Aesculus californica (Spach) Nutt.

More info for the terms: ground fire, woodland

See this Fire Study in FEIS for further information on responses of
California buckeye and other chaparral and woodland species to fire:
Damage and recovery in southern Sierra Nevada foothill oak woodland after
a severe ground fire (blue oak-interior live oak/annual grass community)

California buckeye
buckeye
horsechestnut

More info for the term: cover

The cover value of California buckeye is poor from late spring through
late winter due to early leaf fall.

More info for the terms: fruit, shrub, tree

California buckeye is a large shrub or tree up to 23 feet (7 m) tall.
The 2-to 6-inch-long (5-15 cm) leaves are deciduous and palmately
compound [21]. Flowers are borne on a terminal panicle 4 to 8 inches
(10-20 cm) long. The pear-shaped, light brown fruit contains one to six
glossy brown seeds 0.8 to 1.2 inches (2-3 cm) in diameter [5,21].

California buckeye is endemic to California. It occurs in the
Klamath and Coast Ranges from Siskiyou County south to Los
Angeles County. In the Cascade Range and the foothills of the Sierra
Nevada, it occurs from Shasta County south to Kern County.
California buckeye is occasionally found in the Central Valley in Yolo,
Colusa, and Stanislaus Counties [5].

More info for the terms: fire regime, litter, root crown, seed, top-kill

Plant adaptations: California buckeye sprouts from the root crown after
top-kill by fire [5,28]. Seeds would probably not survive fire because
they are highly susceptible to desiccation by heat [8]. Seed is often
transported by water and could be carried to a burn site in that manner [13].

Fire ecology: Early leaf fall results in accumulation of dry litter
around the plant early in the fire season.

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the term: herbaceous

Grazing considerations: California buckeye cannot be successfully
eliminated by occasional prescribed burning. Fire may control it if
the area is reburned every 7 to 8 years and immediately reseeded with
herbaceous vegetation [14]. Otherwise, California buckeye will recover
at the expense of other plants species, including desiable herbs [14,25].

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More info for the term: phanerophyte

Phanerophyte

California buckeye grows on dry slopes, in canyons, and along waterways
[5,21]. In the Central Valley it occurs along stream and river banks
[5,19]. It is associated with poison-oak (Toxicodendron diversilobum)
in most communities in which it occurs [5,17].

Soil: California buckeye grows in sandy, sandy-loam, or gravelly-loam
soils [5].

Climate: California buckeye occurs in a Mediterranean climate with cool
moist winters and hot dry summers [5,15,18]. The mean annual rainfall
is less than 14 inches, and temperatures are in excess of 100 degrees
Fahrenheit (38 degrees C) for several successive days every summer [14].

Elevation: California buckeye occurs below 4,000 feet (1,219 m) [21].

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

229 Pacific Douglas-fir
231 Port-Orford-cedar
232 Redwood
234 Douglas-fir - tanoak - Pacific madrone
243 Sierra Nevada mixed conifer
244 Pacific ponderosa pine - Douglas-fir
245 Pacific ponderosa pine
246 California black oak
247 Jeffrey pine
248 Knobcone pine
249 Canyon live oak
250 Blue oak - Digger pine
255 California coast live oak

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES27 Redwood
FRES28 Western hardwoods
FRES34 Chaparral - mountain shrub

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: forest, shrub

K003 Silver fir - Douglas-fir forest
K005 Mixed conifer forest
K006 Redwood forest
K009 Pine - cypress forest
K010 Ponderosa shrub forest
K029 California mixed evergreen forest
K030 California oakwoods
K033 Chaparral
K034 Montane chaparral

Fire top-kills California buckeye [25].

California buckeye is toxic to all classes of livestock and wildlife.
The bark, leaves, stems, fruits, and seeds all contain glycosidal
compounds which cause haemolytic action on red blood cells and depress
the central nervous system when ingested. This species has been
implicated in inducing abortion in cattle [5,18].

More info for the terms: climax, shrub, tree, woodland

California buckeye woodland is recognized as a distinct plant community
[13]. The species may also codominate oak (Quercus spp.) woodland.
Interior live oak (Q. wislizenii) and blue oak (Q. douglasii) are the
most common codominants of oak woodland [1,2,3,22,23]. In chaparral, it
is sometimes a dominant shrub or tree [2,4].

