Sitka Alder, Slide Alder, Wavy-leaved Alder: Alnus alnobetula ssp. sinuata (Synonyms: Alnus crispa ssp. laciniata, Alnus crispa ssp. sinuata, Alnus sinuata, Alnus sitchensis, Alnus viridis ssp. fruticosa, Alnus viridis ssp. sinuata, Alnus viridis var. sinuata, Duschekia sinuata) -
Gray Alder, Mountain Alder, Thinleaf Alder, Thin-leaf Alder: Alnus incana ssp. tenuifolia (Synonyms: Alnus incana var. occidentalis, Alnus rugosa, Alnus tenuifolia) -
California Alder, White Alder: Alnus rhombifolia (Synonym: Alnus rhombifolia var. bernardina) -
Oregon Alder, Red Alder: Alnus rubra (Synonyms: Alnus oregona, Alnus oregona var. oregona, Alnus oregona var. pinnatisecta, Alnus rubra var. pinnatisecta) -
Bog Birch, Dwarf Birch, Swamp Birch, Resin Birch, Scrub Birch: Betula glandulosa (Synonyms: Betula glandulosa var. glandulosa, Betula terrae-novae) - Native shrub of moist areas at mid- to high elevations.
Water Birch, River Birch, Red Birch: Betula occidentalis - Native tree or shrub of moist areas and streambanks at low elevations.
Paper Birch: Betula papyrifera var. commutata - Native Tree of moist, open to dense woods at low to moderate elevations.
European White Birch, European Weeping Birch: Betula pendula - Introduced ornamental tree.
Bog Birch, Dwarf Birch: Betula pumila (formerly Betula glandulosa var. hallii) - Native shrubs of the high Oregon Cascades but also found in southwestern Lake County, OR.
Hybrid Shrubby Birch: Betula xsargentii - Shrub found in southwestern Lake County, OR.
California Hazel: Corylus cornuta var. californica (Synonyms: Corylus californica, Corylus cornuta ssp. californica) -
Beaked Hazelnut: Corylus cornuta var. cornuta (Synonym: Corylus cornuta ssp. cornuta)