WHERE HAS NATURE SPREAD THE FOREST?

Our forefathers who came across the water to America found forests stretching away from the water’s edge into an unknown wilderness. The settlements spread very slowly into the pathless woods, for there lurked danger from the Indians and wild animals. The Allegheny Mountains also held the settlers back for a long time.

The pioneers found the country, as far as the Ohio River and beyond, still forest covered; but by and by openings or prairies began to appear. By the time they had crossed the Great River the forests had been left behind, except for fringes of trees upon the lowlands along the streams.

From this point westward the open prairies stretched away to the horizon. Antelope, deer, and buffalo were often seen feeding on the rich grasses. The adventurous pioneers pushed on across the fertile prairies, coming at last to a drier and higher region which we have called the Great Plains. On these plains the Rocky Mountains came in sight. These mountains gradually became higher as the travelers approached, until they rose before them like a mighty wall. Here they again met vast forests, which covered all the higher slopes.

Beyond the Rocky Mountains they crossed a broad land of deserts where little rain fell. The vegetation was so scanty and springs so far apart that many of their horses and cattle died. The dreary and barren deserts were followed by another lofty range of mountains. Entering these mountains, the pioneers came upon the most magnificent forest that had yet been seen upon our continent. After traveling for some days over rugged mountains, they at last emerged from the forests upon the Great Valley of California.

Scattered over portions of the valley were oak trees, giving it the appearance of a park. When the valley had been passed the pioneers climbed the last mountain range, and from this range looked down upon the waters of the Pacific Ocean. Here they found forests again, some of the trees being of enormous size. Thus we see that the eastern part of the continent was nearly all forested, but that in the West the forests grew chiefly on the mountains, because there is not enough rainfall upon the plains and in the valleys.

The trees that make up most of the forests of our country are of two very different kinds. There is one kind that has narrow or needle-like leaves which they keep through the winter. These we commonly call narrow-leaved trees or conifers. The most important of the narrow-leaved trees are the pines, firs, spruces, and hemlock. Such trees form the forests of the greater part of the highlands of the northern and northeastern parts of our country. The pines also find a congenial home upon the lowlands of the Southern states. Trees of the second kind have broad leaves, and usually their wood is rather hard. Hence we call them broad-leaved or hardwood trees. Since most of these trees drop their leaves in winter, we often speak of them as deciduous trees. By far the larger part of the lands of the Eastern states that are now cultivated were found by the first settlers to be covered with hardwood trees. We are familiar with many of the hardwoods through their use in furniture and various household utensils and farm implements. The most important varieties are the walnut, hickory, chestnut, beech, maple, ash, oak, elm, locust, and linden.

There are not many broad-leaved trees in the forests of the West. The children of the West miss all the nut trees that the boys and girls of the East enjoy. But to make up for this lack there are some in the West that are not found in the East. The sugar pine, the piñón pine, and the digger pine afford delicious nuts which once formed an important article of food for the Indians. In the West the broad-leaved trees do not form dense forests. They are scattered among the pines on the lower mountain slopes, in the valleys, and along the streams. The most important of these trees are oaks of many kinds, soft maple, alder, cottonwood, sycamore, and laurel.

The dense forests of the Western mountains consist almost wholly of narrow-leaved trees. Among them are the pines and firs of different kinds, spruce, cedar, redwood, and “big trees.” The redwoods and “big trees” are both known as séquoias; they grow to an immense size upon the mountains of California. The coniferous forests of which these trees form a part are among the most wonderful and interesting ones on the earth.

If you will take a forest map of our country and place it beside a rainfall map, you will quickly discover why the forests are found where they are. You will see that the forests are found where there is more than thirty inches of rain each year, except in the far North, where it is very cold. You can say, then, that the climate is the chief thing that determines where the forests shall grow.

If the climate is warm and the rainfall heavy, the forest vegetation is so dense and rank that you can hardly travel through it. Such forests are found in the tropical parts of the country. Where little rain falls there is scanty vegetation, as upon the deserts of the Southwest. But where it is very cold, even if there is much snow or rain, you will find no trees.

We must not forget that there is another thing that affects the growth of trees, and that is the soil. Pines like a sandy soil, while most other trees do not. Certain cedars and cypresses like swampy places where no other trees will grow. Many beautiful meadows and prairies have no trees, because the soil is not well drained.

It is very easy to understand why trees cannot grow where it is dry, but how shall we learn of the effect of cold upon them? Shall we have to take a journey of thousands of miles into the far North, until we finally come to the land called the Barren Lands or tundras, where the trees become stunted and at last disappear a land where they cannot longer fight against the cold and live?

Fortunately such a long journey is not necessary. All we have to do is to climb a great mountain range, like the Sierra Nevadas, to pass through all the different climates which we would experience on a long journey to the arctic regions.

It is only a few miles from the hot San Joaquin Valley, at the base of the Sierras, where it is so dry that irrigation is necessary, to the summit of the range, where the winter climate is as cold as it is in the arctic regions.

In going up the mountains we first come to the foothills, where there is a little more rain than in the valley. Here we find oak trees growing. Farther up there is still more rain and we come to the pines. Soon we reach the most wonderful coniferous forest in all the world. Here not only is there a great variety of trees, but because of the favorable climate they grow to a great size. As we approach the summit of the mountains the trees become smaller, and at an elevation of about two miles they shrink to the size of little bushes and finally disappear. They can no longer stand the fierce winds and cold storms of this arctic region.

We have learned now that the trees do not grow haphazard over our country, but that the rain, the temperature, and the soil determine where they can live.

Within the heart of the forest the trees will come again if we cut them down, but upon its borders, where the air is drier, it is more difficult for them to spring up anew. If we cut them down carelessly and allow fires to burn over the surface, and the water to wash away the soil, they may never come back.

It is important, then, that we understand why trees grow in some places and not in others, in order that we may know how to take care of them.