The kinds of wood which you are likely to use are commonly known as either hard or soft, the former class from trees with broad leaves, as the oak, the latter from the coniferous or needle-leaved trees, as the white pine. This distinction between hard and soft wood you may find somewhat puzzling at first, for the common whitewood of the hardwood class you will find softer and easier to work than hard pine of the softwood class, but the distinction is based on botanical reasons. The hard woods are usually more durable as well as stronger than the soft. For various woods see [Appendix].
Timber.—The word timber is applied in a general way to the log and to the material itself, and to the standing trees. It is also applied more specifically to the larger squared pieces, or "dimension" stock, such as sills, beams, etc.
Lumber.—As the term is used in the United States, lumber consists, according to Webster, of "timber sawed or split for use, as beams, joists, boards, planks, staves, hoops, and the like."
Lumber may be either undressed or dressed, that is, rough (as it comes from the saw) or planed. It is usually sawed in regular thicknesses, and for stock which is in steady demand, such as joists, floor timbers, etc., in regular widths, as 2" x 4", 4" x 6", etc. It is commonly sold in lengths varying from 10 feet to 20 feet. Twelve feet is a common length for boards. Planing (by machine) rough or undressed boards on both sides will usually reduce the thickness of an inch board to about seven eighths of an inch. Other thicknesses will of course be reduced correspondingly. Bear this in mind. The terms 1" board, 2" plank, etc., apply, as a rule, to the stock in the rough state as it comes from the saw. When you buy planed or dressed lumber it will be thinner—that is, the "inch board" that you wish to get for a shelf will not be one inch thick (unless you get it unplaned), but seven eighths of an inch.
You must make allowance for this when you figure on dressed lumber. If for example the board must be one inch thick when planed, you will have to get a thin plank and have it planed down, or pull over the pile until you find a board which happens to be sawed as thick as one inch and one eighth. You can sometimes find boards planed one inch thick, but as a rule you will find the thickness seven eighths of an inch. A similar statement will apply to the various thicknesses of planks also. The sawing is often very irregular, however, and frequently some boards or planks will run thick enough in sawing to give the required thickness when planed, so it is well to look for such when you need pieces a little thicker than planed stock usually runs.
For such work as you are likely to do you will chiefly need boards, planks, and joists. Other forms will be referred to farther on.