If there is any truth in the theory of a desiccating action in evergreen trees, plantations of this sort might have a value as drainers of lands not easily laid dry by other processes. There is much ground on the great prairies of the West, where experiments with this method of planting are strongly to be recommended.
It is common in Europe to permit the removal of the fallen leaves and fragments of bark and branches with which the forest-soil is covered, and sometimes the cutting of the lower twigs of evergreens. The leaves and twigs are princ.i.p.ally used as litter for cattle, and finally as manure, the bark and wind-fallen branches as fuel. By long usage, sometimes by express grant, this privilege has become a vested right of the population in the neighborhood of many public and even large private forests; but it is generally regarded as a serious evil. To remove the leaves and fallen twigs is to withdraw much of the pabulum upon which the tree was destined to feed. The small branches and leaves are the parts of the tree which yield the largest proportion of ashes on combustion, and of course they supply a great amount of nutriment for the young shoots. "A cubic foot of twigs," says Vaupell, "yields four times as much ashes as a cubic foot of stem wood. ... For every hundred weight of dried leaves carried off from a beech forest, we sacrifice a hundred and sixty cubic feet of wood. The leaves and the mosses are a subst.i.tute, not only for manure, but for ploughing. The carbonic acid given out by decaying leaves, when taken up by water, serves to dissolve the mineral const.i.tuents of the soil, and is particularly active in disintegrating feldspar and the clay derived from its decomposition. ...
The leaves belong to the soil. Without them it cannot preserve its fertility, and cannot furnish nutriment to the beech. The trees languish, produce seed incapable of germination, and the spontaneous self-sowing, which is an indispensable element in the best systems of sylviculture, fails altogether in the bared and impoverished soil."
[Footnote: Vaupell, Bogens Indvandring i de Danske Skove, pp. 29, 46.
Vaupell further observes, on the page last quoted: "The removal of leaves is injurious to the forest, not only because it r.e.t.a.r.ds the growth of trees, but still more because it disqualifies the soil for the production of particular species. When the beech languishes, and the development of its branches is less vigorous and its crown less spreading, it becomes unable to resist the encroachments of the fir.
This latter tree thrives in an inferior soil, and being no longer stifled by the thick foliage of the beech, it spreads gradually through the wood, while the beech retreats before it and finally perishes."
Schleiden confirms the opinion of Vaupell, and adds many important observations on this subject.--Fur Baum und Wald, pp. 64, 65.]
Besides these evils, the removal of the leaves deprives the soil of much of that spongy character which gives it such immense value as a reservoir of moisture and a regulator of the flow of springs; and, finally, it exposes the surface-roots to the drying influence of sun and wind, to accidental mechanical injury from the tread of animals or men, and, in cold climates, to the destructive effects of frost.
Protection against Wild Animals.
It is often necessary to take measures for the protection of young trees against the rabbit, the mole, and other rodent quadrupeds, and of older ones against the damage done by the larvae of insects hatched upon the surface or in the tissues of the bark, or even in the wood itself. The much greater liability of the artificial than of the natural forest to injury from this cause is perhaps the only point in which the superiority of the former to the latter is not as marked as that of any domesticated vegetable to its wild representative. But the better quality of the wood and the much more rapid growth of the trained and regulated forest are abundant compensations for the loss thus occasioned, and the progress of entomological science will, perhaps, suggest new methods of preventing the ravages of insects. Thus far, however, the collection and destruction ofthe eggs, by simple but expensive means, has proved the most effectual remedy. [Footnote: I have remarked elsewhere that most insects which deposit and hatch their eggs in the wood of the natural forest confine themselves to dead trees. Not only is this the fact, but it is also true that many of the borers attack only freshly-cut timber. Their season of labor is a short one, and unless the tree is cut during this period, it is safe from them. In summer you may hear them plying their augers in the wood of a young pine with soft, green bark, as you sit upon its trunk, within a week after it has been felled, but the windfalls of the winter lie uninjured by the worm and even undecayed for centuries. In the pine woods of New England, after the regular lumberman has removed the standing trees, these old trunks are hauled out from the mosses and leaves which half cover them, and often furnish excellent timber. The slow decay of such timber in the woods, it may be remarked, furnishes another proof of the uniformity of temperature and humidity in the forest, for the trunk of a tree lying on gra.s.s or ploughland, and of course exposed to all the alternations of climate, hardly resists complete decomposition for a generation. The forests of Europe exhibit similar facts. Wessely, in a description of the primitive wood of Neuwald in Lower Austria, says that the windfalls required from 150 to 200 years for entire decay.--Die Oesterreichischen Alpenlander und ihre Forste, p. 312.
