|Scientific Name:||Calocedrus decurrens|
|Species Authority:||(Torr.) Florin|
Libocedrus decurrens Torr.
|Red List Category & Criteria:||Least Concern ver 3.1|
|Reviewer/s:||Thomas, P. & Stritch, L.|
This species is too widespread and numerous to be threatened with extinction, despite historical decline and risks to smaller southern subpopulations.
|Range Description:||USA: California, Oregon; NW Mexico: Baja California Norte. The extent of occurrence is in excess of 100,000 km2.|
Native:Mexico (Baja California); United States (California, Oregon)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||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.|
|Habitat and Ecology:||In mixed conifer forest with Pinus jeffreyi, P. ponderosa, P. lambertiana, P. monticola, Abies concolor, A. grandis, A. 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, A. viscida, Ceanothus cordulatus, C. integerrimus, C. parvifolius, Castanopsis sempervirens, Gaultheria shallon and many other shrubby species. In most conifer forest associations C. 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.|
|Major Threat(s):||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.|
|Conservation Actions:||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.|
|Citation:||Farjon, A. 2013. Calocedrus decurrens. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 08 December 2013.|
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