Description:
This coniferous tree is 50-120' tall, forming an unbranched straight
bole and a crown that is conical to oblongoid in outline.
Toward the base of a mature tree, the trunk is 1½-3' across. The trunk
bark is gray and rough-textured, becoming scaly with age. Both
crustose lichens and algae often
colonize its bark. Numerous lateral branches originate along the entire
length of the bole. These lateral branches are slightly incurved and
ascending. Along
the length of each lateral branch, there are several drooping
branchlets that divide into divergently branched twigs. The bark of
these branches and
branchlets is slightly rough and gray, while the twigs are pale
yellow to reddish brown. Along the smaller branches, branchlets, and
twigs are short needle-like leaves about ½-1" long. These needle-like
leaves are medium to dark green, 4-angular, and slightly flattened
with blunt tips; they are stiff-textured and curve slightly toward the
tips of each branch or twig. Along the sides of each leaf, there
are pairs of faint white lines that are formed by rows of stomata (air
pores). At the base of each leaf, there is a short peg-like extension
of the twig from which the leaf breaks off when it turns brown from
age. Individual leaves are evergreen, persisting on a tree for 3-7
years. They have a pine-like fragrance.
Norway Spruce is monoecious,
forming separate male and female cones on the same tree during mid- to
late spring. Male pollen cones are produced from the axils of the
needle-like leaves; they are ½-1" in length, oblongoid-ovoid in shape,
and purplish red to whitish pink. Female seed cones are produced from
the tips of twigs; they are initially pink to reddish pink and
oblongoid-ovoid in shape, but change color and become longer after the
blooming period. At this stage, both male and female cones are more or
less erect. Afterwards, fertile seed cones become green and hang
downward; they are covered with overlapping appressed scales. At
maturity, these seed cones become brown to gray-brown and slightly
woody from their thin scales; they are 4-7" in length and cylindrical
in shape. Individual scales are about ¾-1" in length and ½-¾" across;
they are obovate-rhombic in shape, glabrous, and
irregularly toothed to toothless along their outer margins.
Hidden behind each scale, is a pair of winged seeds (not always fully
developed). Each seed body is 3-5 mm. in length, while
its membranous wing is 10-15 mm. in length. The winged seeds are
distributed by the wind. The root system consists of
shallow lateral
roots. This tree can reproduce vegetatively by "layering" when its
lower branches become inserted in moist soil.
Cultivation:
The
preference is partial to full sun, well-drained moist conditions, and
an acidic fertile soil consisting of sandy loam or other soil types. A
cool, moist, and humid climate is also preferred, although this tree
can tolerate a temperate climate that is more warm and dry. Growth is
relatively fast for a conifer during the early stages of
development. Under
favorable conditions in North America, this tree will live 100-200
years, if not longer. Where the soil has a low pH, it is vulnerable to
acid rain.
Range
& Habitat: The non-native Norway Spruce has
naturalized only in the NW corner of Illinois in Jo Daviess County,
where it is rare. It was introduced into North
America from Europe, where it is native. In Illinois, this tree
has naturalized in a woods (Mohlenbrock, 2002), where it is apparently
successfully reproducing. Norway Spruce is far more common in
cultivation, where it used as a landscape tree, a windbreak tree, and a
plantation tree (for Christmas trees and other commercial markets).
Faunal
Associations: A number of insects feed on the foliage,
bore through
bark, or suck plant juices from Norway Spruce and other spruce trees
(
Picea spp.).
These insects include the caterpillars of such
moths as
Choristoneura
fumiferana (Spruce Budworm),
Elaphria versicolor
(Variegated Midget),
Endothenia
albolineana (Spruce Needle Miner), and
Feralia comstocki
(Comstock's Sallow); see the
Moth Table for a
more
complete listing of these species. Another group of insect feeders
include the wood-boring larvae of such long-horned beetles as
Monochamus marmorator (Balsam
Fir Sawyer),
Monochamus
titillator
(Southern Pine Sawyer), and
Semanotus
litigiosus (Fir Tree Borer); see
the
Long-Horned Beetle Table
for a more complete listing of these
species. Other miscellaneous insect feeders include
Adelges abietis
(Eastern
Spruce Gall Adelgid),
Chionaspis
pinifoliae (Pine Needle Scale),
Physokermes piceae
(Spruce Bud Scale), the aphids
Cinara
pinicola and
Cinara pruinosa,
the plant bug
Psallovius
piceicola, the weevils
Hylobius pales
(Pales Weevil) and
Pissodes
approximatus (Northern Pine
Weevil), and the root-feeding larvae of
Strigoderma
arboricola (False Japanese Beetle).
An arachnid invertebrate species,
Oligonychus
ununguis (Spruce Spider
Mite), also feeds on these trees.
Among vertebrate animals, the seeds
of spruces are eaten by such birds as the Red Crossbill, White-Winged
Crossbill, Red-Breasted Nuthatch, Slate-Colored Junco, and Pine Siskin;
the Red Squirrel also consumes the seeds. Norway Spruce is one one of
the least preferred sources of food of White-Tailed Deer, although
Cottontail Rabbits occasionally browse on seedlings of this tree during
the winter. Because of their dense branching structure and evergreen
foliage, spruce trees are used as nesting habitat by such birds as
the Golden-Crowned Kinglet, Blackburnian Warbler, and Blackpoll
Warbler; this generally occurs in boreal areas to the north or
northeast of Illinois. Some birds like to roost in spruces,
particularly during the winter, because of the protective cover that
they provide.
Photographic
Location: Near the veterinarian building of the University
of Illinois
in Urbana, Illinois.
Comments:
The wood of Norway Spruce is used to make furniture, musical
instruments (pianos & violins), pulp, and in general
construction.
It is light-colored, light-weight, rather soft, and reasonably strong.
Norway Spruce has the longest seed cones of any spruce (
Picea sp.) in
Illinois; they exceed 4" in length, while the seed cones of other
spruces within the state (which are largely cultivated) are less than
4" in length. Spruces resemble firs (
Abies spp.), but
their mature seed
cones hang downward from their branches. In contrast, the mature seed
cones of firs are erect. Spruces produce their leaves
individually along their twigs and branches, while pines (
Pinus spp.) produce
their
leaves in clusters (typically 2-5 leaves per cluster). Thus, spruces
are fairly easy to distinguish from firs and pines. Like Norway Spruce,
other spruces in Illinois are rarely observed in the
wild. The coniferous trees in this group are more typical of boreal
regions or mountainous areas where the climate is more cool and damp.