The comparative immunity of the American native forests from attacks by insects is perhaps in some degree due to the fact that the European destructive tribes have not yet found their way across the ocean, and that our native species are less injurious to living trees. On the European lignivorous insects, see Siemoni, Manuale d"Arte Forestale, 2d edizione, pp. 369-379.]
Exclusion of Domestic Quadrupeds.
But probably the most important of all rules for the government of the forest, whether natural or artificial, is that which prescribes the absolute exclusion of all domestic quadrupeds, except swine, from every wood which is not destined to be cleared. No growth of young trees is possible where horned cattle, sheep, or goats, or even horses, are permitted to pasture at any season of the year, though they are doubtless most destructive when trees are in leaf. [Footnote: Although the economy of the forest has received little attention in the United States, no lover of American nature can have failed to observe a marked difference between a native wood from which cattle are excluded and one where they are permitted to browse. A few seasons suffice for the total extirpation of the "underbrush," including the young trees on which alone the reproduction of the forest depends, and all the branches of those of larger growth which hang within reach of the cattle are stripped of their buds and leaves, and soon wither and fall off. These effects are observable at a great distance, and a wood-pasture is recognized, almost as far as it can be seen, by the regularity with which its lower foliage terminates at what Ruskin somewhere calls the "cattle-line." This always runs parallel to the surface of the ground, and is determined by the height to which domestic quadrupeds can reach to feed upon the leaves. In describing a visit to the grand-ducal farm of San Rossore near Pisa, where a large herd of camels is kept, Chateauvieux says: "In pa.s.sing through a wood of evergreen oaks, I observed that all the twigs and foliage of the trees were clipped up to the height of about twelve feet above the ground, without leaving a single spray below that level. I was informed that the browsing of the camels had trimmed the trees as high as they could reach." F. Lullin De Chateuvieux, Lettres sur l"Italie, p. 118.
Browsing animals, and most of all the goat, are considered by foresters as more injurious to the growth of young trees, and, therefore, to the reproduction of the forest, than almost any other destructive cause.
According to Beatson"s Saint Helena, introductory chapter, and Darwin"s Journal of Researches in Geology and Natural History, pp. 582, 583, it was the goats which destroyed the beautiful forests that, three hundred and fifty years ago, covered a continuous surface of not less than two thousand acres in the interior of the island [of St. Helena], not to mention scattered groups of trees. Darwin observes: "During our stay at Valparaiso, I was most positively a.s.sured that sandal-wood formerly grew in abundance on the island of Juan Fernandez, but that this tree had now become entirely extinct there, having been extirpated by the goats which early navigators had introduced. The neighboring islands, to which goats have not been carried, still abound in sandal-wood."
In the winter, the deer tribe, especially the great American moose-deer, subsists much on the buds and young sprouts of trees; yet--though from the destruction of the wolves or from some not easily explained cause, these latter animals have recently multiplied so rapidly in some parts of North America, that, not long since, four hundred of them are said to have been killed, in one season, on a territory in Maine not comprising more than one hundred and fifty square miles--the wild browsing quadrupeds are rarely, if ever, numerous enough in regions uninhabited by man to produce any sensible effect on the condition of the forest. A reason why they are less injurious than the goat to young trees may be that they resort to this nutriment only in the winter, when the gra.s.ses and shrubs are leafless or covered with snow, whereas the goat feeds upon buds and young shoots princ.i.p.ally in the season of growth. However this may be, the natural law of consumption and supply keeps the forest growth, and the wild animals which live on its products, in such a state of equilibrium as to insure the indefinite continuance of both, and the perpetuity of neither is endangered until man interferes and destroys the balance.
When, however, deer are bred and protected in parks, they multiply like domestic cattle, and become equally injurious to trees. "A few years ago," says Clave, "there were not less than two thousand deer of different ages in the forest of Fontainebleau. For want of gra.s.s, they are driven to the trees, and they do not spare them ... It is calculated that the browsing of these animals, and the consequent r.e.t.a.r.dation of the growth of the wood, diminishes the annual product of the forest to the amount of two hundred thousand cubic feet per year, ... and besides this, the trees thus mutilated are soon exhausted and die. The deer attack the pines, too, tearing off the bark in long strips, or rubbing theie heads against them when shedding their horns; and sometimes, in groves of more than a hundred hectares, not one pine is found uninjured by them."--Revue des Deux Mondes, Mai, 1863, p. 157.
