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Western Hemlock

Tsuga heterophylla

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Plant Profile

Flowering Months:
Pinaceae (Pine)
Life Cycle:
Maximum Size:
45 metres tall
Gardens, parks, woodland.

Purple, no petals
The small pendulous egg-shaped cones when young are green with papery scales. On maturing, the cones become brown, up to 3cm in size.
Small, stalkless, reddish brown and egg-shaped hanging cones.
An evergreen conifer with needle-like leaves, up to 2cm long. The dark green, glossy needles are blunt-tipped with 2 white bands on the underside.
The needles when crushed smells of grapefruit.
Other Names:
Pacific Hemlock, Western Hemlock-spruce.
Frequency (UK):

Other Information


Tsuga heterophylla, also known as western hemlock or Pacific hemlock, is a species of coniferous tree in the pine family (Pinaceae). It is native to the west coast of North America, from southern Alaska to northern California. It can grow up to a height of 45 m and it has a conical shape, drooping branches and a narrow crown. The needles are green, short and arranged all around the branches, and the cones are small, cylindrical and hang down. Western hemlock is an important tree species in the Pacific Northwest, providing habitat for wildlife, and it is also an important commercial species, used for lumber, paper and other products.


Western Hemlock, or Tsuga heterophylla, is a coniferous tree species native to the Pacific Northwest region of North America, from Alaska to Northern California. It is a long-lived tree, with some individuals living for more than 1200 years, and can grow up to 45 meters tall and over 2 meters in diameter. Western Hemlock is an ecologically important species, providing habitat for a variety of animals and playing a key role in forest ecosystems.

Physical Characteristics

The Western Hemlock is an evergreen tree, with a narrow, conical crown that becomes more broad and rounded as the tree ages. Its needles are small, about 1-2 centimeters in length, and are arranged spirally around the branches. They are also flattened and soft to the touch, making them less prickly than the needles of other coniferous trees. Western Hemlocks produce small cones that are about 2-4 centimeters long, with thin, papery scales.

Ecological Importance

Western Hemlocks are a keystone species in the forests of the Pacific Northwest. Their shade-tolerant nature allows them to grow in the understory of other trees, and their deep root systems make them particularly resilient to wind and other disturbances. Western Hemlocks also provide important habitat for a variety of animals, including birds, squirrels, and deer.

Western Hemlocks also play a key role in the nutrient cycling of forest ecosystems. Their needles and cones contain high levels of nutrients, which are slowly released as they decompose on the forest floor. This decomposition process enriches the soil and provides essential nutrients for other plants and organisms in the ecosystem.


Western Hemlock wood is commonly used in the production of paper and lumber, as well as in the construction of homes and buildings. It is a lightweight wood, but is also strong and durable, making it a popular choice for a variety of applications. The bark of the Western Hemlock was also used by Native American tribes for making baskets and clothing.


Although the Western Hemlock is not currently considered a threatened species, it is facing a number of threats due to human activities. Logging and land development can have a significant impact on Western Hemlock populations, as can invasive species like the hemlock woolly adelgid, a type of insect that feeds on the tree's needles and can cause significant damage.

Efforts are currently underway to protect and conserve Western Hemlock populations. Forest management practices are being developed to minimize the impact of logging on the species, and efforts are being made to control invasive species and restore damaged habitat. By protecting Western Hemlock populations, we can help to maintain the ecological balance of forest ecosystems and ensure that future generations can enjoy the benefits of this important species.

More Information

In addition to its ecological importance and various uses, Western Hemlock also has cultural significance for the Indigenous peoples of the Pacific Northwest. Many Indigenous communities have traditional stories and legends that feature the tree, and its bark and needles have been used for medicinal and spiritual purposes.

For example, the Haida people of British Columbia, Canada consider the Western Hemlock to be a sacred tree. They use the bark and needles for making baskets, clothing, and ceremonial regalia, and believe that the tree has spiritual power and can protect them from harm.

The Western Hemlock is also an important symbol in the art and crafts of Indigenous communities. Carvings and sculptures of the tree are commonly found in totem poles, masks, and other traditional art forms. The intricate patterns and textures of the bark and needles make them popular materials for weaving, embroidery, and other decorative arts.

One interesting feature of Western Hemlock is its ability to adapt to different environments. It can grow in a variety of soil types, including acidic soils and nutrient-poor soils. It can also tolerate a wide range of moisture levels, from very wet to very dry conditions. This adaptability has allowed the Western Hemlock to colonize a variety of habitats throughout the Pacific Northwest, from coastal rainforests to mountain slopes.

Another important ecological function of the Western Hemlock is its role in regulating water flow in forest ecosystems. The tree's extensive root system helps to stabilize soils and prevent erosion, while its dense foliage intercepts rainfall and reduces runoff. This can help to prevent flooding and maintain a stable water supply for other plants and animals in the ecosystem.

The Western Hemlock also provides important benefits for human health and well-being. Studies have shown that exposure to forests and natural environments, including Western Hemlock forests, can have a positive impact on mental and physical health, reducing stress and improving overall well-being. The tree's unique beauty and calming presence can also provide a sense of peace and tranquility for those who spend time in its presence.

Finally, it is important to note that while Western Hemlock is an important economic resource, responsible forestry practices are essential to ensure its continued health and sustainability. Sustainable forestry practices, such as selective logging and reforestation, can help to maintain healthy populations of Western Hemlock and ensure that the benefits of this important species are available for generations to come.

Distribution Map

Reproduced by kind permission of the BSBI.

Click to open an Interactive Map