Conservation Reader Part 4

The farmer does not know that he has me to thank for the richest of his lands, those lands where the soil is deep and dark, and filled with plant food. I and my brother rivulets have been thousands of years in collecting the soil which forms the fertile lowlands in the valleys through which we flow. We all unite to form the mighty river which finally ends in the sea.

[Ill.u.s.tration: _H. W. Fairbanks_ Because some farmer was careless, a rivulet has nearly destroyed this rich valley.]

Upon all the slopes which drain toward the river we rivulets are at work. Other servants of Nature are working here. Some of them are making the rocks soften and fall apart. Others are bringing seeds of the gra.s.ses and trees that they may take root in the crumbling rock. It is their business to make a carpet of plants over the earth and thus stop my work. But wherever the slopes are steep we rivulets have our way. We pick up and carry away the particles of sand and clay so that only the bare, hard rocks remain.

When the steep slopes become gentle, and we can no longer carry away all the particles of crumbled rock, then the carpet of plants spreads over the surface. Now our waters become clear. We seem like different beings. Once in a while, when the rains fall very heavily, some of us break through the protecting carpet and dig great hollows and gullies into the earth.

Would you like to know how we rivulets get rid of the load we carry from the mountain slopes? When we are muddy and swollen with the heavy rains, we turn the river into a flood. The river then breaks its banks and spreads out over all the lowlands along its course. Now the river flows more slowly and drops a part of the sand and mud which we rivulets brought to it. Finally, when the storm is over and the river goes back into its channel, there is left on the surface of the valleys a layer of earth rich in plant food. We brought the river the finest of the rock particles, together with the leaves and stems of plants that lay in our way.

[Ill.u.s.tration: _H. W. Fairbanks_ The rivulets have united to form the broad, shallow river loaded with the soil from the farms along its upper course.]

As year after year we made the river overflow, the soil of the lowlands grew deeper and deeper until it became as you see it today. Now the slopes about the head of the river are not so steep as they were once.

Our waters do not run away so rapidly and the river seldom overflows.

Thus the farmer can use the land for his crops, which grow so luxuriantly that he is envied by his less fortunate neighbors who live upon the hills.

[Ill.u.s.tration: _U. S. Office of Farm Management_ The soil of this valley has been washed to its present location by flood waters.]

Upon the slopes about the valleys we rivulets did not leave so much soil. The farther one goes up the slopes the thinner one finds the soil, until at the top the bare rock may appear.

But our work, says the muddy rivulet, was not finished with the making of the fertile valley lands. We carried a part of our load of sand and mud on to the mouth of the river. Here in the bay into which the river empties we began another great task. It seemed hopeless at first to try to turn the bay into dry land, but year after year we kept at work, through a time so long that I have forgotten when we began. At last we succeeded in bringing so much material to the bay that the waters became shallow. Then the soft mud began to show itself when the water was low. At last the water was replaced by dry land, which appeared much like the lowlands which we had made along the river.

Now you who think we muddy rivulets do only harm see what we have accomplished. We have built a great delta of the richest land that extends away on every hand as level as a floor and almost as far as you can see. The soil of the delta is hundreds of feet deep and the richest to be found on the whole earth. It is on such river deltas that the first civilized men made their homes, and became rich and powerful.

Now I have told you what Nature has appointed the muddy rivulets to do.

Is not the good that we do far greater than the harm? When we do harm it is because people have not learned how, or have not tried, to obey Nature's laws. If we make people poor, it is their own fault.

We still find much to do upon the earth. Nature is still making mountains which we have to tear down. We are still building deltas which will sometime be inhabited by rich and prosperous people. We do not willingly spoil the lands of the farmers on the hills and make them labor hard for a living.

In those happy lands where people understand Nature we rivulets have a different kind of work to do. We become pure and clear. We furnish a home for the fish, drink for the thirsty flocks, and a never-failing power to turn the mill wheels. Our waters are of service to every living thing.

CHAPTER SEVEN

HOW FAR WILL NATURE RESTORE HER WASTED GIFTS?

The natural wealth of our country is its soil, water, forests, minerals, animal and bird life, and, finally, its climate and scenery.

Of all these, _climate_ and _scenery_ are the only ones which we can use and enjoy as much as we like without any danger of their ever failing us. The sun will shine through the blue sky, the winds will blow, and the storms will come just the same, no matter what we may do.

Did you ever think how long a time it has taken to make the wonderful world in which we live, and place upon it the mountains and valleys, lakes and oceans? Did you ever think how long a time it has taken to make the rocks and store away in them gold, silver, copper, and iron?

Did you ever think how long a time it has taken to cover the rocks with soil, and spread over the surface the flowers and trees and to stock it with uncounted numbers of animals and birds?

Nature usually works very slowly, but she never rests. The earth and all things on its surface, have always been changing, but changing so slowly that we do not ordinarily notice what is going on. When there is an earthquake, or a slide of rock on a mountain side, or an eruption of a volcano, we are astonished and often terrified.

Stories that have come down to us from the distant past tell us that the earth looked then much the same as it does now. If we could look away back to a time long before the first men lived, when even the animals and plants were different from those around us, we should discover that the surface of the earth was quite different from that of today. We should then see mountains and hills where now we find valleys, and dry land where now lies the blue ocean.

