Popular Science Monthly/Volume 32/December 1887/Our Forestry-Problem

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DOUBTLESS you have all seen, during the last ten years, numerous references in newspapers, magazines, etc., to the necessity of forest-preservation. This plea, however, even in this country, is not as novel and of as recent date as may be imagined. As far back as our colonial times, the fear of an exhaustion of lumber-supply alarmed New England legislators; and as early as 1801, the Massachusetts Society offered its prizes for timber-planting. We may smile over the fears of those times when railroads had not yet revolutionized methods of transportation, bringing the whole world under contribution for supplies. Yet, while those fears were premature, they were nevertheless prophetic, and the very railroads which have opened up the vast forest areas of the Northwest have brought rapidly near to us the possibility of a time when a scarcity of wood may be felt. For the haulage over so long distances of so bulky freight, in addition to other obstacles, allows only a small amount of the timber growing in those distant forests to be profitably moved to market, and from fifty to sixty per cent, often even more, of the trees cut is left in the woods to rot or to furnish food for the yearly conflagrations. Even now, in the more remote lumber-camps, any part of a tree less than one foot in diameter is considered unprofitable, and is left in the woods.

But while—as I will show farther on—the fear of those early alarmists is with renewed force, and upon a more reasonable basis, again pressed upon us, other considerations besides a waning lumber supply compel our attention to forest-preservation. A vague idea that some connection existed between the forest-cover and the climatic conditions of a country has been prevalent from olden times. "The tree is the mother of the fountain," or "the father of the rain," are significant expressions of the sages of old. But it was due to the representations of such eminent naturalists as Humboldt, Boussingault, and Becquerel, that the important and complicated part which the forest plays in the economy of Nature was first clearly recognized. And now, in the light of recent scientific experiments and investigations, added to the historical evidence of earlier times, we are forced to consider the forests of a country in a fourfold aspect:

1. As furnishers of raw material.
2. As regulators of climatic conditions.
3. As regulators of hydrologic conditions, influencing the water-flow in springs, brooks, and rivers.
4. As regulators of soil-conditions.

I need not stop to call to your mind the endless variety of articles into which the product of the forest enters. There is hardly any manufacture, hardly any branch of human industry, in which wood does not find application in some way or other; and we can say, without exaggeration, that the progress of the human race in civilization has been largely dependent on this material. A continued supply of such an important substance must, then, be deemed a necessity. To the assertion that substitutes are being and will be easily found, I would reply that, with the invention of substitutes, new applications of wood are also invented; that with the growth of civilization the use of wood has grown disproportionately; and that the population of the earth is constantly increasing, so that substitutes would have to be found to meet a demand for wood by far greater than that of the present. Besides, if we can, by reasonably husbanding present supplies, and by exercise of management, prolong for the human race the use of this most convenient material, should we not rather curb our spendthrift tendencies than rely upon the ingenuity of our children in supplying substitutes?

The value of the forest as a producer gains additional significance in the economy of a nation from, the fact that it yields a return on land which for other purposes may be useless. Timber is the crop which we can raise on our wastes and barrens, and which enriches and improves the soil instead of exhausting it. For the forest-tree generates most of its substance from the carbonic acid of the atmosphere through assimilation in the leaves, while from the soil it requires mainly water, most of which and of the exceedingly small amounts of mineral food that enter its composition, are derived from the deeper strata. The greater part of this mineral food is returned by the falling leaves to the surface of the soil, and thus that circulation of matter is set up which makes forest-growing a means of improving poor soils.

The prospects of private gain might seem to be sufficient to insure the raising of timber as well as of grain or vegetables to the full extent desirable. But against the advantages of the wood-crop just mentioned must be set certain drawbacks. The agricultural crop is produced in one year, during which it is easy, by constant cultivation, to keep up favorable conditions, and the expenditures yield their profit within a year's time. The forest-crop requires ten, twenty, forty, nay one hundred and more years to grow to useful size, does not admit of much aid on the part of the cultivator, and must have the favorable conditions for its development provided in the methods by which it is originated. It not only requires a greater amount of capital, but a greater amount of foresight, to carry on a systematic forestry with similar objects in view to those of systematic agriculture.

