22 BULLETIN 544, IT. S. DEPARTMENT OF AGRICULTURE. 
hardwood leaves. In the spring the warm rains and sun start fer- 
mentation of this mulch, and while this at first affords conditions 
exceedingly favorable to the germination of the spruce seed, the 
young seedlings are unable to survive the continued heat and humid- 
ity and the general smothering effect of the hardwood leaf litter. 
The trouble thus seems to be not that the seedlings are unable to 
get their roots into mineral soil or other suitable material as is usually 
claimed, but that the heavy mulch prevents them from getting their 
shoots up into the needed light and air. 
FORM. 
The form of spruce varies widely and is determined largely by its 
stage of development and whether it grows in the open or in the 
forest. Like all other conifers, however, it always develops a well- 
defined central axis. In the open and before arriving at the stage 
in the forest where its lower limbs begin to be suppressed, spruce has 
a long, wide-spreading, conical-shaped crown, which extends well 
down to the ground. Its bole tapers rapidly. This form is retained 
to a large extent throughout life by the trees growing in the open, 
although their crowns open out and become less regular in outline 
with advancing age. In .the forest the crown is more compact and 
has a conically topped head. As the tree grows in height the crown 
becomes shorter in proportion to the total height through the lower 
branches dying out more rapidly than new ones can be produced 
above. The bole at the same time takes on a more cylindrical form 
below the crown. Trees growhig in the selection forest are likely to 
taper a little more rapidly than those in the even-aged stands, since 
they receive more side light and thus retain a longer crown than the 
more densely crowded, even-aged ones. 1 
LENGTH OF LIFE AND MAXIMUM SIZE. 
Spruce may be classed as one of the longest-lived trees in the 
eastern United States, ranking with the white oak in this respect. 
In a virgin stand spruce seldom matures under 200 years, and the 
average age of the trees in such stands is undoubtedly nearer 250 or 
300 years. According to Mr. Austin Cary, the oldest spruce which 
came under his notice in Maine was approximately 400 years (372 
1 An example of the variable form and development of sprace growing under different conditions is shown 
in the following abstract from a memoir on the Adirondack spruce by the late Col. W. F. Fox, Superin- 
tendent of State Forests, in the Report of the Forest Commission, State of New York, 1894: " V 
spruce 20 inches in diameter growing in a clump of spruces will yield five logs 13 feet 4 inches in length, 
while one of the same diameter in a scattered growth mixed with hardwoods will yield but four logs. In 
the one growing among hard woods after four logs have been cut from the trunk the diameter of the last 
or top log at its small end will be from. 10 to 12 inches, but the limbs above this point will be so thick and 
large that the fifth log would not be over 5 or 6 inches at the top and would not be accepted by the lumber- 
man. A tree of the same species and size growing in a clump will yield five logs because the shaft does not. 
diminish in size so fast owing to the lighter growth of limbs that form its top. While the larger spruce are 
found scattered among the hardwoods, the tallest ones of like diameter are found growing in the spruce 
clumps." 
