BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Corylus cornuta var. californica | California Hazel 



GENERAL BOTANICAL CHARACTERISTICS : 
California hazel is an erect, deciduous, native, perennial shrub, or
occasionally small tree [17].  It is multistemmed and loosely spreading,
averaging 5 to 12 feet (1.5-4 m) in height.  It can exceed 20 feet (6 m)
in height and develop a treelike form with a singular trunk.  The bark
is smooth.  The twigs are brown, slender, and zigzagged.  The current
year's twigs are hairy.  Staminate flowers are borne in pedent catkins
on the previous year's twigs.  Pistillate fowers are borne singularly
from small rounded buds and have bright red stigmas.  The fruit is a
round, smooth nut with a very hard shell.  It is enclosed in a leafy sac
which protrudes beyond the nut like a beak and is covered with stiff
hairs.  These sacs are borne singularly, or in groups of two or three,
at the end of the current year's twigs.  [6,13,19,22,26,28]


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Sexual:  California hazel produces large seed crops at irregular
intervals, every 2 or 3 years to every 5 years [6,12].  Late frosts can
kill flowers, and dry weather can affect fertilization [12].  Seed
production increases with stem age, peaking at 10 or 11 years, and
ceasing when twigs are 18 years old [12].  Small mammals and birds are
the primary dispersal agents [6].
 
Seeds have poor viablity in storage and must remain moist.  Two to six
months of chilling is required before germination can take place [6].
Germination rates are low.  In laboratory tests, best results were
achieved when the nuts were covered with humus to prevent drying [12].
Mirov and Kraebel [18] obtained 20 percent germination from seed
stratified for 3 months in peat moss; seeds germinated 96 days after
sowing.  Seed survival is low due to animal predation.  Although only a
small number of nuts produce seedlings, in good seed years regeneration
by seed allows California hazel to to invade new sites [12].

Vegetative:  California hazel sprouts from the root crown after its
aerial crown has been removed [26].  It does not sprout from lateral
root suckers, as beaked hazel does [12].  California hazel also
regenerates by layering [12].


SITE CHARACTERISTICS : 
California hazel is typically found on moist and well-drained sites.  It
occurs on cool shaded sites on north-facing slopes, along streambanks,
in moist wooded canyons and slopes, in the understory of oak and conifer
forests, and in open, burned or cut-over lands [20,22,26,28].

Soil:  California hazel occurs on a variety of soils ranging from moist,
black loam to dry, stony soils, and even appears in crevices in rocks.
It is most abundant on the moderately fertile but stony soils of slopes,
on dry and rocky islands, and along streambanks [26].

Climate:  California hazel is adapted to a mild, temperate climate.  It
has lower frost resistance than beaked hazel [12].

Elevation:  In the coastal mountains of California and at the northern
edge of its range in British Columbia, California hazel occurs at low
elevations.  It occurs at increasingly higher elevations inland and at
its southern perimeter [12,22,26].  It generally occurs below 7,000 feet
(2,134 m) in California and from sea level to 2,625 feet (0-800 m) in
British Columbia.


SUCCESSIONAL STATUS : 
California hazel exhibits both tolerant and intolerant behavior.  It is
able to survive in the forest understory and to invade open sites.

In central Oregon, California hazel was found growing under crown
openings in a 36- to 40-year-old stand of Douglas-fir; it formed an even
shrub layer in a 20-year-old Douglas-fir plantation; and it was found
growing scattered over a recently clearcut unit [23].  In the Oregon
Cascades, California hazel has been listed as an invader of clearcut and
burned units of old-growth Douglas-fir (it was absent from the
undergrowth of adjacent uncut units) [29].


SEASONAL DEVELOPMENT : 
Male and female flower buds are formed in late summer and remain dormant
over the winter.  Fowers emerge in January to March before the leaves
appear [6,12,13,26].  Fruits develop by late summer or early fall [6]
and ripen from from September to October in California [6] and from
August to September in British Columbia [5].  In Oregon, vegetative buds
begin to swell in mid-March, three-quarters of the leaves are fully
developed by mid-June, and growth ceases in August [12].

Related categories for Species: Corylus cornuta var. californica | California Hazel