UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1485 
Washington, D. C. 
May, 1927 
THE SUITABILITY OF AMERICAN WOODS FOR PAPER PULP 1 
By Sidney D. Wells, Engineer in Forest Products, and John D. Rue, in charge 
of Section of Pulp and Paper, Forest Products Laboratory, Forest Service 
CONTENTS 
Introduction 1 
Scope and objects of the investigation _ . 1 
The pulp wood situation 2 
Standard pulping methods 5 
Mechanical process r 5 
Chemical processes 7 
Experimental procedure 11 
Equipment 11 
Conduct of tests 11 
Species investigated 16 
Pulping characteristics of groups of woods... 17 
Softwoods. 17 
Hardwoods.. 20 
Bark disposal 21 
Page 
Suitability of individual species for pulping. . 21 
Estimation of pulping value 21 
Application of data to operating condi- 
tions 23 
Summaries by species 25 
1. Spruces 25 
2. Pines 29 
3. Firs 38 
4. Hemlocks and other conifers 42 
5. Hardwoods — diffuse porous 47 
6. Hardwoods — ring porous 57 
7. Miscellaneous species 62 
8. Chilean woods 64 
Tables of cooking and strength data 65 
INTRODUCTION 
SCOPE AND OBJECTS OF THE INVESTIGATION 
In 1906 the Forest Service commenced, at its pulp and paper 
laboratory, then located in South Boston, Mass., a study of the 
pulping characteristics of American woods for the manufacture 
of paper pulp. Since that time the work has been continued as 
one of the major research projects of the service. This bulletin 
is a report of what may be termed the general or " extensive" phase 
of the investigation, covering all available species which seemed 
to offer possibilities. 
Most of the 94 species studied have been tested by the soda, 
sulphate, and sulphite processes. Twenty-two have also been 
tested by the mechanical process in the commercial sized experi- 
mental unit operated at Wausau, Wis., from 1911 to 1914, and 
i The investigation herein reported was started by the Forest Service in 1906-07 under the supervision 
of H. S. Bristol, at South Boston, Mass. In 1907 the work was transferred to Washington, D. C, where 
Edwin Sutermeister was in charge, and since 1910 has been carried on at the Forest Products Laboratory, 
Madison, Wis. The following have been successively in charge of the section of pulp and paper at the 
laboratory: H. E. Surface, 0. L. E. Weber, Otto Kress, and John D. Rue. Pulping experiments have been 
supervised by: Mechanical process, J. H. Thickens and G. C. McNaughton; soda and sulphate processes, 
R. E. Cooper and Sidney D. Wells; sulphite process, R. E. Cooper, C S. Gwynne, S. E. Lunak, V. P. 
Edwardes, and R. N. Miller. Throughout the investigation the beater and paper-machine runs have 
been superintended by J. J. Laing. 
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