Popular Science Monthly/Volume 79/October 1911/Civilization and Vegetation
|CIVILIZATION AND VEGETATION|
CERTAIN experiences, national and personal, have caused me to reflect of late on this subject, the outlines and meaning of which will become clear, I hope, as we proceed.
With the modesty which we all recognize to be the supreme characteristic distinguishing man from all other living organisms, we regard the human race as the dominant one in nature. We consider it not only the one whose mental, if not physical, evolution has proceeded furthest toward the highest good, but the one which by natural or divine right should subjugate and rule all others, should domesticate or exterminate at will, should plow or disembowel the earth, should make the desert bear crops or strip the slopes of their forest cover, centuries old. In fact, so complete is human modesty, that the race does all these things and many more with no thought but as to the means and the gain, never a question as to the right. That is modestly assumed.
Human modesty even goes so far as to compel competition among men. The gross material cannibalism that once prevailed has given place to that refined cannibalism which, on bourse and stock exchange, in manufacture and sale of commodities, even in the numberless Olympuses of our American colleges, "eats up" the "lambs," devours the weak competitor, and oppresses the friendless. Peace is not in the scheme of nature, that nature in which man has taken the role of Ishmael, whose hand was against every man and every man's hand against him.
With this Ishmael, as in all nature, struggle is universal and inevitable; struggle, competition, war if you will, which can have only one end, the extermination of one of the stragglers. There is such a thing as extermination by assimilation. The King of the Cannibal Islands exterminated the first missionaries by assimilating them after murder. We are to-day exterminating the Indian as such by assimilating him without murder as certainly as in the days of the Indian wars.
Where are the races of wild animals from which we have "developed" cows and hens, the intelligence, alertness and gaiety of whose countenances is so obvious? We have assimilated them. Some of their excellences have even been imitated on the stage.
What is the joy of living as a tame hen, as a domesticated cow, as a pruned pear tree? "The ox that treadeth out corn" is sure of daily food; so is "the cock of the walk"; so also are the subjugated plants of farm and garden; but individuality has been sacrificed for safety, they have been conquered in the war which every man is waging against every other living thing, human or other.
Whether the Ishmaelitic rôle of man in nature be right or wrong, it is very real, and we can not escape playing our share in that rôle. It may be merely as competitors against other human beings, holding the positions which others would like, but which we call ours; or it may be as competitors against other kinds of organisms.
On beautiful spring days, when the country calls us from desk and laboratory, we see the fields turning over under the plow, the wild flowers, the native shrubs, and the young trees existing, if at all, only in the fence corners, the trees and other plants of the wood-lot leaping their bounds only to be killed bye and bye by the cultivator. In place of the variety which once covered an acre, we shall presently see only a waving field of grain, wheat or barley or oats, no one of which is native; or there will come up corn in formal rows which can reach its hypertrophic maturity only by the destruction of numberless smaller plants of which this field was once the possession. Or the unnatural trees of an orchard shade a hillside on which once stood a forest, and in place of clear streams the air tinkles with the music of brooks and creeks turbid with soil and perhaps infected with typhoid.
