BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Chamaecyparis lawsoniana | Port-Orford-Cedar 



GENERAL BOTANICAL CHARACTERISTICS : 
Port-Orford-cedar is a long-lived, shade-tolerant, coniferous, evergreen
tree.  Mature trees typically grow up to 200 feet (60 m) tall and have 4
to 6 foot (122-183 cm) diameter trunks [7].  The largest tree on record
is 239 feet (73 m) tall with a 12 foot (3.6 m) diameter trunk [11].
Trees can live more than 600 years.  Old trees have an enlarged base, a
50 to 70 foot (15.2-21.3 m) long branch-free bole, and a spirelike head
of small horizontal or pendulous branches with slender flattened
branchlets [24,35].  Occasionally the trunk will fork.  The leaves are
small, scalelike, and arranged close to the branchlets.
Port-Orford-cedar has no taproot but produces vertical sinkers from the
wide-spreading horizontal root system [37].  This makes trees subject to
windthrow.  The bark of mature trees is very thick, up to about 10
inches (25 cm) [37].

Growth and height of mature trees varies considerably among different
forest communities.  Height-to-age relationships of Port-Orford-cedar
trees in different forest communities throughout its range is summarized
below [12]:

Community          Height of Port-Orford-cedar at different ages (years)
                                   100            200            300
                              meters  feet   meters  feet   meters  feet

western hemlock/swordfern
(TSUHET-CHALAW/POLMUN-OXAORE)   30     98      47     154     63     207

western hemlock/rhododendron
(TSUHET-CHALAW/RHOMAC-GAUSHA)   --     --      45     148     53     174

mixed fir
(Abies spp.-CHALAW/herb)        12     39      36     118     50     164

white fir
(ABICON-CHALAW/herb)            13     43      25      82     46     151

tanoak
(CHALAW/LITDEN)                 12     39      29      95     44     144

white fir-hemlock
(ABICON-TSUHET-CHALAW)          12     39      26      85     41     134

western hemlock/beargrass
(CHALAW-TSUHET/XERTEN)          13     43      25      82     31     102

mixed pine
(Pinus spp.-CHALAW/QUEVAC/      18     59      21      69     29      95
 XERTEN)

Port-Orford-cedar readily grows under the shade of other conifers but
grows faster in the open [13].  Generally it grows slower than
Douglas-fir (Pseudotsuga menziesii).  Recent research suggests that
Port-Orford-cedar is one of the most shade-tolerant conifers throughout
its range [12,36].  Seedlings and saplings are often found in the shade
of old-growth forests.


RAUNKIAER LIFE FORM : 
   Undisturbed State:  Phanerophyte (megaphanerophyte)
   Burned or Clipped State:  Therophyte


REGENERATION PROCESSES : 
Sexual regeneration:  The primary method of natural reproduction of
Port-Orford-cedar is via seed.  Trees produce seed in sufficient
abundance to ensure seedling establishment under forest stands.
Currently, where root rot is not a problem, Port-Orford-cedar is
reproducing itself in almost all Port-Orford-cedar communities [12].

Male and female flowers are found on the same branch but on different
branchlets.  Flower buds begin growth in the spring and become fully
developed by the end of the summer.  Pollination occurs the following
spring, and seeds become fully developed by September or October [13].
The seeds are borne in small cones that are from 0.25 to 0.5 inch
(0.6-1.2 cm) in diameter [11].

Port-Orford-cedar seeds have small, thin marginal wings, weigh about 2
mg each, and are about 0.11 to 0.16 inch (3-4 mm) long [37].  Harris
[11] reports that seeds are quite variable in weight and size, requiring
from 60,000 to 600,000 to equal a pound.

Port-Orford-cedar begins to produce seed early, between 5 and 9 years of
age.  Cone production becomes greatest at about age 100 and continues
throughout the life of the tree [13].  Although trees produce seed every
year, heavy seed crops are produced every 4 or 5 years [13,32].  Zobel
[32] found annual seed production to vary considerably from year to year
and from site to site within a given year, from 8,097 to 1,862,348 seeds
per acre (20,000-4,600,000/ hectare) and from 56 to 17,193 seeds per
square foot of tree basal area (600 to 185,000/sq m).  The variability
was not clearly related to stand or site factors.  Seed fall begins in
September and continues throughout winter and spring.  Generally about
50 to 60 percent of the seed has fallen by mid-January, with 90 percent
or more fallen by the beginning of May [13,32].  Dispersal distance is
generally short.  One to three tree heights is a common distance of
invasion into clearcuts [37].  The small wings aid in floating on water.
Dispersal by water may be of some importance in streamside habitats.

