Common Name: Incense Cedar

General Information

Calocedrus decurrens is an evergreen tree that can grow up to 57 metres tall. The bole can be 90 - 150cm in diameter, exceptionally to 360cm[, ]. The crown is broadly conic with horizontal branches in California and the Mediterranean,, varying in other areas according to climate and becoming narrowly fastigiate in eastern England and Scandanavia[].
Incense-cedar is an important commercial softwood species[], and also has a range of traditional uses. It is widely grown as an ornamental where it can be trimmed to make a hedge.
This species is too widespread and numerous to be threatened with extinction, despite historical decline and risks to smaller southern subpopulations. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

, ,

Range

South-western N. America - Oregon, California, Nevada, Baja California

Habitat

Montane forests; at elevations from 300 - 2,800 metres[]. Found on a variety of soils, usually on western slopes; at an elevation from 700 - 2,500 metres[]. The best specimens are found on deep well-drained slightly acidic sandy loam soils[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	20.00 m
Growth Rate	Slow
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Calocedrus decurrens is found at elevations from near sea level in the north of its range, ascending to almost 3,000 metres in the south. It tolerates hot, dry summers, but is also tolerant of winter frost and snow, being unharmed with temperatures falling to -34°c in the north of its range[, , ]. Plants grow slowly in Britain, but they are perfectly hardy[].
This species is rather tolerant to soil types, with a huge range of pH values from strongly acid to around neutral, but the soil usually well drained[, ]. It is rarely found on limestone. It tolerates hot, dry summers well, but is equally insensitive to frost and snow cover[]. Succeeds in full sun in a moist well-drained soil that is neutral to acid, though it will also survive on dry alkaline soils[]. Plants are shade tolerant when young[]. It grows best in a position that is sheltered from strong winds[].
All parts of the plant are strongly aromatic[, ].
Trees are slow growing but long-lived in the wild, with specimens up to 1,000 years old recorded[]. Young trees can grow 60cm in a year but they seldom average more than 30cm[]. In cultivation growth virtually stops once the tree reaches around 30 metres tall, but specimens up to 57 metres have been recorded in the wild[, , , , ].
Mature trees develop a thick bark and this can help protect them from damage by fires that are not too intense[].
This species is strongly resistant to honey fungus[, ].
The tree exhibits very different crown habits, ranging from almost vertical branches to almost horizontal. It has been shown that these different habits are a result of the area in which it is being grown[, ]. At one time these different habits were considered to be different sub-species, but it is recognised now that it is only climatic forces that cause the differences. The crown can vary as follows:-
In the south of its range, and in similar Mediterranean climates the branches are long and more or less horizontal, forming an open, broadly conic crown
In the north of its range where summers are cooler and the climate moister the branches are more or less erect, forming a broadly ovoid crown. Cultivated trees in eastern USA, western England and Ireland also take this shape.
Cultivated trees in eastern England and Scandanavia, with warm, moderately dry summers and cool to cold winters the trees become narrowly fastigiate[].

Edible Uses

The dense leaflets have been used as a flavouring and protection when leaching acorns[].

Medicinal

A decoction of the leaves has been used to treat stomach troubles[].
Steam from an infusion of the leaves has been inhaled in the treatment of colds[].

Agroforestry Uses:

The tree responds well to light trimming and can be used as a hedge if trimmed regularly[].
Incense cedar is often a pioneer species within its native range[]. It is planted to control erosion along road cuttings and the sides of streams[]

Other Uses

The boughs and twigs have been used to make brooms[].

The roots have been used as overlay twine warps and overlay twine weft bases in making baskets[].
The bark has been made into baskets[].

A resin is obtained from the wood[].

Wood - soft, light, close grained, very durable in the soil though it is often damaged by dry rot[]. It has a powerful, incense-like fragrance[] and is used for making shingles, lathes, fencing, pencils, construction etc[, , , ]. Mature trees are often infected by dry rot, so they are not considered to be a major timber species[].
The wood is exceptionally resistant to decay and highly durable when exposed to weather. It is is manufactured into many products, including lumber, pencil stock (for which it is the major United States source), fence posts, shakes, and landscape timbers, which are attractive because of punky spots resulting from fungus[].

Propagation

Seed - sow early spring in a greenhouse[]. When large enough to handle, prick the seedlings out into individual pots and grow them on in light shade in a greenhouse or cold frame for their first winter. Plant them out in late spring or early summer, after the last expected frosts and consider giving them some protection from the cold for their first winter outdoors.
Cuttings of the current season's growth, taken in mid autumn, in a light sandy soil in a cold frame[].