678 A NATIONAL PLAN FOR AMERICAN FORESTRY 



on which any work has been done by the Forest Service as a basis for 

 grading is on pulps and papers, and such efforts have been confined 

 to the last two or three years. Although lumber is one of the most 

 important forest products, there are others in which there is need for 

 a sound scientific basis for grading. 



MODIFICATION OF PROPERTIES 



Investigations of methods for the modification of the properties of 

 wood such as durability against decay, fire resistance, and shrinkage, 

 fall in this group. Perhaps, arbitrarily, such allied subjects as paint- 

 ing and gluing are also included. Modification of properties by dry- 

 ing has already been discussed. The logical order of attack is first 

 the application of standard treating materials by standard methods 

 to various species, and then the methods of application; but finally 

 the treating materials themselves, the preservatives, glues, paints, 

 etc., must be investigated and their properties correlated with prop- 

 erties of different wood species and the methods of treatment. The 

 gluing and durability investigations have been in the latter stage for 

 some time; the fire resistance and painting studies have recently 

 reached it. The modification of shrinkage properties has been at- 

 tacked in two distinct ways, the protection of the wood from moisture 

 by moisture-proof coatings, and the treatment of wood by chemicals 

 that reduce normal shrinkage. The first phase has been very thor- 

 oughly investigated; the study of the second is just beginning. 



Since modification of properties may have to be so drastic that the 

 original character and form of the wood is lost, it introduces another 

 diversified group of products and hence of investigations. The most 

 important example of this group is pulp and paper. The pulp and 

 paper investigations, which began with tests of the pulp-making and 

 paper-making qualities of practically all important American species 

 under standard pulping processes, have now reached advanced stages 

 of development. Intensive technological studies of the standard 

 processes have now made it possible to increase their efficiency and 

 to modify the processes to fit new species. Entirely new processes 

 have also been developed. In reaching this advanced stage of re- 

 search, greater refinement of method has been required, more accurate 

 measurement and control, and attention to more details than in the 

 preliminary species studies. 



On the possibility of developing other modified forms, such as plas- 

 tics, only work on a small scale and for a short period has been done. 

 On many more modified products, such as artificial leathers, rayon, 

 etc., nothing has been attempted. 



A wide field for research still remains in modifications to prevent 

 the absorption of moisture and hence shrinking and swelling, to de- 

 velop satisfactory preservatives and treatments to prevent decay 

 under all conditions, to develop economical treatments which will 

 insure fire resistance, etc. In the pulp and paper field there is still 

 room for vast improvement. It should be possible eventually to 

 develop a number of the more common pulps and papers from many 

 common tree species. Possibly ways and means can be developed to 

 reduce excessive wastes in chemical pulping processes which are now 

 responsible for the loss of approximately half of the original volume 

 of the wood. Many agents, such as bacteria, fungi, etc., for the modi- 



