Alder Trees: What Should I Know?

The alder tree is a deciduous tree and often grows near water. There are very few alder species that prefer drier climates. Overall, the alder thrives along riverbanks or in wetlands. The leaves from the alder are the preferred meal for many butterflies. The alder will grow in barren lands, providing fertility to the soil. In turn, this allows many other species to move into the barren lands and fill it with life. Therefore, plants thrive off nitrogen-rich soil. The alder adds significant nitrogen to the soil, supporting a vast ecosystem.

Also, the alder is widespread. It supports ecosystems from North America to Russia and even into Europe. While the leaves of the alder are poor tasting, they are also high in protein. In a survival situation, you will receive good nutrition from the alder leaves if you can make it past the taste. The alder genus contains approximately 35 species divided into three subgenera. The genus rangers from shrubs to trees.

The Alder Genus is part of the Birch Family (Betulaceae) that includes in addition to Alder, Birch (Betula), Hornbeam (Carpinus), and Hazel (Corylus).

So How Many Kinds of Alder Trees Are There?

The alder genus comprises 35 species. Furthermore, scientists deem the genus of the alder as the Alnus genus. This genus is further separated into three subgenera. Moreover, there are also about a dozen species that are not categorized into a subgenus yet. We categorize alder trees that produce their flowers in the fall and pollinate in late winter as the Alnus subgenus. Approximately 20 species fall into this category. Some of these species include:

  • Andean alder
  • Italian alder
  • Black alder
  • Grey alder
  • Japanese alder

The next subgenera is the Clethropsis subgenus. The trees in this subgenus produce and open their flowers in the fall. Also, only three species fall into this subgenus:

  • Formosan alder
  • Seaside alder
  • Himalayan alder

The final subgenus is the Alnobetula subgenus. By all means, the trees in this subgenus work in opposite seasons of the other two. The flowers on these trees produce and open in the spring. Additionally, most of the species in this subgenus do not have common names. Some species in this subgenus are:

  • Alnus alnobetula
  • Alnus firma
  • Alnus mandshurica

Finally, there are about a dozen species without a subgenus currently. They are primarily located across China, Korea, and Japan.

How Large Do Alder Trees Grow?

According to NPS, the white alder grows to 50 feet in height and is short than the red alder. Red alders are the tallest of the genus, standing closer to 100 feet in height. At the maximum, the tree will reach 6 feet in diameter. Overall, they are fast-growing trees reaching the standard 2-foot growth rate for fast-growing trees. With the genus containing not only trees, but some shrubs, the maximum heights vary from species to species. Some species reach only 10 to 20 feet, while others reach 70 to 100 feet in height. For this reason, we categorize these as small trees.

What Does an Alder Tree Look Like?

While the alder is deciduous, it produces a small fruity body like a cone. It is the easiest way to identify an alder, but they are only present on the tree in fall and winter. However, there are a few species that the cones are present in spring. The fruit-like cones are called strobiles.

The leaves of the alder are egg-shaped.

Alder Leaf

They boast a singular, sturdy trunk. Not all alder's sport the oval-shaped leaves. Some species sport serrated leaves while others sport a wedge-like leaf. Unlike many other trees, the leaves fall from alder trees in autumn, still their natural green. Only the leaves of the red alder change to a brownish color before falling.

The flowers of the alder are slender and conical. Scientists call them a catkin. The male cones are long and hang downward. On the other hand, the female cones grow upright on the ends of the branches.

Finally, the bark of the tree is gray or white. It is smooth, but because it grows in damp wetlands, moss often covers the trunk.

Where Can I Find an Alder Tree?

Alder grow all over the Northern Hemisphere and we can even find some in the Southern Hemisphere. The Andean alder grows in Mexico, Central America, and South America. Additionally, the growth stretches almost to Chile. All throughout the United States and Canada. Different species dominate different portions of the Northern Hemisphere. There are very few species that prefer a dry climate. These species thrive in Arizona and New Mexico. Also, the red alder is the most common alder tree found growing in the United States.

