More info for the terms:
association,
climax,
forest,
mesic,
sclerophyllous,
series,
shrub,
woodlandCalifornia buckthorn is a shrub component of chaparral, woodland, and
forest communities throughout its distribution [
4,
8,
52,
55,
56]. It has
not been used as an indicator species in published classification
schemes for California. In the Siskiyou Mountains of southwestern
Oregon and extreme northern California, Atzet and Wheeler [
1] describe a
tanoak/California buckthorn (Lithocarpus densiflorus/Rhamnus
californica) plant association on ultrabasic parent materials. Although
the tanoak series typically occurs on deep, fertile soils in the
Siskiyou Mountain province, this association is the ultrabasic version
of a tanoak climax. Dominance of coffeeberry apparently indicates a
soil imbalance [
1].
In southern and central California, California buckthorn is a frequent
member of coastal chaparral and sage scrub [
13,
18] and is most commonly
associated with relatively mesic scrub oak (Quercus spp.) chaparral
[
30]. It also becomes locally abundant on cool, fog-dominated sites
along the central Coast Range where it occurs beneath mixed-hardwood
forests dominated by coast live oak (Quercus agrifolia) [
15,
54,
65,
70].
Although never very abundant, California buckthorn is often associated
with woodland and forest mosaics throughout southern and central
California. Within oak woodlands, knobcone pine (Pinus attenuata), and
coastal forests, it occurs both as a scattered understory shrub and as a
component of intermixed stands of "woodland chaparral" [
35,
30,
67,
68].
Some common associates are chaparral whitethorn (Ceanothus leucodermis),
toyon (Heteromeles arbutifolia), skunkbush sumac (Rhus trilobata),
redberry (Rhamnus crocea), hollyleaf redberry (R. crocea var.
ilicifolia), and poison-oak (Toxicodendron diversilobum).
In northern California and southwestern Oregon, California buckthorn
occurs in mixed evergreen, red fir (Abies magnifica var. shastensis),
and redwood (Sequoia sempervirens) forests [
49,
52,
65]. On
mixed-evergreen sites with ultrabasic parent materials, the
sclerophyllous subcanopy is largely replaced by a shrub layer dominated
by California buckthorn (ssp. occidentalis) and evergreen huckleberry
(Vaccinium ovatum) [
1,
64,
65]. The open, conifer overstory is usually
composed of Port-Orford cedar (Chamaecyparis lawsoniana), knobcone pine,
sugar pine (Pinus lambertiana), and Douglas-fir (Pseudotsuga menziesii)
with a sparse subcanopy of tanoak, huckleberry oak (Quercus
vaccinifolia), and California laurel (Umbellularia californica)
[
1,
2,
3,
65].
California buckthorn is also a characteristic shrub within extensive,
evergreen brushfields in the Siskiyou Mountain province [
21,
24,
25].
Common brushfield associates include whiteleaf manzanita (Arctostaphylos
viscida), greenleaf manzanita (A. patula), hoary manzanita (A.
canescens), wedgeleaf ceanothus (Ceanothus cuneatus), and deer brush (C.
integerrimus) [
21,
25].
