Eastern White Cedar (Thuja occidentalis L.)
Northern white-cedar
Eastern thuja
Eastern arborvitae

Family: Cupressaceae (Cypress family)

Native Range: Eastern North America, primarily in swampy and limestone-rich areas

Widely planted as an ornamental and hedge species

Canadian Hardiness Zones: Hardy from Canadian Zone 3 to 7 (North American Zone 2 to 7), tolerating –45 °C to –15 °C winters; naturally found from eastern Canadian provinces like Manitoba, Ontario, Quebec, and New Brunswick, south into U.S. states such as Minnesota, Wisconsin, Michigan, and New York.

Size & Growth

Typical Height: Up to 15 m (50 ft).

Maximum Recorded Height: Massive specimen on South Manitou Island, Michigan, standing at 34 meters (112 feet) tall, with a trunk diameter of 175 cm (69 inches).

Trunk Diameter: Up to 30 cm (1 ft); occasionally 90 cm (3 ft).

Growth Rate: Slow

Typical Lifespan: Several hundred years

Record Age: Over 700 years (notably in cliffside conditions)
Not be the tallest trees in the forest though they hold records for some of the oldest trees in North America. On the limestone cliffs of the Niagara Escarpment, small, stunted cedars have been aging in place for over 700 years—some in northern Quebec are even older. Their ability to survive in extreme conditions makes them invaluable for birds and small animals, providing stable habitat across centuries.

For comparison: Some cedars alive today on the escarpment were already mature when the printing press was invented (1440). A 500-year-old cedar might be shorter than a 100-year-old maple, yet it's lived through entire civilizations rising and falling.

Their ability to persist despite their size makes them a hidden cornerstone of forest ecosystems, often overlooked but essential for biodiversity.

Quick Recognition Features

Scale-like leaves in four rows, yellowish-green, turning bronze in winter.

Flattened, fan-like twigs with conspicuous resin glands.

Small, upright seed cones (7-12 mm) with 5-6 leathery scales.

Thin, reddish-brown bark that peels into long, narrow strips.

Reproduction & Life Cycle

Seed Maturity: Begins producing viable seeds at a young age usually late summer.

Reproductive Cycle: Annually, with cones ripening in late summer.

Pollination Method: Wind.

Seed Dispersal Mechanism: Wind dispersal, cones shed gradually over months (beginning in late summer)

Seed Dormancy Requirements: Requires cold stratification for germination

Natural Germination vs. Nursery Germination

In the wild: Seeds fall from cones in late summer and scatter via wind. Natural germination is slow and requires the right conditions—cold stratification (exposure to cold, moist conditions) is needed to break dormancy.

In a nursery: Seeds are artificially stratified by storing them at temperatures just above freezing (0–4°C) for about 30–90 days. After stratification, they are sown in well-draining soil with partial shade to mimic their natural understory habitat.

Stratification Explained

Stratification is nature’s way of preventing premature germination. Without a cold period, the seed “thinks” it’s still in autumn and won’t sprout. By undergoing cold, moist exposure over winter, the seed “knows” spring has arrived and germinates when conditions are favorable.

Environmental Preferences

Soil Preferences: Thrives in calcareous (limestone-based) soils; tolerates poor, shallow, and boggy soils.

Water Needs: Prefers moist environments but can adapt to drier conditions.

Drought Tolerance: Moderate

Flood Tolerance: High, often found in swamps.

Shade Tolerance: High, can grow in understory conditions

Root System Type: Shallow, wide-spreading.

Climate Adaptability: Prefers cool, humid climates but adaptable within its range.

Physical & Chemical Properties

Wood Density: Light, soft, and weak

Strength Rating: Low

Decay Resistance: High (heartwood is rot-resistant)

Fire Resistance: Low

Fire Regeneration Ability: Limited

Ecological Role & Interactions

Wildlife Value: Essential winter food source for white-tailed deer, often creating "browse lines" in forests

Companion Species: Commonly found with
Eastern white pine
Yellow birch
Eastern hemlock
Silver maple
Black ash
and white elm

Invasive Status: Not invasive, but widely planted in landscapes

Threats: Susceptible to heart rot, overbrowsing by deer, and climate-related shifts in habitat

Human & Cultural Uses

Traditional Uses: Used by Indigenous peoples for medicinal purposes and lightweight construction materials

Modern Uses: Used in fencing, small poles, and canoe building; widely planted as a hedge species

Some of the oldest cedars on the Niagara Escarpment were alive before the first European explorers arrived in Canada.

The tree’s unique ability to cling to cliffs has led to some individuals being nicknamed “hanging trees.”

The thin, peeling bark makes it look fragile, but its ability to live for centuries proves otherwise.

Additional Notes & Fun Facts

Some of the oldest known trees in North America are Eastern White Cedars growing on limestone cliffs in Ontario and Quebec.

Highly valued for its aromatic, rot-resistant wood.

Used in traditional herbal remedies for colds, fevers, and infections.

Cedar is well known as a highly palatable and nutritious deer food. Back in the days when park rangers killed wolves and Algonquin consequently had an unnaturally high deer population it used to be an almost impossible challenge to find a Cedar seedling. In addition, along Park lakeshores every Cedar's foliage was removed up to the height of a deer's head. This left a sharp, conspicuous division, known as a "browse line," between the browsed lower branches and the untouched foliage above. With the cessation of wolf control in 1959 and the subsequent decline of deer (and their replacement by Moose which browse Cedar much less) the pressure on Cedar has lessened and in many places browse lines have now become blurred or non-existent.