28 BULLETIN 149 9, U. S. DEPARTMENT OF AGRICULTURE 
On the better soils stands up to 200 years old have shown good 
response to thinning. On the poor soils, response to thinning may 
be very slow or negligible. 
IN SAW-LOG OR TIE STANDS 
In the saw-log or tie stands containing trees the majority of which 
are full crowned and thrifty, clear cutting will probably never be 
justified. A selective cutting is needed in all types. In these stands 
sizes range from seedlings to large trees 30 inches in diameter in the 
spruce type, or 36 inches or larger in the fir type. The objective 
should be to remove all trees that have reached or passed maturity; 
as well as those that are defective, diseased, or suppressed, and also 
trees of inferior species. Cutting should be based on maturity of the 
tree; size is not a reliable indicator of condition. For example, 
Douglas fir in southern Idaho 20 inches in diameter is often im- 
mature, whereas in dense stands on poorer rocky sites in Colorado 
mature trees may be no more than 4 inches in diameter. 
Since a good growing stock is necessary if future yields are to be 
as large as possible, cuttings should always be conservative. The 
ratio of the most desirable amount to cut as compared to the whole 
volume of the stand varies with the different types. 
Lodge 'pole pine type. — In stands of this type which are thrifty or 
even in those which are approaching maturity it would be desirable 
to remove about 30 or 40 per cent of the volume of trees 10 inches in 
diameter and larger, and to make additional cuttings about every 20 
to 30 years. (PL 8.) However, the condition of the stand will 
often be such as to call for the removal of 60 to TO per cent of the 
volume. This will means greater intervals between cuts. 
These stands that have grown up under crowded conditions may be 
subject to damage from wind throw after partial cutting. This 
feature must be considered, particularly on exposed ridges or on un- 
protected flats. On account of wind-throw danger, it may often be 
necessary to leave mature trees which are in a sufficiently thrifty 
condition to continue to grow, even though at a relatively slow rate, 
until the next cut. 
Thinnings in these thrifty, mature stands should be made in the 
same manner as in pole stands. The immature trees removed should 
be only those containing spike tops, basal fire scars, dying or poorly 
formed crowns, frost or lightning cracks, insect infestation, canker 
infections, serious scarring by porcupines, or other defects which 
are so serious as to make it probable that these trees will be less 
valuable at the time of the next cutting. 
On the soils best adapted for lodgepole pine a growth of from 100 
to 200 board feet annually per acre can be expected. If markets 
for small products were at all sufficient to utilize the quantity of this 
material that can be grown, much more could be done in the way of 
thinning and improvement cutting. This would mean a much closer 
utilization of the growth than at present and the salvage of much 
that is now being lost because of nonuse. 
In overmature stands of lodgepole pine, where the majority of 
trees have passed maturity and are overripe — as evidenced by sparse, 
short crowns or spike tops, smooth gray and thin bark, and a general 
