28 BULLETIN 11, U. S. DEPARTMENT OF AGRICULTURE. 
largest yield of timber per acre on a short rotation, and give the best 
chance of development to the trees composing them. Cuttings can 
best be regulated in such stands, both reproduction cuttings in mature 
and improvement thinnings in immature stands. Moreover, con- 
ditions for the germination of seed and the growth of seedlings are 
much better following the cutting of a densely stocked than of an 
openly stocked stand. Only a small percentage of unmanaged 
loblolly stands are fully stocked, or normal. It will usually be 
possible, however, by leaving several good loblolly seed trees per acre, 
evenly distributed, to secure sufficient natural reproduction on a 
cut-over area to form a fully stocked stand of second growth. On 
areas with an insufficient number of loblolly seed trees, or with seed 
trees unevenly distributed, sowing or planting to supplement natural 
reproduction will be necessary if it is wished to get a normal stand. 
One of the first steps in forest management is to decide the rotation, 
or age at which the forest is to be considered mature, and at which 
to cut and reproduce it. On a rotation of from 20 to 30 years for 
loblolly pine it is only possible to produce round-edge box boards, 
crating stuff, and lumber of the lowest grades and of small value. 
On a rotation of from 35 to 45 years considerable medium-grade 
lumber can be produced which will command a fair stumpage price. 
But to produce any very considerable percentage of lumber of the 
best grades a rotation of from 50 to 100 years is necessary. The 
rotation to obtain the highest rate of interest on the original invest- 
ment in a loblolly-pine forest appears from Tables 19, 20, 21, 22, 23, 
and 24 to be, for the most part, from 30 to 50 years — longer on 
Quality III and shorter on Quality I soils. Although these tables go 
only to 50 years, it is safe to say that a longer rotation, even after 
allowing for increase in the board feet yield and stumpage value 
would not show such a high rate of interest on the money invested 
There is also to be considered the danger from fire, insects, and 
disease, which is against a long rotation. A rotation of from 35 to 
45 years is also the best silviculturally, because at this age loblolly- 
pine stands can be most easily reproduced. This is especially true 
where loblolly occurs as a temporary forest type, which, if left to the 
course of nature, would gradually revert to the original type. 
The time for cutting any particular stand, however, should not 
necessarily be made to coincide with the rotation which has been 
previously decided upon as the best, but should also be influenced 
by the condition of the lumber market and the occurrence of seed 
years. In some cases the market may make it advisable to let the 
stand grow for a much longer period than the rotation calls for, in 
order to produce more lumber of the higher grades, or a combination 
of a good seed year and a good market for low-grade stuff may warrant 
cutting on a shorter rotation. 
