354 A HANDBOOK OF CONIFERS 



The Sitka spruce extends further north-west than any other N. 

 American conifer, its westerly limit being the east end of Kadiak 

 Island. It extends through the coast region of Alaska, British 

 Columbia, W. Washington, Oregon, southwards to N. California, 

 rarely extending inland more than 50 miles. It was first found 

 in 1792 at Puget Sound by Archibald Menzies, the distinguished 

 traveller after whom it was first named by Lindley, but was not 

 in cultivation until introduced by Douglas in 1831. 



Wood light in weight, straight-grained, long-fibred, strength 

 value very high in comparison to weight ; soft, easily worked, finish- 

 ing with a fine, smooth, satiny surface, sapwood cream-coloured, 

 heartwood a little darker or sometimes pinkish ; shrinkage small, 

 even. The most valuable of all spruce woods, and obtainable in 

 large dimensions ; planks up to 30 ft. long and 30 in. wide, and 

 narrower planks up to 40 ft. long. It is used for building con- 

 struction, aircraft, general joinery, and all the other purposes 

 of spruce, including pulp for paper manufacture. Its combined 

 qualities of strength and Hghtness render it peculiarly suitable 

 for aeroplane construction, and during the war the timber, 

 which had previously been scarcely known in England, was in 

 great demand and became one of the most widely used woods 

 for this purpose. Large quantities were imported from British 

 Columbia and U.S. ports under the name of silver spruce, a trade 

 name which at first included other woods, probably Picea 

 Engelmanni and Tsuga Albertiana, but was later restricted to 

 P. sitchensis. 



Tests made on green material by the Canadian Forest Pro- 

 ducts officials are given in the Catalogue of the Empire Timber 

 Exhibition (London), 1920, as follows : 



Weight, green (moisture 25 per cent., wood 75 per cent.), 

 29 lb. per cubic ft. 



Tension, strength across the grain, 299 lb. per square in. 



Compression, strength across grain at elastic limit, 288 lb. 

 per square in. 



Compression, crushing strength with the grain, 2,574 lb. per 

 square in. 



Shearing, strength with the grain, 625 lb. per square in. 



Bending, modulus of rupture (breaking strength), 5,454 lb. 

 per square in. 



Bending, modulus of elasticity (stiffness), 1,413,000 lb. per 

 square in. 



Hardness, weight required to half imbed a 0*444 in. steel 

 ball, 352 lb. 



Compared with the wood of P. Engelmanni, it is much stronger, 

 and each species should therefore be marketed under distinct 

 names. 



P. sitchensis gives excellent results imder cultivation in 



