PUTTING WOOD WASTE TO WORK 145 



periments, these woods are now being used to 

 better advantage with less waste in the building 

 and manufacturing industries. A potential 

 saving of at least 20 per cent, of the timbers used 

 for building purposes is promised, which means 

 a salvage of about $40,000,000 annually as a re- 

 sult of strength tests of southern yellow pine and 

 Douglas fir. Additional tests have shown that 

 the red heartwood of hickory is just as strong and 

 serviceable as the white sapwood. Formerly, 

 the custom has been to throw away the heart- 

 wood as useless. This discovery greatly extends 

 the use of our hickory supply. 



Heretofore, the custom has been to season 

 woods by drying them in the sun. This method 

 of curing not only took a long time but also was 

 wasteful and expensive. The forestry scientists 

 and lumbermen have now improved the use of 

 dry kilns and artificial systems of curing green 

 lumber. Now more than thirty-five of the leading 

 woods such as Douglas fir, southern yellow pine, 

 spruce, gum and oak can be seasoned in the kilns 

 in short time. It used to take about two years of 

 air drying to season fir and spruce. At present 



the artificial kiln performs this job in from 

 10 



