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 
grows 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 To 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 EARLY H1STOEY. 
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. TVTiite spruce was the first of our spruces 
to receive published notice, an account of it appearing as early as 
1535 1 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. 
- John Mason, "A Brief Discourse of the Newfoundland." 
