26 BULLETIN 1061, U. S. DEPARTMENT OF AGRICULTURE. 
diameter at breastheight, or about 10 inches on the stump, yields gum 
in such small amounts as to be considered below a workable size. 
Faces per tree. — Observations on virgin crops indicate that the 
addition of the second face, when conservatively made and worked 
on longleaf pine trees from 10 to 12 inches in diameter at breast - 
height, increases the yield of the tree by about 70 per cent over the 
yield of one face. However, when trees under 12 to 14 inches in 
diameter have been worked with a second face their growth has nearly 
stopped. They have often been found to be in a sickly or dying condi- 
tion. The more observing and practical operators feel justified for 
that reason in not permitting a second face on trees less than 15 inches 
in diameter; but. if a second face is allowed, they require that bars 
shall measure at least 4 inches across and that at least 40 per cent of 
the surface or circumference of the tree shall remain uncut. 
Heavy chip ping. — For conclusive results regarding the effect of 
heavy and light chipping, reference may be made to the experiments 
carried on in Florida by Dr. Charles F. Herty and published by the 
Forest Service 6 (PL VIII). To this may be added some results 
obtained by the Forest Service on the Florida National Forest near 
Pensacola. In these workings the trees were conservatively cupped, 
and chipping was limited to one-half inch in depth and the same in 
height. Under these conditions the results per crop of 10.000 cups 
from five successive years* work on a specified body of timber have 
been as follows : First year, 46 barrels ; second year, 40 barrels : third 
year, 41 barrels ; fourth year, 38 barrels ; fifth year, 41 barrels. 
The average season's production of gum per crop was, therefore, 
41 barrels, with a total of 206 barrels. It will be noted that there 
was a slight alternation in the amounts, with production the third 
and last years equal to the average for the operation. A significant 
result was the subsequent death of only 2 per cent of the trees from 
dry- facing. Private operations in the same locality using the ordi- 
nary old-time system commonly lose from 10 to 20 per cent of their 
timber and the average yield of gum obtained is approximately as 
follows: First year, 46 barrels; second year, 38 barrels; third year, 
25 barrels ; average yearly, 36.3 barrels. 
This total yield of 109 barrels in three seasons' working with an 
average yearly production of 36.3 barrels per crop stands in bold 
contrast to the result of 206 barrels obtained under similar condi- 
tions on the National Forest by the use of better methods. 
SUGGESTED SYSTEMS OF TURPENTINING. 
A method that is now being tried out on the Florida National 
Forest in fully stocked second-growth stands starts with the gradual 
6 " Relation of Light Chipping to the Commercial Yield of Naval Stores.'* by Dr. Charles 
F. Herty. Forest Service Rulletin 00. For sale by Superintendent of Documents, Govern- 
ment Printing Office, Washington, D. C. Price, 10 cents. 
