THE OUTLOOK FOR TIMBER DEMANDS 



33 



greater insulating qualities of wood, and greater 

 ease of repairing cars built with wood interiors. 

 On the other hand, substitution of steel is con- 

 tinuing in all classes of cars, and in the case of 

 refrigerator cars, plywood is also being used to 

 some extent in lieu of lumber. 



In the past; considerably more lumber has been 

 used in the repair of freight cars than in the con- 

 struction of new cars. Use of lumber for car 

 repair has been declining, however, as a result of 

 the changing types of cars in service ; some further 

 decline in lumber use for car repairs has been 

 assumed. 



Considering these trends, it has been estimated 

 that use of lumber in car construction and repairs 

 may approximate 250 million board feet of lumber 

 annually in the decades ahead, plus modest 

 amounts of plywood (table 21). 



Use of lumber for new construction and for 

 maintenance of buildings, bridges, and other 

 structures on projects undertaken by railway 

 personnel amounted to about 80 million board feet 

 annually in the 1950's. It was estimated that 

 consumption of lumber for miscellaneous railway 

 structures would continue to approximate this 

 recent average. 



Table 22. — Wood consumed in mining, by type of 

 mine, 1905-2000 





Lumber 



Round, split, and 

 hewn products 



Year 



Total 



In coal 

 mines 



In 



other 

 mines 



Total 



In coal 

 mines 



In 



other 

 mines 



1905 



1923 



1935 



1950 



1962 



Mil- 

 lion 

 board 

 feet 

 436 

 507 

 467 

 836 

 330 



Mil- 

 lion 

 board 

 feet 

 242 

 296 

 347 

 597 

 182 



Mil- 



lion 



board 



feet 



194 



211 



120 



239 



148 



Mil- 

 lion 

 cubic 

 feet 

 166 

 174 

 113 

 108 

 48 



Mil- 

 lion 

 cubic 

 feet 

 135 

 152 

 102 

 90 

 41 



Mil- 

 lion 

 cubic 

 feet 

 31 

 22 

 11 

 18 

 7 



PROJECTIONS 



1970. 

 1980. 

 1990. 

 2000. 



300 



170 



130 



40 



35 



330 



200 



130 



45 



40 



360 



220 



140 



60 



50 



400 



240 



160 



60 



50 



5 

 5 



10 

 10 



Projected Use of Lumber by Railroads 

 Estimated at 1.5 Billion Board Feet Annually 



Total demand for lumber for all railway uses, 

 including crossties, switch and bridge ties, car 

 construction and repair, and miscellaneous struc- 

 tures, are estimated to average about 1.5 billion 

 board feet annually over the period 1962-2000 

 (tables 20 and 21). Projected demands for ply- 

 wood average about 100 million square feet 

 annually. 



MINE CONSTRUCTION AND MAINTENANCE 



Lumber, sawn mine ties, and round and split 

 mine timbers have long been used in substantial 

 quantities in the mining of coal and other minerals 

 such as iron and copper. Changing mining prac- 

 tices in recent years, however, have resulted in 

 sharp declines in the use of these wood products. 



In 1962 the total volume of wood products used 

 in rnining operations included an estimated 330 

 million board feet of lumber, and 48 million cubic 

 feet of round, split, and hewn products (table 22). 

 These volumes were substantially below com- 

 parable estimates for 1950 and prior years. 



One of the major causes of this decline in use of 

 wood has been the drop in production of coal and 

 other minerals from underground mines, where 

 practically all wood products used in mining are 

 consumed. Other factors include changes in min- 

 ing techniques, such as the use of conveyor belt 

 systems and rubber-tired vehicles, which have 

 reduced the use of mine ties; metal roof bolts and 

 steel arches, which have substituted on a large 

 scale for wooden mine props; and greater use of 

 preservatives, which has extended the service life 

 of wood products. 



The effects of these changes are illustrated by 

 factors of wood use per ton of coal output de- 

 veloped in several national surveys of wood use 

 in mining conducted periodically by the Forest 

 Service, as follows: 



Lumber Roundwood 



Year: (board feet) {cubic feet) 



1905 0.62 0.34 



1923 .45 .23 



1935 .83 .24 



1950 l.a7 .16 



1962 .41 • .09 



Small Increases Expected in 

 Future Use of Wood in Mining 



Recent appraisals of future requirements for 

 coal and other sources of energy materials indicate 



