'''Thuja occidentalis''', a species of
thuja, is an
evergreen coniferous tree in the cypress family
Cupressaceae, native to the northeastern
U.S. and southeastern
Canada, from central
Saskatchewan east to
New Brunswick, and south to eastern
Tennessee in the
Appalachian Mountains.
Unlike the closely related ''
Thuja plicata'' (Western Redcedar), it is only a small tree, to 10-20 m tall and 0.4 m trunk diameter (exceptionally to 30 m tall and 1.6 m diameter). The
bark is red-brown, furrowed and peels in narrow, longitudinal strips. The
foliage forms in flat sprays with scale-like
leaves 3-5 mm long. The
cones are slender, yellow-green ripening brown, 10-15 mm long and 4-5 mm broad, with 6-8 overlapping scales.
It is known as 'Eastern Arborvitae', 'American Arborvitae', 'Techny Arborvitae', or just 'Arborvitae', the last particularly in the
horticultural trade. Other names by which it is known include 'Northern Whitecedar', 'Eastern Whitecedar' (sometimes split into two words as "White Cedar", though this causes confusion, as it is not a
cedar), and the colloquial "swamp-cedar". ''Thuja occidentalis'' should not be confused with the 'Chinaberry', ''
Melia azedarach'', an
Australian
deciduous tree also known as the White Cedar.
Ecology
''Thuja occidentalis'' grows naturally in wet forests, being particularly abundant in
swamps where other larger and faster-growing trees cannot compete successfully. It also occurs on other sites with reduced tree competition such as
cliffs. Although not currently listed as endangered, wild ''Thuja occidentalis'' populations are threatened in many areas by the very high
deer numbers encouraged by
hunting associations; deer find the soft evergreen foliage a very attractive winter food, and strip it rapidly. The largest known is 34 m tall and 175 cm diameter, in
South Manitou Island within
Leelanau County, Michigan. It can be a very long-lived tree in certain conditions, with notably old specimens growing on cliffs where they are inaccessible to deer and
wildfire; the oldest known living specimen is just over 1,000 years old, but a dead specimen with over 1,500 growth rings has been found. These very old trees are, despite their age, small and stunted due to the difficult growing conditions.
Uses
Eastern Arborvitae is very widely used as an
ornamental tree, particularly for screens and
hedges. Over 300
cultivars have been selected and named for garden use; some of the commoner in the horticultural trade include 'Degroot's Spire', 'Ellwangeriana', 'Hetz Wintergreen', 'Lutea', 'Rheingold', 'Smaragd' (a.k.a. 'Emerald Green'), 'Techny', and 'Wareana'. It was introduced into
Europe as early as 1540 and today is widely cultivated there, especially in parks and cemeteries.
The oils of ''Thuja occidentalis'' can be found in
organic medications that claim to eliminate warts, including the
Human papillomavirus. No scientific evidence proves this claim (reference: "Forces of Nature: Warts No More").
The needles of the Eastern White Cedar can also be boiled to make a tea. This tea contains 50mg of Vitamin C per 100 mg which makes this a helpful cure for Scurvy, and is believed to be the
annedda which cured
Jacques Cartier and his party in the winter of 1535–1536.
References
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Gymnosperm Database: ''Thuja occidentalis''
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Borealforest.org: ''Thuja occidentalis''