Hansen's Northwest Native Plant Database

Alnus rubra (Red Alder)



 Plantae – Plants


 Tracheobionta – Vascular plants


 Spermatophyta – Seed plants


 Magnoliophyta – Flowering plants


 Magnoliopsida – Dicotyledons






 Betulaceae – Birch family


 Alnus Mill. – alder


 Alnus rubra Bong. – red alder

An attractive, fast growing tree, Red Alder attains heights of 75.’

A coastal tree, it grows no more than 100 miles inland, from southern Alaska to California in USDA zones 7-10.

They are found growing on poor, moist soils and on steep slopes, where they prevent erosion.

The bark is gray and the leaves remain a vibrant green until they drop.

Red Alder has many medicinal qualities and is also used as a dye plant. It is the most important commercial hardwood in the Pacific northwest. The roots of Red Alder fix nitrogen at rates of 40-300 lbs per acre, (compared to 105 lbs per acre for soybeans). This is an outstanding species for reclaiming bare land.

Red Alder can tolerate some drought and thrives in brackish wetlands.

It transplants well.

Red Alder, Western Hemlock, and Bigleaf Maple neighborhood with thick understory of Sword Ferns

Photo Credit: Walter Siegmund


Left, Photo Credit: Bureau of Land Management; Center Photo Credit: Pat Temple, US Forest Service,

http://earthobservatory.nasa.gov/Library/OzoneWx showing ozone discolouration;  Photo Credit: WalterSiegmund


Left, Photo Credit: Walter Siegmund at Nisqually National Wildlife Refuge, broken branch showing red weathered bark;

Right Photo Credit: Walter Siegmund, Red Alder stump. "This c.20 year old individual was about 0.2 m in diameter."


Left, Photo Credit: Bureau of Land Management; Center and Right Photos Credit: WalterSiegmund


Bark on tree at Cougar Mountain Regional Wildland Park; Snag at Squaw Mountain State Park

Photos Credit: Walter Siegmund

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