Sequoia sempervirens

Scientific name:Sequoia sempervirens (D.Don) Endlicher 1847

Synonyms:Condylocarpus sempervirens Salisb. ex Carrière, Gigantabies taxifolia J.Nelson, Schubertia sempervirens (Lamb.) Spach, Sequoia pyramidata Carrière, Sequoia religiosa C.Presl, Sequoia taxifolia K.Koch, Steinhauera sempervirens (D.Don) Voss, Taxodium nutkaense Lamb. ex Endl., Taxodium sempervirens D.Don

Common names:Redwood, California redwood, Coast redwood

Description

Single –trunked or clustered tree to 112 m tall, with trunk to 9 m in diameter. Bark reddish brown at first, weathering grayish, to 35 cm thick, the ridges and furrows sometimes spiraling gently around the trunk. Crown more or less conical to cylindrical throughout the life span, composed of numerous horizontal to gently drooping branches. Needles straight or slightly curved outward, fairly parallel-sided for most of their length to recognizably widest near the middle, abruptly narrowed to the triangular tip topped by a weak prickle and to the rounded base, dark green (or sometimes with a waxy bloom) and with a few lines of stomates above, the stomatal bands beneath whitened, up to 30 mm long, lasting 3-5 years or more. Pollen cones 2-5 mm long. Seed cones 1.3-3.5 cm long, the external face of each cone scale (5-)8-10 mm wide and (3-)5-6 mm high. Seeds 3-6 mm long, about two-thirds as wide, including the wings.

Seaward slopes of coastal mountains of southernmost Oregon and California south through Monterey County. Clothing slopes and valleys of the fog belt with solid stands or mixed with Pseudotsuga menziesii at sea level to 300-(-1,000) m, reaching greatest size in deep alluvial soils of sheltered valleys.

Conservation Status

Red List Category & Criteria: Endangered

(According to forestry estimates in Burns and Honkala (1990) there remained by the end of the twentieth century a total of 260,200 ha of commercial forest with “more than 50% redwood stocking”, while a further 80,940 ha was ‘old-growth redwood’ mostly within protected areas. If the latter forests were also 50% redwood, this would translate in a minimal area of occupancy (AOO) of 1,400 km², to which would have to be added an unknown figure for redwoods occurring as a minor component. The AOO is thus likely to fall below 2,000 km², the threshold for Vulnerable.

Past decline is, as always, difficult to estimate as there were no accurate estimates of an AOO when logging operations began. It is almost certainly in excess of 50% over three generations, which in the case of this very long-lived species takes us back to the period before Europeans and their impact on the forest arrived in northern California.

Continuing decline is inferred from the fact that the proportion of redwood in commercially exploited forests containing this species is still declining, due to deliberate or accidental replacement by more competitive species in the early phases of succession after clear-felling, especially Pseudotsuga menziesii. Under the A2 criterion this species should therefore be listed as Endangered)

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

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