Standard Trees - Oregon Alder
Although, as is American name Oregon Alder suggests, Alnus rubra comes from the western parts of America, Red Alder is very similar to the Old World Alders. The most visible differences are that it produces fewer suckers and has a more elegant, conical form. It is a quick growing, deciduous tree with serrated oval shaped leaves that turn a gentle yellow in Autumn. In spring, before the leaves appear, it is festooned with lovely red and green catkins that can be up to 15cms, 6 inches, long. Oregon Alder produces a red dye where its bark is damaged, hence its other name, Red Alder. The feature of Alders in general that makes them so useful is their root nodules and the bacteria living in them that fix nitrogen from the air, thus improving the soil quality and enabling the tree to thrive on very poor earth, including waterlogged areas. They are used in all sorts of restoration projects to prepare the ground for other trees and are especially useful for quickly binding loose, rocky soil on motorway verges or the slopes of old quarries. Once considered an undesireable "weed" tree, the importance of Red Alder in the forest cycle is now better understood and they are used to repair the damage done by forest fires and clearcut logging. Native Americans used Red Alder dye extensively and today the wood is still considered the charcoal of choice for smoking salmon. Alders begin to fall apart past the age of 70, often losing their main trunk. This clears the way for other trees to take over. Alnus rubra is possibly the tallest Alder, with a 32 metre, 100 foot high specimen recorded in... Oregon in the 70's.
Planting Alder alnus Rubra
Alders love their light and Red Alder is no exception. A position with as close to full sun as possible is recommended. It is not fussy about soil at all, however, and would only suffer in acidic peat or shallow, chalky earth. It does not mind very waterlogged soil and will grow on islands in lakes or muddy river banks. It is well suited to roadside planting.
If you are unclear about the way standard trees are sized, take a look at our Guide to Standard Tree Sizing or you can go back to our main standard trees page.
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