Vaupell, though agreeing with other writers as to the injury done to the forest by most domestic animals and by half-tamed deer--which he ill.u.s.trates in an interesting way in his posthumous work, The Danish Woods--thinks, nonetheless, that at the season when the mast is falling, swine are rather useful than otherwise to forests of beech and oak, by treading into the ground and thus sowing beechnuts and acorns, and by destroying moles and mice.--De Danake Skore, p. 12. Meguschor is of the same opinion, and adds that swine destroy injurious insects and their larvae.--Memoria, etc., p. 233.
Beckstein computes that a park of 2,500 acres, containing 250 acres of marsh, 250 of fields and meadows, and the remaining 2,000 of wood, mny keep 364 deer of different species, 47 wild boars, 200 hares, 100 rabbits, and an indefinite number of pheasants. These animals would require, in winter, 123,000 pounds of hay, and 22,000 pounds of potatoes, besides what they would pick up themselves. The natural forest most thickly peopled with wild animals would not, in temperate climates, contain, upon the average, one-tenth of these numbers to the same extent of surface.]
These animals browse upon the terminal buds and the tender branches, thereby stunting, if they do not kill, the young trees, and depriving them of all beauty and vigor of growth.
Forest Fires.
The difficulty of protecting the woods against accidental or incendiary fires is one of the most discouraging circ.u.mstances attending the preservation of natural and the plantation of artificial forests. [Footnote: The disappearance of the forests of ancient Gaul and of mediaeval France has been ascribed by some writers as much to accidental fires as to the felling of the trees. All the treatises on sylviculture are full of narratives of forest fires. The woods of Corsica and Sardinia have suffered incalculable injury from this cause, and notwithstanding the resistance of the cork-tree to injury from common fires, the government forests of this valuable tree in Algeria have been lately often set on fire by the natives and have sustained immense damage. See an article by Ysabeau in the Annales Forestieres, t.
iii., p. 439; Della Marmora, Voyage en Sardaigne, 2d edition, t. i., p.
426; Rivista Forestale del Regno d"Italia, October, 1865, p. 474. Five or six years ago I saw in Switzerland a considerable forest, chiefly of young trees, which had recently been burnt over. I was told that the poor of the commune had long enjoyed a customary privilege of carrying off dead wood and windfalls, and that they had set the forest on fire to kill the trees and so increase the supply of their lawful plunder. The customary rights of herdsmen, shepherds, and peasants in European forests are often an insuperable obstacle to the success of attempts to preserve the woods or to improve their condition. See, on this subject, Alfred Maury, Les anciens Forets de la Gaule, chap. xxix.] In the spontaneous wood the spread of fire is somewhat r.e.t.a.r.ded by the general humidity of the soil and of the beds of leaves which cover it. But in long droughts the superficial layer of leaves and the dry fallen branches become as inflammable as tinder, and the fire spreads with fearful rapidity, until its further progress is arrested by want of material, or, more rarely, by heavy rains, sometimes caused, as many meteorologists suppose, by the conflagration itself.
In the artificial forest the annual removal of fallen or half-dried trees and the leaves and other droppings of the wood, though otherwise a very injurious practice, much diminishes the rapid spread of fires; and the absence of combustible underwood and the greater distance between the trees are additional safeguards. But, on the other hand, the comparative dryness of the soil, and of any leaves or twigs which may remain upon it, and the greater facility for the pa.s.sage of wind-currents through a regularly planted and more open wood, are circ.u.mstances unfavorable to the security of the trees against this formidable danger. The natural forest, unless isolated and of small extent, can be protected from fire only by a vigilance too costly to be systematically practised. But the artificial wood may be secured by a network of ditches and of paths or occasional open glades, which both check the running of the fire and furnish the means of approaching and combating it. [Footnote: It is stated that in the pine woods of the Landes of Gascony a fire has never been known to cross a railway-track or a common road. See Des Incendies, etc., dans la Region des Maures in the Revue des Eaux et Forets for February, 1869. Many other important articles on this subject will be found in other numbers of the same very valuable periodical.]
The experience of 1871 ought not to be wholly without value as a lesson.
It is not possible to estimate the damage by forest fires in that disastrous year, in what were lately the North-western States, and in Canada, but as the demand for lumber, and consequently, its market price, are rising at a rate higher than the interest on capital, in a geometrical ratio, one may almost say it is probable that ten years hence those fires will be thought to have diminished the national wealth by a larger amount than even the terrible conflagration at Chicago.
