Callitropsis nootkatensis

Kartesz (1994 checklist) and Flora of North America (1993) treat this species in the genus Chamaecyparis.

Yellow-cedar occurs in coastal mountain ranges from Prince William Bay in south-central Alaska, through British Columbia and Washington, to northern California with some disjunct inland occurrences in British Columbia and Oregon. Declines that began in the 1800's are expected to continue as higher elevations and more northern reaches of the species range experience warming winters. A similar fate is expected due to reduced snow pack that protects freeze sensitive shallow roots, which tend to be most pronounced in poorly drained soil, where shallow roots are normally advantageous. While there is ample available habitat, species migration into these areas is slow, partly due to limited reproductive capacity. Future conservation of this species should consider predicted changes in climate and biotic factors contributing to tree mortality.

This species occurs in coastal temperate rainforest of the coastal mountain ranges from Prince William Bay in south-central Alaska, through British Columbia and Washington, to northern California (Hennon et al. 2012). Disjunct inland occurrences to the east are found in the Selkirk Mountains (southeastern British Columbia) and the Aldrich Mountains (central Oregon) (FNA 1993).

This species is wide ranging and occurs continuously over large tracts of land; estimating the number of occurrences is not feasible.

Fine root freezing which leads to foliar die off, and eventually mortality, is believed to be the primary threat to this species. This species tends to have shallow roots that are sensitive to deep freeze (upper horizon soil temperatures below -5 °C are lethal) and experiences early dehardening with warmer winters. Environmental influences including site characteristics (drainage, soil depth), microclimate (influencing soil temperate fluctuations), and climate change (warmer springs, late winters and reduced snow pack) or recurring climatic events (decadal oscillations) determine the degree to which fine root freezing occurs. It is counter intuitive for a species threatened by freezing roots to be negatively impacted by warmer winters but they contribute to early dehardening of the plant and loss off or reduced snowpack, which buffers roots during extreme cold events. Low elevation sites with poorly drained soils, where roots are typically shallow, are at a greater risk, whereas sites with well drained soils, where roots grow more deeply, tend to be protected (Hennon et al. 2012, 2016; Schaberg et al. 2008, 2011). Future declines are predicted at the northern edge of the species range and progressively higher elevation sites where snowpack may decrease with warming winters due to climate change. A threat to the regeneration of the species includes the Sitka black-tailed deer (Odocoileus hemionus sitkensis), who browse seedlings. Reduced snow pack exposes the seedlings to browsing during the winter (ABR, Inc. 2018; Hennon et al. 2009; Oakes et al. 2016).

Timber harvest is not believed to be a significant threat, although it is unclear if the species is being overutilized or with harvest exceeding the mean annual growth (ABR, Inc., 2018). Indigenous people use the wood and bark in a variety of ways including shelter construction, clothing, canoe paddles, and totem poles, but not at levels that threaten the species (Turner 1998)