THE SEQUOIAS OF CALIFORNIA
Differences of climate have largely influenced tree growth and types in this country. The distribution of tree families is changing all the time. It shifts just as the climate and other conditions change. Trees constantly strive among themselves for control of different localities. For a time one species will predominate. Then other varieties will appear and displace the ones already established. The distribution of trees changes very remarkably from one century to another. For example, in some sections, the red and black oaks are replacing the white oaks. Some trees are light-lovers. They require much more sunlight than others that do well under heavy shade. Oak trees require plenty of light; maples or beeches thrive on little light.
The seed of trees requiring little light may be scattered in a dense forest together with that of trees which need plenty of daylight in order to make normal growth. The seedlings that like shade will develop under such conditions while those that need light will pine away and die. Gradually the shade-loving trees will replace the light-loving trees in such a forest stand. Even the different trees of the same family often strive with one another for light and moisture. Each tree differs from every other one in shape and size. Trees will adapt themselves to the light and moisture conditions to which they are exposed. A tree that has access to plenty of moisture and sunlight grows evenly from the ground to its top with a bushy, wide-spreading crown. The same tree, if it grows in the shade, will reach a greater height but will have a small compact crown. Trees run a race in their rapidity of growth. The winners get the desirable places in the sunlight and prosper. The losers develop into stunted trees that often die, due to lack of light exposure. A better quality of lumber results from tall straight trees than that produced by the symmetrical, branching trees. That is why every forester who sets out trees tries to provide conditions which will make them grow tall and with the smallest possible covering of branches on the lower part of the trunks.
Where trees are exposed to strong winds, they develop deep and strong root systems. They produce large and strong trunks that can bend and resist violent winds which sway and twist them in every direction. Such trees are much stronger and sturdier than those that grow in a sheltered forest. The trees that are blown down in the forest provide space for the introduction and growth of new varieties. These activities are constantly changing the type of tree growth in the forest.
Our original forests which bordered the Atlantic coast line when America was first settled, were dense and impenetrable. The colonists feared the forests because they sheltered the hostile Indians who lurked near the white settlements. In time this fear of the forest developed into hatred of the forest. As a result, the colonists cut trees as rapidly as they could. In every way they fought back the wilderness. They and their children's children have worked so effectively that the original wealth of woodlands has been depleted. At present, cleared fields and cutover areas abound in regions that at one time were covered with magnificent stands of timber.
In many sections of the country our forests are now so reduced that they are of little commercial importance. However, these areas are not yet entirely denuded. Predictions have been made frequently that our woodlands would soon disappear. Scientific foresters report that such statements are incorrect. There are only a few districts in the country which probably will never again support much tree growth. Their denuded condition is due largely to the destruction of the neighboring mountain forests and to the activities of erosion. Under ordinary conditions, natural reforestation will maintain a satisfactory tree growth on lands where a practical system of forest protection is practiced. The complete removal of the forest is now accomplished only in fertile farming regions, where the agricultural value of the land is too high to permit it to remain longer in forest cover. Even in the Mississippi Valley and the Great Lakes belts there are still large areas of forest land. Most of the farms have woodlots which provide fuel, fencing, and some lumber. For the most part, these farm woodlots are abused. They have not been managed correctly. Fortunately, a change for the better is now evident. The farm woodlot owners are coming to appreciate the importance of protecting the trees for future use. In some cases, they are even replanting areas that have been cut over. There are large tracts of sandy, rocky and swampy land in these districts that are satisfactory for tree production. In fact, about all these fields are good for is the growing of timber. Campaigns are now under way to increase tree planting and develop the production of lands adapted for forestry which previously have been idle.
The United States of the future will not be a desert, tree-less country. However, immediate measures to save our remaining trees must be developed. The greater part of our virgin timber has already been felled. The aftermath forests, which succeed the virgin stand, generally are inferior. Our supplies of ash, black walnut and hickory, once abundant, are now seriously limited. Formerly, these mixed forests covered vast stretches of country which today support only a scant crop of young trees which will not be ready for market for many years. These second-growth stands will never approach in value or quality the original forests. Over large areas, poplar, white birch, and Jack pine trees now predominate on lands which formerly bore dense stands of white pine. In many places, scrubby underbrush and stunted trees occupy lands which heretofore have been heavy producers of marketable timber trees.
Generally speaking, farm lands should not be used for forestry purposes. On the other hand, some forest lands can be profitably cleared and used for agriculture. For example, settlers are felling trees and fighting stumps in northern Wisconsin, Michigan, and Minnesota. Some of these virgin lands are valuable for farming purposes, others are not. It is preferable that they should produce farm crops instead of tree crops if the land is best adapted to agricultural use. It is an economic necessity that all lands in this country best suited for farming purposes should be tilled. Our ever-increasing population demands that every acre of land useful for growing crops should be cleared and devoted to farming. Under such conditions, the settlers should reserve sufficient woodlands for their home needs, carefully distinguishing between the land that is best for agricultural purposes and the land that is best for forestry purposes, and thus doubling their resources.