the wood, for here only grow the shrubs and gra.s.ses, and here only are found the seeds and insects, which form the sustenance of the non-carnivorous birds and quadrupeds. [Footnote: Clave, as well as many earlier writers, supposes that primitive man derived his nutriment from the spontaneous productions of the wood. "It is to the forests,"

says he, "that man was first indebted for the means of subsistence.

Exposed alone, without defence, to the rigor of the seasons, as well as to the attacks of animals stronger and swifter than himself, he found in them his first shelter, drew from them his first weapons. In the first period of humanity, they provided for all his wants: they furnished him wood for warmth, fruits for food, garments to cover his nakedness, arms for his defence."--Etudes sur l'Economie Forestiere, p. 13.

But the history of savage life, as far as it is known to us, presents man in that condition as inhabiting only the borders of the forest and the open grounds that skirt the waters and the woods, and as finding only there the aliments which make up his daily bread. The villages of the North American Indians were upon the sh.o.r.es of rivers and lakes, and their weapons and other relics are found only in the narrow open grounds which they had burned over and cultivated, or in the margin of the woods around their hamlets.

Except upon the banks of rivers or of lakes, the woods of the interior of North America, far from the habitations of man, are almost dest.i.tute of animal life. Dr. Newberry, describing the vast forests of the yellow pine of the West, Pinus ponderosa, remarks: "In the arid and desert regions of the interior basin, we made whole days' marches in forests of yellow pine, of which neither the monotony was broken by other forms of vegetation, nor its stillness by the flutter of a bird or the hum of an insect."--Pacific Railroad Report, vol. vi., 1857. Dr. Newberry's Report on Botany, p. 37.

Cheadle and Milton's North-west Pa.s.sage confirms these statements.

Valvasor says, in a paragraph already quoted, "In my many journeys through this valley, I did never have sight of so much as a single bird."

The wild fruit and nut trees, the Canada plum, the cherries, the many species of walnut, the b.u.t.ternut, the hazel, yield very little, frequently nothing, so long as they grow in the woods; and it is only when the trees around them are cut down, or when they grow in pastures, that they become productive. The berries, too--the strawberry, the blackberry, the raspberry, the whortleberry, scarcely bear fruit at all except in cleared ground.

The rank forests of the tropics are as unproductive of human aliment as the less luxuriant woods of the temperate zone. In Strain's unfortunate expedition across the great American isthmus, where the journey lay princ.i.p.ally through thick woods, several of the party died of starvation, and for many days the survivors were forced to subsist on the scantiest supplies of unnutritious vegetables perhaps never before employed for food by man. See the interesting account of that expedition in Harper's Magazine for March, April, and May, 1855.]

First Removal of the Forest.

When multiplying man had filled the open grounds along the margin of the rivers, the lakes, and the sea, and sufficiently peopled the natural meadows and savannas of the interior, where such existed, he could find room for expansion and further growth only by the removal of a portion of the forest that hemmed him in. The destruction of the woods, then, was man's first geographical conquest, his first violation of the harmonies of inanimate nature.

Primitive man had little occasion to fell trees for fuel, or for the construction of dwellings, boats, and the implements of his rude agriculture and handicrafts. Windfalls would furnish a thin population with a sufficient supply of such material, and if occasionally a growing tree was cut, the injury to the forest would be too insignificant to be at all appreciable.

The accidental escape and spread of fire or possibly, the combustion of forests by lightning, must have first suggested the advantages to be derived from the removal of too abundant and extensive woods, and at the same time, have pointed out a means by which a large tract of surface could readily be cleared of much of this natural inc.u.mbrance. As soon as agriculture had commenced at all, it would be observed that the growth of cultivated plants, as well as of many species of wild vegetation, was particularly rapid and luxuriant on soils which had been burned over, and thus a new stimulus would be given to the practice of destroying the woods by fire, as a means of both extending the open grounds, and making the acquisition of a yet more productive soil. After a few harvests had exhausted the first rank fertility of this virgin mould, or when weeds and briers and the sprouting roots of the trees had begun to choke the crops of the half-subdued soil, the ground would be abandoned for new fields won from the forest by the same means, and the deserted plain or hillock would soon clothe itself anew with shrubs and trees, to be again subjected to the same destructive process, and again surrendered to the restorative powers of vegetable nature. [Footnote: In many parts of the North American States, the first white settlers found extensive tracts of thin woods, of a very park-like character, called "oak-openings,"

