The most important tasks of the trained Forester on a National Forest are the preparation of working plans for the use of the forest by methods which will protect and perpetuate it as well, and the carrying out of the plans when made. This is forestry in the technical sense of the word. It involves a thorough study of the kinds of timber, their amount and location, their rate of growth, their value, the ease or difficulty of their reproduction, and the methods by which the timber can be cut at a profit and at the same time the reproduction of the forest can be safely secured. A working plan usually includes a considerable number of maps, which often have to be drawn in the first place from actual surveys on the ground by the Forest Examiner. These maps contain the information secured by working-plan studies, and are of the first necessity for the wise and skilful handling of the forest. They often constitute, also, most important documents in the history of its condition and use.
On many of the National Forests the need for immediate use of the timber is so urgent and so just that there is no time to prepare elaborate working plans. Timber sales must be made, and made at once; but they must be made, nevertheless, in a way that will fully protect the future welfare of the forest. Whether working plans can be prepared or not, a most important duty of the technical Forester is to work out the conditions under which a given body of timber can be cut with safety to the forest, especially with safety to its reproduction and future growth. The principal study for a timber sale will usually include an examination of the general features and condition of the forest, and the determination of the diameter down to which it is advisable to cut the standing trees, a diameter which must be fixed at such a size as will protect the forest and make the lumbering pay. It will include also an investigation, more or less thorough and complete, as the conditions warrant, of the silvical habits of one or more of the species of trees in that forest. The areas which form natural units for the logging and transportation of the timber must be worked out and laid off, and careful estimates, or measurements, of the amount of standing timber and of its value on the stump must be made, as well as of the cost of moving it to the mill or to the railroad.