60 



BULLETIN 983, IT. S. DEPARTMENT OE AGRICULTURE. 



yielded fermentable sugars and alcohol in proportion to their cellulose 

 content. In order to throw additional light on this subject, and also 

 to ascertain whether another common waste material other than mill 

 waste could be used for the production of alcohol, cook No. 50 was 

 made on western larch. 



The logging of western larch shows a woods loss of about 8 per cent, 

 caused by butting off the lower portion of the tree. 46 The presence 

 of shakes in the butt is chiefly responsible for this practice. In addi- 

 tion, the base of the tree is usually swollen. This portion is denser 

 than the rest of the trunk, and usually sinks, thus preventing rafting. 

 The length of the butts left in the woods varies from 4 to 8 feet, 

 although a 16-foot piece is sometimes rejected. 



Hitherto the utilization of this waste material has not met with suc- 

 cess, and it was hoped that it might profitably be employed as a raw 

 material in the production of alcohol. A sample of sawdust from a 

 butt log was cooked with 1.8 per cent of sulphuric acid, 125 per cent 

 of water, 7.5 atmospheres of pressure, for 10 minutes. A yield of 

 sugars equal to 29.72 per cent and of total solids equivalent to 35.18 

 per cent of the dry weight of the wood was obtained. Under the same 

 conditions white spruce would yield from 22 to 23 per cent of total 

 sugars of which 60 to 65 per cent would be fermentable, making an 

 alcohol yield of 6.8 to 7 per cent of the dry weight of the wood. The 

 extracts obtained from the hydrolysis of the larch were fermented 

 under standard conditions, the fermentation records and the alcohol 

 yields being shown in the tables in the Appendix. 



The larch yielded about 35 per cent more of total sugars than did the 

 spruce, and yet only 37.9 per cent of that sugar fermented as com- 

 pared with 60 or 65 per cent of the total sugar from spruce. A. W. 

 Schorger, of the Forest Products Laboratory, has analyzed both of 

 these woods with the following results: 





Western 

 larch 

 (base) 

 (per 

 cent). 



White spruce (4 samples). 





Range (per cent). 



Mean 

 (per 

 cent). 



Soluble in ether 



9.75 

 14.47 

 16.52 

 32.72 

 38.58 

 6.99 

 3.42 

 42.57 

 .84 



0.90 to 1.95 

 .82 to 1.45 



1.88 to 2.52 



6.72 to 8.84 

 11. 18 to 13. 87 

 10. 04 to 10. 78 



3.08 to 3.95 

 51. 95 to 58. 47 



1.36 



Soluble in cold water 



1. 12 



Soluble in hot water 



2.14 



Soluble in 1 per cent of NaOH, 10 minutes heating 



7.70 



Soluble in 1 per cent of NaOH', 60 minutes heating 



12.21 



Pentosan 



10.39 





3.55 



Cellulose 



56.17 



Volatile oil 





Ash 



.36 



.285 lo .326 



.307 







It will be noticed that the larch contained a large amount of 

 material soluble in water and a proportionately small amount of cel- 



« U. S. Department of Agriculture, Forest Service, Bulletin 122, "The Mechanical Properties of Western 

 Larch," by O. P. M. Goss. 



