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California Bay Laurel

Umbellularia californica (Hook. & Arn.) Nutt.

Comments

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Native Americans used Umbellularia californica for medicinal purposes and occasionally as an insecticide (D. E. Moerman 1986).
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
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Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Description

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Trees or shrubs , to 45 m; twigs terete, glabrous or sparsely appressed-pubescent, rarely minutely tomentose. Leaf blade deep yellow-green, shiny, narrowly oblong or narrowly elliptic, 3-10 × 1.5-3 cm, base acute or obtuse, apex acute; surfaces abaxially glabrous, sparsely appressed-pubescent or minutely tomentose, adaxially glabrous; domatia absent. Inflorescences pubescent. Flowers 5-10; tepals 6-8 mm. Drupe usually solitary, 2 cm or more diam. 2 n =24.
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
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Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Synonym

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Tetranthera californica Hooker & Arnott, Bot. Beechey Voy., 159. 1833
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Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA
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Flora of North America Vol. 3 in eFloras.org, Missouri Botanical Garden. Accessed Nov 12, 2008.
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Geographic distribution

provided by EOL authors
Umbellularia californica occurs broadly in California and in southern Oregon. The California distribution chiefly includes northwestern California, Cascade Range foothills, Sierra Nevada foothills, San Francisco Bay Area, Outer South Coast Ranges, scattered in Transverse Ranges, Peninsular Ranges.

Common Names

provided by Fire Effects Information System Plants
More info for the terms: shrub, tree

California laurel
California bay

TAXONOMY:
The scientific name of California laurel is Umbellularia californica
(Hook. & Arn.) Nutt. [9,22,31]. Recognized varieties are [9]:

Umbellularia californica var. californica
Umbellularia californica var. fresnensis Eastwood.


LIFE FORM:
Tree, Shrub

FEDERAL LEGAL STATUS:
No special status

OTHER STATUS:
NO-ENTRY





DISTRIBUTION AND OCCURRENCE
SPECIES: Umbellularia californica
GENERAL DISTRIBUTION:
California laurel occurs in the Klamath, Siskiyou, and Coast Ranges from
Douglas County, Oregon south to San Diego County, California, and on the
western slope of the Sierra Nevada from Shasta County south to Kern
County. It is found along drainages in the Central Valley, California
[16,23,31,48]. Umbellularia californica var. fresnensis occurs in
Fresno County, California [9].
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bibliographic citation
Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Distribution

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More info for the term: forest

California laurel occurs in the Klamath, Siskiyou, and Coast Ranges from
Douglas County, Oregon south to San Diego County, California, and on the
western slope of the Sierra Nevada from Shasta County south to Kern
County. It is found along drainages in the Central Valley, California
[16,23,31,48]. Umbellularia californica var. fresnensis occurs in
Fresno County, California [9].



Distribution of California laurel. 1971 USDA, Forest Service map digitized by Thompson and others [52].

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Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Fire Management Considerations

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More info for the terms: hardwood, prescribed fire, top-kill

Hardwood timber: Prescribed burning is an effective tool for reclaiming
California laurel in hardwood forests invaded by conifers [9].

Conifer timber: Prescribed burning alone is not effective in removing
California laurel from clear-cut timber areas. Prescribed fire will
top-kill California laurel, but follow-up mechanical or chemical control of
sprouts will be necessary until conifer seedlings are established [9].

Other considerations: California laurel was an integral part of a fire
hazard reduction project in the Berkeley Hills, where highly flammable
exotic eucalyptus were removed to release the less flammable understory
of California laurel and coast live oak [38].

California laurel in riparian areas is not usually threatened because fire
is rare there [19,40].
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Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Key Plant Community Associations

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More info for the terms: codominant, forest, hardwood, tree, woodland

California laurel is sometimes codominant or dominant in various hardwood
forests. Pure stands are rare, but there are a few California laurel
forests in the Coast Ranges and in Tehama County, California [7,11,15].
The tree also occurs in various coniferous forests, where it is a
codominant or dominant in the subcanopy or is an understory associate.
Published classifications listing California laurel as codominant or
dominant in community types (cts), ecoassociation types (eco), plant
associations (pas), or vegetation types (vts) are as follows:

AREA CLASSIFICATION AUTHORITY
CA: outer Coast Ranges Ca. laurel forest cts Holland 1986
CA: Coast Ranges Ca. hardwoods eco Allen & others 1991
nCA: Klamath; N.Coast Ranges cismontane woodland cts Holland 1986
nCA: Muir Woods NM redwood forest vts McBride & Jacobs 1980
sCA: S.Coast Ranges riparian pas Paysen & others 1980
sCA: Santa Ana Mts. canyon woodlands cts Vogl 1976
swOR: Siskiyou NF mixed evergreen cts Sawyer & others 1977
swOR: Siskiyou; Klamath tanoak-Ca. laurel pas Atzet & Wheeler 1984
Ranges
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Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Life Form

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More info for the terms: shrub, tree

Tree, Shrub
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Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Management considerations

provided by Fire Effects Information System Plants
More info for the terms: codominant, fire management, forest, hardwood, root crown

Hardwood timber: Silviculture of California laurel may become more
important as East Coast hardwood production lessens. Although
California laurel wood is valuable, young trees are not currently planted
for future commercial harvest. A serious management problem of this
species is heart rot. The fungus (Ganoderma applanatum) causing this
disease will infect even young trees. Heart rot can be virtually
eliminated from a stand by cutting down trees to stumps of less than 8
inches (20 cm) in height to promote root crown sprouting. Root crown
sprouts have a very low incidence of heart rot. Slash disposal by
broadcast burning is recommended to increase sprouting and kill fungi
harbored in the slash [27]. California laurel has no serious insect pests,
although the powderpost beetle (Ptilinus basalis) and various oak bark
beetles (Pseudopithyophthorus spp.) will sometimes attack injured trees
[9]. California laurel is not windfirm [27].

