Nootka Cypress (Callitropsis nootkatensis), formerly Cupressus nootkatensis, Xanthocyparis nootkatensis or Chamaecyparis nootkatensis, is a cypress (Cupressaceae) with a chequered taxonomic and nomenclatural history.
First described in the genus Cupressus as Cupressus nootkatensis in 1824, it was transferred to Chamaecyparis in 1841 on the basis of its foliage being in flattened sprays, as in other Chamaecyparis, but unlike most (though not all) other Cupressus species.
However, this placement does not fit with the morphology and phenology of the cones, which are far more like Cupressus, like them maturing in two years, not one. Genetic evidence, published by Gadek et al. (2000), strongly supported its return to Cupressus and exclusion from Chamaecyparis.
More recently, Farjon et al. (2002) transferred it to a new genus Xanthocyparis, together with the newly discovered Vietnamese Golden Cypress Xanthocyparis vietnamensis; this species is remarkably similar to Nootka Cypress and the treatment has many arguments in its favour, as while they are not related to Chamaecyparis, neither do they fit fully in Cupressus despite the many similarities.
Little et al. (2004), while confirming the above relationship with further evidence, pointed out that an earlier nomenclatural combination in the genus Callitropsis existed, as Callitropsis nootkatensis (D.Don) Oerst., published in 1864 but overlooked or ignored by other subsequent authors. Little et al. therefore synonymised Xanthocyparis with Callitropsis, the correct name for these species under the ICBN when treated in a distinct genus. The name Xanthocyparis has now been proposed for conservation, but until that is decided on at the 2011 International Botanical Congress, it is correctly classified in Callitropsis.
Although acceptance of the revised classification of this tree is widespread among botanists, inertia in the horticultural and forestry industries (both typically very slow to adopt the results of botanical research), mean the name Chamaecyparis nootkatensis is likely to continue being listed in many situations.
This species goes by many common names including Nootka Cypress, Yellow Cypress, and Alaska Cypress. Even though it is not a cedar, it is also often confusingly called "Nootka Cedar", "Yellow Cedar", "Alaska Cedar", or even "Alaska Yellow Cedar". Its name derives from its discovery on the lands of a First Nation of Canada, the Nuu-chah-nulth of Vancouver Island, British Columbia, who were formerly referred to as the Nootka.
Nootka Cypress is native to the west coast of North America, from the Kenai Peninsula in Alaska, south to northernmost California, typically occurring on wet sites in mountains, often close to the tree line, but sometimes also at lower altitudes.
It is an evergreen tree to 40 m tall, commonly with pendulous branches. The foliage is in flat sprays, with dark green, 3-5 mm long scale-leaves. The cones have 4 (occasionally 6) scales, and resemble the cones of Mexican Cypress (Cupressus lusitanica, another Cupressus species which can show foliage in flat sprays) fairly closely, except being somewhat smaller, typically 10-14 mm diameter; each scale has a pointed triangular bract about 1.5-2 mm long, again similar to other Cupressus and unlike the crescent-shaped, non-pointed bract on the scales of Chamaecyparis cones. The Caren Range on the west coast of British Columbia is home to the oldest Nootka Cypress specimens in the world, with one specimen found to be 1,834 years old (Gymnosperm Database).
It is one of the parents of the hybrid Leyland Cypress; as the other parent, Monterey Cypress, is also in genus Cupressus, the ready formation of this hybrid is a further argument for the placement of the Nootka cypress close to Cupressus.
Due to its expense, it is used mainly for finished carpentry. Typical uses include exterior siding, shingles, decking, exposed beams, glue-laminated beams, paneling, cabinetry, and millwork. In historic preservation it can be used as a substitute for Western Redcedar and Baldcypress, due to current difficulties in obtaining quality timber of those species due to environmental concern and past over-exploitation, although this applies equally to Nootka Cypress.
Other uses for Nootka Cypress include saunas, and battery containers due to its resistance to acids. Traditionally, paddles, masks, dishes, and bows were made from the wood.
It will grow in USDA plant hardiness zones 5-9, but can be difficult to grow. Best growth is in light or heavy soil, preferably well drained, and in climates with cool summers. It prefers semi-shade to full sun.
Nootka Cypress can also be used in bonsai.