When trees are grown in nurseries, the practice is to sow the seed in special beds filled with rich soil. Lath screens are used as shade. They protect the young seedlings from the sun just as the parent trees would do in the forest. The seedbeds are kept well cultivated and free of weeds so that the seedlings may have the best opportunities for rapid growth. Generally the seeds are sown in the spring between March and May. Such seeds as the elms and soft maples, which ripen in the early summer, are sown as soon as possible after they are gathered. Practical tests have shown that thick sowings of tree seeds give the best results. There is little danger of weeds smothering out the seedlings under such conditions. After the seed has germinated the beds may be thinned so that the seedlings will have more room to develop.
During the fall of the same year, or in the following spring, the seedlings should be transplanted to nursery rows. Thereafter it is customary to transplant the young trees at least once again during damp weather. When the trees finally are robust and vigorous and have reached the age of two to five years, they are dug up carefully and set out permanently. The usual practice is to keep the seedlings one year in the seedbed and two years in the nursery rows before they are set out. Whether the transplanting should take place during the spring or fall depends largely on the climate and geography of the locality. Practical experience is the best guide in such matters.
Some farmers and land owners are now interested in setting out hardwood forests for commercial purposes. If they do not wish to purchase their seedlings from a reliable nursery-man, they can grow them from carefully selected seed planted in well-prepared seedbeds. The popular practice is to sow the seed in drills about 2 to 3 feet apart so that horses may be used for cultivation. The seeds are sown to a depth of 2 to 3 times their thickness. They are placed close enough in the drill so that from 12 to 15 seedlings to the linear foot result. In order to hasten the sprouting of the seeds, some planters soak them in cold water for several days before sowing. In the case of such hard-coated seed as the black locust or honey locust, it is best to soak them in hot water before planting.
CHAPTER II
THE FOREST FAMILIES
Trees are as queer in picking out places to live and in their habits of growth as are the peoples of the various races which inhabit the world. Some trees do best in the icy northland. They become weak and die when brought to warm climates. Others that are accustomed to tropical weather fail to make further growth when exposed to extreme cold. The appearance of Jack Frost means death to most of the trees that come from near the equator. Even on the opposite slopes of the same mountain the types of trees are often very different. Trees that do well on the north side require plenty of moisture and cool weather. Those that prosper on south exposures are equipped to resist late and early frosts as well as very hot sunshine. The moisture needs of different trees are as remarkable as their likes and dislikes for warmth and cold. Some trees attain large size in a swampy country. Trees of the same kind will become stunted in sections where dry weather persists.
In some parts of the United States forestry experts can tell where they are by the local tree growth. For example, in the extreme northern districts the spruce and the balsam fir are native. As one travels farther south these give way to little Jack pine and aspen trees. Next come the stately forests of white and Norway pine. Sometimes a few slow-growing hemlock trees appear in the colder sections. If one continues his journey toward the equator he will next pass through forests of broad-leaved trees. They will include oak, maple, beech, chestnut, hickory, and sycamore.
In Kentucky, which is a centre of the broad-leaved belt, there are several hundred different varieties of trees. Farther south, the cone-bearing species prevail. They are followed in the march toward the Gulf of Mexico by the tropical trees of southern Florida. If one journeys west from the Mississippi River across the Great Plains he finally will come to the Rocky Mountains, where evergreen trees predominate. If oak, maple, poplar, or other broad-leaved trees grow in that region, they occur in scattered stands. In the eastern forests the trees are close together. They form a leafy canopy overhead. In the forests of the Rockies the evergreens stand some distance apart so that their tops do not touch. As a result, these Western forests do not shade the ground as well as those in the east. This causes the soils of these forests to be much drier, and also increases the danger from fire.
The forests of western Washington and Oregon, unlike most timberlands of the Rocky Mountain Region, are as dense as any forests in the world. Even at midday it is as dark as twilight in these forests. The trees are gigantic. They tower 150 to 300 feet above the ground. Their trunks often are 6 feet or larger in diameter. They make the trees of the eastern forests look stunted. They are excelled in size only by the mammoth redwood trees of northern California and the giant Sequoias of the southern Sierras.