still need an explanation of its aims and principles.

Forestry deals with the establishment, protection and utilization of
forests.

By establishment, is meant the planting of new forests and the cutting
of mature forests, in such a way as to encourage a natural growth of new
trees without artificial planting or seeding. The planting may consist
of sowing seed, or of setting out young trees. The establishment of a
forest by cutting may consist of the removal of all mature trees and
dependence upon the remaining stumps to reproduce the forest from
sprouts, or it may consist of the removal of only a portion of the
mature trees, thus giving the young seedlings on the ground room in
which to grow.

By protection, is meant the safeguarding of the forest from fire, wind,
insects, disease and injury for which man is directly responsible. Here,
the forester also prevents injury to the trees from the grazing and
browsing of sheep and goats, and keeps his forest so well stocked that
no wind can uproot the trees nor can the sun dry up the moist forest
soil.

[Illustration: FIG. 122.--A Forest of Bull Pine Cut on Forestry
Principles. (Photograph taken on the Black Hills National Forest, South
Dakota.)]

By utilization, is meant the conservative and intelligent harvesting of
the forest, with the aim of obtaining the greatest amount of product
from a given area, with the least waste, in the quickest time, and
without the slightest deterioration of the forest as a whole. The