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 CfflPPEMG. 



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 CmPPING. 



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 f-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 CHD?PING. 



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. 