Nature has been such a long time making the beautiful world in which we live, that we ought to treat it with great consideration. It is also a wise thing for us to be heedful of her requests, for, if we will work with her, the earth with all its treasures will be at our command.

Shall we not now seek to learn which of the natural resources of our land will never be replaced if we squander them? Let us also learn which may be made good again by Nature, if we are willing to wait long enough, as well as to a.s.sist her in her slow work.

Each year the growing plants take certain substances from the soil. It is necessary for us to put back like substances if we would keep up the fertility of the soil. If we are neglectful of this law, or allow water to wash the soil away until only the bare rocks remain, poverty will be our lot for many years.

Nature will, however, if we give her a chance, renew the soil. The rocks will crumble and, by and by, seeds will sprout and tiny plants obtain a foothold. But it may take a whole lifetime, or hundreds of years, even, for a new and fertile soil to come again.

During the early years of placer mining in California thousands of acres of rich lands in the foothills were destroyed. Only boulders were left.

Now fifty years have pa.s.sed and a new soil is being formed, but it will be a long time yet before it will be as good as it was in the first place.

Upon the Western prairies only grain has been raised for so many years that in many places the soil will scarcely grow a crop worth gathering.

Many farmers have never thought of this, but the wise ones understand that they must frequently add plant food to the soil to replace that taken by crops. They understand also that it is a good thing to change the crops grown upon any particular field from year to year, since different plants take different substances from the soil.

[Ill.u.s.tration: _H. W. Fairbanks_ The miner in his search for gold ruins the beautiful valley, leaving it a ma.s.s of boulders.]

Water goes through a ceaseless round. It rises from the sea and lakes to form the clouds, falls as rain or snow, and then flows back down the slopes to the sea. Although we have learned that we cannot change the quant.i.ty of rain that falls in any place, we can influence the way in which it runs back to the sea. This in turn affects the lives of people.

We can store water in reservoirs, and by building ca.n.a.ls have it to use on the land during the summer. We can also keep it from flowing back to the sea as rapidly as it otherwise would, by leaving uninjured the covering of vegetation which has been spread over the mountain slopes.

The water will run from bare rocks and bare soil much more quickly than it will from soil that is covered with leaf mold and held by plant roots. Do you not see, then, that we have almost as much control over water and its distribution as though we could increase or decrease the rainfall?

What about the forests? If we cut them down, will they ever come back?

All through the eastern part of our country and in the mountains of the West are lands once forested which have been cleared and turned into farms. Many of these farms, when abandoned, have in a few years been covered with a growth of young trees. The scattering trees that had been left in the vicinity of the clearings furnished the seed. The winds and the birds carried the seed to the open fields and so the forests began again.

[Ill.u.s.tration: _H. W. Fairbanks_ But Nature, after a lapse of fifty years, has spread a new carpet of soil over the valley.]

It will be hundreds of years before the trees are as large and valuable as those of the first forest. The "big trees" of the Sierra Nevada Mountains are found nowhere else in the world, for they are the last of their race. Some of these trees are more than 4000 years old.

They stood here when our forefathers were still savages and lived in trees or caves. Much of the region where these trees are found has now been reserved as a park. If the lumberman had been allowed to get at them, they would have soon been gone forever.

[Ill.u.s.tration: _George J. Young_ Uncle Sam has preserved both forests and water power.]

It is far more difficult to destroy completely most of the species of forest trees than it is to destroy the species of animals and birds. We can cut down the trees and in some cases they will grow again from sprouts. Many will hide away in remote places and furnish seed for new forests.

The animals as well as the plants have had a long history. They have had a harder struggle than the plants, because many of them prey upon one another. We often dig up the skeletons of strange animals unlike any now living. These must have all been killed long ago. Each species or kind of animal now living must have come off victorious in the struggle with its enemies.

Does it not seem a heartless thing for us, who call ourselves civilized, to destroy so completely any species of animal or plant that not one of its kind remains alive? No species which we destroy will ever come back again, and its place will always remain empty. There are a few predatory animals and birds that destroy vast numbers of useful ones. We should keep these in check by every means in our power, but for our thoughtless destruction of the valuable ones the world will always be poorer.

What of the mineral treasures hidden away in the earth? Will these be replaced when once they have all been used up? It took Nature a very long time to make coal out of the vegetation which had gathered in some ancient swamp. It took her fully as long to make the oil and gas from the bodies of the little organisms that once lived in the sea.

The bodies of the little creatures from which oil is made are still gathering upon the bottom of the sea, and there are many swamps where we find vegetation and peat acc.u.mulating. But it is a long story from these substances to oil and coal. I am afraid we should get tired of waiting for Nature to make a new supply.

Gold, silver, copper, and other minerals, so useful to us, are found in very small quant.i.ties scattered throughout most of the solid rocks of the earth. It would be impossible for us to obtain these from rocks, because there is so little in any one place. But Nature has collected a part of them in veins in the rocks. We sink shafts upon these veins and mine the ores. It will be a long time before we shall have mined all there is of these minerals. Because they are so hard to get we are not likely to waste them. But it is quite certain that there is a limit to the supply of mineral treasures, and equally certain that they can be renewed either very, very slowly, or not at all. Shall we cause our remote descendants to suffer for our carelessness?

CHAPTER EIGHT

THE SOIL--THE MOST IMPORTANT GIFT OF NATURE