Most Port-Orford-cedar seed germinates the first spring after dispersal,
but a very small amount may lay dormant for up to 5 years [13].
Germination generally occurs from mid to late June [33].  Viability of
seed can be low.  Germination of seed collected from seed traps from
many sites ranged from 13.8 to 44.2 percent [32].  In this study, seeds
which fell early or late had lower germination percentages than seeds
which fell during peak seed fall, and seed collected from trees had
higher germination percentages (37, 52, and 55 percent) than seed
collected from seed traps [32].  This is much closer to the 48 to 52
percent range reported by Harris [11].  Seed may be stored in sealed
containers at temperatures below freezing with seed moisture content
below 10 percent.  Viability of seed stored in this manner for 7 years
dropped from an initial 56 to 43 percent [11].

Seedling establishment on forest floor litter accounts for the majority
of natural Port-Orford-cedar reproduction.  The litter layer under
Port-Orford-cedar is generally shallow, averaging about 0.4 to 1.6
inches (1-4 cm) [12].  First year survival of seedlings is often about
50 percent [13,33] but drops dramatically thereafter.  Disturbance of
the mineral soil can greatly enhance establishment.  Native
Port-Orford-cedar seed was sown on plots that were treated as follows:
(1) undisturbed with the litter left intact, (2) the litter removed, (3)
burned, or (4) spaded after litter was removed.  The most germinants and
the most surviving germinants after one growing season were found on
spaded plots [33].  By the end of two growing seasons, no seedlings
survived on plots that were burned or had the litter removed.  After
three seasons, 5 percent of the original germinants survived on spaded
plots and 6 percent survived on undisturbed plots.  Seedlings and
saplings are often found growing in the open or under shade but not
under extremely dense shade.  One study found that live seedlings were
found growing in 0.7 to 2.5 percent of full light, but that dead or
nearly dead seedlings were on sites receiving only 0.2 to 0.4 percent of
full light [36].  Thus seeds may germinate in dense, young stands, but
extreme shading can cause total mortality of emerging seedlings.
Following clearcutting or shelterwood cutting, Port-Orford-cedar
successfully establishes from seed within about about 88 to 132 yards
(80-110 m) from a seed tree [18].  Emerging seedlings are delicate and
probably sensitive to drought [13].  Within a deer exclosure 1-year-old
seedlings averaged 1.4 inches (3.6 cm) in height, and 2-year-old
seedlings averaged 3.1 inches (7.9 cm) [11].

Vegetative regeneration:  Vegetative regeneration is very limited in
Port-Orford-cedar.  Plants do not naturally sprout.  However, stem
cuttings root relatively easily if proper methods are followed [5,37].
Layering occurs infrequently and is restricted mostly to trees buried by
sand or thrown by wind [37].


SITE CHARACTERISTICS : 
Although restricted to a small range that covers only 220 miles (350 km)
from north to south, Port-Orford-cedar occupies many vegetation zones,
soil types, and elevations.  It commonly grows in mixed stands but
occasionally forms pure stands.  It occurs mainly within Sitka spruce,
western hemlock, white fir, redwood (Sequoia sempervirens), red fir
(Abies magnifica), mixed-pine, and mixed-evergreen forests
[3,8,10,12,27,28,31].  Within each forest, Port-Orford-cedar is
primarily restricted to moist locations such as benches, drainageways,
or some type of concavity which receives a constant seepage of water
[3,12,36,37].  It is mostly absent from ridges and upper slopes due to
the lack of water; however, some coastal Oregon and upper elevation
Klamath Mountain stands do occupy top-slope positions [12,36,37].
Port-Orford-cedar also occurs on coastal dunes and in bogs with
ultramafic soils.

