10 
BULLETIN 1061, U. S. DEPARTMENT OF AGRICULTURE. 
of trees per acre (tree density) and the rate of growth of the trees 
in the stand. The number of longleaf trees per acre for well-stocked 
stands does not seem to be widely variable at any given age for the 
different classes of situations, and those shown in Table 1 represent 
for the various ages about the average for all classes of land. The 
numbers of trees shown for successive ages indicate how tree popula- 
tion gradually decreases, because the more vigorous ones crowd out the 
others which are unable to keep up in the competition for light and 
root space. 
GROWTH ON CUT-OVER LAND. 
Trees of longleaf pine left in logging on the better classes of soils 
usually show an accelerated rate of growth, sometimes to a very 
Average Diameter (At4|Ft.;.:.5.0 in.. .6.9m fl.3m 9.3 in. 1 0.0m 10.4m. 
" Height 34 ft:. .48 ft..... .58 ft .6 4ft....... 68 ft.. 70ft. 
Volume (F t. B.Mj_ _ , J __25......_ 4-0 70.. ,._. . .80 
1,500.. .6.000. 10,500 ..14500.. 
'Yield per AcrefFt B.M.). 
.18000 
Fig. 3. — Growth and yield of longleaf pine on medium soil. 
marked extent. On thin, poor, poorly drained soils, and on very 
deep, dry, sandy soils an absence of stimulated growth following 
logging has generally been reported. 
In central Louisiana (Winn and La Salle Parishes) accelerated 
growth in diameters as high as 200 to 300 per cent has been found. 
Trees, for example, that measured 10 inches in diameter at the time 
of logging and had grown only 1.6 inches during the preceding 10 
years, at the end of 10 years after logging had increased 3 inches in 
diameter. This represents an actual increase in timber volume of 
about 200 per cent, or a final volume of three times the former size — 
a rate which held generally true for trees up to 15 inches in diameter, 
but fell off considerably for larger trees. With the increase both in 
size and stumpage value in the 10 years the value of the 15-inch tree 
went from 23 cents to 72 cents, while the 10-inch tree increased its 
former value six times. 
