l or artificial, the extent to which it will hold its own
with any considerable quantity of other species is doubtful. If
such are present and the situation is adapted to them, any expensive
effort to get spruce merely by modifying methods of logging or
handling the slash is certainly likely to be disappointing. Under
the conditions mentioned as peculiarly favorable for spruce, gradual
natural restocking may be expected if some seed supply is preserved,
but since the growth is rather slow and a thin stand will remain
limby, it may pay to hasten returns by supplementary artificial
planting. Some authorities question the financial practicability
of this on the ground that since spruce is of slower growth it will
pay better to use the ground for fir, but the latter is unlikely
to be true of bottom land.

After summing all its advantages, the peculiar merits of spruce for
certain purposes should be weighed, for sufficiently higher stumpage
value will compensate for delay in harvesting the crop. Moreover,
Sitka spruce has not been as thoroughly studied by foresters as
the more prominent Western trees, and while the foregoing notes
represent general present opinion, further figures on rate of height
growth may be more encouraging. There is no doubt that diameter
increase is rapid from the start. Most of the disadvantages mentioned
also decrease toward the southern limit of the spruce range, the
growth on the Oregon Coast being rapid.

WESTERN YELLOW PINE (_Pinus ponderosa_)

In this species we have the important western conifer which most
often permits the selection system of management. With certain
exceptions in which the entire stand is mature, the object of
conservative logging should be to remove trees past the age of rapid
growth and foster those that remain for a later cut. When comprising
the entire stand, or at least clearly dominating it, with all ages
fairly evenly represented, successful in reproduction, and not so
dense as to present mechanical difficulties, it is ideally adapted
to this form of management. The important underlying principle is
that, since for a period of its life the normal individual tree
increases in wood production and then declines, it is bad economy
to cut it while it is still growing rapidly or to allow it, after
slowing down, to occupy ground which might be used by a tree still
in the vigor of production. For example, if at 100 years old it
contains 500 board feet, it has averaged an