Xanthocyparis nootkatensis

(D. Don) Farjon et Harder 2002

Common Names

Alaska yellow-cedar, Alaska cedar, yellow cypress (Peattie 1950, Pojar & Mackinnon 1994), Nootka cypress, Alaska cypress.

Taxonomic notes

Syn: Cupressus nootkatensis D. Don 1824, Chamaecyparis nootkatensis (D. Don) Spach 1841, Callitropsis nootkatensis Örsted 1864. Chamaecyparis nootkatensis is still widely used, but studies following on the recent discovery of Xanthocyparis vietnamensis have shown that a variety of lines of evidence justify placing these two species in the same genus (Farjon et al. 2002, Little et al. 2004).

"In addition to variation in habit within the species, occasional plants have divergent forms of foliage. In light of the foliar and habit phenotypes recognized in the horticultural literature (for example, A. J. Rehder [1949] listed, with full bibliographic citations, 22 published varieties and forms best considered as cultivars), no taxonomic significance is attached to this variation here" (Michener 1993).

Description

Trees to 40 m or dwarfed at high elevations; trunk to 200 cm dbh. Bark grayish brown, 1-2 cm thick, irregularly fissured. Branchlet sprays pinnate. Leaves of branchlets mostly 1.5-2.5 mm, stout, occasionally glandular on keel, apex rounded to acute or acuminate, bases of facial leaves often overlapped by apices of subtending facial leaves; glands usually absent (circular when present). Pollen cones 2-5 mm, grayish brown; pollen sacs yellow. Seed cones maturing and opening the second year, rarely in some southern lowland populations late in the first year, in (10-)16-18 months (El-Kassaby et al. 1991, Owens & Molder 1975), 8-12 mm broad, glaucous, dark reddish brown, becoming resinous; scales 4-6, valvate with an open apex; a small central columella between the apical pair of scales. Seeds 2-4 per scale, 2-5 mm, wing equal to or broader than body (Michener 1993, M.P. Frankis e-mail 5-Feb-1999).

Range

USA, Canada: Pacific Coast area from S and SE Alaska through British Columbia, Washington and Oregon to extreme NW California; locally found farther inland; at 600-2100 m in the S, to sea level in the N (Peattie 1950). Disjunct inland populations occur in BC and OR (Michener 1993). Usually found on mesic to hygric sites including avalanche chutes, snowy timberlines, and bog-forest transition areas (Pojar & Mackinnon 1994). Although it usually occurs in mixed conifer forests (most often with Tsuga mertensiana), it occasionally forms pure stands (Little 1980).

I have long wondered why this species has its characteristic range limitations (I should note that this same remark could be made of many species in this database, though it mostly has an answer for the widespread North American and European species). A backcountry ski trip in 2002 suggested part of the answer. In the southern Cascade Mountains of Washington, yellow-cedar grows in the company of subalpine conifers such as Abies amabilis and Tsuga mertensiana. The area experiences very heavy winter snowfall, sometimes in excess of 10 meters. Most of the trees develop very heavy mantles of snow, and breakage due to snow loading is a common cause of death among saplings. C. nootkatensis, however, sheds the snow because its foliage hangs almost straight down and both foliage and bark are smooth and not easily wetted. The photographs at left illustrate this, with a C. nootkatensis sapling showing bare and dark against the snow-clad firs around it. This bare tree, however, is therefore put greatly at risk of the chief enemy of trees living in the high mountains, which is exposure to winter's icy blast. Snow crystals blown above the snow can erode the cuticle from exposed foliage, readily drying and killing it, and a sheltering cloak of snow offers critical protection from such desiccation. Thus we find the C. nootkatensis distribution limited to areas where winters are mild and the risk of blasting by blown ice crystals is low, i.e., in the maritime mountains of the wet Pacific Northwest.

See also Thompson et al. (1999). USDA hardiness zone 6.

Big Tree

Diameter 416 cm, height 61.0 m, located in Kelsey Bay, Vancouver Island, British Columbia (R. Van Pelt [pers. comm. 18-Mar-1998], who measured it). Also, diameter 364 cm, height 37.8 m, located in Olympic National Park ,Washington (American Forests 2000).

Oldest

1834 years for a specimen from the Caren Range, Sechelt Peninsula, BC, collected by M.L. Parker (Robert Van Pelt e-mail 18-Mar-1998). 1636 years for a specimen from Vancouver Island collected by L. Jozsa (Brown 1996). Both ages represent ring counts from stumps in clearcuts. It is to be hoped that comparably old trees remain uncut.

Dendrochronology

Has been studied to date periods of bark harvesting by native peoples and to determine stand ages. Generally has poor circuit uniformity and low sensitivity, so of limited use in dendroclimatic studies. See Laroque and Smith (1999).

Ethnobotany

The tough, straight-grained wood was used by nearly all Northwest Coast peoples for bows, canoe paddles, ceremonial masks, chests, dishes, digging sticks, adze handles, and fish net hoops. The bows were a popular trade item, sometimes traded well beyond the species' range. Branch tips and green cones were used medicinally. In folklore, the tree was believed to have once had human form (Pojar & Mackinnon 1994).

Modern society uses the wood for furniture, finish carpentry, and boats (Little 1980).

The hybrid of this species with Cupressus macrocarpa (Leyland cypress), is of major horticultural importance, particularly in Britain where it arose about 100 years ago. It accounts for 99.5% of the suburban hedge plant market there, despite being far too vigorous for this purpose, growing at 0.5-0.8 m per year to 35 m or more if not trimmed frequently. Two other hybrids, with Cupressus arizonica var. glabra and Cupressus lusitanica, are also known in cultivation, but are not widely planted (M.P. Frankis e-mail 5-Feb-1999). I believe these are still the only intergeneric hybrids known among the conifers, and more remarkably, the hybridization works with both male and female Cupressus, and the F1 hybrids are interfertile as well (Jackson and Dallimore 1926, in Little et al. 2004).

Observations

Common in high montane and subalpine forests of the Cascade Range, Washington and Oregon. Some pure old-growth stands are found in Mt. Rainier National Park, and it is codominant with Tsuga mertensiana near timberline at Jefferson Park, Mt. Jefferson Wilderness, Oregon.

Remarks

The crushed foliage and freshly cut wood has a rather rank odor.

Citations

El-Kassaby, Y.A. et al. 1991. Reproductive-cycle plasticity in yellow-cedar. Canadian Journal of Forest Research 21: 1360-1364.

Jackson, A.B. and W. Dallimore. 1926. A new hybrid conifer. Kew Bulletin of Miscellaneous Information 3: 113-115.

Laroque, C., and D.J. Smith. 1999. Tree-ring analysis of yellow-cedar (Chamaecyparis nootkatensis) on Vancouver Island, British Columbia. Canadian Journal of Forest Research 29: 115-123.