Practical Forestry in the Pacific Northwest / Protecting Existing Forests and Growing New Ones, from the Standpoint of the Public and That of the Lumberman, with an Outline of Technical Methods

by E. T. Allen

WINDBREAKS

The planting of windbreaks and shelter belts around dwellings and fields is of prime importance to the settler in an open country. Nothing adds more to the comfort of the dweller than a belt of timber about the home to protect it from the wind. Orchards need windbreaks to save them from injury in a wind-swept country, and gardens are more successful when surrounded by trees. One of the most important functions of the windbreak, however, is the saving of soil moisture within the protected area, for it is a well established fact that evaporation takes place more rapidly when there is a movement of the atmosphere than when it is calm. It is safe to say that a windbreak is effective in preventing evaporation for a distance equal to ten to fifteen times its height.

Some species, because of the form of their crowns and their rapid growth, are more effective for windbreaks than others. Since more coniferous trees retain their foliage throughout the entire year, they afford protection in winter as well as in summer. Such species as western yellow, Scotch and Austrian pine grow rapidly, are hardy, and serve the purpose well. In regions of abundant moisture Douglas fir or Norway and Sitka spruce are unequaled. European larch has also been very successful in many regions, but, unlike most conifers, it sheds its leaves in winter. Where a windbreak is to consist of a single row only, it should be of a densely growing type that branches close to the ground. For low breaks of this character the Russian mulberry and Osage orange are excellent.

Trees for woodlot or windbreak planting can be purchased from commercial nurserymen or grown by the farmer. Many growers of orchard trees, particularly in the states in the middle West, do a large business in forest tree seedlings. Since the transportation charges are often high, and since most farmers can give the attention and labor necessary to raising the trees themselves without inconvenience or extra expense, it is often desirable for them to do so. The Forest Service of the U. S. Department of Agriculture has issued several publications containing full directions for the establishment of nurseries, and these can be obtained from the Superintendent of Public Documents, Washington, D. C., free or at a nominal cost.[*]

[Footnote *: Reprint from Yearbook, Dept. of Agr., 1905, "How to Grow Young Trees for Forest Planting."
Bulletin No. 29, "The Forest Nursery."
Planting leaflets for almost all important forest trees.]

Planting may be done in the spring or fall, the latter being often preferable in regions where a dry season occurs early in the summer. For plantations of broadleaf species, one-year-old seedlings are best suited, while coniferous species should be two to three years old. The chief points to remember in setting out the trees are not to allow the roots, particularly of coniferous trees, to dry out; to dig the holes large enough to enable the roots to take a normal position without doubling up, and to pack the soil firmly around them. Where planting is done on open ground, it is highly advantageous to plow and harrow the soil before setting out the trees in order to preserve the moisture and kill weeds and sod.

Willows, cottonwoods and other poplars are very easily propagated from cuttings. Cuttings should be of strong, healthy wood of the previous season's growth which ripened well and did not shrivel during the winter. A good length is 8 to 12 inches, with the upper cut just above a bud. They may be made when wanted and planted with a spade, or if the ground is mellow they can be merely shoved into the soil until only one bud is above the surface and then tramped.

The spacing of the trees is a question largely of utility, with some variation for different species. In general, however, close planting is advisable in treeless regions, since an artificial forest must stand in a dense mass if it is to succeed in the struggle against native vegetation, wind, sunshine, frost and dry weather. A single tree or row unprotected by associates has a poorer chance. Cultivation is the best method of conserving soil moisture. To obtain the best results plantations should be cultivated, if possible, at least during the first few years. The less care the trees are to have, the thicker they should be set in order that they will be close enough to establish forest conditions of shade, litter and underbrush. Thinnings can then be made as they grow and need more room. The material thus obtained will provide an early supply of fuel, stakes and posts. A spacing of 4x4 feet is common, but this does not allow for cultivation. For this reason 2x8 feet is preferable. Shelter belts should be planted closely in order to give protection quickly.