consistent with logging methods now in practice. Diameter is far
from exact indication of age, for the location of the forest and
the situation of the individual tree, especially as it affects the
relation between height and diameter growth, are potent factors,
but as a rule merchantability for saw-material is not far from
maturity.

In a great majority of cases the approximate minimum diameter for
cutting which would be fixed by it forester would be somewhere
between 16 and 30 inches, but say it were 18 inches, for example,
it would not arbitrarily apply throughout the stand. Most trees with
yellow, smooth bark and small heavy-limbed tops, perhaps partially
dead, are mature regardless of their size. If small, they have
been crowded or stunted and may as well be cut. Trees with large,
healthy crowns composed of many comparatively small branches, and
with rough dark bark showing no flat scaling, are sure to be growing
rapidly, even if quite large. They are also less desired by the
lumberman, who often calls them black pine or black jack, so may
often be spared, without much sacrifice, for seed trees or in order
to continue their rapid wood production.

The seed tree problem in such a pine forest and under such a system
as has been described is comparatively simple, for there are likely
to be enough young trees of fruiting age left to fill up the blanks
between existing seedlings. The density of the latter determines
to a large extent the number and location of seed trees necessary,
but there should always be two to four to the acre, even if this
requires leaving some that would otherwise be logged.

Under this system recurring cuts may be made at periods of perhaps