PINACE^ 313 



to Alaska and spreading southwards down the Atlantic coast to 



S. Maine, N, New Hampshire, Vermont, New York, Michigan, 

 Wisconsin, and Dakota ; its most southerly limit being in Massa- 

 chusetts. It is the most important timber tree in the forests of 

 Cent. Alaska, and succeeds even where the soil is permanently 

 frozen 2-3 ft. beneath the surface. It is said to have been 

 introduced into Europe by Bishop Compton in 1700. 



Wood creamy-white or straw-coloured, straight and even- 

 grained, long-fibred, soft, easily worked, finishing with a satiny 

 surface. It is used extensively for the indoor finish of houses, 

 joinery and boxmaking ; selected quaUties being employed for air- 

 craft, for sounding boards for pianos and viohns, and for organ 

 pipes, but probably the largest quantity is consumed in the manu- 

 facture of paper pulp. It is one of the principal economic woods 

 of Newfoundland and E. Canada, where, with the wood of P. 

 7iigra and P. rubra, it furnishes a large proportion of wood pulp. 

 For this purpose the wood is reduced to cellulose either by a 

 mechanical or chemical process, full accounts of which are given 

 by Nelson Courtlandt Brown {Forest Products, their Manufacture 

 and Use). The quantity of spruce wood used for pulp in N. 

 America in 1916 is there given as 3,101,660 cords, and the yield 

 of pulp from a cord of wood is stated to be 1,600-2,200 lb., 

 manufacturers usually estimating a yield of about 2,000 lb. of 

 air-dry pulp from spruce, the yield by the mechanical process 

 being higher than by the chemical process. Spruce pulp in New- 

 foundland, Canada, and N.E. United States is used extensively 

 in the manufacture of newspaper. 



Strength tests conducted in the Forest Products Laboratory, 

 Canada, and pubUshed in the Empire Timber Exhibitio7i Catalogue 

 (London, 1920), give the following results : — 



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

 28| lb. per cu. ft. 



Tension, strength across grain, 300 lb. per sq. in. 



Compression, strength across grain at elastic hmit, 229 lb. per 

 sq. in. 



Compression, crushing strength with the grain, 2,540 lb. per 

 sq. in. 



Shearing strength with grain, 630 lb. per square in. 



Bending, modulus of elasticity (stiffness), 1,139,000 lb. per 

 sq. in. 



Hardness, weight required to half -imbed a 0444 in. steel 

 ball, 278 lb. 



The wood of P. alba, P. nigra, and P. rubra appears to be 

 often mixed in commerce. Canadian spruce is obtainable in four 

 quaUties and is shipped from Quebec, Montreal, and other ports. 

 In 1916 ^ the total cut of spruce in the United States amounted 



^ Nelson Courtlandt Brown, loc. cit. 4-8. 