We can even find alder growing across Europe. Italy claims its own alder tree. While other parts of Europe boast other species. The black alder is the most common alder tree found growing in Europe.

Finally, alders are incredibly widespread across Asia. Species grow from Turkey to Russia. A great number of species grow in Japan, China, Taiwan, and Korea.

How Long Can an Alder Tree Live?

Alder are not long-lived trees. Most alder live for only 60 to 70 years. There are some recordings of alder living to 100 years, but these are incredibly rare.

Can I Grow an Alder Tree?

You will rarely find an alder in a residential setting. We do not grow them as privacy shrubs nor as ornamental additions to a backyard or garden. Even though, if you do desire to grow your own alder, the most important thing is moisture. In nature, alder thrive in wetlands or along stream banks. Overall, the seeds of the alder will germinate rapidly after pre-treatment. In the first year, the alder seedling will grow almost two feet. After this year, you can transplant the seedling outside. Water will be vital to the alder. Otherwise, there is very little that the alder seedling will need from you to survive and thrive in your backyard.

It is Time to BRANCH out into some fun tree facts!

  • Alder trees produce so much nitrogen, they can grow start a whole ecosystem where it was once barren.
  • The leaves of the alder tree do not change with autumn even though they will fall off the tree.

What Are Some Uses For Alder Trees?

Natural Uses

You will rarely find an alder in a residential setting. We do not grow them as privacy shrubs nor as ornamental additions to a backyard or garden. Even though, if you do desire to grow your own alder the most important thing is moisture. In nature, alder thrive in wetlands or along stream banks. Overall, the seeds of the alder will germinate rapidly after pre-treatment. In the first year, the alder seedling will grow almost two feet. After this year, you can transplant the seedling outside. Water will be vital to the alder. Otherwise, there is very little that the alder seedling will need from you to survive and thrive in your backyard.

The seeds and cones from the alder provide sustenance to many birds and small animals. Even deer, elk, and moose snack on the branches of an alder tree. Thanks to the location of the alder along embankments, beavers absolutely love to chew on alder branches and build dams with them.

Also, the nitrogen produced from the alder is unique. Many bacteria and other plants create symbiotic relationships with the alder tree. These relationships create a thriving ecosystem around the alder. The catkins are high in protein for a wild growing cone. It will allow anyone in a survival situation to receive ample protein. Throughout Europe and Asia, many use the black alder for fever, bleeding, and a sore throat. Also, alder bark helps with digestion and bloating. It helps move the digestive tract along without causing significant issues. The tree is astringent and helps to heal skin disorders and open wounds.

Furthermore, many Native Americans turn the alder bark into an orange dye. To brighten many of their fabrics.

Artistic Uses

The Celts use the alder throughout art and mythology. When an alder is cut, the wood turns a bright red. Many ancient Celtics believed the tree was bleeding. For this reason, they believed man originated from the alder tree. These beliefs led to the alder tree being through Irish mythology. The red of the alder tree points to the sacredness of blood and fire. Therefore, throughout art for centuries, the alder tree holds a special place in Irish history.

Residential/Commercial Uses

Ancient Celts used the alder tree for shields. The belief was that shield would bleed in place of the warrior and protect them against dangers with the magic of the alder. Pipes, whistles, clogs and even furniture were crafted from the wood of the alder tree. They also built wheels for carts and spinning wheels. Because of the extraordinarily high durability to water, ancient Celts built their lake houses from the alder tree. Furthermore, many of the buildings found in Venice were built on top of alder foundations.

In modern times, we consider alder wood to be high end. We use it for crafting decorative woodwork, cabinetry, and furniture.

Wrap Up

The alder tree is a unique tree that creates relationships with other plants and bacteria to build new ecosystems around bodies of water. The catkins will provide ample protein if you are ever in need of sustenance. The 35 species in the genus live for approximately 60 years and rarely reach 100 years. Overall, they grow quickly and reach 70 feet in height. While the leaves fall off the alder tree in autumn, they do not change colors. Finally, if you are looking to grow an alder tree on your own property, moisture is key. An alder tree thrives in a wet environment.

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