UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 508 
Contribution from the Forest Service 
HENRY S. GRAVES, Forester 
Washington, D. C. 
PROFESSIONAL PAPER 
March 6. 1917 
YIELDS FROM THE DESTRUCTIVE DISTILLATION 
OF CERTAIN HARDWOODS. 
SECOND PROGRESS REPORT. 
By R. C. Palmee, Chemist in Forest Products. 
CONTENTS. 
Purpose of experiment 
Plan of investigation 
Method of recording data 
Yields on per cent weight basis . 
Yields per cord 
Pyroligneous acid, tar, and charcoal . 
Commercialdistillation 
PURPOSE OF EXPERIMENTS. 
The object of the investigations reported in this bulletin and in 
Bulletin 129, to which this is supplementary, was to determine the 
relative value of the various hardwoods commonly used for de- 
structive distillation, and of the different forms of material, such as 
bodywood, limbs, and slabs. The experiments were carried on at 
the Forest Products Laboratory, maintained at Madison, Wis., in 
cooperation with the University of Wisconsin. The standard 
species — beech, birch, and hard maple — were included in the labora- 
tory tests so as to make the results on other species comparable with 
them and hence commercially applicable. Bulletin 129 gives the 
yields for these three standard species, and, in addition, red gum, 
chestnut, hickory, white oak, and tupelo. The present bulletin gives 
the yields for white elm, slippery elm, silver maple, green ash, blue 
ash, yellow ash, chestnut oak, tanbark oak, California black oak, 
Louisiana swamp oak,^ and eucalyptus. 
The results here reported are of most value when compared with 
laboratory distillations of species whose yields in commercial prac- 
1 " Swamp oak " was a mixture of laurel, post, water, willow, Spanish, and cow oaks, 
usually growing in mixed stands. Acknowledgment is made of the assistance of Mr. H. 
Cloukey in analyzing some of the distillates. 
Note. — This bulletin gives the results of experiments in destructive distillation of 
hardwoods and is of interest to manufacturers of by-products. 
70252°— Bull. 508—17 
