BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Chrysolepis chrysophylla | Giant Chinquapin 



GENERAL BOTANICAL CHARACTERISTICS : 
Giant chinquapin is a native, broad-leaved, sclerophyllous, evergreen
tree or shrub [22,32,51].  When it is a subcanopy component of coastal
and cismontane forests, giant chinquapin typically develops into a small
tree or arborescent shrub ranging from 20 to 50 feet (6-15 m) tall
[1,30,32,42,54].  Tree forms of giant chinquapin may reach heights of 50
to 150 feet (15-45 m) [51], with some individuals occasionally reaching
127 feet (38 m) in height and 5 feet (1.5 m) in diameter [1,55].  Large,
single-trunked trees are usually restricted to mesic valley bottoms and
cool north-facing slopes [40].  Shrubby growth forms develop on more
xeric sites with poor soils and at higher elevations [22]; heights
generally do not exceed 16 feet (5 m) [40,42,51].  Giant chinquapin bark
is thin, smooth, and dark gray when young.  As it ages, the bark becomes
thick and fissured, with wide, reddish-brown plates [1,41].  Mature
trees have stout, spreading branches; open-grown crowns exhibit a
conical shape, with principal branches deflexed [1,40].  The narrow,
leathery evergreen leaves are dark green on the upper surface and are
commonly folded upward along the midrib, revealing yellow-green to
golden undersides [32,44].

Giant chinquapin is monecious.  Chestnutlike spikes of creamy-white male
flowers are borne in the leaf axils; female flowers usually occur in a
cluster at the base of male spikes [37].  Giant chinquapin produces a
distinctive, spine-covered bur which encloses from one to three
sweet-tasting nuts [1,41].  At the soil surface, giant chinquapin
possesses a woody regenerative organ known as a burl [40,54].
Established individuals are both drought tolerant and wind firm [48,54].
Despite being closely related to chestnuts (Castanea ssp.), giant
chinquapin remains unaffected by the chestnut blight [1].

Tree forms of giant chinquapin may live to be 400 to 500 years old on
favorable growth sites [1,40].  Growth beneath redwood and
mixed-evergreen forests is slow and uniform; trees typically reach 24
inches (60 cm) d.b.h. within approximately 210 to 260 years [40].  In
contrast, giant chinquapin sprouts grow rapidly after disturbance
[18,20].  On mixed-evergreen sites, giant chinquapin sprouts attain
diameters of 18 inches (46 cm) within 50 years following burning;
seedlings in the understory attain comparable diameters in approximately
140 years [40].  Greatest longevity and stem diameters are more
consistently achieved on xeric mixed-evergreen sites; heartrot causes
death of mature trees on mesic sites [40].



RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Giant chinquapin regenerates both sexually and vegetatively.  Seedling
reproduction is generally restricted to mesic sites and is characterized
by a slow, steady accumulation of seedlings on undisturbed sites
[40,63].  Vegetative regeneration becomes more prevalent as sites become
increasingly xeric [40].

Sexual regeneration:  Giant chinquapin is a poor and irregular seeder
[62].  Seed production generally occurs at 2- to 5-year intervals, and
most of the filbertlike nuts are infertile [1].  Nut production may be
adversely affected by the filbert worm [48].  Giant chinquapin nuts
mature during the fall of their second year [37] and are usually
deposited directly beneath the parent plant [48].  Some long-distance
dispersal occurs via animal vectors [40,42,48].  Rate of germination
varies from 14 to 53 percent, lower than in many other hardwood species
[37,48].  In laboratory studies, germination occurs 16 to 24 days after
sowing; cold stratification does not enhance germination [37].  Nuts
remain viable for at least 2 years when stored at 41 degrees Fahrenheit
(5 deg C) [37].