There is no good reason why insurance companies should not guarantee the proprietor of a wood as well as the owner of a house against damage by fire. In Europe there is no conceivable liability to pecuniary loss which may not be insured against. The American companies might at first be embarra.s.sed in estimating the risk, but the experience of a few years would suggest safe principles, and all parties would find advantage in this extension of security.
Forest Legislation.
I have alleged sufficient reasons for believing that a desolation, like that which has overwhelmed many once beautiful and fertile regions of Europe, awaits an important part of the territory of the United States, and of other comparatively new countries over which European civilization is now extending its sway, unless prompt measures are taken to check the action of destructive causes already in operation. It is almost in vain to expect that mere restrictive legislation can do anything effectual to arrest the progress of the evil in those countries, except so far as the state is still the proprietor of extensive forests. Woodlands which have pa.s.sed into private hands will everywhere be managed, in spite of legal restrictions, upon the same economical principles as other possessions, and every proprietor will, as a general rule, fell his woods, unless he believes that it will be for his pecuniary interest to preserve them. Few of the new provinces which the last three centuries have brought under the control of the European race, would tolerate any interference by the law-making power with what they regard as the most sacred of civil rights--the right, namely, of every man to do what he will with his own. In the Old World, even in France, whose people, of all European nations, love best to be governed and are least annoyed by bureaucratic supervision, law has been found impotent to prevent the destruction, or wasteful economy, of private forests; and in many of the mountainous departments of that country, man is at this moment so fast laying waste the face of the earth, that the most serious fears are entertained, not only of the depopulation of those districts, but of enormous mischiefs to the provinces contiguous to them. [Footnote: "The laws against clearing have never been able to prevent these operations when the proprietor found his advantage in them, and the long series of royal ordinances and decrees of parliaments, proclaimed from the days of Charlemagne to our own, with a view of securing forest property against the improvidence of its owners, have served only to show the impotence of legislative action on this subject."--Clave, Etudes sur l"Economie Forestiere, p. 32.
"A proprietor can always contrive to clear his woods, whatever may be done to prevent him; it is a mere question of time, and a few imprudent cuttings, a few abuses of the right of pasturage, suffice to destry a forest in spite of all regulations to the contrary."--Dunoyer, De la Liberte du Travail, ii., p. 452, as quoted by Clave, p. 353.
Both authors agree that the preservation of the forests in France is practicable only by their transfer to the state, which alone can protect them and secure their proper treatment. It is much to be feared that even this measure would be inadequate to preserve the forests of the American Union. There is little respect for public property in America, and the Federal Government, certainly, would not be the proper agent of the nation for this purpose. It proved itself unable to protect the live-oak woods of Florida, which were intended to be preserved for the use of the navy, and it more than once paid contractors a high price for timber stolen from its own forests. The authorities of the individual States might be more efficient.] The only legal provisions from which anything is to be hoped, are such as shall make it a matter of private advantage to the landholder to spare the trees upon his grounds, and promote the growth of the young wood. Much may be done by exempting standing forests from taxation, and by imposing taxes on wood felled for fuel or for timber, something by more stringent provisions against trespa.s.ses on forest property, and something by premiums or honorary distinctions for judicious management of the woods; and, in short, in this matter rewards rather than punishments must be the incentives to obedience even to a policy of enlightened self-interest. It might be difficult to induce governments, general or local, to make the necessary appropriations for such purposes, but there can be no doubt that it would be sound economy in the end.
In countries where there exist munic.i.p.alities endowed with an intelligent public spirit, the purchase and control of forests by such corporations would often prove advantageous; and in some of the provinces of Northern Lombardy, experience has shown that such operations may be conducted with great benefit to all the interests connected with the proper management of the woods. In Switzerland, on the other hand, except in some few cases where woods have been preserved as a defence against avalanches, the forests of the communes have been of little advantage to the public interests, and have very generally gone to decay. [Footnote: A better economy has been of late introduced into the management of the forest in Switzerland. Excellent official reports on the subject have been published and important legal provisions adopted.] The rights of pasturage, everywhere destructive to trees, combined with toleration of trespa.s.ses, have so reduced their value, that there is, too often, nothing left that is worth protecting.
In the canton of Ticino, the peasants have very frequently voted to sell the town-woods and divide the proceeds among the corporators. The sometimes considerable sums thus received are squandered in wild revelry, and the sacrifice of the forests brings not even a momentary benefit to the proprietors. [Footnote: See in Berlepscu, Die Alpen, chapter Holzschlager und Flosser, a lively account of the sale of a communal wood.]
