The Earth as Modified by Human Action

by George P. Marsh

The legislation of European states upon sylviculture, and the practice of that art, divide themselves into two great branches—the preservation of existing forests, and the creation of new. Although there are in Europe many forests neither planted nor regularly trained by man, yet from the long operation of causes already set forth, what is understood in America and other new countries by the "primitive forest," no longer exists in the territories which were the seats of ancient civilization and empire, except upon a small scale, and in remote and almost inaccessible glens quite out of the reach of ordinary observation. The oldest European woods are indeed native, that is, sprung from self-sown seed, or from the roots of trees which have been felled for human purposes; but their growth has been controlled, in a variety of ways, by man and by domestic animals, and they almost uniformly present more or less of an artificial character and arrangement. Both they and planted forests—which, though certainly not few, are of comparatively recent date in Europe—demand, as well for protection as for promotion of growth, a treatment different in some respects from that which would be suited to the character and wants of the virgin wood.

On this latter branch of the subject, the management of the primitive wood, experience and observation have not yet collected a sufficient stock of facts to serve for the construction of a complete system of this department of sylviculture; but the government of the forest as it exists in France—the different zones and climates of which country present many points of analogy with those of the United States and of some of the British colonies—has been carefully studied, and several manuals of practice have been prepared for the foresters of that empire. I believe the Cours Elementaire de Culture des Bois cree a l'Ecole Forestiere de Nancy, par M. Lorentz, complete et public par A. Parade, with a supplement under the title of Cours d'Amenagement des Forets, par Henri Nanquette, has been generally considered the best of these. The Etudes sur l'Economie Forestiere, par Jules Clave, which I have often quoted, presents a great number of interesting views on this subject, but it is not designed as a practical guide, and it does not profess to be sufficiently specific in its details to serve that purpose. [Footnote: Among more recent manuals may be mentioned: in French, Les Etudes de Maitre Pierre, Paris, 1864, 12mo; Bazelaire, Traite de Roboisement, 2d edition. Paris 1864; Paston, L'Amenagemend des Forets, Paris, 1867; in English, Gregor, Arboriculture, Edinburgh, 1868: in Italian, Siemoni 's very valuable Manuale teorico-pratico d'Arte Forestale, 2d ediz., Firenze, 1872; the excellent work of Cerini, Dei Vantaggi di Societe, por l'Impianto e Conservazione dei Boschi, Milano, 1844, 8vo; and the prize essay of Meguscher, Memoria sui Boschi, etc., 2d edizione, Milano, 1859, 8vo. Another very important treatise of the uses of the forest, though not a manual of sylviculture, is Schleiden, Fur Baum und Wald, Leipzig, 1870.]Notwithstanding the difference of conditions between the aboriginal and the trained forest, the judicious observer who aims at the preservation of the former will reap much instruction from the treatises I have cited, and I believe he will be convinced that the sooner a natural wood is brought into the state of an artificially regulated one, the better it is for all the multiplied interests which depend on the wise administration of this branch of public economy.

One consideration bearing on this subject has received less attention than it merits, because most persons interested in such questions have not opportunities for the comparison I refer to. I mean the great general superiority of cultivated timber to that of strictly spontaneous growth. I say GENERAL superiority, because there are exceptions to the rule. The white pine, Pinus strobus, for instance, and other trees of similar character and uses, require, for their perfect growth and best ligneous texture, a density of forest vegetation around them, which protects them from too much agitation by wind, and from the persistence of the lateral branches which fill the wood with knots. A pine which has grown under those conditions possesses a tall, straight stem, admirably fitted for masts and spars, and, at the same time, its wood is almost wholly free from knots, is regular in annular structure, soft and uniform in texture, and, consequently, superior to almost all other timber for joinery. If, while a large pine is spared, the broad-leaved or other smaller trees around it are felled, the swaying of the tree from the action of the wind mechanically produces separations between the layers of annual growth, and greatly diminishes the value of the timber. The same defect is often observed in pines which, from some accident of growth, have much overtopped their fellows in the virgin forest.

