Western hemlock facts for kids
Quick facts for kids Western hemlock |
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Tsuga
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| Species: |
heterophylla
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The western hemlock (scientific name: Tsuga heterophylla) is a type of hemlock tree. It grows naturally along the west coast of North America. You can find it from the Kenai Peninsula in Alaska all the way down to northern Sonoma County, California. It is also known as the western hemlock-spruce.
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Where Western Hemlocks Live
The western hemlock is a very important tree in the forests of the Pacific Northwest. These forests are found west of the Coast Ranges. Here, the western hemlock is a "climax species." This means it is the main type of tree that will grow in an old, undisturbed forest.
This tree is also very important for timber. People use its wood for many things. It often grows alongside other large cone-bearing trees in the region.
What Western Hemlocks Look Like
The western hemlock is a huge evergreen tree. Evergreen trees keep their leaves all year round. These trees can grow to be about 50 to 70 meters (165 to 230 feet) tall. Some can even reach an amazing 83 meters (273 feet) tall! Their trunks can be up to 2.7 meters (9 feet) wide. It is the biggest type of hemlock tree.
The tree's bark is brown, thin, and has grooves in it. When young, the tree has a neat, wide cone shape. Its top shoot often droops down. As the tree gets older, it becomes more like a cylinder. Very old trees might not have any branches on their lowest 30 to 40 meters (100 to 130 feet).
You can easily spot a western hemlock by its drooping branch tips. The new shoots are very pale brown, almost white. They have tiny hairs on them.
Western Hemlock Leaves and Cones
The leaves of the western hemlock are like needles. They are 5 to 23 millimeters (about 1/4 to 1 inch) long and 1.5 to 2 millimeters wide. They are flat and have tiny saw-like edges. The tip of each needle is a bit blunt.
The top side of the needles is a medium to dark green. The underside has two clear white stripes. These stripes are made of tiny pores called stomata, which help the tree breathe. There is a thin green line between the white stripes. The needles grow in a spiral pattern around the shoots. However, they twist at their base to lie in two rows on each side of the shoot.
The cones are small and hang down. They are thin and cylinder-shaped. When closed, they are 14 to 30 millimeters (about 1/2 to 1 inch) long and 7 to 8 millimeters wide. When they open, they become 18 to 25 millimeters wide. Each cone has 15 to 25 thin, bendy scales. Young cones are green. They turn gray-brown about 5 to 7 months after the tree is pollinated. The seeds are brown and 2 to 3 millimeters long. They have a thin, pale brown wing that is 7 to 9 millimeters long. This wing helps the seeds fly away in the wind.
Where Western Hemlocks Grow
Western hemlocks are often found in temperate rain forests. Most of these trees grow less than 100 kilometers (60 miles) from the Pacific Ocean. However, some also grow inland in the Columbia Mountains. You can find them there in southeast British Columbia, northern Idaho, and western Montana.
These trees usually grow at low elevations, from sea level up to 600 meters (2,000 feet). But in the inland areas like Idaho, they can grow as high as 1,800 meters (6,000 feet).
How Western Hemlocks Grow and Survive
The western hemlock is very good at growing in the shade. Among other trees in the Pacific Northwest, only the Pacific yew and Pacific silver fir can handle as much or more shade.
Young western hemlock plants often start growing under the shade of other large trees. These can be trees like Sitka spruce or Douglas fir. The hemlock seedlings can stay small for many years, waiting for a gap to open in the forest canopy. When a larger tree falls, the hemlock can then grow quickly. Eventually, western hemlocks can replace these other trees in a mature forest. This is because Sitka spruce and Douglas fir do not like shade as much. However, storms and wildfires can create big open spaces. In these areas, the other tree species can grow again.
Western hemlock seedlings grow slowly at first. A one-year-old seedling is usually only 3 to 5 centimeters (1 to 2 inches) tall. A two-year-old seedling might be 10 to 20 centimeters (4 to 8 inches) tall. Once they are established, young trees in full sunlight can grow 50 to 120 centimeters (20 to 47 inches) each year. Sometimes they grow even faster. Even when they are 40 to 50 meters (130 to 165 feet) tall, they can still grow 30 to 40 centimeters (12 to 16 inches) annually in good conditions.
The tallest known western hemlock is 82.83 meters (271 feet 9 inches) tall. It is located in Prairie Creek Redwoods State Park in California. These trees can live a very long time. Some western hemlocks are known to be over 1,200 years old!
Western Hemlock and Fungi
Western hemlocks form special partnerships with certain fungi. These fungi help the tree's roots take in nutrients. Some of these fungi are famous edible mushrooms, like chanterelles (Cantharellus formosus, C. subalbidus, and Craterellus tubaeformis).
Western hemlocks can also work with fungi that decay wood. This is special because it means their seedlings can grow and survive on rotting tree stumps and logs.
Uses of Western Hemlock
The western hemlock is the official state tree of Washington.
Growing Western Hemlocks
People grow western hemlocks as ornamental trees in gardens. This is especially true in areas where they grow naturally, like along the U.S. Pacific Coast. They grow best in wetter places. In drier areas, like Victoria, British Columbia, they need very specific soil conditions. They need soil with a lot of organic material, like well-rotted wood from an old log. Animal fertilizers might have too much nitrogen and salt. The soil also needs to be moist and acidic.
Western hemlocks are also grown in temperate regions around the world. The Royal Horticultural Society has given it their Award of Garden Merit. This award means it is an excellent garden plant.
Western Hemlock in Forestry
When western hemlocks are planted well along riverbanks, they can help stop the soil from washing away.
Outside of its native home, the western hemlock is important for forestry. Its wood is a type of softwood. It is used to make timber and paper. People use western hemlock wood for doors, furniture, and other building parts. It can also be an ornamental tree in large gardens, especially in northwest Europe and southern New Zealand.
The tree has started to grow naturally in some parts of Great Britain and New Zealand. It is not considered an invasive species there, but it is an introduced species.
Western Hemlock as Food
The soft inner bark, called the cambium, can be eaten. People can scrape it from removed bark. The shavings can be eaten fresh. Or, they can be dried and pressed into a type of bread. Native Americans in southeastern Alaska used to do this. The bark also provides tannin, which is used for tanning leather.
The tender new needles (leaves) can be chewed directly. You can also make them into a slightly bitter tea. This tea is rich in vitamin C, similar to teas made from some other hemlock and pine trees.
Western hemlock branches are used to collect herring eggs in the spring. This happens during the herring spawn in southeast Alaska. The branches give the eggs an easy place to stick. They also give the eggs a special taste. This way of gathering food comes from traditional methods used by Native Alaskans from southeast Alaska, especially the Tlingit people.
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