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Alnus rubra

life science Maturity 5-7 Next article →

The red alder is a very special tree from western North America. It is the largest species of alder in North America.

RedAlder 7504
RedAlder 7504

This tree can grow very tall. One official tall tree stands in Clatsop County, Oregon. The trunks can be quite wide too. The bark is smooth and ashy-gray. It often has white lichen or moss growing on it. If you scrape the bark, it turns a rusty red color. This is how the tree got its name.

Alnus rubra 28199
Alnus rubra 28199

This tree has a very interesting way of working with the earth. It has tiny bumps on its roots called nodules. These nodules hold a germ named Frankia. This germ helps the tree take nitrogen from the air. Nitrogen is like food that helps plants grow. Because of this, the red alder can grow in poor soil. It is an early colonizer, which means it is often the first tree to grow in new areas.

RedAlder 7504
RedAlder 7504

It can quickly cover areas after a fire or logging. When its leaves fall, they decay and make the soil better for other plants.

Scientists use this tree to learn about the air. The leaves can act like a warning sign. If there is too much ozone pollution, the leaves change color. They might turn red, brown, or even purple.

Alder showing ozone discolouration
Alder showing ozone discolouration

This helps researchers find areas with high ozone levels. The tree's leaves are also easy to recognize. They are long and have edges that curl under. In the fall, the leaves turn dark before they drop to the ground.

Many living things rely on the red alder for food. Deer and elk eat the twigs in the winter and spring. Some birds, like the common redpoll, eat the seeds. Even deer mice like to eat them too.

Alnus rubra 28199
Alnus rubra 28199

The tree makes small, woody fruits that look like tiny cones. These cones hold seeds with thin, paper-like wings. These wings help the seeds fly long distances on the wind. This way, the tree can spread to new places.

People have used the red alder for a long time. Native Americans used the bark to make a red dye. They used it to color fishing nets so they were hard to see underwater. They also used the bark for medicine to treat skin irritations. Today, the wood is used for many things. It is used to make furniture and even electric guitars.

RedAlder 7504
RedAlder 7504

Some people even use the wood to smoke salmon because it makes an oily smoke.

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🖼️ Images & Media (3)
File:Alnus rubra 28199.JPG
Alnus rubra 28199.JPG
File:Alder showing ozone discolouration.jpg
Alder showing ozone discolouration.jpg
File:RedAlder 7504.jpg
RedAlder 7504.jpg
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