Conifer timber: California laurel severely reduces growth of conifer
timber seedlings through allelopathic inhibition. The leaves contain
water-soluble terpenes which retard root elongation [16]. A study done
in the Siskiyou National Forest of southwestern Oregon showed that root
elongation of Douglas-fir (Pseudotsuga menziesii) seedlings was 16
percent of normal following treatment with California laurel leaf extract.
This was a greater rate of suppression than that shown by 10 other
chaparral species tested for potential conifer growth inhibition [44].

Unless controlled, the California laurel understory in coniferous forests
often becomes dominant or codominant within a few years following
clear-cutting of mature timber trees [9].

Control: California laurel can be controlled by aerosol or injection/cut
surface treatment with 2,4-D [8]. (also see Fire Management
Considerations regarding control by burning)
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bibliographic citation
Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Phenology

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More info on this topic.

More info for the term: seed

The seasonal development of California laurel varies with latitude and
elevation. The general development is as follows [9]:

Northern Ca Southern Ca
flowers out: April-Sept year-round
new leaves out: May-June Dec-April
seeds ripe: Sept-Nov Sept-Nov
flora primordia develop: Sept-Nov Sept-Nov
seed disseminated: Nov-Jan Nov-Jan
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cc-publicdomain
bibliographic citation
Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Post-fire Regeneration

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

survivor species; on-site surviving root crown
off-site colonizer; seed carried by animals or water; postfire yr 1&2
secondary colonizer; off-site seed carried to site after year 2
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bibliographic citation
Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Taxonomy

provided by Fire Effects Information System Plants
The scientific name of California laurel is Umbellularia californica
(Hook. & Arn.) Nutt. [9,22,31]. Recognized varieties are [9]:

Umbellularia californica var. californica
Umbellularia californica var. fresnensis Eastwood.
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cc-publicdomain
bibliographic citation
Howard, Janet L. 1992. Umbellularia californica. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/

Associated Forest Cover

provided by Silvics of North America
California-laurel is more commonly found in mixture with other species than in pure stands. Choice pure stands were eliminated when coastal and inland valleys were cleared for agriculture, and only scattered groves and tracts of large mature trees remain-many in parks or preserves (40). Pure stands of tall young growth are also limited, but pure stands of shorter trees, thickets, or prostrate mats are common on coastal bluffs, in canyons, and elsewhere in California (19,24,35,61).

California-laurel is listed as an associated species in six forest cover types: Port Orford-Cedar (Society of American Foresters Type 231), Redwood (Type 232), Oregon White Oak (Type 233), Douglas-fir-Tanoak-Pacific Madrone (Type 234), Canyon Live Oak (Type 249), and California Coast Live Oak (Type 255) (13). Its prominence in these types, as well as in several others for which it is not specifically listed, varies widely.

Many trees, shrubs, and herbaceous plants are associated with California-laurel in different parts of its extensive range (table 1). The listing in table 1 is not exhaustive; it indicates the variety of associated species. Usually, fewer species and fewer individuals per species are found under the California-laurel canopy than under the canopy of associated trees, and the area bare of all vegetation is greater. In the Coast Ranges south of San Francisco Bay, an average of 36 species per site, mostly perennials, was found under the California-laurel canopy, 55 species beneath the canopy of other trees (61). Distances bare of vegetation along transects ranged from 9 to 48 percent of the total under California-laurel, 0 to 10 percent under other trees. Where the laurel canopy is particularly dense and extensive, understory vegetation may almost be limited to mosses, ferns, and laurel seedlings (7,51).