Common associates:  Besides the above mentioned species,
Port-Orford-cedar is commonly associated with Douglas-fir, grand fir
(Abies grandis), lodgepole pine (Pinus contorta), western redcedar
(Thuja plicata), and Pacific yew (Taxus brevifolia) in coastal areas
[12,13].  Inland tree associates include sugar pine (P. lambertiana),
western white pine (P. monticola), incense-cedar (Libocedrus decurrens),
and Pacific yew [3,12,13].  Hardwood tree associates include tanoak
(Lithocarpus densiflorus), Pacific madrone (Arbutus menziesii), golden
chinkapin (Castanopsis chrysophylla), red alder (Alnus rubra), and
canyon live oak (Quercus chrysolepis) [3,12,13].  Associated shrubs
include dwarf Oregongrape (Berberis nervosa), salal (Gaultheria
shallon), oceanspray (Holodiscus discolor), the shrub form of tanoak (L.
densiflorus var. echinoides), Sadler oak (Q. sadleriana), huckleberry
oak (Q. vaccinifolia), Pacific rhododendron (Rhododendron macrophyllum),
western azalea (Rhododendron occidentale), baldhip rose (Rosa
gymnocarpa), red huckleberry (Vaccinium parvifolium), and evergreen
huckleberry (V. ovatum) [3,12,13].

Soils:  Port-Orford-cedar occurs on many different soil types including
dune sands, organic bog soils, and soils derived from gabbro, diorite,
serpentine, peridotite, river alluvium, and other rock types [30,37].
On diorite it is more commonly found above 2,500 feet (760 m) [30].
Most low elevation Port-Orford-cedar forests occur on soils dervived
from ultramafic parent materials [37].  Port-Orford-cedar is more
successful in communities where the parent material is at least
partially derived from ultramafic rock and where competition is somewhat
reduced [77].  On all soil types, Port-Orford-cedar is limited to mesic
situations [37].

Litter:  The litter layer under eight Port-Orford-cedar communities was
found to be relatively shallow, averaging only 0.4 to 1.6 inches (1-4
cm) deep [12].  The foliage of Port-Orford-cedar is less acidic than
Pinaceae.  Thus the litter and soil under Port-Orford-cedar stands are
less acidic than under nearby conifer stands [37].

Climate:  Port-Orford-cedar is distributed over an area that has warm,
dry summers and cool, wet winters.  Most stands in California receive at
least 59 inches (150 cm) of precipitation annually [37].  Inland
disjunct stands receive at least 49 inches (125 cm) of precipitation
annually.

Elevation:  Port-Orford-cedar is found from sea level to 5,100 feet
(1,554 m) in elevation [3].  


SUCCESSIONAL STATUS : 
Port-Orford-cedar occurs as both an early seral invader and as a
long-lived, shade-tolerant climax species.  Seedlings become established
after disturbances such as clearcutting or fire but also become
established within mature forests.  Continual seedling establishment and
shade tolerance produce stands with many age classes [12].

Following disturbances such as fire or cutting, Port-Orford-cedar
readily establishes where a seed source exists.  Fire can eliminate
young trees, but old-growth trees are very fire-resistant and often
survive fire to reseed the site.  In some old forests, two or more size
classes of Port-Orford-cedar may exist, resulting from the establishment
of trees following periodic fires [12].


SEASONAL DEVELOPMENT : 
Shoot growth of Port-Orford-cedar differs greatly from that of pines and
firs.  Pines and fir species have bud tissue which preforms the
following year's shoots.  Port-Orford-cedar does not have preformed
buds; therefore shoot elongation over the summer takes longer than
competing Pinaceae.  Port-Orford-cedar grows much slower than
Douglas-fir, and in the northern part of its range where
Port-Orford-cedar grows best, prolonged shoot elongation may be
necessary for it to compete.  Port-Orford-cedar's twig growth phenology
may partially explain its northern distributional limit.  North of its
range, the prolonged shoot elongation needed to make plants more
competitive with other conifers would make them susceptible to frost.
Port-Orford-cedar grows on hot open sites and tends to initiate twig
growth earlier and often completes growth more quickly than trees on
colder sites. (the above information is summarized from Zobel 1983 [34])

Port-Orford-cedar flower buds are typically set in the fall with
pollination taking place the following spring [13].  Cones ripen in
September or October with seed dispersal occurring immediately
thereafter and continuing until spring [11,32].

Related categories for Species: Chamaecyparis lawsoniana | Port-Orford-Cedar