The white pine, growing in the fields, or in open glades in the woods, is totally different from the true forest-tree, both in general aspect and in quality of wood. Its stem is much shorter, its top less tapering, its foliage denser and more inclined to gather into tufts, its branches more numerous and of larger diameter, its wood shows much more distinctly the divisions of annual growth, is of coarser grain, harder and more difficult to work into mitre-joints. Intermixed with the most valuable pines in the American forests, are met many trees of the character I have just described. The lumbermen call them "saplings," and generally regard them as different in species from the true white pine, but botanists are unable to establish a distinction between them, and as they agree in almost all respects with trees grown in the open grounds from known white-pine seedlings, I believe their peculiar character is due to unfavorable circumstances in their early growth. The pine, then, is an exception to the general rule as to the inferiority of the forest to the open-ground tree. The pasture oak and pasture beech, on the contrary, are well known to produce far better timber than those grown in the woods, and there are few trees to which the remark is not equally applicable. [Footnote: It is often laid down as a universal law, that the wood of trees of slow vegetation is superior to that of quick growth. This is one of those commonplaces by which men love to shield themselves from the labor of painstaking observation. It has, in fact, so many exceptions, that it may be doubted in whether it is in any sense true. Most of the cedars are slow of growth; but while the timber of some of them is firm and durable, that of others is light, brittle, and perishable. The hemlock-spruce is slower of growth than the pines, but its wood is of very little value. The pasture oak and beech show a breadth of grain—and, of course, an annual increment—twice as great as trees of the same species grown in the woods; and the American locust, Robinia pseudacacia, the wood of which is of extreme toughness and durability, is, of all trees indigenous to North-eastern America, by far the most rapid in growth. Some of the species of the Australian Eucalyptus furnish wood of remarkable strength and durability, and yet the eucalyptus is surpassed by no known tree in rapidity of growth.

As an illustration of the mutual interdependence of the mechanic arts, I may mention that in Italy, where stone, brick, and plaster are almost the only materials used in architecture, and where the "hollow ware" kitchen implements are of copper or of clay, the ordinary tools for working wood are of a very inferior description, and the locust timber is found too hard for their temper. At the same time the work of the Italian stipettai, or cabinet-makers, and carvers in wood, who take pains to provide themselves with tools of better metal, is wholly unsurpassed in finish and in accuracy of adjustment as well as in taste. When a small quantity of mahogany was brought to England, early in the last century, the cabinet-makers were unable to use it, from the defective temper of their tools, until the demand for furniture from the new wood compelled them to improve the quality of their implements. In America, the cheapness of wood long made it the preferable material for almost all purposes to which it could by any possibility be applied. The mechanical cutlery and artisans' tools of the United States are of admirable temper, finish, and convenience, and no wood is too hard, or otherwise too refractory, to be wrought with great facility, both by hand-tools and by the multitude of ingenious machines which the Americans have invented for this purpose.]

Another advantage of the artificially regulated forest is, that it admits of such grading of the ground as to favor the retention or discharge of water at will, while the facilities it affords for selecting and duly proportioning, as well as properly spacing, and in felling and removing, from time to time, the trees which compose it, are too obvious to require to be more than hinted at. In conducting these operations, we must have a diligent eye to the requirements of nature, and must remember that a wood is not an arbitrary assemblage of trees to be selected and disposed according to the caprice of its owner. "A forest," says Clave, "is not, as is often supposed, a simple collection of trees succeeding each other in long perspective, without bond of union, and capable of isolation from each other; it is, on the contrary, a whole, the different parts of which are interdependent upon each other, and it constitutes, so to speak, a true individuality. Every forest has a special character, determined by the form of the surface it grows upon, the kinds of trees that compose it, and the manner in which they are grouped." The art, or, as the Continental foresters rather ambitiously call it, the science of sylviculture has been so little pursued in England and America, that its nomenclature has not been introduced into the English vocabulary, and it would not be possible to describe its processes with technical propriety of language, without occasionally borrowing a word from the forest literature of France and Germany. A full discussion of the methods of sylviculture would, indeed, be out of place in a work like the present, but the want of conveniently accessible means of information on the subject, in the United States, will justify me in presenting it with somewhat more of detail than would otherwise be pertinent.