Fortunately for the immense economical and sanitary interests involved in this branch of rural and industrial husbandry, public opinion in many parts of the United States is thoroughly roused to the importance of the subject. In the Eastern States, plantations of a certain extent have been made, and a wiser system is pursued in the treatment of the remaining native woods. [Footnote: When the census of 1860 was taken, the States of Maine and New York produced and exported lumber in abundance. Neither of them now has timber enough for domestic use, and they are both compelled to draw much of their supply from Canada and the West.] Important experiments have been tried in Ma.s.sachusetts on the propagation of forest-trees on seash.o.r.e bluffs exposed to strong winds.
This had been generally supposed to be impossible, but the experiments in question afford a gratifying proof that this is an erroneous opinion.
Piper gives an interesting account of Mr. Tudor"s success in planting trees on the bleak and barren sh.o.r.e of Nahant. "Mr. Tudor," observes he, "has planted more than ten thousand trees at Nahaut, and, by the results of his experiments, has fully demonstrated that trees, properly cared for in the beginning, may be made to grow up to the very bounds of the ocean, exposed to the biting of the wind and the spray of the sea. The only shelter they require is, at first, some interruption to break the current of the wind, such as fences, houses, or other trees." [Footnote: Trees of America, p. 10.]
Young trees protected against the wind by a fence will somewhat overtop their shelter, and every tree will serve as a screen to a taller one behind it. Extensive groves have thus been formed in situations where an isolated tree would not grow at all.
The people of the Far West have thrown themselves into the work, we cannot say of restoration, but rather of creation, of woodland, with much of the pa.s.sionate energy which marks their action in reference to other modes of physical improvement. California has appointed a State forester with a liberal salary, and made such legal provisions and appropriations as to render the discharge of his duties effectual. The hands that built the Pacific Railroad at the rate of miles in a day are now busy in planting belts of trees to shelter the track from snow- drifts, and to supply, at a future day, timber for ties and fuel for the locomotives. The settlers on the open plains, too, are not less actively engaged in the propagation of the woods, and if we can put faith in the official statistics on the subject, not thousands but millions of trees are annually planted on the prairies.
These experiments are of much scientific as well as economical interest.
The prairies have never been wooded, so far as we know their history, and it has been contended that successful sylviculture would be impracticable in those regions from the want of rain. But we are acquainted with no soil and climate which favor the production of herbage and forbid the rearing of trees, and, as Bryant well observes, "it seems certain that where gra.s.s will grow trees may be made to grow also." [Footnote: The origin of our Western treeless prairies and plains, as of the Russian steppes, which much resemble them, is obscure, but the want of forests upon them, seems to be due to climatic conditions and especially to a want of spring and summer rains, which prevents the spontaneous formation of forests upon them, though not necessarily the growth of trees artificially planted and cared for.
Climatic conditions more or less resembling those of our Western territories produce a.n.a.logous effects in India. Much valuable information on the relations between climate and forest vegetation will be found in an article by Dr. Brandis, On the Distribution of Forests in India, in Ocean Highways for October, 1872.
In the more eastwardly prairie region fires have done much to prevent the spread of the native groves, and throughout the whole woodless plains the pastorage of the buffalo alone would suffice to prevent a forest growth. The prairies were the proper feeding-grounds of the bison, and the vast number of those animals is connected, as cause or consequence, with the existence of these vast pastures. The bison, indeed, could not convert the forest into a pasture, but he would do much to prevent the pasture from becoming a forest.
There is positive evidence that some of the American tribes possessed large herds of domesticated bisons. See Humboldt, Ansichten der Natur, i., pp. 71-73. What authorizes us to affirm that this was simply the wild bison reclaimed, and why may we not, with equal probability, believe that the migratory prairie-buffalo is the progeny of the domestic animal run wild?
There are, both on the prairies, as in Wisconsin, and in deep forests, as in Ohio, extensive remains of a primitive people, who must have been more numerous and more advanced in art than the present Indian tribes.
There can be no doubt that the woods where such earthworks are found in Ohio were cleared by them, and that the vicinity of these fortresses or temples was inhabited by a large population. Nothing forbids the supposition that the prairies were cleared by the same or a similar people, and that the growth of trees upon them has been prevented by fires and grazing, while the restoration of the woods in Ohio may be due to the abandonment of that region by its original inhabitants. The climatic conditions unfavorable to the spontaneous growth of trees on the prairies may possibly be an effect of too extensive clearings, rather than a cause of the want of woods.