Here, however, enters the national interest in the business of forestry, based upon the indirect significance of the forest, namely, its influence on climate, water-flow, and soil. Even in ancient times this significance was vaguely realized, when Critias spoke of the "sickness of the country in consequence of deforestation." The earliest written expression which ascribes to the forest a definite influence upon climatic conditions we owe to the Spaniard, Fernando Colon (about the year 1540), when he states that, "on Madeira, and the Azores and Canary Islands, the rains have become rarer since the trees, which spread their shade, were cut down." In later times we find similar observations and allusions to this connection between forests and climatic or agricultural conditions in the literature of almost all civilized nations.

But these occasional notes assumed a practical significance only when, after the extensive clearings which were perpetrated by an unbridled populace during the French Revolution, the injurious consequences upon some of the most fertile districts of France made themselves felt, when fields and pastures which had sustained a thrifty and prosperous population were turned into sand-wastes or made sterile by torrential action of mountain-streams, carrying away the fertile soil, and substituting débris and unfertile ground from the mountains, and pauperizing the once productive lands, inflicting damages, which now, by the expenditure of millions of dollars yearly, and with the exercise of the greatest ingenuity, can hardly be repaired. Within the last twenty years, France has reforested about two hundred and fifty thousand acres of mountain-lands, at a cost of $30,000,000 of which the Government paid one half, the local communities the other half. In addition, two hundred thousand acres of sand-dunes, which were the result of injudicious clearing, have been reforested since 1862, and thus been made productive.

An extensive literature on the subject of forest benefits has now accumulated. But I do not intend to rehearse these often-cited arguments, which are so well elaborated in George P. Marsh's classical book, "The Earth as modified by Man." We must admit, however, that historical evidence alone can not be held sufficient proof of any natural law, and a problem of natural science needs for its solution to be subjected to scientific methods of investigation and reasoning. This has only lately been done with regard to forest influences; and, though systematic and continuous observations have not yet extended over a long period, we are already prepared at least to understand the character, though not always the extent, of the part which the forest plays in the economy of Nature. We have learned to discriminate between the different functions of forest influences. We have learned that the mechanical influence of forest-cover upon hydrologic and soil conditions is undeniable; we have learned that climatic changes due to deforestation may be favorable as well as unfavorable; that the great characteristics of a climate, due to cosmic conditions, such as the twofold movement of the earth, the presence of water-surfaces, elevation, the prevailing winds, etc., are probably beyond the reach of forest influence; that such influence must, in the main, be local, and its nature and extent be dependent largely upon the geography of the locality.

The rationale of forest influences is easily enough understood, if we consider them step by step. The climate of a locality—i. e., the interdependent oscillations of temperature and humidity of the air (not as it is popularly expressed the mean condition of these factors)—is, in the first place, dependent upon the heating effect of the sun's rays; in one word, upon "insolation," The temperature of the air derives its heat, for the most part, only from contact with the heated earth or objects on the earth, and by radiation from these. Any mechanical barrier, then, against insolation of the soil, like a shady, dense forest, must have the effect of lowering the temperature of the soil and consequently of the air above it. The immediate consequence of this is diminished evaporation from the surface of the soil; while, on the other hand, the transpiration through the leaves makes the groundwater of greater depths available to the atmosphere. Thus cooler and moister air is found within and above the forest, which is communicated to the surroundings, and tends to bring to condensation any passing clouds, which the hot air ascending from the open field would have prevented. In this manner the forest acts exactly like a large sheet of water, as a starting-point of local winds, by which the characteristic features of the forest climate—i. e., shorter range of thermometrical extremes, and greater humidity—are communicated to the surroundings. Yet, whether under all circumstances, a direct increase of precipitation over surrounding areas may be produced through forest influence remains still unproved, and appreciable effects can only be expected from dense and extensive forest areas.

