314 A HANDBOOK OF CONIFERS 



to 1,250,000,000 board ft., and the standing spruce timber in 

 the United States at that period was estimated at 60 billion 

 board ft. 



The white spruce occurs naturally on moist but well-drained 

 land from sea-level to an elevation of 5,000 ft. Very wet or very 

 dry land exerts a dwarfing influence. It is often found pure 

 in extensive forests, but also occurs in mixed stands. P. alba 

 withstands a good deal of shade in its earher years, and suppressed 

 trees make a good recovery when given additional hght. A 

 moderate crop of seed is borne every year with heavy crops every 

 5-8 years. Natural reproduction is said to be good ^ under mature 

 spruce on damp moss over organic soil, and on moss-covered 

 decayed logs and stumps. White spruce reproduces itself poorly 

 on deep leaf-litter of broad-leaved trees. 



P. alba is chiefly useful in Britain by reason of its great cold- 

 resisting quahties, and is used sparingly in some parts of the 

 N. of England and in Scotland for silvicultural work in cold, 

 exposed positions at high altitudes, particularly for shelter. As 

 a timber tree in Britain, however, it is inferior to P. excelsa and 

 P. sitchensis. For ornamental purposes it is scarcely equal 

 to European spruce, and is shorter-lived in England. In N. 

 America its natural age is 250-300 years. 



ainton-Baker, Illust. ConiJ. ii, 34 (1909). 



Picea Albertiana, Stewardson-Brown.^ (Fig. 67.) 



A tree 160 ft. high in W.N. America. Bark fissured, at the 

 base of old trunks thin and greyish, white higher up where it 

 scales off in squarish plates. Young shoots light yeUow or greyish, 

 becoming darker with age ; glabrous or with minute hairs on the 

 pegs from which the leaves arise. Buds about 5- in. long, ovoid, 

 slightly resinous, with rounded scales, the terminal bud with long- 

 pointed scales at its base. Leaves bluish green, spreading more 

 or less round the shoot, but more crowded on the upper side, 

 \-\ in. long, curved, shortly pointed, quadrangular in section, 

 with 3-5 lines of stomata on each side. Cones cylindrical, 

 1-2| in. long, about 1 in. wide when the scales are open, shining 

 brown at maturity, with thin flexible fan-shaped scales which 

 are flatter than those of P. alba, the upper margin entire, undulate 

 or faintly toothed. Seed \ in. long with a wing | in. long. 



Var. conica, Bean. 



Picea glauca, Voss, var. Albertiana, Sargent, forma conica, Rehder. 



A dense bush of narrow, conical habit, with slender, closely 

 packed shoots which are yellowish grey at first and sHghtly 



1 Sudworth, loc. cit. 10. ^ Torreya, vii, 126 (1907), 



