Canadian Forestry Journal, May, iq20. 



213 



the use of other woods during the 

 war. Douglas fir and Port Orford 

 cedar proved quite satisfactory, and 

 it was found that even several of the 

 western firs, and the various white 

 pines could be used to some extent. 



Wood Propellers and Skids. 



Hardwoods are used for propellers, 

 engine bases, skids, packin pieces, 

 etc. Though walnut and mahogany 

 are considered the best woods for 

 propellers, it was found that oak. 

 beech, maple and ash could be used 

 where the requirements are not too 

 exacting. Ash, especially white ash, 

 is used extensively for longerons, 

 bent work on wings and fuselage, 

 landing skids and other parts of the 

 framework. 



In view of the special efforts re- 

 quired to secure enough aeroplane 

 wood to meet the war demands, it is 

 of interest to- consider what the possi- 

 bilities are of meeting the demands 

 which may be made in the future. 



How Much Sitka Spruce? 



There is estimated to be still al)out 

 13,700 million board feet of Sitka 

 spruce in British Columbia, 9,400 mil- 

 lion feet in Washington and Oregon, 

 and from 15,000 to 18,000 million feet 

 in Alaska. A considerable proportion 

 of this timber is so situated that it 

 will not be commercially accessible in 

 the near future, and most of it is so 

 scattered in stands with other species 

 that it cannot be profitably taken out 

 except as the other timber is logged. 

 Unless another emergencv arises, the 



This is what is called a "spiral grain" spruce log. 

 Because the tree grew with this defect, all such 

 logs were discarded for aeroplane manuf ictur? 

 and indeed for nearly any other timber purpo r-. 



supply will have to be secured from 

 the ordinary annual cut. If it had 

 been necessary to continue the pro- 

 duction in British Columbia at the 

 rate attained by the end of 191S. 

 through the concentration of efforts, 

 the available supply of aeroplane 

 spruce that could be secured at a 

 reasonable cost would have been ex- 

 hausted in a year or so. 



'Hie United States Spruce Produc- 

 titiu Corporation opened a consid r- 

 al)1c source of supply by railway con- 



INTER-PLANE STRUT 



SECTION OF WING BEAM 

 CHANNELLED OUT TO REDUCE WEIGHT 



