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Figure 37.—The practice of selective cupping leaves part of the trees in the stand unworked to grow and become more valu- 
able for both naval stores and timber products. (Photo courtesy Florida Forest Service.) 
Gum production does not conflict with timber pro- 
duction nearly as much now as it did in the past. 
One reason is that a much smaller proportion of the 
timber is being worked for naval stores. Also, more 
and more operators are adopting improved practices. 
The raising of the minimum diameter of trees 
worked represented an especially significant improve- 
ment in turpentining practices. Before 1936, in most 
sections, about one-third of all the trees cupped were 
less than 9 inches in diameter. Now, largely because 
of the Naval Stores Conservation Program, practically 
no trees smaller than 9 inches are cupped (20). This 
has contributed to a marked reduction in the num- 
ber of small trees which die or blow over every year. 
The rise of the pulp and paper industry has also 
been an important factor in reducing timber mortal- 
ity resulting from turpentining. Worked-out trees 
which were too small or too low in quality to make 
sawlogs were once left in the woods to die or blow 
over; now they are cut for pulpwood. 
One of the main reasons for the significant increase 
in young timber and the accompanying increase in 
net growth since the first forest survey has been this 
reduction in the loss of timber in stands worked for 
naval stores. As pointed out previously, pine mortal- 
ity in 1948 was only 14 percent of what it was in 
1934-36. 
An increasing number of operators are improving 
the quality of their worked-out timber, without 
reducing their returns from gum production, by 
bark chipping and using acid to stimulate the gum 
flow. On the Olustee Experimental Forest, trees 
that had been chipped and treated with sulfuric 
acid every 2 weeks during the naval stores season 
for a period of 5 years were practically equal in 
quality to round trees (9). Contrary to the prevalent 
practice of cutting off the worked portion of the tree, 
the faces were left on the logs. Both the bark-chipped 
face and the pitch soaking beneath the faces were 
entirely removed in normal slabbing of the logs and 
42 Forest Resource Report No. 6, U. S. Department of Agriculture 
