2 BULLETIN 567, U. S. DEPARTMENT OF AGRICULTURE. 
tion upon virgin timber, and that no data are as yet available show- 
ing what effect double chipping would have upon the yield in the 
second and subsequent years. It is the intention to pursue the 
investigations further so that data covering an entire operation 
may be secured. 
The naval-stores industry can not expand at will. About 5,000,000 
acres must be tapped each year to maintain the present production. 
In the same period lumbering removes the trees from about 1,000,000 
acres of virgin longleaf and slash pine, so the available field of 
operation is growing steadily smaller. ‘‘More naval stores from the 
same tree’? must be the watchword of the industry if it is to meet 
the probable demand for turpentine and rosin without crippling itself 
for the future. 
PLAN OF THE EXPERIMENTS. 
The chipping was done on the holdings of a lumber company at 
Columbia, Miss. Three experimental areas were devoted to standard, 
narrow, and double chipping, respectively. 
STANDARD CHIPPING. 
Crops Nos. 2 and 5, with a total of 6,153 cups, were chipped weekly 
with a No. 2 hack. The depth of the streak varied from one-half to 
three-fourths inch. In order that the chipping might conform as 
nearly as possible to that prevailing on the place, no supervision was 
exercised beyond recording the data. 
NARROW CHIPPING. 
The area selected for narrow chipping consisted of all of crop No. 
4 and one drift of crop No. 3, with a total of 6;881 faces. Four stand- 
ard streaks had already been made on this area before the experi- 
ments were started. During the remainder of the season a streak 
about one-fourth inch high and of the same depth as the standard 
was cut every week. This insured that, at the end of the season, the 
faces would be approximately one-half the height of the standard. 
At first a specially constructed hack with a 3-inch bill opening was 
used, but later was abandoned because it broke too easily. After 
that the chipping was done with either a No. 00 or No. 1 hack. 
DOUBLE CHIPPING. 
Five drifts of crop No. 3, totaling 3,107 faces, were used for double 
chipping. This area also had received four standard streaks at the 
beginning of the seson. The chipping was done in the same manner 
as the narrow chipping, except that two streaks were made per week, 
so that at the end of the season the faces would be of the same height 
as the standard faces. Chipping was done at intervals of three days. 
A drift chipped on Monday, for example, was chipped again on 
Thursday. 
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