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Sequoia sempervirens

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Taxonomy [top]

Kingdom Phylum Class Order Family
PLANTAE TRACHEOPHYTA CONIFEROPSIDA CONIFERALES CUPRESSACEAE

Scientific Name: Sequoia sempervirens
Species Authority: (D.Don) Endl.
Common Name/s:
English – Coast Redwood, Redwood
Taxonomic Notes: Was formerly included under the family Taxodiaceae. The Taxodiaceae is now merged with Cupressaceae (see Farjon 2001).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2acd ver 3.1
Year Published: 2006
Assessor/s: Farjon, A. & members of the Conifer Specialist Group
Reviewer/s: Hilton-Taylor, C. (IUCN Red List Programme) & Farjon, A. (Conifer Red List Authority)
Contributor/s:
Justification:
Original area of occupation estimated at 807,000 hectares. Of this, 483,000 ha remains, 324,000 ha have been converted to other land uses than forest, e.g., agriculture and urban areas. A total of 110,000 ha are in protected lands (1999) and recently 2,800 ha of ‘old growth’ have been added to that by purchase from the timber industry. A total of 364,000 ha are under active management for lumber harvesting; these are all second growth. Logging began commercially around 1820 and continues to the present day. In many logged areas the composition of second growth forest has shifted towards lesser abundance of Redwoods and greater abundance of other conifers.

Evaluation of this species under IUCN Red List Criteria only leaves criterion A (population reduction) open for a possible category of threat as under the B criterion both the extent of occurrence and the area of occupancy (ca. 4,830 km²) are larger than the thresholds for Vulnerable. Criteria C–E do not apply for similar reasons.

Under criterion A2 the population can be said to have been observed or estimated to have been reduced by 40% based on the diminished area of occupancy (c). The causes have not ceased as logging is still going on (d) and this still reduces the abundance of the species (e), while causes such as conversion to other land use are largely irreversible. With a 40% reduction within three generations (easily met for this long-lived tree and therefore accountable since logging began in ca. 1820), the threshold of 30% for Vulnerable has been met, whereas that for Endangered (50%) has not. Under A2 the species is therefore Vulnerable.

A further reduction is suspected based on further shifts in logged forests towards other conifers which are better competitors in certain situations, or deliberately seeded and preferred in thinning operations of commercial stands, but it is difficult to quantify this under both A3 and A4 with the current information available to us.
History:
1998 – Lower Risk/conservation dependent (Oldfield et al. 1998)
1997 – Rare (Walter and Gillett 1998)

Geographic Range [top]

Range Description: U.S.A. (Oregon and California) in a coastal belt of forests 725 km long and 50 to 70 km maximal distance inland, from Curry Co. in Oregon to Monterey Co. in California. In the far south the occurrence becomes more patchy and is restricted to the coast.
Countries:
Native:
United States (California, Oregon)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Redwood forests presumably once stretched nearly unbroken from Santa Cruz, well into Orgeon along the coast (A. Farjon, pers. comm). Some 90 to 95% of old growth forest has been felled since, and the remainder is now almost entirely in parks and reserves (A. Farjon, pers. comm).
Population Trend: Decreasing

Habitat and Ecology [top]

Systems: Terrestrial
Citation: Farjon, A. & members of the Conifer Specialist Group 2006. Sequoia sempervirens. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 June 2013.
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