This last is an evidence of revenge. Civilization and man do not have things without struggle, although the outcome of the struggle is certain. Civilization and man will triumph, but not without great mortality on both sides. In the natural forest and on the natural prairie, untouched by man's invasion or by fire or by other profound disturbance, the balance is fairly maintained year after year. Last summer in the northern Rockies, I was struck by the fact that the forest does not encroach on the grass land, nor this spread into the timber. Generation after generation, they are the same, with great grassy bays here and there into the forest and high capes and promontories of timber stretching out into the grazing land. The trees and the grasses bear and shed seed year by year; insects eat the foliage or tunnel bark and wood; parasitic fungi cause smut or rust or rot; but neither set of enemies produces an epidemic or decimates the plant population, nor does the population greatly change. But let man clear the land of its stable native population, and the difference is at once apparent. If he attempt to raise a crop, he must fight as a weed every native plant, or cut back the timber to secure sunshine; he must drain his fields of excessive moisture, but in such manner as to conserve enough; he must till so that fresh soil may be brought to the roots of successive crops; and he must soon begin the endless use of insecticides, fungicides and fertilizers because of the apparently sudden increase in enemies and decrease in fertility. This is what he pays for trying to substitute his balance of population for that of nature. By tools and sprays he drives back the larger and more minute representatives of the former population until finally they are to be found only in such places as man may not yet wish to use for the other purposes. In Muir's "Mountains of California," in the chapter entitled The Bee-Pastures, he describes what used to be. "The Great Central Plain of California during the months of March, April and May, was one smooth continuous bed of honey-bloom, so marvellously rich that in walking from one end of it to the other, a distance of 400 miles, your foot would press about a hundred flowers at every step. The radiant honey-filled corollas, touching and over lapping, and rising above one another, glowed in the living light like a sunset sky—one sheet of purple and gold, with the bright Sacramento pouring through the midst of it from the north, the San Joaquin from the south, and their many tributaries sweeping in at right angles from the mountains, dividing the plain into sections fringed with trees." Now that plain is a checkerboard of grain and alfalfa fields bounded by irrigation ditches. And the lesser valleys, parallel with this great central plain, bounded by mountains still more or less timbered, are consecrated to the culture—of prunes. Undisturbed nature is still accessible, nearer at hand in that golden west than in the green middle west or on the Atlantic slope. Even the tourist can reach it if he will; not in Yosemite with its hotel, camps, and mule-polluted trails; but beyond, at the top of the world, in the higher places of the Sierra.
Civilization in the form of agriculture plays sad havoc with natural native vegetation, destroying, driving back, exterminating most, domesticating and assimilating few, plants.
Where agriculture has not yet reached, the lumberman hews down that man may elsewhere build up. There is, so far as I know, only one of our forests which, given a fair chance, will quickly reproduce itself. The redwood forest which used to stretch for hundreds of miles unbroken over the eastward as well as the westward slopes of the mountains closely paralleling the coast line of California, can reproduce itself and does wherever the lumberman fails to clear by the cheap and costly means of fire. The redwood suckers like a lilac, a rare quality in conifers. If the underground parts of a felled tree are left alive, suckers will spring up, and by their astonishingly rapid growth, almost throughout the twelve month, drenched in life-giving fogs in the rainless summer and checked only by the coldest weather of the mild and rainy winter, they will yield a stand which in thirty years will be merchantable timber. Meantime the soil is held in place, the wash is slow and comparatively harmless, the streams are clear, and those turbid destructive floods so common elsewhere, are almost unknown.
The vast areas which the nation has saved from the lumberman to furnish timber for our children and their children, to cover the watersheds and to conserve and control the yearly run-off, are annually placed in jeopardy by the railroads. Last year, disastrous fires in the far northwest, and the less extensive fires of Wisconsin and Minnesota in the summer preceding, only too plainly showed this. So dreadful has been the loss of human life and of property from this cause that the substitution of sparkless fuel-oil on locomotives traversing forested areas is now not only urged by the forest service, but being seriously considered by the railway companies. Until electric traction or sparkless fuel is employed, each dry season will bring its record of destruction along the tracks of civilization through forest and grazing land.