Table 1- Trees, shrubs, and herbs associated with California-laurel in different parts of its range¹ Trees Shrubs Herbs Abies grandis Adenostoma fasiculatum Actaea rubra Acer circinatum Amelanchier spp. Adiantum pedatum Acer macrophyllum Arctostaphylos canescens Antennaria suffrutescens Acer negundo Arctostaphylos columbiana Arnica spathulata Aesculus californica Arctostaphylos hispidula Aster radulinus Alnus rhombifolia Arctostaphylos mariposa Balsamorhiza deltoides Alnus rubra Arctostaphylos nevadensis Blechnum spicant Arbutus menziesii Arctostaphylos patula Boykinia spp. Castanopsis chrysophylla Arctostaphylos tomentosa Cheilanthes siliquosa Ceanothus thyrsiflorus Arctostaphylos viscida Chimaphila umbellata Cercis occidentalis Artemisia californica Chlorogalum pomeridianum Chamaecyparis lawsoniana Baccharis pilularis Convolvulus polymorphus Cornus nuttallii Berberis spp. Diplacus aurantiacus Corylus cornuta Ceanothus spp. Disporum spp. Eucalyptus globulus Cornus californica Dryopteris arguta Fraxinus dipetala Eriodictyon californicum Eriophyllum lanatum Fraxinus latifolia Garrya buxifolia Erythronium oregonum Garrya elliptica Garrya fremontii Fragaria californica Heteromeles arbutifolia Gaultheria shallon Galium spp. Libocedrus decurrens Holodiscus discolor Hieracium cynoglossoides Lithocarpus densiflorus Juniperus communis Hierochloe occidentalis Myrica californica Juniperus sibirica Horkelia sericata Picea sitchensis Lonicera hispidula Iris spp. Pinus attenuata Lotus scoparius Juncus spp. Pinus contorta Lupinus albifrons Linnaea borealis Pinus coulteri Myrica hartwegii Lomatium spp. Pinus jeffreyi Pickeringia montana Lupinus nanus Pinus lambertiana Quercus dumosa Marah fabaceus Pinus monticola Quercus durata Mimulus guttatus Pinus ponderosa Quercus sadleriana Osmorhiza chilensis Pinus sabiniana Quercus vaccinifolia Oxalis oregana Platanus racemosa Rhamnus californica Pellaea mucronata Populus trichocarpa Rhamnus crocea Pityrogramma triangularis Prunus ificifolia Rhododendron californicum Polypodium vulgare Pseudotsuga menziesii Rhododendron macrophyllum Polystichum munitum Quercus agrifolia Rhododendron occidentale Pteridium aquilinum Quercus chrysolepis Rhus diversiloba Pyrola dentata Quercus douglasii Ribes spp. Sanicula crassicaulis Quercus garryana Rosa gymnocarpa Satureja douglasii Quercus kelloggii Rubus laciniatus Scrophularia californica Quercus lobata Rubus parviflorus Selaginella bigelovii Quercus wislizeni Rubus procerus Senecio bolanderi Robinia pseudoacacia Rubus spectabilis Smilacina stellata Salix spp. Rubus ursinus Stachys rigida Sambucus spp. Rubus vitifolius Synthyris reniformis Sequoia sempervirens Symphoricarpos albus Trientalis latifolia Taxus brevifolia Symphoricarpos mollis Trillium ovatum Thuja Plicata Symphoricarpos rivularis Vicia spp. Torreya californica Vaccinium spp. Viola spp. Tsuga heterophylla Whipplea modesta Xerophyllum tenax ¹Sources: 2,7,10,14,15,22,32,35,38,47,51,55,61,63
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Climate

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California-laurel grows in diverse climates, ranging from the cool, humid conditions found in dense coastal forests to the hot, dry atmospheres found inland in open woodlands and chaparral. Records from 38 climatic observation stations within or bordering its range indicate that California-laurel has endured temperature extremes of -25° to 48° C (-13° to 118° F) (41,46,59). Average annual temperatures range from 8° to 18° C (46° to 64° F); average temperatures in January, from -1° to 10° C (31° to 50° F); and in July, from 13° to 29° C (56° to 84° F).

Average annual precipitation ranges from 338 mm (13.3 in) at Lemon Cove in the southern Sierra Nevada to 2118 mm (83.4 in) at Gold Beach by the mouth of the Rogue River in Oregon. Average annual snowfall ranges from zero at some coastal locations to 742 em (292 in) at Blue Canyon in Placer County, CA. Average precipitation in the growing season (April through September) ranges from 18 to 432 mm (0.7 to 17.0 in). Length of average frost-free season (above 0° C or 32° F) ranges from 139 to 338 days. Clearly, California-laurel demonstrates broad ecologic versatility.

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Damaging Agents

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Wind and snow cause appreciable destruction and deformation in California-laurel stands. Blowdown is common during severe wind and rain storms in California and Oregon (24,51). Wet clinging snow abets windthrow, breaks tops, and splits forks. Striking examples of crown deformation and molding by strong winds are numerous near the coast.

Because of its thin bark, the tree is easily top-killed by fire, but it sprouts rapidly. Dense clumps are often formed on cutover land, which may prevent the establishment of desired conifers. Very young California-laurel seedlings have less capacity than dwarf chaparral broom (Baccharis pilularis) or coast live oak (Quercus agrifolia) to resprout after complete destruction by heat at ground level (34).

California-laurel is relatively tolerant to boron. In comparison tests, it was less tolerant to boron than Digger pine (Pinus sabiniana) but more tolerant than Pacific madrone (Arbutus menziesii) or bigleaf maple (Acer macrophyllum) (18).

More than 40 species of fungi have been observed on California-laurel, and perhaps three (Anthostoma oreodaphnes, Nectria umbellulariae, and Sphaerella umbellulariae) are restricted to this species (48). Few fungi cause serious damage to the living tree. In central coastal California, a severe outbreak of laurel leaf blight followed abnormally heavy precipitation in two of three winters. A bacterium, Pseudomonas lauracearum, and two fungi, Kabatiella phoradendri f. sp. umbellulariae and Colletotrichum gloeosporioides, were isolated from affected leaves (42). No trees were killed and crowns leafed out anew the following year. Dieback of twigs and new shoots was substantial, however, and was followed by scattered dieback of branches up to 2.5 cm (1 in) in diameter associated with a Botryosphaeria sp., a fungus that has been blamed for much damage to this species (23). Incidence of infection by endophytic fungi, primarily Septogloeum sp., averaged 25 percent for leaf samples of California-laurel collected from four sites representing an environmental gradient in southwestern Oregon (44). Several sooty molds and other diseases are found on laurel leaves; the stem canker, Nectria galligena, occurs primarily where snow, ice, or wind cause severe bending and cracks in the bark of stems and branches; and Ganoderma applanatum fruits readily on scarred trees.