Giant chinquapin seedling densities are characteristically low, even on
favorable sites [40,42].  Successful establishment apparently requires
mesic and shady nursery conditions [40].  On mixed-evergreen sites in
northwestern California, seedling establishment occurs most frequently
in moist valley bottoms where cool, shady conditions predominate [40].
Limited information on seedbed ecology suggests that giant chinquapin
requires a moister seedbed than tanoak (Lithocarpus densiflora), a
common hardwood associate on mixed-evergreen sites [40].  Establishment
occurs on either organic or mineral seedbeds [2,42].  Although seedlings
may establish in full or partial shade [10,31,40,63], germination and
early development tends to be hindered on sites with a dense ground
cover [40].

Significant seedling establishment is likely to occur only during a
series of abnormally moist years on more xeric exposures.  Keeler-Wolf
[40] suggests that major establishment episodes occur approximately once
every 200 years on dry upper slopes and ridgetops within mixed-evergreen
forests.  Seedlings appear quite competitive on dry sites with
nutrient-poor soils [48].  Once established, giant chinquapin is very
drought tolerant [40,54].

Vegetative regeneration:  Following disturbance, giant chinquapin
regenerates vegetatively from adventitious buds located on stumps or
basal burls [1,2,48,54,66].  Vegetative regeneration appears to be the
primary means of reproduction on relatively xeric upper slopes where
fires occur more frequently and moisture regimes are less conducive to
seedling establishment [40].


SITE CHARACTERISTICS : 
Giant chinquapin occurs on a variety of sites ranging from coastal
redwood forests to woodland and chaparral communities [8,18,20,42].
Tree and shrub forms occupy distinctly different habitats.  Giant
chinquapin usually grows as a single-stemmed, subcanopy tree on sites
with deep soils, ample winter rainfall, and frequent summer fog
[4,40,54].  Since it is able to tolerate drought, giant chinquapin also
inhabits relatively xeric sites with poor soils where it grows as a
shrub [1,40,51].

Tree forms:  Giant chinquapin trees reach greatest stature and grow most
abundantly in the mixed-evergreen forests of the Klamath Geological
Province of northern California and southwestern Oregon at elevations
ranging from sea level to approximately 5,250 feet (1,600 m) [8,40].
Soils are derived from sandstone and granite and may include acid sands
[55].  Although a characteristic component of mixed-evergreen forests,
tree forms of giant chinquapin are not as ubiquitous as other species of
sclerophyllous hardwoods (tanoak, madrone [Arbutus menziesii], or canyon
live oak).  In the Coast Ranges and Klamath Mountains of California,
giant chinquapin trees are generally restricted to cool north slopes or
moist canyon bottoms.  Trees most often occur as widely scattered
individuals or groves and are rarely found in pure stands [25,54].
However, giant chinquapin may occasionally dominate the sclerophyllous
subcanopy of mixed-evergreen forests on mesic north slopes at elevations
between 3,280 and 4,600 feet (1,000-1,400 m); annual rainfall on these
sites exceeds 60 inches (152.4 cm) [40].  At these upper elevations of
the mixed-evergreen forest, tree forms of giant chinquapin are able to
persist and become dominant over other sclerophyllous hardwoods because
of the superior snowshedding abilities of mature crowns (deflexed
principal branches and conical shape) [40].

Farther north in the western Cascades of central Oregon, giant
chinquapin is associated with warm to cool, dry sites and is a component
of western hemlock forests [18,28].  Increased regional rainfall
apparently allows giant chinquapin to expand into drier habitats than in
the mixed-evergreen zone [24,67,71].  Sites are often associated with
moisture or soil nutrient restrictions which tend to constrain more
shade-tolerant competitors [2,18,42].  Greatest abundance is attained on
relatively xeric exposures, usually beneath a very sparse (<50 percent)
primary canopy of Douglas-fir [18,30].  Sites occur between 1,500 to
2,590 feet (460-790 m) and include steep upper slopes and ridgetops of
low elevation mountains [14,30].  On undisturbed, old-growth sites,
giant chinquapin develops a very dense understory and typically grows as
a small tree or multistemmed, arborescent shrub [22]; average d.b.h.
ranges from 6 to 12 inches (15-30 cm) [30].  Soils are generally rocky,
well-drained, poorly developed, and derived largely from pyroclastic
tuffs and breccias [14,28,30].  Soil depth is highly variable [14,24].
Within this region, predominance of giant chinquapin is indicative of
infertile, droughty soils [2,29,71].

