1. Dichotomous Key: Trees of Sonoma County, CA
1. Leavesshapedlike needlesorscales
A. Needlesarrangedlike abottlebrushorsquirrel’stail
Douglas-fir(Pseudotsuga menziesii)
B. Flatscalescome off a central axis
coast redwood(Sequoia sempervirens)
2. No needlesorscales;leavesare “normal”
A. Acornscan be foundonthe tree
I. Leavesare lobed
a. Lobesare pointedorbristle-tipped
Californiablackoak(Quercuskelloggii)
b. Lobesare roundedor blunt
i.Leavesare softon top;longacorns; 7-11 deeplobes
valleyoak(Quercuslobata)
ii.Leavesare shinyontop; shortacorns; fewerlobes
Oregonoak(Quercusgarryana)
II.Leavesare notlobed
a. Petiole and/orwhole leaf laminaiscoveredwithdense pubescence
tan oak (Lithocarpusdensiflorus)
b. Leavesare longand slender,oftenwithpointedends
willow species(Salix sp.)
c. No pubescence
i. Leavesdark green;orbark blackish; barknot scaly/checkered
G1. Leavescupped;tuftsof hairwhere midveinmeetslateral
coast live oak(Quercusagrifolia)
G2. Leavesflatandhairless
interiorlive oak(Quercuswislenzeni)
ii.Leaveslightgreen/bluish;barkscaly/checkered
B1. Leavesshinygreenontop andwhitishbelow
canyon live oak(Quercuschrysolepis)
B2. Leavesdull blue-greenonbothsides
blue oak(Quercusdouglasii)
B. No acornson tree
I. Leavesare palmately compound
Californiabuckeye (Aesculuscalifornica)
II.Leavesare simple
a. Bark is reddish,smooth,andpeeling
Pacificmadrone (Arbutusmenziesii)
b. Bark is notreddish,smooth,orpeeling
i.Whencrushed,leaveshave pungentodor;leavesare longandskinny
Californiabaylaurel (Umbellularia californica)
ii.Leavesare large (6-12”) withpalmate veination; fivedeeplobes
big leaf maple (Acermacrophyllum)
iii.Leaveshave serratedmargin;flowersproducedincatkins;leavesshinyon
top,oftenthinlayerof pubescence
white alder(Alnusrhombifolia)