Alder

Alder, tree or shrub of genus Alnus of birch family. The 30 known species are found mainly in the northern hemisphere; 3 are native to Canada.

Alder, Speckled
Speckled alder with male flowers (left), female flowers (centre) and cones on the right (artwork by Claire Tremblay).

Alder, tree or shrub of genus Alnus of birch family. The 30 known species are found mainly in the northern hemisphere; 3 are native to Canada. Speckled alder (A. rugosa) is a transcontinental shrub and the most common Canadian alder. Red alder (A. rubra) is a small, short-lived tree of western BC and green alder (A. crispa) is a transcontinental northern shrub. The Sitka alder (A. crispa ssp. sinuata) is found in BC mountains, and is considered by some to be a distinct species (A. sinuata).

The genus displays birchlike characteristics, eg, shallow roots, horizontal bark markings (lenticels) and elongated spring catkins (cylindrical reproductive structures). Alders occupy moist sites and have nitrogen-fixing root nodules. They are distinguished by stalked buds, twig cores somewhat triangular in cross-section, and fruiting bodies resembling miniature cones.

Healers, artisans and warriors used alders. The bark has been used as a throat medicine, the wood for cabinets and for bridge foundations because of endurance under water, and the charcoal as a constituent of gunpowder.


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