The influence of a mechanical barrier against chilling northern and hot southern blasts, such as even a simple wind-break of two or three rows of trees can produce, is well known to the prairie settler. But by far the most important function of the forest lies in the preservation of soil-humidity and in the storage and equable distribution of the water capital of the earth. The moss and leaf-mold act as a sponge, taking up all the atmospheric water which reaches them, and only gradually give up the same to the soil, from which it reappears as springs, brooks, and rivulets, forming the great water reservoir of agricultural lands, giving up its accumulations gradually throughout the season when most needed. While this beneficial action is especially noticeable in the mountainous regions, the forest of the plains acts also as a regulator of hydrologic conditions, as is apparent from the observation that on deforested areas the ground-water level sinks and aridity increases. While the large floods are probably, to a great extent, due to cosmic causes, yet it can not be denied that the deforestations at head-waters of streams must have aggravated the evil, and that local floods and their concomitants, namely, washing away of soil, pauperizing fertile valleys, etc., can be obviated by proper forestry, has been practically demonstrated by the reforestation in France and the Tyrol. On the paramount importance of the proper utilization of the water capital of the world, a volume might be written. Suffice it to say, that our agricultural development, and with it our civilization, depends upon it.

Lastly, I should recite the sanitary effects of the forest, the investigation of which has, of late, brought many important and interesting results. That the activity of individual trees in assimilating carbonic acid and exhaling oxygen improves the air we breathe has been long a recognized fact, and the healthfulness of forest air is therefore generally conceded. It is asserted that, by deforestation, malarial districts have been created, while, on the other hand, the planting of eucalyptus and other trees is said to have produced the opposite effect. It is quite possible that the manifold ramifications of the crowns of the forest act as a kind of filter in purifying the air of the spores of fungi and bacteria, thus diminishing the danger of epidemics, etc.

To dwell on the æsthetic aspect of the forestry question would lead me too far, though its effect upon national life should not be underestimated, and deserves fully our attention.

From this hurried review of the relation which the forest-cover of the earth holds toward the economies of Nature, it should appear that more than a private interest must attach to it; that, wherever men are aggregated as a nation or a government for the protection of the public against the willfulness of the few, the care of the forest should receive earnest and timely consideration, and, if necessary, legislative action.

The forestry-problem, then, exists because of the dependence of favorable agricultural conditions upon the existence, proper management, and location of forests, and because the common interest of the nation in the maintenance of such conditions does not find a responsive appreciation on the part of those private citizens who own the forests, and who refuse to be restricted in the exercise of their free-will and their property rights in respect to them, though they suffer a number of other interferences imposed for the common good without grumbling. The forestry-problem is, to reconcile and adjust these opposing interests, and, either by persuasion or coercion, to insure the preservation and the conservative management of forest areas whose devastation would injure the interests of the whole community, and also to encourage the creation of new forest areas where needed.

Let us now ask. How far are we concerned in this forestry-problem in this country at the present time? Is the condition of our forests, in comparison with our present and future demands upon them, such as to make the immediate consideration and speedy solution of the problem a necessity? Has the time arrived for us when the needs of the future should be considered in our actions in the present?

First, in regard to material supplies: it is a most difficult task to arrive at precise data from which to judge as to supplies at hand; and still more difficult, if not impossible, to predict exhaustion or the time of scarcity. The way of speaking on this aspect of the question has, by necessity, been without proper basis. The vast stretches of so called forest still standing encouraged the notion that exhaustion was impossible—that Nature's provisions would, unaided, recuperate the drains made upon her. "Anyhow, there are a good many years' supplies ahead." Supplies of what, and for what demands? It is evident that we should discern, for instance, between building-timber supplies and hard-wood supplies, which latter, for useful purposes, are reproduced by Nature more easily and in shorter time. Unfortunately, we lack sufficient data to make any such discrimination; but we know tolerably well that the "inexhaustible" white-pine forests of the Northwest, which have supplied the bulk of our building material, will practically be exhausted in a very few years. The hemlock is soon to follow. We hear it stated that the capacity of the Northern mills, which have depleted, in less than fifty years, a crop which it takes one hundred and fifty years to replace, is sufficient to rob the immense forest areas of the South of their valuable timber in very much less than twenty-five years—timber which it has taken one hundred and fifty to two hundred and fifty years to grow; and, though almost inconceivable quantities of standing timber are reported from the Pacific coast, even with the utmost stretch of the imagination, considering the wasteful manner in which that supply is being consumed, there can not be a sufficient supply standing to meet the present requirements of the whole nation for fifty years.

