314 UNITED STATES FOREST POLICY 



kiln-dried without loss of strength in less than a month ; and numerous 

 dry-kilns constructed on the plan laid down at Madison were built 

 by the companies with airplane contracts. 



Plywood formed by gluing together several sheets of veneer was 

 found to be very serviceable for various parts of airplanes. A ply- 

 wood wing rib has been developed which weighs nearly one third less 

 than the rib before used, while its strength is 200 per cent greater. 



These are only a few illustrations of the work being done in forest 

 products. Probably this work will expand in the future, as the in- 

 creasing scarcity of timber compels a more intelligent and economical 

 use of our remaining resources.^* 



i< Review of Forest Service Investigations, 1913. See also the annual reports of 

 the Forester and numerous bulletins issued by the Forest Service. 



