LONGLEAF PIXE. 33 
of spirits of turpentine. (PI. X.) Both shallow and light chipping, 
as practiced on the Florida National Forest, are effective in increas- 
ing the yield of gum. 
6. If the yield for the first year is assumed to be 100 per cent, the 
yields for the following years in per cents for a number of crops were 
for turpentine 91.6, 70.6, and 62.2, and for rosin 93.8, 74.4, and 69.7. 
respectively. 
7. If the total yield from three years' operation is assumed to be 
100 per cent, turpentine operators count on obtaining about 45 per 
cent the first year, 35 per cent the second, and 20 per cent the third 
year. 
A publication of the Department of Agriculture entitled " Turpen- 
tine, its sources, properties, uses, transportation, and marketing, with 
recommended specifications" (Agriculture Bulletin 898, 1920), may 
be obtained upon application to the Superintendent of Documents. 
Government Printing Office, Washington, D. C. Price, 15 cents. 
EFFECT OF TURPENTINING TIMBER. 
It is generally recognized that turpentining longleaf as commonly 
practiced renders the tree very liable to subsequent attack and in- 
jury by insects and various fungi, to being felled by wind (PL X), 
and particularly to severe injury by fires. However, if turpentin- 
ing operations have been carefully conducted by limiting the number 
of faces per tree and the depth of chipping, and if adequate protec- 
tion has been given, the amount of timber in any way injuriously 
affected has been shown to be very small; in one large operation in 
central Alabama it was only about 1 per cent of the total stand. 
On the Florida National Forest a study was made, at the close of 
the third year of working, of several sections of longleaf pine located 
on private lands and adjoining portions of the National Forest. 
There had been a severe drought during the working season imme- 
diately preceding, and the casual observation of a marked difference 
in losses of timber suggested the study. On the timber that had been 
worked under Government regulations the losses were found to be 
about 10 per cent of the total volume of timber, whereas on the pri- 
vately operated timber losses were found ranging from 25 to 60 per 
cent. Natural causes, such as insects, diseases, winds, and lightning, 
were found to have produced about 4 per cent of the losses. Thus 
the result of turpentining was. roundly, a loss of 6 per cent on Gov- 
ernment-operated timber and from 20 to 55 per cent on private 
workings. 
The mechanical properties of the wood are not affected by turpen- 
tining operations. It may be of interest to know that as far back 
as 1895 this subject was studied and it was reported that tests and 