It is a most farcical attempt at deception which has been practiced in comparing the supplies of one particular region with the present requirements of that region. We are one country, one nation; and, unless we build Chinese walls around our different sections, the resources of the entire country must be placed in comparison with the requirements of the entire country. The only rational way of looking at the requirements and supplies of a large continental nation like ours seems to me the following: According to latest estimates, Ave consume yearly, with our present population of sixty million, not less than twenty billion cubic feet of wood. This amount is made up, in round figures, in the following manner:

2,500,000,000 feet for lumber-market and wood-manufactures;
360,000,000 feet for railroad construction;
250,000,000 feet for charcoal;
500,000,000 feet for fence material, etc.;
17,500,000,000 feet for fuel.

To this it will be safe to add, for wasteful practices and for the destruction by yearly conflagrations, at the least, twenty-five per cent.

The average yearly growth of wood per acre in the well-stocked and well-cared-for forests of Germany has been computed at fifty cubic feet. Applying this figure to our present requirements, we should have an area of not less than five hundred million acres in well-stocked forest to give us a continual supply of all kinds for our present needs. Now, a careful canvass made four years ago developed the result that the existing forest area in the United States, excluding Alaska and Indian Territory, comprised almost five hundred million acres (489,280,000); but it is well known to everybody who is acquainted with our forests that they can not compare in yield with the average European continental forests under systematic management. Much of what is reported as forest is useless brush-land, or open woods, and depreciated in its capacity for wood-production by annual fires, by which the physical structure of the leaf-mold is destroyed, and thus, too, its capacity for storing the needful moisture, reducing wood-production, and killing all young growth.

Without care, without management, and left to the kind but uneconomical work of Nature, interfered with, in addition, by rude and ignorant action of man, it is doubtful whether, on the existing area, one half the amount of wood is produced yearly which we now require. We have, therefore, beyond doubt, reached—if not passed—the time when increased drain means squandering of capital, and when regard to husbanding, to careful management, to recuperation of our forests, and planting of new forests is required for the purpose of merely furnishing raw material; and it should not be forgotten that to reproduce the quick-growing white pine of an acceptable quality and sufficient size, requires not less than eighty to one hundred years, and for the long-leaved pine two hundred years; that, altogether, wood crops are slow crops; that nothing of size can be grown under a quarter of a century at the best.

That this is a business requiring intelligent national consideration is apparent; not less so if we appreciate the magnitude of the values resulting from it. The total value of forest products in the census year was placed at $700,000,000, or ten times the value of the gold and silver production, five times the value of all coal and mineral production, and exceeding every one of the agricultural crops, com and wheat not excepted; and representing in value about thirty per cent of the total agricultural production.

Turning to our concern in the climatic aspects of the forestry question, I have recorded my skepticism as regards a wide-reaching forest influence upon the climate of a country; and since the influence can only be local, since its nature and scope depend on geographical position, configuration, elevation, the neighborhood of large water surfaces, and prevailing winds, etc., it is evident that it is entirely impossible to speak of a safe percentage of forest-cover for a continental country like ours. The climatic factors at work and the requirement of regulating influences on the Atlantic shore have no bearing on considerations of the Pacific, and what the treeless plains need may not be needed by the lake-bordered States. A proportion of forest which has been suggested as safe, without any proper basis, however, is twenty-five per cent.