Wood rot is common in California-laurel. Various fungi cause decay associated with wounds, and G. applanatum may function as a heart rot in live wood (23). Even in young stands, dead knots, stem malformations, and root collars are often decayed. Cull in one northern California study averaged 7 and 10 percent of the gross cubic volume in trees of saw log or cordwood size and quality, respectively (31).

California-laurel has no serious insect enemies. A leafblotch miner (Lithocolletis umbellulariae), a stag beetle (Dichelonyx valida), and a thrips (Thrips madronii) cause some damage to leaves. The cottonycushion scale (Icerya purchasi) used to be very damaging but is now under control (48). Several wood borers and beetles attack dead parts of the tree; but only the powderpost beetle (Ptilinus basalis) that attacks dead and stored wood and oak bark beetles (Pseudopityophthorus spp.) that infest injured, felled, and recently dead trees cause damage of economic consequence (16).

Except for seed consumption, animal damage to California-laurel appears minor. In some localities and situations, browsing damage to seedlings and new sprout growth may be of consequence. Young laurel seedlings are browsed less than some associated species (34).

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Flowering and Fruiting

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California-laurel flowers regularly and often profusely. The pale yellow, perfect flowers, 15 mm (0.6 in) in diameter, grow on short-stemmed umbels that originate from leaf axils or near the terminal bud. Flower buds develop early; those for the following year become prominent as current-year fruits are maturing. Flowering within the long north-south range of California-laurel has occurred in all months from November to May, beginning before new leaves appear (24,25,29,61). The flowering period may stretch into late spring and summer by the occasional appearance of flowers originating in axils of developing leaves (48). California-laurel flowers at an early age; flowers have been observed on short whiplike shrubs and on 1-year-old sucker growth that originated on a long broken stub (50). Small insects appear to be the chief pollinators (25).

The fruits-acrid drupes each containing a single, thin-shelled, nutlike seed 15 min (0.6 in) in diameter-ripen in the first autumn after flowering (52). As drupes mature, their thin, fleshy hull changes from medium green to speckled yellow-green, pale yellow, or various other hues from yellow-green tinged with dull red or purple through purplish brown to purple. Ripe drupes may be yellow-green on one tree, dark purple on an adjacent tree (11).

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Genetics

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Several racial variations are recognized. Umbellularia californica forma pendula Rehd. is an uncommon, broad-spreading tree distinctive for its pendulous branchlets that contrast strongly with typically ascending branch growth (24,45). Umbellularia californica var. fresnensis Eastwood has fine white down on the lower surfaces of leaves and on branches of the panicle (11). Gregarious, rockpile, dwarf, and prostrate forms (24) may indicate other varietal differences.

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Growth and Yield

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Over much of its range, California-laurel attains heights of 12 to 24 m (40 to 80 ft) and diameters of 46 to 76 cm (18 to 30 in). On protected bottom lands of southwestern Oregon and northern California, mature trees are 91 to 183 cm (36 to 72 in) in d.b.h. and 30 in (100 ft) or more in height (20,24). A maximum d.b.h. of 404 cm (159 in) (1) and a maximum height of 53.3 m (175 ft) have been reported (49).

California-laurel occurs as a noncontiguous forest type on about 76 080 ha (188,000 acres), 9 712 ha (24,000 acres) in Oregon and 66 368 ha (164,000 acres) in California (4,17). As a component of conifer or other hardwood types, it occurs on an additional 437 060 ha (1,080,000 acres) in California and an undetermined additional acreage in Oregon. Total growing stock volume is approximately 14.7 million m³ (520 million ft³). In California, the mean stand growing-stock volume in the type is 117 m³ per ha (1,677 W/acre), with a maximum of about 218 m³ per ha (3,125 W/acre).

The growth rate of California-laurel varies greatly because of the many climatic, soil, and competitive conditions in which it occurs. Several observers report its height growth is slow, about 0.3 in (1 ft) per year, but on good sites in southern Oregon, height growth averages between 0.3 and 0.6 in (1 to 2 ft) per year (3,12,51). Growth of trees from seed to 38 or 41 cm (15 or 16 in) diameter in 50 years has been reported (57). Total number of stems 10 cm (4 in) in d.b.h. or larger in California and Oregon stands with a large component of California-laurel ranged from 245 to 2,402/ha (99 to 972/acre); reported basal areas ranged from 34.0 to 167.4 m²/ha (148 to 729 ft²/acre) (51,61,62).

Multiple trunks frequently develop in both opengrown and closed stands of California-laurel. Trees in the open often attain a crown spread greater than their height and may not develop a well-defined upper trunk. Many forest-grown trees also fork repeatedly; forking within 3 in (10 ft) of the ground is common. Generally each fork grows vertically and side branches die. Adjacent forked and unforked trees make similar height growth.