It is disputed whether the steppes of Russia were ever wooded. They were certainly bare of forest growth at a very remote period; for Herodotus describes the country of the Scythians between the Ister and the Tanais as woodless, with the exception of the small province of Xylaea between the Dnieper and the Gulf of Perekop. They are known to have been occupied by a large nomade and pastoral population down to the sixteenth century, though these tribes are now much reduced in numbers. The habits of such races are scarcely less destructive to the forest than those of civilized life. Pastoral tribes do not employ much wood for fuel or for construction, but they carelessly or recklessly burn down the forests, and their cattle effectually check the growth of young trees wherever their range extends.
At present, the furious winds which sweep over the plains, the droughts of summer, and the rights and abuses of pasturage, const.i.tute very formidable obstacles to the employment of measures which have been attended with so valuable results on the sand-wastes of France and Germany. The Russian Government has, however, attempted the wooding of the steppes, and there are thriving plantations in the neighborhood of Odessa, where the soil is of a particularly loose and sandy character.
The tree best suited to this locality, and, as there is good reason to suppose, to sand plains in general, is the Ailanthus glandulosa, or j.a.pan varnish-tree. The remarkable success which has crowned the experiments with the ailanthus at Odessa, will, no doubt, stimulate to similar trials elsewhere, and it seems not improbable that the arundo and the maritime pine, which have fixed so many thousand acres of drifting sands in Western Europe, will be, partially at leaat, superseded by the tamarisk and the varnish-tree.
According to Hohenstein, Der Wald, pp. 228, 229, an extensive plantation of pines--a tree new to Southern Russia--was commenced in 1842, on the barren and sandy banks of the Ingula, near Elisabethgrod, and has met with very flattering success. Other experiments in sylviculture at different points on the steppes promise valuable results.] In any case the question will now be subjected to a practical test, and the plantations are so extensive, and, as is reported, so thrifty in growth, that one generation will suffice to determine with certainty and precision how far climate is affected by clothing with wood a vast territory naturally dest.i.tute of that protection.
I have thus far spoken only of the preservation and training of existing woods, not of the planting of new forests, because European experience, to which alone we can appeal, is conversant only with conditions so different from those of our own climate, soil, and arboreal vegetation, that precedents drawn from it cannot be relied upon as entirely safe rules for our guidance in that branch of rural economy. [Footnote: Many valuable suggestions on this subject will be found in Bryant, Forest Trees, chap. vi. et seqq.]
I apprehend that one rule, which is certainly alike applicable to both sides of the Atlantic--that, namely, of the absolute exclusion of domestic quadrupeds from all woods, old or young, not destined for the axe--would be least likely to be observed in our practice. The need of shade for cattle, and our inveterate habits in this respect, are much more serious obstacles to compliance with this precept than any inherent difficulty in the thing itself; for there is no good reason why our cattle may not be kept out of our woods as well as out of our wheatfields. When forest-planting is earnestly and perseveringly practised, means of overcoming this difficulty will be found, and our husbandry will be modified to meet the exigency.
The best general advice that can be offered, in the want of an experimental code, is to make every plantation consist of a great variety of trees, and this not only because nature favors a diversified forest-crop, but because the chances of success among a mult.i.tude of species are far greater than if we confine ourselves to one or two.
It will doubtless be found that in our scorching summer, especially on bare plains, shade for young plants is even more necessary than in most parts of Europe, and hence a fair proportion of rapidly growing trees and shrubs, even if themselves of little intrinsic value, ought to be regarded as an indispensable feature in every young plantation. These trees should be of species which bear a full supply of air and light, and therefore, in the order of nature, precede those which are of greater value for the permanent wood; and it would be a prudent measure to seed the ground with a stock of such plants, a year or two before sowing or transplanting the more valuable varieties.
More specific rules than these cannot at present well be given, but very brief experiments, even if not in all respects wisely conducted, will suffice to determine the main question: whether in a given locality this or that particular tree can advantageously be propagated or introduced.
The special processes of arboriculture suited to the ends of the planter may be gathered partly from cautious imitation of European practice, and partly from an experience which, though not p.r.o.nouncing definitively in a single season, will, nevertheless, suggest appropriate methods of planting and training the wood within a period not disproportioned to the importance of the object. [Footnote: For very judicious suggestions on experiments in sylviculture, see the Rev. Frederick Starr"s remarkable paper on the American Forests in the Transactions of the Agricultural Society for -.]