SPRUCE AND BALSAM FIR TREES. 



OCCURRENCE AND HABITS. 



Picea canadensis occurs on river banks, terraces, dryish margins of 

 swamps and lakes, and on adjacent sides of ridges and hills at ele- 

 vations of from near sea-level up to about 5,000 feet (Map No. 2). 

 It is most frequent on sandy loam soils with moderate moisture, but 

 grows on very shallow soils from the margins of swamps to the tops 

 of mountains. The largest trees are found in moist, well-drained, 

 finely divided porous soil; situations too dry or too wet produce 

 dwarfed, stunted, slowly grown trees. White spruce forms pure 

 dense forests, often of great extent. It occurs also in mixed stands. 

 Usually it forms extensive pure forests in well-drained soils along 

 rivers and on lower valley slopes. On wet or moist flats it often 

 gives way to black spruce, tamarack, or cottonwoods, and on dry 

 terraces to lodgepole pine. At timber line it is sometimes associated 

 with alpine fir. Dense groves and strips of pure white spruce occur 

 frequently, closely associated with birch, alder, aspen, willows, and 

 black cottonwood. 



Picea canadensis is tolerant of considerable shade from the seedling 

 to pole stages of growth. Young trees are able to maintain them- 

 selves for many years under rather heavy crown cover and to recover 

 from suppression when given top light, being surpassed in this re- 

 spect only by the black and red spruces. With top light the trunks 

 of young trees retain their lower side branches persistently, long, 

 clear stems occurring only in very close stands of older growth. 

 Thriving under light shade of poplars and birches, this spruce often 

 replaces these trees after fire or lumbering. 



"White spruce is a moderately prolific seeder. Considerable seed is 

 produced locally every year, while heavy seed production occurs over 

 parts of its range at more or less regular intervals of from five to 

 eight years. The seed has only a moderately high rate of germina- 

 tion, but persistent vitality. Good germination of the seed occurs 



ovate, bright crimson when young, at maturity 2.5 to 3.5 centimeters long and nearly as 

 broad when expanded, early deciduous ; scales stiff and rigid, broadly rounded at the 

 apex, entire, broader than long, cinnamon-brown with a chestnut edging and shading to 

 darker chestnut toward the base ; bract 2 millimeters or less long, 1 millimeter broad, 

 with a sharply angular, more or less acute erose tip. 



" Type : No. 796, S. Brown, Bankhead, Alberta. 



" The common spruce of the lower altitudes through the Canadian Rockies in Alberta 

 and British Columbia, differing from P. canadensis (Mill.), B. S. P., in the longer, 

 strongly reflected sterigmata, shorter, broader, and darker-colored cones, with broadly 

 rounded scales and minute sharply angled bracts and from P. mariana (Mill.), B. S. P., 

 in the lighter-colored smooth twigs with longer sterigmata and light-blue or blue-green 

 leaves, and cones with broader, entire scales with angular-tipped bracts." (Torreya, vol. 

 7, 125, 126, June, 1907.) 



The present author has not seen authentic specimens of this tree on which the above 

 description is based. As nearly as can be judged from descriptions of its characters it 

 appears to be closely related to Picea canadensis, particularly in the color and form of 

 the foliage and cones. Dr. Britton's figures (1. c. 45) of a cone shows some of the cone 

 scales, however, to be decidedly different in form from those of Picea canadensis. 