Peaching almost as far from its source as the fires accidentally set by civilization, is the destruction of vegetation by certain forms of industry. The damage is done in two ways, by drainage and by fumes. The composition of ordinary domestic drainage is disturbing enough to vegetation. I have had occasion to notice this along the shore of Monterey Bay. When I first saw these waters they were bordered on one side by the towns of Monterey and Pacific Grove, sleeping peacefully, the one after a somewhat turbulent past, the other on federal and denominational pensions. Between tide marks and further out were a fauna and flora so rich and so varied that a few years earlier, when the whole coast of California was open for such a choice, this had been selected as the best location for the Marine Biological Laboratory of Stanford University. So far as I can see, the fauna and flora are as rich to-day as then, but with the recent rapid increase in population of these two towns and the consequent increase in sewage pouring into the bay at no great distance below low-tide mark, there has been a decided increase in the quantity of diatoms living attached to the seaweeds growing between tide marks. The body of water in Monterey Bay is so very large and so thoroughly mixed by the tides, and the volume of sewage discharged into it from the towns on its shores is still so small in comparison, that the sea-water, even now, deserves to be called pure. But it is no longer perfect purity. Its increasing though still relatively slight pollution is shown by the change in the balance of the population between tide marks, by indicators exceeding in sensitiveness those of the chemical laboratory, by living things. We all know that, when pollution goes further, certain plants are no longer found in stream and bay; river and mud-flat become huge cultures in which coarse algæ and offensive bacteria flourish.
In all such changes as these, however, there is only a change, not a decrease in the value of the water as a nutrient solution. Nothing poisonous has been added to it, only substances which so abundantly nourish bacteria, blue-green algæ, diatoms and coarse green alga?, that other forms become more or less crowded out. This is so common an effect of civilization on vegetation that we think nothing of it. On the other hand, the actual poisoning of plants and animals by drainage from industrial establishments attracts much more attention and in many states is forbidden by' law. When there are no longer trout in a once famous fishing stream people are much more likely to notice and to remedy the injury than if sawdust or tailings merely make the stream and its borders unsightly or desolate. In the parts of the west dependent upon irrigation, drainage from mines or works which makes the water poisonous to the crops, arouses the public much more than the pollution which makes it dangerous to drink.
Perhaps it is but natural, and only another exhibition of that modesty which constitutes the distinguishing characteristic of the human species, at all events those influences which affect man and other animals are more likely to be recognized by him than those which affect plants; and those which affect his quick-growing crops, with their more frequent money returns, are more promptly recognized than those which may greatly augment or diminish a harvest coming only twice or thrice in a century. What do we know of the effects of illuminating gas in our houses and gardens, of the effects of the gaseous emanations from domestic and factory fires upon the trees of streets and parks? The only reason why gas-piping is no worse, is that greater leakage would be unprofitable to the gas companies, even at the present high rates. As it is, our houses and laboratories reek of gas to the sensitive nostril, and garden and green-house yield less than they would if the soil were not traversed by badly jointed pipes.
We think and speak of the smoke nuisance as if it were merely a soot nuisance. We do not realize that the most perfect and ideal "smoke consumer," which would certainly lessen our laundry bills, would utterly fail to lengthen life. The most perfect fuels, because the least injurious, are wood and alcohol. How often have we seen a farmhouse overtopped by some great tree and through its branches the fragrant wood-smoke floating gently from the chimney. The substitution of coal for wood would be quickly followed by a succession of troubles which would finally kill the tree, not by "closing its pores" with soot, but by poisoning the living cells in leaves and branches by the sulphur and chlorine fumes given off in burning the coal. So in our towns, you may see holes in what should be domes of foliage, bits of sky through what should be hollow masses of translucent green, olives and yellows when there should be a brilliant verdure. More careful examination will show that not only is the foliage deficient in amount and defective in color in carefully tended city trees, but their annual growth in length and thickness is less than that of their fellows uncared for in the purer air beyond the outmost suburbs. The much advertised "tree surgery" of to-day is a species of not altogether useless quackery, developed to treat a symptom in communities which do not yet recognize and remove the cause of disease. Between gas in the soil and gases in the air urban trees lead a more or less poisoned and morbid existence, appreciated and enjoyed only by those who can not or will not go where trees grow rapidly and well, solitary or gregarious, according to their kinds, a delight to the eye, an inspiration to the spirit, a shelter to the birds, and a satisfaction to the lumberman.
Perhaps this seems an exaggerated statement of urban conditions, but an examination of the trees in the parks of Pittsburgh, Cincinnati, St. Louis and Chicago, among the industrial cities using mainly soft coal, and of New York and Boston, in which hard coal is the principal fuel, will convince the fair-minded observer that something is wrong.