Shrubby forms:  Giant chinquapin is quite tolerant of cold and snow and
inhabits comparatively high elevations in the southern Cascades where it
occurs as a shrub beneath mixed conifer, white fir, and Shasta red fir
canopies.  Shrubby forms grow on buttes, escarpments, and ridgetops at
elevations between 3,000 and 5,900 feet (915-1,800 m) [18,36,65].  Soils
are often composed of pumice with lava or ash till [65].  Giant
chinquapin shrubs also occur as a common component of broad sclerophyll,
chaparrallike communities throughout the range of the species, occupying
warm exposures with dry or summer-heated soils [9,20,25,51,55,62].
Essentially pure stands of giant chinquapin frequently occur on dry
sites in the Siskiyou Mountains [22].  Shrubby forms are often
associated with soils that exhibit hydrophobic tendencies [36].

Common associates in forested communities include Douglas-fir, redwood,
western hemlock, white fir, ponderosa pine (Pinus ponderosa), sugar pine
(P. lambertina), Shasta red fir, tanoak, madrone, canyon live oak,
Pacific dogwood (Cornus nuttallii), California laurel (Umbellularia
californica), Pacific rhododendron, California hazel (Corylus cornuta
var.  californica), vine maple (Acer circinatum), Pacific yew (Taxus
brevifolia), red huckleberry (Vaccinium parvifolium), oceanspray, Oregon
grape (Berberis nervosa), salal (Gaultheria shallon), beargrass,
twinflower, prince's pine (Chimaphila spp.), western swordfern
(Polystichum munitum), bracken fern (Pteridium aquilinum).  Brushfield
associates often include tanoak, madrone, snowbrush, squawcarpet (C.
prostratus), greenleaf manzanita (Arctostaphylos patula), and snowberry
(Symphoricarpos albus).


SUCCESSIONAL STATUS : 
Giant chinquapin, a long-lived, moderately shade-tolerant species, is
associated with redwood, mixed evergreen, white fir, western hemlock,
mixed conifer and Shasta red fir climax communities [18,56,63].  Capable
of surviving disturbances which kill aboveground stems, giant chinquapin
can also become a component of early seral situations [18].  Giant
chinquapin is able to establish beneath a full or partial canopy of
either hardwoods or conifers on coastal redwood and mixed-evergreen
sites where year-round and long-lasting moisture regimes prevail
[40,63].  Since seedling establishment appears to occur with or without
fire, resulting giant chinquapin populations are frequently all-aged
when occurring on more mesic locales [40,63].  Within western hemlock
forests giant chinquapin maintains itself beneath comparatively
thin-canopied stands of conifers [24,30,31,42].  Giant chinquapin often
persists as a depauperate shrub beneath mature conifer overstories when
growing under less than optimal conditions on mixed conifer, Shasta red
fir, and white fir sites [1] and is usually maintained by fire in these
communities.  Following release, giant chinquapin increases dramatically
and is a common component of chaparrallike brushfields dominated by
evergreen shrubs [8,17,20,70].  With repeated fire, many of these
brushfields have become semipermanent communities [18].  Under more
normal fire regimes, giant chinquapin coverage gradually decreases as
the conifer canopy closes [36,65].


SEASONAL DEVELOPMENT : 
Giant chinquapin blooms from June to February in the southern portion of
its range [51].  In the Pacific Northwest, plants bloom from April to
June [32].  The distinctive, chestnutlike burs typically ripen from
August through September of their second season [41].

Phenological development of giant chinquapin on the Nash Crater Lava
Flows in Linn County, Oregon, during the 1949 growing season is
presented below [53]:

Phenological stage              Date observed

floral inactivity               May through the 4th week of July
in bud                          3rd week of July
flowering                       first two weeks in August
flowering and fruiting          last two weeks in August
fruiting                        first three weeks in September

Related categories for Species: Chrysolepis chrysophylla | Giant Chinquapin