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Reaction to Competition

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California-laurel is generally classed as shade tolerant, but the tolerance level is not well defined. A very dense canopy is formed by its thick evergreen leaves, which persist 2 to 6 years. The presence of many small seedlings but no saplings under some closed canopies and the development of long boles clear of live limbs indicate that laurel is not always tolerant of its own shade. These indicators are no criteria of tolerance relative to other species, however, and laurel trees are common among moderately dense conifers.

In some localities, California-laurel appears to be the climax vegetation (7,24,34,61). It is relatively long lived, reproduces from both seeds and sprouts, forms dense pure canopies, and appears to have few serious natural enemies. California-laurel reproduces itself at natural light intensities of 1 to 5 percent of full sunlight; the most dry weight in one experiment was produced at 18 percent of full sunlight, but growth was also reasonable at 8 percent (34,61).

Allelopathic influences have been suspected as the cause of more bare ground under canopy of California-laurel than under canopy of associated trees. Bioassay experiments showed that the leaf and litter volatiles, leachates, and extracts of laurel are capable of inhibiting germination and growth of several test species (56,61).

The distribution of California-laurel in the Coast Ranges south of San Francisco appears to represent a vegetational continuum (61). About the same mixture of understory plants was found under California-laurel canopies as under associated trees, but California-laurel and some of its associates seemed to have a greater tendency to spread to other communities than species from those communities to invade California-laurel woodland.

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Rooting Habit

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The root system of California-laurel has been described as fleshy, deep, and widespreading (49). Several exceptions have been noted, however. Root wads of windthrown trees from alluvial soil in southern Oregon were limited in extent and without a prominent taproot (50). Root systems of seedlings and young trees dug near Berkeley, CA, had relatively shallow root systems, as did some fallen older trees (28). Over half the roots in representative California-laurel stands in the Berkeley Hills were distributed in the top 30 cm. (12 in) of Los Osos adobe clay and all were in the top 90 cm. (36 in) (34). In contrast to the paucity of information on the shape and extent of the root system of California-laurel, its root structure has been thoroughly investigated (26,27).

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Seed Production and Dissemination

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Seed crops are abundant in most years. Although umbels bear four to nine flowers each, generally only one to three fruits set (24). The age when a tree first bears fruit, the age for maximum production, and the average quantity produced have not been determined. Seeds are produced in abundance after trees are 30 to 40 years old (20).

Drupes fall stemless to the ground in late autumn or winter and are dispersed by gravity, wind, animals, and water (34). Fallen drupes are easily gathered by hand. The drupes are large and heavy; 454 g (1 lb) of drupes may yield about 300 cleaned seeds (39).

Under favorable natural conditions, seeds on the ground retain viability over winter, but, under adverse conditions, viability may prove very transient. Viability has been maintained for 6 months when seeds were stored at 3° C (37° F) in wet, fungicide-treated vermiculite (34).

Fresh, untreated seeds germinate indoors or outdoors in peat moss, sawdust, vermiculite, or light-textured soil but may require 3 months or longer (25,39,60). Germination can be speeded by scarifying, cracking, or removing the endocarp, or stratifying the seed, but up to 2 months may still be required (25,34,60). In comparison tests made in petri dishes, California-laurel germination was highest in 30 days under a temperature regime of 16° C (61° F) day, 7° C (45° F) night, and when evaporative stress was minimal (34). Germination did not appear to be affected by light level but was highest in soil with moisture tension at 4 to 10 atmospheres.

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Seedling Development

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Germination occurs naturally in autumn soon after seedfall, or in late winter and spring (52). Covered seeds germinate best, but the large seeds are not buried readily without ground disturbance or silt deposition by high water. Seedling establishment is not common in the drier parts of California except in protected areas and where ground is disturbed (24). California-laurel seedlings invade grasslands and brushlands in the Berkeley Hills; similar capabilities were observed in the Santa Cruz Mountains (34,61).

Germination is hypogeal, and the fleshy cotyledons remain within the endocarp and attached to the seedling until midsummer, when the plant may be 15 to 20 cm (6 to 8 in) tall (25,48). Generally there are two large cotyledons, sometimes three, and no endosperm. Seedlings produce leaves of several transitional forms as they develop and do not branch until they are 2 or 3 years old unless induced to do so by removal of the terminal bud. They soon develop a moderately stout taproot and are difficult to transplant if more than 1 year old unless grown in containers. Recovery after transplanting is often slow, and height growth may be limited for several seasons.

Young California-laurel seedlings appear flexible in their growth requirements. In the first 120 days, seedlings potted in vermiculite grew well at several levels of temperature, evaporative stress, soil moisture, and soil nutrients (34). Seedlings grown at 18 percent or more of full sunlight produced the most dry weight.

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Special Uses

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Wood of California-laurel compares favorably in machining quality with the best eastern hardwoods (8) and is used for fancy turned woodenware, interior trim, cabinets, furniture, paneling, veneer, and gunstocks. Burls and other growths with unusual grain are especially prized for making gifts, novelties, and wood carvings, all marketed as myrtlewood. The wood of mature trees is moderately heavy, hard, fine grained, rich yellowish brown to light gray, and often beautifully mottled. The wood of younger trees generally has less distinctive grain and markings. By rough estimate, 19 950 to 22 800 m³ (3.5 to 4 million fbm) are used annually in the myrtlewood industry.