Air and soil analyses and experiments under controllable conditions, will alone reveal the cause of the condition of urban trees and of those growing near industrial plants from which poisonous fumes emanate. Such analyses of air and soil can be made only by a skilled chemist, and such experiments should be attempted only when a skilled chemist and a trained biologist can cooperate under such conditions of climate and equipment as to justify the expenditure of time and money.
In the remarkably pure air of Stanford University, with the nearest domestic coal fire a quarter mile away and with gas supplied to the university by a single small main, a greenhouse has been so constructed that it is completely divided into two exactly similar halves, in which experiments and their controls can be carried on under as nearly natural conditions as can be conceived. In each half of this house there were boxes of growing grain, a considerable variety of potted seedling trees, one, two and three years old, and other plants, aquatic and terrestrial. The grain was grown on the spot from seeds; the trees were grown from the seed in the pots and were brought into the house so long before they were used in experiments, that they were quite accustomed to their surroundings. Into one half of the experiment house, a dose of sulphur dioxide equal to the proportion in pure city air, was introduced daily (Sundays excepted) for months, during the resting period only for one set of trees, during the growing period only of another set, and during the resting and most of the growing period of a third set.
The trees continuously in the side of the house dosed daily with a very minute quantity of sulphur dioxide gas, blown into and thoroughly mixed with the air of the house, showed a growth in length two thirds of that of the trees in the pure air of the other half of the house. There are no visible injuries; only measurement shows that those trees in air purer than that of most cities do not thrive, do not make as much growth as trees in thoroughly pure air. Analyses show that the sulphur dioxide is fixed, mainly in the leaves, and thus disturbs the vital activities of plants. The results with grain correspond. These results obtained by experiment justify, therefore, the assertion that the problem of urban smoke is one of gases as well as solids, of poisonous fumes as well as inconvenient soot.
Turning now from cities, in which the growth of plants is purely for pleasure, and by no means natural or commercially profitable, we may ask what are the effects of smelting and other works from which poisonous fumes may be discharged?
Manufactories of certain chemicals, or of materials in the preparation of which poisonous substances may be volatilized, and establishments in which sulphurous ores are roasted either for the extraction of the metal or in order to obtain sulphur for the preparation of sulphuric acid, will affect surrounding vegetation more or less seriously. Even locomotive smoke injures the plants along the railroads, as anyone may observe. The herbaceous plants along the track, but quite beyond the reach of steam, often show burned spots on their leaves and stems. These are acid burns due to the fumes, of sulphur principally, discharged from the smoke-stacks of passing engines. One seldom travels over an old railway through woods or forests in which there are not many trees close to the line with branches or tops dead. Often the immediate cause of death is insects or fungi or possibly bacteria; just as tuberculosis may be the immediate cause of death in factory workers debilitated by long hours of labor under conditions unfavorable to robust health. But in many cases, locomotive smoke can be shown to be the immediate as well as the mediate cause of damage or death to trees along a railroad.
Such cases as these are, however, as unimportant, except as showing a principle, as they are at present unavoidable. On the other hand, where the prosecution of one industry results in the injury of many others, in the destruction of property, public as well as private, and in such changes in the run-off that the flow of water in streams perhaps hundreds of miles away is affected, the question becomes one of great importance. An illustration of this is found in the southeast corner of Tennessee, where, for many years, a low-grade copper ore, rich in sulphur, has been smelted. There are now two smelters in that region. The country is mountainous, the slopes naturally covered with the large-leaved mixed forest of the southern Appalachians, well watered by the frequent summer rains. The virgin forest was long ago cut for mine-timbers and for fuel in that extensive district known as Ducktown, but the second growth is also gone and, up to three years ago, nothing of any value could be cultivated within a distance of miles from these smelters. In the suit won by the state of Georgia before the Supreme Court of 'the United States, it was shown that the poisonous effects of the fumes were visible in Georgia at a distance of forty miles from these Tennessee smelters. Three and a half years ago, so hopeless was the condition of the people attempting to farm there, that they declare even the soil was poisoned, a mistake, of course. Since there is scarcely any level land in that district, one may imagine the result of removing the forest cover, destroying the undergrowth and preventing any other vegetation which might cover the naked soil with its branches or leaves and hold it together and in place with its roots. Instead, the leaf-mold accumulated during centuries on the forest floor and the fine soil worked and re-worked by roots, worms and other occupants of the ground, were quickly washed down the slopes into the turbid streams, floods took the place of the spring freshets, and the bare earth battered by the rains constantly gave its fertility to the already rich lowlands far away, or to the still more distant and unneeding sea.