The two best known methods of treating already existing forests are those distinguished as the TAILLIS, copse or coppice treatment, [Footnote: COPSE, or COPPICE, from the French COUPER, to cut, means properly a wood, the trees of which are cut at certain periods of immature growth, and allowed to shoot up again from the roots; but it has come to signify, very commonly, a young wood, grove, or thicket, without reference to its origin, or to the character of a forest crop.] and the FUTAIE, for which I find no English equivalent, but which may not inappropriately be called the FULL-GROWTH system. A TAILLIS, copse, or coppice, is a wood composed of shoots from the roots of trees previously cut for fuel and timber. The shoots are thinned out from time to time, and finally cut, either after a fixed number of years, or after the young trees have attained to certain dimensions, their roots being then left to send out a new progeny as before. This is the cheapest method of management, and therefore the best whenever the price of labor and of capital bears a high proportion to that of land and of timber; but it is essentially a wasteful economy. [Footnote: "In America," says Clave (p. 124, 125), "where there is a vast extent of land almost without pecuniary value, but where labor is dear and the rate of interest high, it is profitable to till a large surface at the least possible cost. EXTENSIVE cultivation is there the most advantageous. In England, France, and Germany, where every corner of soil is occupied, and the least bit of ground is sold at a high price, but where labor and capital are comparatively cheap is wisest to employ INTENSIVE cultivation. … All the efforts of the cultivator ought to be directed to the obtaining of a given result with the least sacrifice, and there is equally a loss to the commonwealth if the application of improved agricultural processes be neglected where they are advantageous, or if they be employed where they are not required. … In this point of view, sylviculture must follow the same laws as agriculture, and, like it, be modified according to the economical conditions of different states. In countries abounding in good forests, and thinly peopled, elementary and cheap methods must be pursued; in civilized regions, where a dense population requires that the soil shall be made to produce all it can yield, the regular artificial forest, with all the processes that science teaches, should be cultivated. It would be absurd to apply to the endless woods of Brazil and of Canada the method of the Spessart by "double stages," but not less so in our country, where every yard of ground has a high value, to leave to nature the task of propagating trees, and to content ourselves with cutting, every twenty or twenty-five years, the meagre growths that chance may have produced.">[ If the woodland is, in the first place, completely cut over as is found most convenient in practice, the young shoots have neither the shade nor the protection from wind so important to forest growth, and their progress is comparatively slow, while at the same time, the thick clumps they form choke the seedlings that may have sprouted near them. [Footnote: In ordinary coppices, there are few or no seedlings, because the young shoots are cut before they are old enough to mature fertile seed, and this is one of the strongest objections to the system.] The evergreens, once cut do not shoot up again, [Footnote: It was not long ago stated, upon the evidence of the Government foresters of Greece, and of the queen's gardener, that a large wood has been discovered in Arcadia, consisting of a fir which has the property of sending up both vertical and lateral shoots from the stump of felled trees and forming a new crown. It was at first supposed that this forest grew only on the "mountains," of which the hero of About's most amusing story, Le Roi des Montagnes, was "king;" but stumps, with the shoots attached, have been sent to Germany, and recognized by able botanists as true natural products, and the fact must now be considered as established. Daubeny refers to Theophrastus as ascribing this faculty of reproduction to the 'Elate [word in greek] or fir, but he does not cite chapter and verse, and I have not been able to find the passage. The same writer mentions a case where an entire forest of the common fir in France had been renewed in this way.—Trees and Shrubs of the Ancients, 1865, pp. 27-28. The American Northern pitch possesses the same power in a certain degree.

According to Charles Martins, the cedar of Mount Atlas—which, if not identical with the cedar of Lebanon, is closely allied to it—possesses the same power.—Revue des Deux Mondes, July 15, 1864, p. 315.] and the mixed character of the forest—in many respects an important advantage, if not an indispensable condition of growth—is lost; [Footnote: Natural forests are rarely, if ever, composed of trees of a single species, and experience has shown that oaks and other broad-leaved trees, planted as artificial woods, require to be mixed, or associated with others of different habits.

In the forest of Fontainebleau, "oaks, mingled with beeches in due proportion," says Clave, "may arrive at the age of five or six hundred years in full vigor, and attain dimensions which I have never seen surpassed; when, however, they are wholly unmixed with other trees, they begin to decay and die at the top, at the age of forty or fifty years, like men, old before their time, weary of the world, and longing only to quit it. This has been observed in most of the oak plantations of which I have spoken, and they have not been able to attain to full growth. When the vegetation was perceived to languish, they were cut, in the hope that this operation would restore their vigor, and that the new shoots would succeed better than the original trees; and, in fact, they seemed to be recovering for the first few years. But the shoots were soon attacked by the same decay, and the operation had to be renewed at shorter and shorter intervals, until at last it was found necessary to treat as coppices plantations originally designed for the full-growth system. Nor was this all: the soil, periodically bared by these cuttings, became impoverished, and less and less suited to the growth of the oak. … It was then proposed to introduce the pine and plant with it the vacancies and glades.

"… By this means, the forest was saved from the ruin which threatened it, and now more than 10,000 acres of pines, from fifteen to thirty years old are disseminated at various points, sometimes intermixed with broad-leaved trees, sometimes forming groves by themselves"—Revue des Deux Mondes, Mai, 1863, pp. 153, 154.] and besides this, large wood of any species cannot be grown in this method because trees which shoot from decaying stumps and their dying roots, become hollow or otherwise unsound before they acquire their full dimensions. A more fatal objection still, is, that the roots of trees will not bear more than two or three, or at most four cuttings of their shoots before their vitality is exhausted, and the wood can then be restored only by replanting entirely.