BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Cornus nuttallii | Pacific Dogwood 



GENERAL BOTANICAL CHARACTERISTICS : 
Pacific dogwood is a native, deciduous, long-lived shrub or tree.  The
opposite leaves have a wavy margin and are tapered at both ends
[1,9,10].  The twigs are green at first, but at maturity turn deep red
to almost black [23].  The flowers are small, green, and borne in
clusters at the end of branchlets surrounded by four to six (usually
six) floral bracts [1,10].

Pacific dogwood can obtain heights as great as 60 feet (18 m) with a
d.b.h. of 24 inches (60 cm) on optimum sites, but the norm is 20 to 30
feet (6-9 m) with a d.b.h. of 6 to 12 inches (15-30 cm) [10].  Under a
forest canopy, Pacific dogwood develops a long, tapered bole with a
short narrow crown; in the open, it has a short, branched bole and
rounded crown.  The root system is generally deep with a large taproot
[10].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Pacific dogwood reproduces both sexually and asexually.  It reaches
sexual maturity at 6 to 10 years of age [26].  Large seed crops are
generally produced at 2-year intervals [2].  The fruit is a drupe that
is bright red when ripe [2].  Fresh seed germinates in the fall in many
types of substrate conditions [26]; however, dried seed needs to be
scarified in concentrated sulfuric acid (H2SO4) for 4 hours, rinsed, and
then stratified at 38 degrees Fahrenheit (3 degrees C) for 3 months
[2,26].  The mean lab germination rate for Pacific dogwood is 81 percent
at 100 percent purity.  The average number of cleaned seeds per pound is
4,700 [2].

Pacific dogwood reprouts from the root crown after distubance by fire or
logging [11,12].  Treated cuttings taken in June and July root fairly
well [14].  Cuttings should be cultivated in clay pots due to water
retention and possible root rot from cans [26].  Cuttings should not be
retained for more then 2 years, for transplants after this time frame
have a higher mortality rate [14].


SITE CHARACTERISTICS : 
Pacific dogwood occurs in maritime to submaritime cool mesothermal
climates; it is reduced or lacking in subalpine environments [13].  It
grows best on deep, relatively stone-free, well-drained soils with a
rich humus layer [26,33,34].

Soil:  Pacific dogwood has a strong affinity for soils high in nitrogen
with the moder or mull humus forms in the soil orders of the
Inceptisols, Ultisols, and Alfisols [13,19,20].

Elevation:  Pacific dogwood grows from near sea level to 6,000 feet
(1,820 m) [23] with elevational limits of 3,500 feet (910 m) in British
Columbia [14] and Washington [32] and reaching its elevational maximum
of 6,000 feet (1,820 m) in California [28].

Associates:  Pacific dogwood's primary associates include Douglas-fir,
western hemlock (Tsuga heterophylla), ponderosa pine (Pinus ponderosa),
grand fir (Abies grandis), giant sequoia (Sequoiadendron giganteum),
redwood (Sequoia sempervirens), and giant chinkapin (Castanopsis
chrysophylla) [19,20,28].

Pacific dogwood's understory associates include snowberry, Pacific
bayberry (Myrica californica), Pacific rhododendron (Rhododendron
macrophyllum), ocean spray (Holodiscus discolor), and Pacific yew (Taxus
brevifolia) [19,26,30].


SUCCESSIONAL STATUS : 
Some authors consider Pacific dogwood a climax species on mesic sites
[34,35], while others view it as a seral species in mesothermal forests
[1,13].  Pacific dogwood exhibits characteristics of a climax species:
it is shade tolerant for its first few years, but once it has a
well-developed canopy it becomes shade intolerant [26].


SEASONAL DEVELOPMENT : 
Pacific dogwood flowers from April to May.  It may flower again in
September, but these flowers never mature [1,10].  Seed maturity and
dispersal occur from September to October [2].

Related categories for Species: Cornus nuttallii | Pacific Dogwood