3616 



Chapter 29 



1905 



1923 



1935 



1944 



1950 



1952 



1962 



1970 



Figure 29-22. — Cubic feet of mine timbers annually consumed in the United States, 

 1905-1976. (Drawing after McKeever and Hatfield.^) 



125 



100 



PILING 



POLES 



MINE TIMBERS 



FENCE POSTS 



Figure 29-23. — Production of hardwood piling, poles, mine timbers, and fence posts in 

 1952, 1962, 1970, and 1977. Consumption of fence posts of all species, softwood as 

 well as hardwood, declined steadily from about 900 million pieces annually in 1 920 to 

 less than 100 million pieces in 1977; pole consumption, mostly softwood, was fairly 

 constant from 1950 to 1977 at from 5 million to 7 million pieces annually. Between 

 1970 and 1978, annual consumption of highway guardrail posts declined from about 

 300 million board feet to about 150 million board feet of all species. See figure 29-22 

 for long-term trend of mine timber consumption. (Drawing after McKeever and 

 Hatfield.^) 