The following published classification schemes list California buckeye as a
climax species or a dominant part of the vegetation in community types
(cts) or plant associations (pas):

Area Classification Authority

CA: Coast Ranges mixed oak cts Allen & others 1991
w foothills
Sierra Nevada foothill woodland pas Thorne 1976
Klamath Mts. northern mixed Holland 1986
chaparral pas
Pinnacles
National
Monument Ca buckeye woodland cts Halverson & Clark
1986

More info for the terms: shrub, tree

Tree, Shrub

More info for the term: root crown

Grazing: California buckeye often considered undesirable on rangeland
because of its toxicity.

Apian considerations: Honeybees are the chief pollinators of California
buckeye, but the pollen and nectar are toxic to them [5,9,14]. Losses
of adult honeybees and their larvae due to poisoning can be severe [9].
Human beings have been poisoned by eating honey made from California
buckeye [18].

Control treatments: California buckeye is susceptible to spray or
injection/cut surface treatments of phenoxy herbicides and picloram
[7,14,27]. Hand or mechanical brush control is ineffective unless the
root crown is removed [25,28].

The dry matter composition of California buckeye seeds is 80 percent
carbohydrate, 5 percent protein, 1 percent fat, 2 percent ash, 3 percent
fiber, and 9 percent miscellaneous [12]. Protein content of the leaves
and stems varies from 31 percent in April to 5 percent in October [6].
Carbohydrate content of leaves and stems varies from 50 percent in April
to 1 percent in October [20]. Since California buckeye is a systemic
poison, how much of this nutrition is actually metabolized by
seed-eating or browsing livestock and wildlife in unknown. (see
Importance to Livestock and Wildlife).

CA

California buckeye is used as a landscaping ornamental [24].

The seeds of California buckeye served as a staple for California
Indians, who would mash the roasted seeds and then leach them to remove
the poison [5]. Native Americans also secured the seeds in streams and
other waterways in order to stupefy fish for easy capture [21].

Despite its toxicity, California buckeye flowers, leaves, and shoots are
palatable to livestock and wildlife. Hedrick [14] has listed it among
the 20 chaparral browse plants most preferred by cattle and black-tailed
deer. The palatability of the seeds for black-tailed deer, rodents, and
Steller's jay is fair to poor [5].

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California buckeye flowers from April to September [24]. New leaves
emerge from March to June while soil moisture is abundant [20]. The
leaves dry up and are shed in late spring or early summer in Sierra
Nevada foothill populations but may be retained through fall in coastal
populations when soil moisture remains available [5]. Fruits ripen from
September to October and are dropped from November to December [24].

Information regarding California buckeye's response to fire is limited.
Sampson [25] has said that sprouting chaparral brush species, including
California buckeye, recover rapidly following a fire, sending out new
shoots during the first growing season. Growth in subsequent seasons is
also rapid, with the plant sometimes exceeding its prefire mass within a
few years. Sprouting can occur within a few weeks following fire, even
in the summer months. Growth is supported by drawing on food and water
reserves in the fully developed root system [20].

More info for the terms: root crown, secondary colonizer, seed

survivor species; on-site surviving root crown
off-site colonizer; seed carried by water; postfire yr 1 & 2
secondary colonizer; off-site seed carried to site after year 2

More info for the terms: root crown, seed, tree

Sexual: California buckeye reproduces by seed [5]. The average tree
produces approximately 100 seeds per year. Seed dispersal is poor and
is accomplished mainly by gravity or water; dispersal by animals is rare
[13]. Seeds are viable for only 1 year and are shed from November to
mid-February [24]. Germination occurs within several weeks of shedding
if the soil temperature is above 40 degrees Fahrenheit (4 degrees C).
If the temperature persists below 40 degrees for 2 months or more the
seeds are susceptible to fungal infections or desiccation [12].
Germination success rates of 75 percent have been reported under
laboratory conditions [19].

Asexual: California buckeye can sprout from the stump or root crown
[3,28].

More info on this topic.

This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

3 Southern Pacific Border
4 Sierra Mountains
7 Lower Basin and Range

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More info for the terms: climax, forest, shrub

California buckeye exhibits both tolerant and intolerant
characteristics. It occurs as widely scattered individuals in open
grasslands. It also occurs as an understory shrub in mixed evergreen
forest [3]. It is a climax indicator in chaparral and mixed oak
communities [1] and in California buckeye woodlands [8].

Calothyrsus californica

The currently accepted scientific name of California buckeye is Aesculus
californica (Spach) Nutt. [18,21]. There are no recognized subspecies,
varieties, or forms.

More info for the term: seed

California buckeye is valuable as a soil binder on stream or river banks
and on steep slopes [11,17,26]. Seed can be obtained by harvesting
native plants. Seed propagation methods have been detailed [20,24].

California buckeye is occasionally used for lumber and paper pulp [25].