''Calocedrus decurrens'', with the common names incense cedar and California incense cedar (syn. ''Libocedrus decurrens'' Torr.), is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

ous tree native to western North America. It is the most widely known species in the genus, and is often simply called incense cedar without the regional qualifier.Farjon, A. (2005). ''Monograph of Cupressaceae and Sciadopitys''. Royal Botanic Gardens, Kew.

Description

''Calocedrus decurrens'' is a large tree, typically reaching heights of and a trunk diameter up to . The largest known tree, located in Klamath National Forest,

Siskiyou County, California Siskiyou County ( ) is a county (United States), county located in the northwestern portion of the U.S. state of California. As of the 2020 United States census, 2020 census, the population was 44,076. Its county seat is Yreka, California, Yre ...

, is tall with a circumference trunk and a spread. Specimens form a broad conic crown of spreading branches. The bark is orange-brown weathering grayish, smooth at first, becoming fissured and exfoliating in long strips on the lower trunk on old trees. Specimens can live to over 500 years old. The foliage is produced in flattened sprays with scale-like

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

long; they are arranged in opposite decussate pairs, with the successive pairs closely then distantly spaced, so forming apparent whorls of four; the facial pairs are flat, with the lateral pairs folded over their bases. The leaves are bright green on both sides of the shoots, with only inconspicuous

stoma In botany, a stoma (: stomata, from Greek language, Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the Epidermis (botany), epidermis of leaves, stems, and other organs, that controls the rate of gas exc ...

ta. The foliage, when crushed, gives off an aroma somewhat akin to shoe-polish. The seed cones are long, pale green to yellow, with four (rarely six) scales arranged in opposite decussate pairs; the outer pair of scales each bears two winged

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s, the inner pair(s) usually being sterile and fused together in a flat plate. The cones turn orange to yellow-brown when mature about 8 months after pollination. The pollen cones are long.

Distribution

The bulk of the tree's range is in the United States, from central-southwestern

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

through most of

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and the extreme west of

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

, as well as a short distance into northwest Mexico in northern

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

. It grows at altitudes of .

Ecology

At lower elevations, associated trees include oaks and ponderosa pine. Giant sequoia bears similarities to the species, but has sharp leaves. In the south–southwest U.S. some have confused bushy junipers for incense cedar. With its thick basal bark, the incense cedar is one of the most fire- and drought-tolerant plants in California. Although the tree is killed by hot, stand-replacing crown fire, it spreads rapidly after lower-intensity burns. This has given the incense cedar a competitive advantage over other species such as the bigcone Douglas-fir in recent years. Incense cedar is more shade tolerant than

Douglas-fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is the tallest tree in the Pinaceae family. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Or ...

, but not as much so as grand or white fir. It grows slowly when needed to outlast competition. This tree is the preferred host of a wood wasp, '' Syntexis libocedrii'' a species which lays its eggs in the smoldering wood immediately after a forest fire. The tree is also host to incense-cedar mistletoe ('' Phoradendron libocedri''), a

parasitic plant A parasitic plant is a plant that derives some or all of its nutritional requirements from another living plant. They make up about 1% of angiosperms and are found in almost every biome. All Parasite, parasitic plants develop a specialized organ ...

which can often be found hanging from its branches. Fire scars provide an entry point for ''Tyromyces amarus'' (pocket dry rot). '' Gymnosporangium'' rust disease afflicts the trees, but is rarely fatal. For numerous birds during the wintertime, ''Calocedrus decurrens'' has been seen to be used for foraging. According to the

United States Department of Agriculture The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and producti ...

, in areas of the Western Sierra Nevada in California, numerous species of birds are thought to use the incense cedar as a "foraging substrate" so that they can attain as much food as needed. Human impacts on these trees due to forest management practices have caused issues for many of these birds, threatening the use of the incense cedar as a forage substrate.

Uses

The wood is soft and light, and has a pleasant odor and is generally resistant to rot. It has been used for external house siding, interior paneling, and to make moth-resistant hope chests. It was once the primary material for wooden

pencil A pencil () is a writing or drawing implement with a solid pigment core in a protective casing that reduces the risk of core breakage and keeps it from marking the user's hand. Pencils create marks by physical abrasion, leaving a trail of ...

s, because it is soft and tends to sharpen easily without forming splinters.

