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Calocedrus decurrens

Calocedrus decurrens - Incense cedar, Bastard cedar, California incense cedar, California post cedar, White cedar, Cedro incienso
  • Calocedrus decurrens - Incense cedar, Bastard cedar, California incense cedar, California post cedar, White cedar, Cedro incienso  - Click to enlarge
  • Calocedrus decurrens branches - Click to enlarge
  • Calocedrus decurrens tree - Click to enlarge

Scientific name: Calocedrus decurrens  (J. Torrey) Florin 1956

Synonyms: Abies cupressoides Poir., Heyderia decurrens (Torr.) K.Koch, Libocedrus decurrens Torr., Thuja craigana A.Murray bis, Thuja decurrens (Torr.) Voss

Common names: Incense cedar, Bastard cedar, California incense cedar, California post cedar, White cedar (English), Cedro incienso (Spanish)

 

Description

Tree to 46 m tall, with trunk to 3.7 m in diameter. Bark rich reddish brown. Crown cylindrical to narrowly conical, dense at first but becoming more ragged with age. Branchlet sprays yellowish green to dark green on both sides, without conspicuous stomatal zones. Scale leaves of branchlets 2-3 mm long (to 14 mm on main twigs), the short, bluntly triangular free tips directed forward but not tight to the twig, usually with inconspicuous glands. Pollen cones 4-6 mm long, with six to eight pairs of pollen scales. Seed cones 2-3 cm long, hanging down and light tan or yellowish brown at maturity. Seeds 1.5-2.5 cm long, including the wing.

Pacific North America from Oregon to Baja California (Mexico). Montane conifer forests; 50-2,960 m.

 

Conservation Status

Red List Category & Criteria: Least Concern

This species is too widespread and numerous to be threatened with extinction, despite historical decline and risks to smaller southern subpopulations.

This species is a numerous component in the mixed coniferous forests of the Pacific West of the USA, generally occurring in a broad belt in the Cascade Range and Sierra Nevada. In southern California and Baja California the subpopulations become smaller and much more scattered, restricted as they are to the upper altitudes of the highest (and often isolated) mountains.

In mixed conifer forest with Pinus jeffreyi, Pinus ponderosa, Pinus lambertiana, Pinus monticola, Abies concolor, Abies grandis, Abies magnifica, and Pseudotsuga menziesii, locally with Sequoiadendron giganteum, Chamaecyparis lawsoniana, Tsuga heterophylla or Thuja plicata, and in drier southern sites with Pinus coulteri and Pseudotsuga macrocarpa. The undergrowth of these mixed conifer forests varies mostly with altitude and edaphic conditions and is diverse, especially on ultramafic rocks, with Arctostaphylos patula, Arctostaphylos viscida, Ceanothus cordulatus, Ceanothus integerrimus, Ceanothus parvifolius, Castanopsis sempervirens, Gaultheria shallon and many other shrubby species. In most conifer forest associations Calocedrus decurrens is a relatively minor component, where it often occupies open canopy stands on hot, dry sites. In the Sierra Nevada Mixed Conifer Forest it may play a much greater role in the canopy locally. Other forest types include also Quercus spp., Castanopsis chrysophylla, Lithocarpus densiflorus and Arbutus menziesii, together with conifers. The altitudinal range of C. decurrens is from 50 m to 2010 m a.s.l. in the north and between 910 m and 2,960 m a.s.l. in the south of its range. This species is rather tolerant to soil types, with a huge range of pH values, but the soil usually well drained; it is only rare on limestone. It tolerates hot, dry summers well, but is equally insensitive to frost and snow cover.

Historically logging has had a negative impact on the AOO of this species, especially where the natural forest has not come back due to changes in land use since European settlement. It is very difficult to quantify this past decline, while in areas where the forest itself was not removed or drastically altered (plantation) is has since regenerated. In southern California and Baja California isolated subpopulations could be threatened by fires if these are too intense and hot. A theoretical threat there is climate change, if this would mean expansion of desert-like habitat up the mountains, while there is no higher refuge available for the trees of the conifer forests.

Incense cedar is an important timber tree. The wood is used for the manufacture of pencils and in building for exterior siding and windows of houses and garden amenities like fences and trellises. As with many taxa in this family, the wood is decay resistant, which makes it especially useful for these purposes in the wetter coastal areas of the Pacific States in the USA. It is also widely planted as an ornamental tree and only then often grows into a fastigiate habit (probably mostly as the cultivar 'Columnaris' which was named by Beissner Libocedrus decurrens var. columnaris but does not occur in nature). Incense cedar performs well in urban settings as it is relatively tolerant of air pollution. In horticulture a number of cultivars are known, especially with variegated or differently colored foliage. Despite its common name, it is not used for incense burning, although its foliage is fragrant.

This species is present in many protected areas throughout its range, including several famous national parks where any exploitation is ruled out indefinitely by law.

 

References

  • Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
  • Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
  • IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland

Copyright © Aljos Farjon, James E. Eckenwalder, IUCN, Conifers Garden. All rights reserved.


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