Alders like moist surroundings and there are few creeks in western Oregon not overhung by them. Their peculiar woody cones (called strobiles) identify alders as surely as a flat tail identifies a beaver. They hang from the tree throughout winter like miniature lanterns. Alder leaves are shed while still green. Alders add nitrogen to the soil in the manner of legumes, and decomposing alder leaves improve soil structure.
Eight species of alder are native to North America; Oregon has four: red, white, Sitka, and thinleaf, but only two commonly reach tree size - and only red alder is abundant. Knowing their ranges and leaf traits will help in separating one species from another.
Large tree:(40'-80' tall; single trunk)
Shrub or small tree: (under 25' tall; multiple trunks)
trees by common name trees by scientific name dichotomous key mystery tree
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