In order to study the need of considering forest climatic influences, I have divided the country roughly, as far as our scanty forest statistics permit, into eight or ten regions, or rather grouped the States together, which are more or less similarly situated as regards possible climatic influences of a cosmic nature. These groups are, to some extent, arbitrary, and, being based upon political divisions, for which alone approximate forest statistics exist, can not closely correspond to the range of actual climatic conditions. It would appear, however, that the Atlantic States, with over forty-three per cent of forest, as well as the Gulf and central Southern States, and even the lake-bordered Northern lumbering States, with nearly fifty per cent of forest cover, can not, in general, be said to have gone below that safe proportion for climatic considerations; though in special localities the inroads may have been severe enough to produce undesirable results. But the agricultural States—Ohio, Indiana, and Illinois, with 14·7 per cent; the Prairie States, with a continental climate, and with only 4*4 per cent; Texas, with 23·2 per cent, all in one corner; the Rocky Mountain States, with 14·1 per cent of forest-land, and their water-supply depending on the forest-cover; the Pacific slope States, though heavily timbered on the Northwestern coast, with 34 per cent, and in the southern and interior parts largely dependent on irrigation—these, I may say, come nearer to that lowest limit of forest-cover which is claimed as desirable for climatic considerations. Especially where the forest had been destroyed, and the climate made unfavorable before the advent of the white man, in the vast prairies, reforestation is demanded for purely climatic amelioration.

This has been recognized by the prairie settlers, tree-planting in shelter-belts and small groves has been begun, and the change for the better, aided by the breaking of the soil in large areas, is gratefully acknowledged. But a radical change in the inclement climate of those plains we can expect only from extensive and densely shaded forest belts, dispersed over the country, such as only entire communities, or citizens aggregated in a government, will be able to provide.

Of injuries wrought locally by the reckless clearing of hill-sides and of deterioration of the soil due to inconsiderate action of man, I could entertain you by the hour; the country is full of examples. Any one who wishes to study the effect of such denuding of hill-sides upon the soil, the water-flow, and agricultural conditions, need not go to France, Spain, Italy, Greece, or Palestine. The Adirondack Mountains are within easier reach, where the thin cover of earth exposed to the washing rains is carried into the rivers, leaving behind a bare, forbidding rock and desolation, while at Albany the Hudson River is being made unnavigable by the débris and soil carried down the river; the Government has spent more than ten million dollars, I believe, and spends every year a goodly sum, to open out a passage over the sand-bar thus formed.

Go to the eastern Rocky Mountains, or to Southern California, and you can gain an insight into the significance of regulated water-supply for the agriculture below, and also learn how imprudently we have acted and are acting upon the knowledge of this significance by allowing the destruction of mountain-forests in the most reckless and unprofitable manner. Along the shores of Lake Michigan, and along the sea-coast, we are creating shifting sands by the removal of the forest cover, to make work for the ingenuity of our children in devising methods for fixing these sands again. The vegetable mold with which the kind forest had covered the alluvial sands of the Southern coast-plain we are taking pains to burn off in order to replace it with expensive artificial fertilizers.

That the great flood of the Ohio, which cost the country more than twenty million dollars, was entirely due to deforestation, I will not assert, but it must have been considerably aggravated by the accumulation of minor local floods due to the well-known reckless clearing of the hill-sides, which sent their waters down into the river in torrents. At the season, when the winter snows are melting, watch the newspapers, and you will find an almost daily mention of the disastrous ravages of brooks and streams, many of which injuries could have been prevented by avoiding the creation of their distant and indirect cause. Thus we may multiply examples all over the country, showing harmful local influences upon agricultural conditions due to forest devastation.

That the vast stretches of land in the Northwest, from which the white pine has been cut and burned off, present the aspect of a desolation which sickens the heart, you may hear from every one who has seen these deserts unnecessarily wrought by man. Every traveler in this country, be it to the White Mountains, to the Adirondacks, along the Alleghany Mountains; be it through the Rockies or the redwoods of California, can not but be startled by the desolate, sad aspect of many of these once beautifully-clad mountain-crests.

And we are a nation hardly a hundred years old, with over thirty acres per capita to spread ourselves upon. What will become of us, when we must live upon five acres per head? We are far enough advanced in our recklessness of disregarding the indirect significance of forest areas to have learned a lesson at home, and to feel the necessity of being more careful in the utilization of the forest, so as not to lose its protection for our agricultural and general interests.