from the predominance of different species of that tree upon them. These were the semi-artificial pasture-grounds of the Indians, brought into that state, and so kept, by partial clearing, and by the annual burning of the gra.s.s. The object of this operation was to attract the deer to the fresh herbage which sprang up after the fire. The oaks bore the annual scorching at least for a certain time; but if it had been indefinitely continued, they would very probably have been destroyed at last. The soil would have then been much in the prairie condition, and would have needed nothing but grazing for a long succession of years to make the resemblance perfect. That the annual fires alone occasioned the peculiar character of the oak-openings, is proved by the fact that as soon as the Indians had left the country, young trees of many species sprang up and grew luxuriantly upon them. See a very interesting account of the oak-openings in Dwight s Travels, iv., pp. 58-63. This rude economy would be continued for generations, and, wasteful as it is, is still largely pursued in Northern Sweden, Swedish Lapland, and sometimes even in France and the United States. [Footnote: The practice of burning over woodland, at once to clear and manure the ground, is called in Swedieh svedjande, a participial noun from the verb att svedja, to burn over. Though used in Sweden as a preparation for crops of rye or other grain, it is employed in Lapland more frequently to secure an abundant growth of pasturage, which follows in two or three years after the fire; and it is sometimes resorted to as a mode of driving the Laplanders and their reindeer from the vicinity of the Swedish backwoodsman's gra.s.s-grounds and hay-stacks, to which they are dangerous neighbors. The forest, indeed, rapidly recovers itself, but it is a generation or more before the reindeer-moss grows again. When the forest consists of pine, tall, the ground, instead of being rendered fertile by this process, becomes hopelessly barren, and for a long time afterwards produces nothing but weeds and briers.--Laestadius, Om Uppodlingar i Lappmarken, p. 15. See also Schubert, Resa i Sverge, ii., p. 375.

In some parts of France this practice is so general that Clave says: "In the department of Ardennes it (le sartage) is the basis of agriculture."]

Princ.i.p.al Causes of the Destruction of the Forest.

The needs of agriculture are the most familiar cause of the destruction of the forest in new countries; for not only does an increasing population demand additional acres to grow the vegetables which feed it and its domestic animals, but the slovenly husbandry of the border settler soon exhausts the luxuriance of his first fields, and compels him to remove his household G.o.ds to a fresher soil. The extent of cleared ground required for agricultural use depends very much on the number and kinds of the cattle bred. We have seen, in a former chapter, that, in the United States, the domestic quadrupeds amount to more than a hundred millions, or nearly three times the number of the human population of the Union. In many of the Western States, the swine subsist more or less on acorns, nuts, and other products of the woods, and the prairies, or natural meadows of the Mississippi valley, yield a large amount of food for beast, as well as for man. With these exceptions, all this vast army of quadrupeds is fed wholly on gra.s.s, grain, pulse, and roots grown on soil reclaimed from the forest by European settlers. It is true that the flesh of domestic quadrupeds enters very largely into the aliment of the American people, and greatly reduces the quant.i.ty of vegetable nutriment which they would otherwise consume, so that a smaller amount of agricultural product is required for immediate human food, and, of course, a smaller extent of cleared land is needed for the growth of that product, than if no domestic animals existed. But the flesh of the horse, the a.s.s, and the mule is not consumed by man, and the sheep is reared rather for its fleece than for food. Besides this, the ground required to produce the gra.s.s and grain consumed in rearing and fattening a grazing quadruped, would yield a far larger amount of nutriment, if devoted to the growing of breadstuffs, than is furnished by his flesh; and, upon the whole, whatever advantages may be reaped from the breeding of domestic cattle, it is plain that the cleared land devoted to their sustenance in the originally wooded part of the United States, after deducting a quant.i.ty sufficient to produce an amount of aliment equal to their flesh, still greatly exceeds that cultivated for vegetables, directly consumed by the people of the same regions; or, to express a nearly equivalent idea in other words, the meadow and the pasture, taken together, much exceed the ploughland. [Footnote: The two ideas expressed in the text are not exactly equivalent, because, though the consumption of animal food diminishes the amount of vegetable aliment required for human use, yet the animals themselves consume a great quant.i.ty of grain and roots grown on ground ploughed and cultivated as regularly and as laboriously as any other.

The 280,000,000 bushels of oats raised in the United States in 1870, and fed to the 7,000,000 horses, the potatoes, the turnips, and the maize employed in fattening the oxen, the sheep, and the swine slaughtered the same year, occupied an extent of ground which, cultivated by hand-labor and with Chinese industry and skill, would probably have produced a quant.i.ty of vegetable food equal in alimentary power to the flesh of the quadrupeds killed for domestic use. Hence, so far as the naked question of AMOUNT of aliment is concerned, the meadows and the pastures might as well have remained in the forest condition. It must, however, be borne in mind that animal labor, if not a necessary, is probably an economical, force in agricultural occupations, and that without animal manure many branches of husbandry could hardly be carried on at all. At the same time, the introduction of machinery into rural industry, and of artificial, mineral, and fossil manures, is working great revolutions, and we may find at some future day that the ox is no longer necessary as a help to the farmer.]