Native Americans

Indigenous peoples of California Indigenous peoples of California, commonly known as Indigenous Californians or Native Californians, are a diverse group of nations and peoples that are indigenous to the geographic area within the current boundaries of California before and afte ...

use the plant in traditional medicine, basket making, hunting bows, building materials, and to produce fire by friction. A Northern California tribe used branchlets to filter out sand from water when leaching toxins from acorn meal; foliage also served as a flavoring. The Maidu Concow tribe name for the plant is hö'-tä ( Konkow language).

Cultivation

''Calocedrus decurrens'' is cultivated as an ornamental tree, for planting in gardens and parks. It is used in traditional, xeriscapic,

native plant In biogeography, a native species is indigenous to a given region or ecosystem if its presence in that region is the result of only local natural evolution (though often popularised as "with no human intervention") during history. The term is equi ...

, and

wildlife garden A wildlife garden (or habitat garden or backyard restoration) is an Biophysical environment, environment created with the purpose to serve as a sustainable haven for surrounding wildlife. Wildlife gardens contain a variety of habitats that cater t ...

s; and also in designed

natural landscaping Natural landscaping, also called native gardening, is the use of native plants including trees, shrubs, groundcover, and grasses which are local to the geographic area of the garden. Benefits Maintenance Natural landscaping is adapted to t ...

and habitat restoration projects in California. It is valued for its columnar form and evergreen foliage textures. The tree is also grown in gardens and parks in cool summer climates, including the

Pacific Northwest The Pacific Northwest (PNW; ) is a geographic region in Western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though no official boundary exists, the most common ...

in the Northwestern United States and

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

, eastern Great Britain and continental

Northern Europe The northern region of Europe has several definitions. A restrictive definition may describe northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54th parallel north, 54°N, or may be based on other ge ...

. In these areas it can develop an especially narrow columnar crown, an unexplained consequence of the cooler climatic conditions that is rare in trees within its warm summer natural range in the California Floristic Province. Other cultivated species from the family Cupressaceae can have similar crown forms.Mitchell, A. F. (1996). ''Alan Mitchell's Trees of Britain''. Collins .

Award of Garden Merit

This plant has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

, and has the cultivar 'Berrima Gold'.

Essential oils

Various species in the family Cupressaceae can be utilized for the creation of

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the ...

s. Scientific studies have shown that these essential oils have "strong antimicrobial properties." Antimicrobial properties are those properties of a substance that lower the levels of microbes, such as

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

and

virus A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...

es. These antimicrobial properties could potentially be used for therapies in developing countries, although more testing and

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human subject research, human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel v ...

s should be done before such measures are implemented.

Gallery

Calocedrus decurrens copa.jpg, Adult specimen Calocedrus decurrens Incense Cedar.jpg, Tree in

McMinnville, Oregon McMinnville is the county seat of and the most populous city in Yamhill County, Oregon, Yamhill County, Oregon, United States at the base of the Oregon Coast Range. The city is named after McMinnville, Tennessee. As of the 2020 United States cens ...

Incense Cedar in Lassen VNP.jpg, Trunks in Lassen Volcanic National Park, California Calocedrus decurrens MHNT.BOT.2004.0.810.jpg, Cones and seeds Calocedrus decurrens 7976.jpg, Foliage and pollen cones Calocedrus decurrens 7947.jpg, Opened cones Calocedrus decurrens (young female cones).jpg, Young female cones Calocedrus decurrens_CL_MHNT.jpg , Section of wood

References

External links

* * * {{Authority control decurrens Least concern plants Trees of Northern America Flora of California Flora of Oregon Flora of the Cascade Range Flora of the Klamath Mountains Flora of the Sierra Nevada (United States) Natural history of the California Coast Ranges Natural history of the Peninsular Ranges Natural history of the Transverse Ranges Plants used in traditional Native American medicine Least concern flora of North America Least concern flora of the United States