This coniferous evergreen tree is typically 40-60' tall at maturity,
consisting of a short single trunk about 1¼-2½' across and a densely
branched oblongoid-conical crown. However, sometimes mature trees are
substantially smaller or larger in size than this, depending on their
age and habitat. The trunk may remain unbranched along the
of the tree, or it may divide into 2-3 erect branches. Trunk bark is
reddish brown or reddish gray and less than ½" deep, consisting of
narrow vertical strips that are slightly ragged. Occasionally, large
older trees will develop shallow furrows on their trunks. Branches are
gray to reddish gray or brown to reddish brown; smaller branches are
fissured and irregular, while the smallest branches have gray or brown
leaf-remnants along their sides. Fan-like sprays of flattened
branchlets develop from the smallest branches; these branchlets are
covered on 4 sides with 2 pairs of opposite leaves that are appressed
and slightly overlapping. Pairs of opposite leaves on 2 sides of each
branchlet are strongly keeled and curved, while the remaining pairs of opposite
leaves on the other two sides are flattened.
Individual leaves are 1.5-5 mm. long, yellow green to green, hairless,
and either dull or shiny; they have a scale-like appearance. On young
branchlets, the leaves are 1.5-3 mm. long and ovate, tapering to
short blunt tips. On older branchlets that are either green or brown,
the leaves are 3-5 mm. long and lanceolate, tapering to long narrow
Northern White Cedar is monoecious, developing male pollen cones
and female seed cones on the branchlets of the same tree. The blooming
period occurs from late spring to early summer; the cones are
cross-pollinated by the wind. The male cones are about 2 mm. long,
rounded, and yellowish in color. The female cones are initially pink to
purple, but they become brown and woody at maturity later in
same year. Mature female cones are 9-13 mm. (1/3 to 1/2")
long, ellipsoid in shape, and more or less erect; they usually
occur in loose clusters on the branchlets. Each female cone has several
pairs of appressed overlapping scales that are ovate in shape
and minutely mucronate (with rounded tips, except
for tiny points at their centers); these scales spread apart
release their seeds from late summer into the fall. Each mature female
cone has about 8 seeds (4 fertile scales with 2 seeds each).
Individual seeds are about ¼" in length and brown with
wings. They are distributed by the wind. The root system is shallow and
spreading. Northern White Cedar can reproduce by layering when its
branchlets extend into moist soil; the woody branches can also develop
roots when a tree falls to the ground.
preference is full sun to light shade, moist conditions, and a
peaty calcium-rich soil that has a neutral to alkaline pH. In the
southern portion of its range (including Illinois), Northern White
Cedar prefers some protection from the sun during the afternoon. This
tree develops slowly, but it can live 400-800 years under favorable
conditions. However, individual trees are often damaged or killed by
fire, strong winds, ice storms, heavy snow, and other problems.
& Habitat: Northern White Cedar is
restricted to NE
where it is native. In natural areas, this native tree is rare and
state-listed as 'threatened.' However, it is more common in boreal
areas to the north of the state. In Illinois, habitats
forested fens, seeps, and springs. Outside of the state, it
occurs in forested bogs and along rocky cliffs. This tree has been
extirpated from some localities within Illinois because of development.
It is also threatened by an overpopulation of deer within the state.
Northern White Cedar is widely cultivated throughout the state as a
landscape tree in yards, parks, and cemeteries. However, these
cultivated trees have rarely, if ever, escaped into natural areas.
Associations: Northern White Cedar is a host plant of
Both the Black Carpenter Ant (Camponotus
pennsylvanicus) and Red
Carpenter Ant (Camponotus
ferrugineus) develop chambers within the
rotting wood of the trunk and branches of older trees. Larvae of
the moths Argyresthia
thujaella mine the scale-like leaves. Other moth larvae that feed on this tree
amitaria (Cranberry Spanworm), Digrammia
continuata (Curve-Lined Angle), and Anomogyna badicollis
Variable Dart); the larvae of this last moth attack young seedlings.
Other insect feeders include the larvae of Monoctenus melliceps
(Arborvitae Sawfly), Carulaspis
juniperi (Juniper Scale), Parthenolecanium
fletcheri (Fletcher Scale), Cinara tujafilina
(Arborvitae Aphid), the
plant bugs Dichrooscytus
elegans and Dichrooscytus
repletus, and the
larvae of Phyllobius
intrusus (Arborvitae Weevil). The larvae
canadensis (Northern Cedar Bark Beetle) bore through the wood, as do the
of several long-horned beetles: Atimia
confusa confusa, Callidium
and Semanotus ligneus
ligneus (Cedar Tree Borer).
In addition, the foliage of this tree is attacked by some species of
(Tip-Dwarf Mite), Oligonychus
Spider Spite), and Platytetranychus
thujae (Arborvitae Spider Mite).
Some vertebrate animals are associated with Northern White Cedar and
its surrounding habitat. Such birds as the Ruffed Grouse, Pine Siskin, Common
Redpoll, Slate-Colored Junco, and Tree Sparrow eat the seeds or cones,
as does the Red Squirrel. The branchlets and twigs of this tree are the
preferred winter browse of White-Tailed Deer, which also find shelter
within stands of Northern White Cedar during the winter. The Pileated
Woodpecker searches for carpenter ants within the wood of older trees.
Because of its dense branching habit and evergreen foliage, this tree
provides good nesting habitat for such migratory songbirds as the Cape
May Warbler, Blackburnian Warbler, and Golden-Crowned Kinglet (north of
Illinois); the Ovenbird constructs its nests on the ground within stands of Northern White Cedar (also north of Illinois). Other
migratory songbirds that are attracted to this tree during the summer
include the Swainson's Thrush, Northern Parula, Black-Throated Green
Warbler, Black-and-White Warbler, Magnolia Warbler, and White-Throated
Location: Along a roadside in Urbana, Illinois.
it is planted in an appropriate location, Northern White Cedar is a
beautiful tree that has foliage with a pleasant fragrance. In spite of
its common name, this tree is more closely related to a cypress or
juniper, rather than a true cedar. Another common name for this tree is
American Arborvitae. Many cultivars have been developed that vary in
size, shape, color of foliage, and tolerance of heat. There are also
Asiatic Thuja spp.
that are often cultivated, although there are no
records of their naturalizing in Illinois. Generally, these Asiatic
species have less flattened branchlets than Northern White Cedar, and
there are differences in the characteristics of their seed cones.