WORK OF THE FOREST SERVICE 313 



tine, and various miscellaneous products. Recent experiments in 

 the production of ethyl alcohol from wood waste have resulted in 

 great economies. Methods of producing naval stores devised by the 

 laboratory are reported to have increased the . yield 30 per cent. 

 Nearly a million dollars' worth of dye is now manufactured annually 

 from Osage-orange wood — an industry built up as a result of investi- 

 gations carried on in the laboratory at Madison. 



Statistical studies have been made from time to time covering the 

 amounts, prices, sources, and uses of various forest products. Such 

 studies are of course of an economic nature, but are necessary to the 

 development of an intelligent forest policy. 



FOREST PRODUCTS RESEARCH AND THE WAR 



The entry of the United States into the war in 1917 brought out 

 clearly the importance of the forest products investigations. Much 

 of the technical information that had been secured in this research 

 work was immediately important in the solution of war problems, 

 which demanded exact knowledge of the properties of wood, and the 

 mechanical, physical, and chemical methods of conditioning. In the 

 construction of airplanes, for instance, there was a demand for 

 knowledge of the qualities of different woods, the availability of 

 substitutes for the spruce commonly used, methods of drying woods 

 speedily, the strength of laminated structures and veneers and ply- 

 wood — a multitude of problems of great importance in the prosecu- 

 tion of the war. The Forest Products Laboratory had a large amount 

 of data on the properties of airplane woods at the beginning of the 

 war, but much more was needed immediately, and soon the war air- 

 craft problems occupied the attention of about two thirds of the 

 force at the Madison laboratory. 



At the beginning of the war, it was customary to air-dry all wood 

 used in airplane construction, because of the danger of reducing the 

 strength by methods employed in commercial kiln-drying. It takes 

 about two years to air-dry spruce for this purpose, and large quan- 

 tities of material were needed at once, so kiln-drying was absolutely 

 necessary. Investigations in kiln-drying had been under way at Madi- 

 son for several years, and methods had been worked out for a number 

 of woods. Similar experiments with spruce showed that it could be 



