6 BULLETIN 327, U. S. DEPARTMENT OF AGRICULTURE. 



It is very tolerant of shade, being able to recover from suppression 

 up to an advanced age. Dense stands of black spruce produce a 

 heavy crown cover, which frequently shades out tamarack and other 

 intolerant trees. Black spruce is most tolerant on wet soils, which 

 are often covered with dense stands of slow-growing trees, and least 

 tolerant of shade in dry, well-drained situations, where it usually 

 growg in more open stands. Ability to endure dense shade enables the 

 trees to retain their side branches for a relatively long time, those 

 with clear trunks occurring only in the densest stands. 



Black spruce is not a prolific seeder, although some seed is usually 

 borne locally each year; abundant seed production occurs only at 

 rather long, irregular intervals. The seed has a moderately high 

 germination and persistent vitality. Germination is best on con- 

 stantly moist mineral or humus soils, on wet, decayed fallen trees, 

 moss, and moist, decomposed spruce leaf litter. The leaf litter of 

 broadleaf trees is not, as a rule, favorable to germination, because 

 the seedling roots can not penetrate the tough mass of duff. Seed- 

 lings require at least moderate shade for their development during 

 the first one or two seasons, while the young plants grow most 

 thriftily in dense shade. 



The lower branches of black spruce trees frequently take root when 

 lying in close contact with moist earth or leaf mould, and produce 

 clusters of little trees under the shade of the mother tree. 



LONGEVITY. 



In general, black spruce is moderately long-lived, trees of average 

 size being from 125 to 200 years old. Trees in wet situations grow 

 very slowly, often only 1 to 2 inches in diameter in 75 or nearly 100 

 years. Further age determinations are desirable of trees grown in 

 the moister and drier situations. 



WHITE SPRUCE. 



Picea canadensis (Mill.) B., S., and P. 



COMMON NAME AND EAELT H1STOBY. 



Picea canadensis is most commonly and widely known as white 

 spruce, this name referring to the whitish hue of the foliage. It is 

 also locally known as " cat spruce " and " skunk spruce " because of 

 the polecatlike odor given off by the foliage and young twigs, 

 especially when crushed. White spruce was the first of our spruces 

 to receive published notice, an account of it appearing as early as 

 1535 x and again in 1620. 2 The first of these records refers to trees 



1 " Bref Recit et Succincte Narration de la Navigation faite in mdxxxv. mdxxxvi, Parle 

 Capt. Jacques Cartier aus lies de Canada," 24, 1535. 



2 John Mason, "A Brief Discourse of the Newfoundland." 



