Volume of The statistic., of the timber cut for the war years of 1917 and 1918 are not available; they would show a tremendous increase because of the great quan tity of timber required for shipbuilding during the war and also the special woods required for airplane construction. The following table, compiled by the United States Forest Service, gives statistics of the country's lumber pro duction 1899-1916: The table on following page compiled by the Forest Service lists the prmcmal woods in the order of their commerical importance by reason of volume of production and affords a basis for comparison of productiofi over a period of 17 years.
Characteristics of the Principal Commer cial For purposes of botanical class ification, and also in commercial practice in the lumber trade, trees are divided into two principal classes, the Conifers or Softwoods, and the Broadleaf trees or hardwoods. The hard woods are often referred to, also, as ((Decidu ous" but this term is unfortunate, since in fact some of the broadleaf woods are not deciduous. The terms "Hardwood" and "Softwood" have little relation to the actual hardness or soft characteti of the wood of any given variety. In fact some of the hardwoods are considerably less hard than the average of the softwoods.
The woods whose characteristics are dis cussed in the following paragraphs are those of chief importance from the standpoint of lumber production and commercial utility. No attempt is made to cover the tremendous range • of minor woods.
Softwoods or Conifers.—Yellow pine, which leads all other woods in volume of production, includes three important species, longleaf pine (Pinar pal:Writ), shortleaf pine (Pinar echi nata) and loblolly pine (Pinus keda) and sev eral of less commercial importance. Longleaf pine is characterized by its greater average strength, is usually very resinous, shows a high percentage of heartwood and typical pieces are very durable, even under exposure to moisture and other adverse conditions without preserva tive treatment. It is a slow-growing timber and its strength and durability are practically proportionate to its density. It is particularly well adapted to the production of high grade structural timbers and construction lumber for use where strength and durability are required, or where hard wear is involved, as in the case of flooring. Longleaf pine is sometimes known
as °Georgia pine,'" °hard pine,° etc., and in the export trade as °pitch pine.° Shortleaf pine is a lighter wood, softer than typical longleaf, and typical specimens show a larger percentage of sapwood, which is always less durable than heartwood. It is more easily worked than longleaf and because it usually contains less resinous material is more suitable for finishing lumber, taking stains, paints and varnishes satisfactorily. It makes good flooring and the low grades are extensively used in the box trade.
Loblolly pine is the least valuable of the three principal varieties of yellow pine, being a variety of rapid growth seldom suited to uses requiring great strength, but yielding a good quality of interior finish. It is extensively used for boxes and crates. It is characterized by coarse annular rings and small heart.
The trade name °North Carolina pine° is used to describe a mixture of shortleaf and loblolly pines marketed from the States of North and South Carolina and Virginia. The term °Arkansas Soft pine° covers a peculiarly soft variety of shortleaf pine manufactured in Arkansas and sold largely for finish.
Douglas fir (Pseudotsuga taxifolia) is the most important product of the northwestern part of the United States, particularly Oregon and Washington, and also of British Columbia. In respect to supply it is the most important timber of the United States and in utility covers practically the same range as the yellow pines. Its most important use is in building construction, and eventually it will be the most important wood used in building.
White pine, by virtue of its light weight and soft texture, is the most favored of all soft woods for uses where strength is not the chief factor, being used extensively in building con struction and also in the manufacture of many articles requiring a wood that is soft, easily workable and free from pronounced grain, such as musical instrument parts, foundry patterns, etc. In addition to the common white pine of the Eastern and Lake States (Pinus strands), Western white pine (Pinar monticola), which is frequently marketed as Idaho white pine, and the sugar pine (Pinus lambertiana) of Califor nia and Oregon are legitimate members of the white pine family.