Alders are pretty, fast-growing trees with a multitude of uses. They can be found growing in many different parts of the world, but what about right here at home? Do alder trees grow in the U.S., and if so, where? Read on as we answer this and several related questions.
What You'll Learn Today
Where Are Alder Trees Found in the U.S.?
Alder trees are members of the Betulaceae family, which makes them close relatives of birch trees. Like birches, they are often found growing in northern and mountainous areas of the United States.
There are about 30 different species of alder, which belong to the genus Alnus. Different species are typically found growing in different regions without a lot of overlapping.
Species commonly found growing in the U.S. include:
- White alder: Often called the Sierra alder, white alders are native to California but are found growing widespread throughout the forests of the Pacific Northwest. They can grow at elevations between sea level and 8,000 feet and are a common sight in Washington, Oregon, Montana, and Idaho in addition to California.
- Red alder: The red alder is sometimes called the Pacific Coast alder because it is found in coastal regions from northern California to Alaska. This tree typically grows closer to the coast than its cousin the white alder, and it grows about three times as tall (up to 150 feet).
- Mountain alder: The mountain alder has various other names, especially gray alder and speckled alder. It is a small, shrubby tree rarely exceeding 35 feet tall; it is native to various mountainous areas of the western United States, especially the Rocky Mountains.
- American green alder: The green alder has various subspecies native to different parts of the world. As the name suggests, the American green alder is native to North America and is found throughout many of the northern, western, and midwestern states.
Each type of alder has slightly different characteristics and features. To learn more about alders in general, check out the following video:
Where Do Alder Trees Grow in Other Parts of the World?
As noted at the beginning of this article, alder trees don’t just grow in the United States; they can be found in many parts of the world.
In fact, alders are common trees throughout much of the Northern Hemisphere, especially in mild to cool regions. They can even be found in cool, wet regions of South America, growing up to 8,200 feet above sea level.
We mentioned white alders, red alders, mountain alders, and green alders in the section above. Another common species, found primarily in other parts of the world, is the black alder.
The black alder is widely distributed across Europe and Asia. It grows in the wild all over those continents, and it is sometimes grown as an ornamental throughout North America.
What Type of Environment Do Alder Trees Prefer?
Alder trees are fairly adaptable, which is what has allowed them to spread throughout so much of the world. That said, they seem to thrive best in particular conditions.
Most alder species grow best in cool, damp climates. They tolerate both high and low elevations well, as they can be found in coastal areas as well as mountainous regions more than 8,000 feet above sea level.
Alders seem to prefer growing along the banks of rivers and streams, or on high cliffs overlooking these bodies of water. Their roots are highly tolerant of damp soil conditions, so they are often planted intentionally near rivers to reduce erosion and improve soil quality.
Is Alder a Shade-Tolerant Tree?
Though they tolerate a variety of habitats and climates and do well growing near water, alders are not very shade-tolerant. They do best when growing in full sun.
Many alder species are shorter than other trees, so they should not be planted in areas where taller trees provide too much shade.
If you are planting an alder in your yard, make sure to choose a spot that receives at least six to eight hours of full sunshine throughout the day.
How Tall Do Alder Trees Grow?
Alder trees grow to different heights depending on the specific variety in question.
As noted, red alders grow primarily in coastal areas. Like other coastal plants and trees, they can grow extremely tall thanks to the ideal growing conditions.
Red alders can grow up to 150 feet tall. Most alders, however, are much shorter than that.
Some varieties reach moderate heights of 50 to 80 feet, but most range somewhere between 20 and 50 feet. The green alder, one of the shortest varieties, may only grow 6 to 14 feet tall.
Alders are fast-growing trees, adding up to two feet of new growth each year while they are growing. Once they reach maturity, they are extremely disease-resistant and usually healthy for most of their lives.
Conclusion
Alder trees grow primarily in northern, western, and coastal regions of the United States. They are commonly found in states such as California, Oregon, Washington, Montana, Idaho, Colorado, and Alaska. Check out here for more interesting facts about alder trees.
