TIMBER GROWING IN THE LODGEPOLE PINE REGION 29 
appearance of being in poor growing condition — all mature, over- 
mature, and seriously defective trees of marketable size should be 
cut, even though this may result in practically a clear cut. Thrifty 
immature trees which are windfirm should be left to grow and to 
insure reproduction in case the young growth should subsequently 
be destroyed bj^ fire. 
Engelmo/nn spruce type. — Because of the all-sized stands character- 
istic of the type, Engelmann spruce is naturally adapted to partial 
or selective cutting. There should be no hesitancy in immature 
stands of Engelmann spruce in leaving thrifty trees, at least up to 
20 inches in diameter. It is desirable in this type, as in lodgepole 
pine, to retain a good growing stock after cutting if the full capacity 
of the soil is to be realized. The trees remaining should be well 
spaced and, under ideal conditions, should constitute about 60 per 
cent of the original volume contained in trees 10 inches diameter 
breast high and larger. 
If this plan is followed, a sufficiently dense stand of young and 
middle-aged trees will usually remain after cutting to protect itself 
against wind throw, which appears to be controllable only by main- 
taining high density. Tall trees, the crowns of which extend much 
above the general height of the larger trees remaining after cut- 
ting, and which afford no protection to others and are the ones most 
likely to be wind thrown, should ordinarily be removed. 
Annual growth will vary from 100 to 250 board feet to the acre, 
and on the better soils a second cut should be possible in 30 to 50 
years. If the growing stock is seriously depleted through heavy 
and destructive cutting of young trees, it may require a long period 
for the stand to recover sufficiently to make a growth which even 
approaches this, and the period between cuts will be greatly 
increased. 
In overmature spruce stands made up of large trees which have 
passed maturity (though usually they contain an understory of 
immature trees and reproduction) all mature and overmature trees, 
as well as those immature trees that are seriously defective, diseased, 
or nonwindfirm, should be removed. Inferior species should be cut 
heavily to favor the more valuable ones. Under the conditions that 
usually prevail, this means the removal of practically all saw-log 
timber and the leaving of such thrifty immature trees as are wind- 
firm to put on valuable growth and serve in seed distribution. 
Additional cuts in overmature stands will ordinarily not be possi- 
ble for 100 years or more, depending upon market conditions and 
the time when the young trees approach maturity. The growth will 
be much less than in immature stands, for the growing stock will 
ordinarily be deficient for many years. However, heavy cutting is 
the only feasible way by which such stands can be converted into a 
productive forest. 
Douglas fir type. — A selective system of cutting, as already noted, 
should work out particularly well in the Douglas fir type. Usually 
from 60 to 70 per cent of the volume in trees 10 inches in diameter 
and larger should be removed, which will ordinarily make possible 
a second cut in from 30 to 50 years. Growth will vary greatly on 
account of soil differences and variations in stands left after cutting, 
possibly from 50 to 200 board feet per acre per annum. 