Indians and early settlers used all parts of the tree for food and medicinal purposes (6,21). Leaves are still collected and dried for home use and commercial sale as a food seasoning (5,37,61). The leaves, seeds, and wood have strong chemical properties and should be used for food, seasoning, or medicinal purposes with caution (5,9,36,48,61).

California-laurel is used for hedges, windbreaks, and indoor and outdoor ornamental evergreens (3,29,41,43). It also provides food and cover for wildlife (53). Silver gray squirrels, dusky-footed woodrats, California mice, and Steller's jays feed extensively on the seeds (54,55). Hogs eat both seeds and roots. Young sprouts are choice browse for deer and goats in spring and summer (33,47) when volatile components of leaves are at lowest concentrations (30).

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Vegetative Reproduction

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California-laurel can be reproduced by cuttings (60), but techniques need further development. Under natural conditions, it may sprout prolifically from the root collar, stump, and trunk. Sprouts and suckers develop wherever a canopy opening admits strong light from the side or overhead. Stumps ringed with root-collar sprouts and both fallen and standing live trunks entirely enveloped in new green sucker growth are common (24). Crowns formed by clumps of sprouts growing in the open typically assume a distinctive, very dense, and symmetrically rounded shape (12,50).

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Distribution

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The range of California-laurel spans more than 11° of latitude, from below the 44th parallel in the Umpqua River Valley of Douglas County, OR, south beyond the 33d parallel in San Diego County, CA. In the Coast Ranges, the southern limit is on eastern slopes of the Laguna Mountains, a short distance from the Mexican border (19). In the Sierra Nevada, it extends as far south as the west slope of Breckenridge Mountain in Kern County (58). Eastward from the coast, California-laurel extends to the foothills of the Cascade Range in Oregon and California, into the western Sierra Nevada for its entire length, and to the inland side of the Coast Ranges south of San Luis Obispo, CA. Its farthest extent inland, about 257 km (160 mi), is in the southern Sierra Nevada.

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Brief Summary

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Lauraceae -- Laurel family

William L. Stein

California-laurel (Umbellularia californica) is the most valued and best publicized hardwood species in the Western United States. It is a monotypic, broadleaved evergreen with many common names, including bay, laurel, California-bay, Oregon-myrtle, myrtlewood, Pacific-myrtle, spice-tree, and pepperwood (50). The names are derived from leaf, fruit, or wood characteristics and also from some similarities often mistaken for relationships with the myrtle and laurel trees of the Mediterranean area (12,25). Decorative items made from the hard, beautifully grained wood are widely marketed as myrtlewood.

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Umbellularia

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Umbellularia californica is a large hardwood tree native to coastal forests and the Sierra foothills of California, as well as to coastal forests extending into Oregon.[1] It is endemic to the California Floristic Province. It is the sole species in the genus Umbellularia.

The tree was formerly known as Oreodaphne californica.[2] In Yuki, it is called pōl’-cum ōl.[3] In Oregon, this tree is known as Oregon myrtle, while in California it is called California bay laurel, which may be shortened to California bay[4] or California laurel. It has also been called pepperwood, spicebush, cinnamon bush, peppernut tree, headache tree,[5] mountain laurel,[6] and balm of heaven.[6]

The tree's pungent leaves have a similar flavor to bay leaves, though stronger, and it may be mistaken for bay laurel. The dry wood has a color range from blonde (like maple) to brown (like walnut). It is considered an excellent tonewood and is sought after by luthiers and woodworkers.

The tree is a host of the pathogen that causes sudden oak death.

Habitat

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This tree, on Permanente Creek in Rancho San Antonio County Park, Santa Clara County, California, is one of the largest of its species in the state. Since this photograph, the tree was split, and half the tree broke off and fell in a storm. The other half is still thriving, and has more or less resumed the original canopy shape.
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Lignotuber near ground level provides fire-resistant storage of energy and sprouting buds if fire damage requires replacement of the trunk or limbs.

This tree mostly inhabits redwood forests, California mixed woods, yellow pine forest, and oak woodlands. Bays occur in oak woodland close to the coast, and in northern California where moisture is sufficient, usually in or near riparian areas.

During the Miocene, oak-laurel forests were found in Central and Southern California. Typical tree species included oaks ancestral to present-day California oaks, and an assemblage of trees from the laurel family, including Nectandra, Ocotea, Persea, and Umbellularia.[7][8] Only one native species from the laurel family, Umbellularia californica, remains in California today.

Distribution

In the north, it reaches its distributional limit through southwest Oregon to (infrequently) Newport, Lincoln County, Oregon, on the coast, extending from there south through California to San Diego County. It is also found in the western foothills of the Sierra Nevada mountains. It occurs at altitudes from sea level up to 1600 m. An isolated, more northern occurrence of the species can be found in Tacoma, Washington, around Snake Lake near the Tacoma Nature Center.[9] There are also two recorded instances of trees growing in coastal British Columbia.[10][11]

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Naturalized occurrence of species in Snake Lake Park, Tacoma, Washington

Description

It is an evergreen tree growing to 30 m tall with a trunk up to 80 cm thick. The largest recorded tree is in Mendocino County, California, and measured (as of 1997) 108 feet (33 m) in height and 119 feet (36 m) in spread.[12]

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The leaves are entire and lance-shaped about 3–10 centimetres (1.2–3.9 in) long. They may substitute for the Mediterranean bay leaf in cooking.

