Weyand, Phyllis
Alnus viridis (Vill.) Lam. & DC.
Green alder
Betulaceae (Birch Family)
Thicket-forming
shrub or small
tree, often with several trunks, and with shiny yellow-green leaves, gummy when young.
In Alaska, Green Alder is a pioneer in disturbed areas, following landslides, logging, and glacial retreat. Adapted to soils too barren for other trees, this species improves soil conditions by adding organic matter and nitrogen from bacteria in its roots. Alder roots have clusters of nodules containing nitrogen-fixing bacteria, which convert atmospheric nitrogen into a form usable by plants. Alders therefore thrive on nutrient-poor sites, and when these shrubs die and decompose, they release stored nitrogen and enrich the soil for other plants. (Kershaw) It acts as a short-lived nurse
tree for Sitka Spruce (
Picea sitchensis), later dying when shaded by the larger conifer.
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Bloom Information
Bloom Color: Yellow , Green , Brown
Bloom Time: May , Jun
Distribution
USA: AK , CA , ID , ME , MA , MI , MN , MT , NH , NY , NC , OR , PA , TN , VT , WA , WI , WY
Canada: NB ,
NL ,
ON ,
PE Native Distribution: SW. and central Alaska and Yukon southeast to NW. California and central Montana; in Alaska to alpine zone above timberline; in NW. California to 7000 (2134 m).
Native Habitat: Along streams and lakes and in valleys.
USDA Native Status: L48(N), AK(N), CAN(N), GL(N), SPM(N)
Growing Conditions
Light Requirement: Part Shade , Shade
Soil Moisture: Wet
Soil Description: Sandy
Conditions Comments: Alder roots have clusters of nodules containing nitrogen-fixing bacteria, which convert atmospheric nitrogen into a form usable by plants. Alders therefore thrive on nutrient-poor sites, and when these shrubs die and decompose, they release stored nitrogen.
Benefit
Use Wildlife: Birds, Other Showy Insects
Attracts: Birds
Last Update: 2012-07-03
