fficulty 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.

The Forest Examiner must also consider, in many cases, the building of
logging roads or railroads, timber slides, etc., and must make a careful
study of the material into which the trees to be cut can best be worked
up, and of the value of such material in the market. Most of all,
however, he must study, think over, and decide what he will recommend as
to the conditions which are to govern the logging conditions by which
the protection of the forest is to be insured. These conditions, fixed
by his superiors