The fragrant leaves are smooth-edged and lance-shaped, 3–10 cm long and 1.5–3 cm broad, similar to the related bay laurel, though usually narrower, and without the crinkled margin of that species.

The flowers are small, yellow or yellowish-green, produced in small umbels (hence the scientific name Umbellularia, "little umbel"). Unlike other "bay laurels" of the genus Laurus, Umbellularia has perfect flowers (male and female parts in the same flower).[13]

The fruit, also known as "California bay nut", is a round and green berry 2–2.5 cm long and 2 cm broad, lightly spotted with yellow, maturing purple. Under the thin, leathery skin, it consists of an oily, fleshy covering over a single hard, thin-shelled pit, and resembles a miniature avocado. Umbellularia is in fact closely related to the avocado's genus Persea, within the family Lauraceae. The fruit ripens around October–November in the native range.

Uses

Historical usage

Umbellularia has long been valued for its many uses by Native Americans throughout the tree's range, including the Cahuilla, Chumash, Ohlone, Pomo, Miwok, Yuki, Coos, and Salinan people.[14] The Concow tribe call the plant sō-ē’-bä (Konkow language).[15]

Poultices of Umbellularia leaves were used to treat rheumatism and neuralgias.[16] A tea was made from the leaves to treat stomach aches, colds, sore throats, and to clear up mucus in the lungs.[17] The leaves were steeped in hot water to make an infusion that was used to wash sores.[16] The Pomo and Yuki tribes of Mendocino County treated headaches by placing a single leaf in the nostril or bathing the head with a laurel leaf infusion.[17]

The chemical responsible for the headache-inducing effects of Umbellularia is known as umbellulone.[5]

Both the flesh and the inner kernel of the fruit have been used as food by Native Americans. The fatty outer flesh of the fruit, or mesocarp, is palatable raw for only a brief time when ripe; prior to this the volatile aromatic oils are too strong, and afterwards the flesh quickly becomes bruised, like that of an overripe avocado.[18] Native Americans dried the fruits in the sun and ate only the lower third of the dried mesocarp, which is less pungent.[17]

The hard inner seed underneath the fleshy mesocarp, like the pit of an avocado, cleaves readily in two when its thin shell is cracked. The pit itself was traditionally roasted to a dark chocolate-brown color, removing much of the pungency and leaving a spicy flavor.[16] Roasted, shelled "bay nuts" were eaten whole, or ground into powder and prepared as a drink which resembles unsweetened chocolate. The flavor, depending on roast level, has been described variously as "roast coffee," "dark chocolate" or "burnt popcorn".[19] The powder might also be used in cooking or pressed into cakes and dried for winter storage.[16] It has been speculated that the nuts contain a stimulant;[20][21] however this possible effect has been little documented by biologists.

Modern usage

The leaf can be used in cooking, but is spicier and "headier" than the Mediterranean bay leaf, and should be used in smaller quantity. Umbellularia leaf imparts a somewhat stronger camphor/cinnamon flavor compared to the Mediterranean bay.[22]

Some modern-day foragers and wild food enthusiasts have adopted Native American practices regarding the edible roasted fruit, the bay nut.[18][20][23]

Umbellularia californica is also used in woodworking. It is considered a tonewood, used to construct the backs and sides of acoustic guitars. The wood is very hard and fine, and is also made into bowls, spoons, and other small items and sold as "myrtlewood". It is also grown as an ornamental tree, both in its native area, and further north up the Pacific coast to Vancouver in Canada, and in western Europe. It is occasionally used for firewood.

According to a modern Miwok recipe for acorn soup, "it is essential that you add a generous amount of California laurel" when storing acorns to dry, to keep insects away from the acorns.[24]

One popular use for the leaves is to put them between the bed mattresses to get rid of, or prevent, flea infestations.

The wood is used as lumber in furniture making, especially highly figured specimens.[25]

"Myrtlewood" money

"Myrtlewood" is the only wood still in use as a base "metal" for legal tender.[26] During the 1933 "interregnum of despair" between Franklin Roosevelt's election and his inauguration, the only bank in the town of North Bend, Oregon—the First National—was forced to temporarily close its doors, precipitating a cash-flow crisis for the City of North Bend. The city solved this problem by minting its own currency, using myrtlewood discs printed on a newspaper press. These coins, in denominations from 25 cents to $10, were used to pay employees, with the city promising to redeem them for cash as soon as it became available.

