26 BULLETIN 1064, U. S. DEPARTMENT OF AGRICULTURE. 
of chipping surface or working face (about 32 streaks) was allowed 
in any one chipping season, so that the operator was at liberty to 
use more streaks, provided they were less than one-half inch high. 
(PL VII, fig. 4.) 
This method was found to give satisfactory and sustained returns 
even over periods of six or more years. Indeed, timber owners in 
the vicinity who observed the results thus secured voluntarily aban- 
doned the heavier chipping which they had previously practiced in 
favor of this method. The question of whether the height of chip 
used could advantageously be reduced somewhat further — as the 
results of the narrow chipping at Columbia, Miss., indicated might 
be the case, at least on the timber of that section — is one needing 
immediate attention. The yield from the narrow chipping did not 
show appreciable reduction during the second year, as was generally 
the case with the crops operated by the standard Forest Service 
method. 
EXPERIMENTS ON THE FLORIDA NATIONAL FOREST. 
Very interesting results have been obtained by experiments made 
on the Florida National Forest near Camp Pinchot in an effort to 
find a system for working longleaf pine that would produce (at the 
same cost or, if possible, at smaller cost than that which now is 
customary in ordinary practice) as high an immediate yield of 
gum as is now obtained, and also a good sustained yield for a 
longer period. Some of the methods tested are illustrated in Plate I, 
figures 5 and 6. Special attention was given to finding a method 
adapted to application on relatively small, young, second-growth 
timber. A striking illustration of the effect of heavy as compared 
with conservative chipping on wood formation and general tree 
responses was observed when some material from the tract on which 
the French method of turpentining was being used was compared 
with specimens from very heavily chipped trees from the same 
locality on a private tract. Figures 5 and 6, Plate VI, illustrate 
the relative effects of these methods. Both specimens were cut on 
May 6, 1916. At that time practically no wood cells had been differ- 
entiated in the case of the heavily chipped tree (streak three- 
fourths inch or more deep and three-fourths to 1 inch in height), 
whereas a considerable number of wood cells and a number of resin 
passages had formed in the specimens from the French-chipped area. 
(PL VI, fig. 6.) Moreover, in this latter specimen the ring width 
and the amount and density of the summer wood formed after tur- 
pentining were not reduced, as compared with the conditions found 
in the round timber. In the case of the heavy chipping, however, 