While we have seen that all aspects, in which the forest must be considered, from the standpoint of national economy, show our conditions to be such as to call for solicitous consideration and action; this is still more apparent, if we analyze the difficulties to be overcome. These are much greater, in our case, than those encountered by any of the European nations. For abroad, government is so regarded as to give wider scope to its action, and not only are government forests and government forestry permissible and natural, but government interference, if for the interest of the general welfare, is borne less impatiently. Besides, forest management by these nations has been gradually led up to by an interest outside of forestry proper—the protection of the chase, which was fostered by the king, and then by nobles, on entailed estates, so that to the present generation a nucleus of forests has been preserved, upon which to expend the needful care and management.

Our difficulties lie mainly in the unique manner in which our country has been settled, and in the spirit of our institutions, which is too prone to resent interference with private rights, even where the common interest seems to call for such. The rapid development of railroad facilities has brought a whole vast continent within easy reach of market, and has allowed a population of only sixty million people to spread itself over more than three million square miles of territory. In consequence, the necessity, or even desirability, for economical use of our resources can hardly be realized. The necessity of clearing woodlands for agricultural purposes, without a market for the timber, has bred a spirit of wastefulness in regard to that material; and this has been fed by the seeming inexhaustibility of existing natural supplies. The vast expanse of our country, with its endless possibilities and opportunities, has produced a tendency of instability and speculation—a tendency inimical to a business whose profits lie so remote as in forestry, and which presupposes a concern in the future conditions and welfare of a given locality.

Add to this the difficulty, over our vast and sparsely-settled country, of guarding forest property against theft and fire, which invites the owner to cut and realize as fast as possible upon his holdings, and deters him from risking any expense on management; further, add that, as long as natural supplies can be brought to market from distant regions, and at prices far below the cost of their production—and all financial incentive to apply systematic forestry is wanting. While thus the ruthless slashing of the primeval forests goes on without regard to future or consequences, the comparatively insignificant beginnings of new plantations in the treeless plains can hardly be considered an attempt at compensation. Time, of course, would cure many of these unfavorable conditions; but meanwhile we are increasing the dangers of deforestation, and are preparing for those who come after us hardships which we could and should avert. How, in spite of the difficulties that oppose a systematic forestry, to insure a continuous and sufficient supply of raw material, and to preserve the favorable conditions which depend on proper forest areas—that is the forestry problem.

The means for its solution I may only briefly indicate: they are education, example, encouragement, legislation. Some of these are of slow effect; others can be made to give results at once. Let the United States Government, which still holds some seventy million acres of the people's land in forests, mostly on the Western mountains, where its preservation is most urgently needed—let the Government set aside these otherwise valueless lands, and manage them as a national forest domain, and then the first effective step, a feasible and not a forcible one, is made. Let the military reservations on the Western treeless plains, which are still in the hands of the General Government, be planted to forests and managed as such; this would be no doubtful experiment, would interfere with nobody, would enhance the value of the surrounding country—and education, example, and encouragement are provided, as far as it is in the legitimate province of the General Government. And such example, instead of costing anything to the country, can be made self-sustaining—nay, productive—and would add appreciably to the people's wealth.

I have avoided introducing any sentiment in the treatment of this question, simply presenting its bearing upon a tangible basis; but it is, indeed, a question into the discussion of which sentiment of the highest order should enter; a problem in the solution of which we should be actuated by the grandest conceptions of our duty as citizens of this nation, as citizens of this world, with the solemn creed of one of our great naturalists (Frederick von Müller) before us:

"I regard the forests as a heritage given us by Nature, not for spoil or to devastate, but to be wisely used, reverently honored, and carefully maintained, I regard the forests as a gift intrusted to any of us only for transient care during a short space of time, to be surrendered to posterity again as an unimpaired property, with the increased riches and augmented blessings, to pass, as a sacred patrimony, from generation to generation."


  1. A Lecture given at the National Museum, Washington, D.C., April 2, 1887.