Changes in numbers of all live softwood trees by diameter 
class between the most recent forest surveys in the South 
are consistent with the overall decline in young pine stands 
(fig. 3.26). The decline in softwood saplings identified in 
the 1970’s has now progressed up through the 6-inch class 
(Boyce and Knight 1979). The declines in numbers of pine 
trees on other private land have progressed up through the 
8-inch class. In a few areas, the decline in live softwood 
trees has already reached the 12-inch and larger classes. 
In addition to the inadequate regeneration on other private 
land following harvest and an overall loss of timberland to 
other uses, a third factor affecting the slowdown in softwood 
growth in the South is a sharp increase in softwood mor- 
tality since about 1970. Since then, the annual mortality of 
softwood growing stock has more than doubled (table 
3.17). Currently, about 15 percent of the gross annual 
growth of softwood is lost to mortality. This increase in 
mortality extends across the entire South and each of the 
major ownerships. Much of the increase in mortality can be 
attributed to periodic outbreaks of pine bark beetles over 
extensive areas in recent years. Forest survey statistics 
suggest insects account for 35 to 40 percent of the softwood 
mortality each year. Disease and suppression are the other 
Percentage change 
30 
20 
10 
6 8 
leading causes of death: together, they account for another 
35 to 40 percent. 
Fusiform rust, littleleaf disease, and annosus root rot are the 
three leading diseases affecting pine in the South. Increases 
in mortality caused by suppression are attributed to signi- 
ficant buildups in average stand densities and some increase 
in average age in recent years. 
Table 3.18—Distribution of pine and mixed pine—hardwood stands 
in the South, by age group and broad ownership class, 1985 
Million acres 
Broad ownership class 
Total 
Stand age Forest Other all 
(years) Public industry private ownerships 
0-10 0.9 6.4 6.1 13.4 
11-20 1.3 6.9 9.6 17.8 
21-30 2.0 6.6 12.9 21.4 
31-40 1.7 4.1 10.2 15.9 
41-50 1.3 2.0 6.2 ONS 
50+ 2.1 rl 6.7 10.9 
Total 93 28.1 Silay 89.1 
10 12 14 16 + 
Diameter class 
(diameter-breast-height in inches) 
Figure 3.26—Percentage change in the number of live softwood trees on timberland in the South between the most recent 
forest surveys, by diameter class 
155 
