his method allowed the trees to continue to produce gum 
longer. Investigations by the U.S. Division of Forestry 
showed that tapped trees produced lumber as strong as that 
from untapped trees and did not need to be discarded as 
waste. 
The cup and gutter method was widely adopted in the na- 
val stores industry. Subsequent decades saw further prog- 
ress in chemical stimulation of gum flows and in selecting 
and breeding genetically superior trees that produced high 
yields of gum. 
In 1900, both rosin and turpentine were produced entirely 
by the distillation of gum from southern pines (figs. 2.1 
and 2.2 and app. tables 2.1 and 2.2). The gum naval stores 
industry has declined steadily in importance since the 
Thousand drums* 
2400 
oe 
1600 
1200 
800 
400 
1900 1910 1920 1930 
1940 
1930’s. This decline reflects in part the final cutting of old- 
growth timber, more recent labor shortages, some drop in 
markets for naval stores, and particularly the development 
of alternative sources of supply. Beginning in the 1920's, 
steam distillation of stumps left during logging of old-growth 
pine stands produced sizable quantities of both rosin and 
turpentine. The production process peaked in the early 
1950’s and has subsequently dropped to low levels. In re- 
cent decades, the drop in gum production and steam distil- 
lation has been nearly offset by major increases in recovery 
of tall oil and turpentine from the sulfate pulping process 
at southern pulp mills, now the primary source of rosin and 
turpentine. In 1984, tall oil represented 76 percent of the 
total production of rosin, while sulfate turpentine made up 
93 percent of the total production of turpentine. 
Tall oil 
1950 1960 1970 1980 
Figure 2.1—Rosin production in the United States, by source, 1900-84 
*520-pound drums for steam-distilled 
wood and tall oil; 517-pound drums for 
gum 