However, when the bank reopened and the city appealed for people to bring their myrtlewood money in to redeem it, many opted to keep their tokens as collector's items. After several appeals, the city announced that the tokens would remain legal tender in the city of North Bend in perpetuity. The unredeemed tokens have become very valuable, because of scarcity and historical interest. Fewer than 10 full sets are believed to exist.[27]

Sudden oak death

Umbellularia californica is a host of Phytophthora ramorum, the pathogen that causes the disease sudden oak death. It is important in this sense because it is one of two tree species (tanoak is the other) on which the pathogen readily produces spores.[28]

Gallery

See also

References

  1. ^ "Umbellularia californica (Hook. & Arn.) Nutt". CalFlora. Retrieved 2012-02-05.
  2. ^ "The Plant List".
  3. ^ Plants Used by the Indians of Mendocino, California.
  4. ^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
  5. ^ a b Nassini, R.; et al. (2011). "The 'headache tree' via umbellulone and TRPA1 activates the trigeminovascular system". Brain. 135 (2): 376–90. doi:10.1093/brain/awr272. PMID 22036959.
  6. ^ a b John Henry Clarke (1986). A Dictionary of Practical Materia Medica. B. Jain Publishers/Médi-T. ISBN 978-81-7021-013-9.
  7. ^ Axelrod, D. I. (2000). "A Miocene (10-12 Ma) Evergreen Laurel-Oak Forest from Carmel Valley, California". University of California Publications: Geological Sciences. Berkeley, CA, USA: University of California Press. 145.
  8. ^ Barbour, M. G.; Keeler-Wolf, T.; Schoenherr A. A. (2007). Terrestrial Vegetation of California. Berkeley, CA, USA: University of California Press. p. 56.
  9. ^ http://www.pnwherbaria.org/data/results.php?DisplayAs=WebPage&ExcludeCultivated=Y&GroupBy=ungrouped&SortBy=Year&SortOrder=DESC&SearchAllHerbaria=Y&QueryCount=1&IncludeSynonyms1=Y&Genus1=Umbellularia&Species1=californica&Zoom=4&Lat=55&Lng=-135&PolygonCount=0
  10. ^ http://bridge.botany.ubc.ca/herbarium/details.php?db=vwsp.fmp12&layout=vwsp_web_details&recid=160896&ass_num=V227198
  11. ^ http://bridge.botany.ubc.ca/herbarium/details.php?db=vwsp.fmp12&layout=vwsp_web_details&recid=91360&ass_num=V209829
  12. ^ "National register of big trees: California-laurel: Umbellularia californica". American Forests, Washington D.C. Retrieved 2012-09-21.
  13. ^ "California Laurel". Urban Forest Ecosystems Institute. Retrieved 2018-02-04.
  14. ^ "Umbellularia Californica". USDA Plant Guide.
  15. ^ Chesnut, Victor King (1902). Plants used by the Indians of Mendocino County, California. Government Printing Office. p. 408. Retrieved 24 August 2012.
  16. ^ a b c d Goodrich, J. S.; Lawson, C.; Lawson, V. P. (1980). Kashaya Pomo Plants. Heyday Books. p. 176. ISBN 978-0-930588-86-1.
  17. ^ a b c Chesnut, V. K. (1902). Plants Used by the Indians of Mendocino County, California. Contributions from the U.S. National Herbarium Vol. VII. Reprinted 1974 by Mendocino County Historical Society. p. 114. LCCN 08010527. OCLC 6218739.
  18. ^ a b FeralKevin: Foraging, Bushcraft, Permaculture, and Rewilding blog.
  19. ^ Kelly, I. (1978). Coast Miwok. Handbook of North American Indians. 8. Smithsonian Institution. p. 108. ISBN 0-16-004574-6.
  20. ^ a b "The California Bay Laurel". Paleotechnics. Paleotechnics.com.
  21. ^ Moerman, D. E. (1998). Native American Ethnobotany. Timber Press. p. 927. ISBN 978-0-88192-453-4.
  22. ^ Vizgirdas, R. S.; Rey-Vizgirdas, E. M. (2006). Wild Plants of the Sierra Nevada. University of Nevada Press. p. 108. ISBN 978-0-87417-535-6.
  23. ^ Sunny Savage (March 6, 2008). "California Bay Laurel". Wild Food Plants (blog). Retrieved 2012-09-21.
  24. ^ "Nupa (Acorn) Soup". NativeTech: Indigenous Food and Traditional Recipes. Retrieved 2012-09-16.
  25. ^ "Northwest Timber: Wood Terms & Info". nwtimber.com. Retrieved 25 July 2016.
  26. ^ "Myrtle Tree Story". Realoregongift.com. Archived from the original on 2013-12-18. Retrieved 2012-08-17.
  27. ^ Finn J.D. John (August 29, 2010). "When banks closed, town of North Bend minted its own money — out of wood". Offbeat Oregon History. Retrieved 2012-08-17.
  28. ^ "UC Tries to Stop Northward Movement of Sudden Oak Death". University of California, Division of Agriculture and Natural Resources. May 3, 2006. Retrieved 2012-09-21.

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Umbellularia: Brief Summary

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Umbellularia californica is a large hardwood tree native to coastal forests and the Sierra foothills of California, as well as to coastal forests extending into Oregon. It is endemic to the California Floristic Province. It is the sole species in the genus Umbellularia.

The tree was formerly known as Oreodaphne californica. In Yuki, it is called pōl’-cum ōl. In Oregon, this tree is known as Oregon myrtle, while in California it is called California bay laurel, which may be shortened to California bay or California laurel. It has also been called pepperwood, spicebush, cinnamon bush, peppernut tree, headache tree, mountain laurel, and balm of heaven.

The tree's pungent leaves have a similar flavor to bay leaves, though stronger, and it may be mistaken for bay laurel. The dry wood has a color range from blonde (like maple) to brown (like walnut). It is considered an excellent tonewood and is sought after by luthiers and woodworkers.

The tree is a host of the pathogen that causes sudden oak death.

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