Conditions are better now. Instead of throwing away as a poisonous waste the sulphur dioxide formed in smelting their ores, the smelters are now collecting as large a proportion of this gas as possible for the manufacture of sulphuric acid. This they sell to the manufacturers of phosphate fertilizer. Instruction is leading to improved methods of farming, to the use of the phosphates made from converted smelter waste, the farms are beginning to yield crops which repay tillage, and the woodlands are improving. To complete this romance of industry reformed under federal compulsion, it need only be said that the manufacture of sulphuric acid is so profitable that the smelters would be run for that purpose now if for no other, and that their copper costs them nothing!
In this conflict of industry with agriculture and the native vegetation the outcome has been a happy one; for industry, forced to recognize prior and more general rights, has been so modified as to eliminate its injurious effects and to enhance its own profits. This is seldom possible to anything like the same extent. The greater the industrial plant requiring reform, the more intense and extensive the damage it does, and the greater must be the difficulty of making the needed changes in method of operation. And yet even manufacturers are coming to see, by compulsion to be sure in most cases, that their rights are not unlimited, that they must conduct their business in such a manner that agricultural or other legitimate and established interests will not suffer and that the property of the nation be not injured.
This is the significance of the agreement reported in the newspapers as recently made by the Attorney General of the United States with the owners of the great smelters in Montana. These smeltermen, rather than fight a suit brought in the federal court by the Attorney General, have promised to modify their methods of extracting copper and the other metals from their ores, so that they will no longer injure the property of the nation. One of these smelters handles 10,000 tons of ore per day, when running to its capacity, and last summer I drove twenty-five miles away from it, passing over the continental divide, before reaching apparently sound uninjured forest. Such has been the widespread damage by one industrial plant in the ten years of its existence. The national forests at the headwaters of the Missouri and the Columbia are dying, and the Attorney General, in compelling their protection by reform in the extraction of copper, has done his duty well.
Another case in point is afforded by a recent decision in southern California. In the heart of the orange-producing region of the San Bernardino valley, the manufacture of cement, begun on a small scale, has developed to considerable proportions. Going eastward on the Southern Pacific Railroad from Los Angeles, one passes through almost continuous groves of orange trees, their dark green leaves glistening in the brilliant sunshine which has given that land its name. Suddenly one notices that the foliage is no longer green, but gray, not glossy but dull, and that on the opposite side of the train is a cement works constantly wasting part of its laboriously manufactured product. This dust settles on leaves and soil, enters houses, and becomes a nuisance everywhere. It sets wherever there is moisture, in dew or fog or rain, and does not wash off like ordinary dust. By reason of this opaque coating over the leaves, the manufacture of food in these green organs is interfered with, and the insufficiently nourished trees yield a correspondingly diminished crop. So serious has this injury to the orange industry become, that the court has decided that the manufacture of cement in one plant must be stopped entirely, and in another may be carried on only on a small scale, until such changes have been made that manufacture can be resumed without disadvantage to the orange-growers. That such changes will be made in this plant I have no doubt.
Such cases as this, revealing the conflict of civilization and vegetation, decided with wisdom as well as justice, leading to improved methods of manufacture, go far toward establishing that new balance which must be attained in America, as it was reached long ago in more populous Europe, that balance between civilization and vegetation which will ensure the stability and the prosperity of both.