|Scientific Name:||Cupressus sargentii|
Callitropsis sargentii (Jeps.) D.P.Little
Hesperocyparis sargentii (Jeps.) Bartel
|Taxonomic Notes:||The correct name for this species is now (again) Cupressus sargentii (Farjon 2010, Christenhusz et al. 2011) as previous proposals to split the genus into an old world genus Cupressus and a new world segregate based on results of molecular data and cladistic principles were premature: the latest of such studies, with comprehensive taxon sampling, has shown the genus to be ‘monophyletic’ after all (Mao et al. 2010) when broadly circumscribed, and excluding Juniperus.|
|Red List Category & Criteria:||Vulnerable B2ab(ii,iii,v) ver 3.1|
Although extending over a long distance and still abundant, the area of occupancy (AOO) is calculated with a grid of 4×4 km to fall within the threshold for Vulnerable (AOO = 704 km2, number of locations = 8-10). A continuing decline is inferred from the fact that fires will be either suppressed or too intense to benefit this species.
|Range Description:||This cypress is found in California, USA: Coast Ranges, divided into a northern and a southern group of (sub)populations. The northern group is more widespread and is mostly found north of the San Francisco Bay area to ca. 40° N; the southern group occurs mostly in the Santa Lucia Range. The distance between the two main groups is more than 250 km. Numerous scattered groves occur in the Coast Ranges from northern Mendocino County south to Santa Barbara County.|
Native:United States (California)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species is not at all rare. It is locally abundant in scattered subpopulations along 400 miles of coastal ranges. Some of the most extensive stands are in the Eden Valley region of eastern Mendocino County. Another large subpopulation exists in the Cedar Mountain Ridge (Alameda County) which is thought to have the most vigorous seedlings due to germination in serpentine soil.|
|Habitat and Ecology:||
Sargent Cypress is a component of the northern interior cypress forest. This community is an open, scrubby forest, maintained through fire. It occurs in dense thickets as well as in open groves and sparse stands which are widely scattered throughout its range. Sargent Cypress is associated with serpentine chaparral, and intergrades on less severe sites with upper Sonoran mixed chaparral, montane chaparral, or Knobcone Pine forest community types. On more mesic sites the northern interior cypress forest intergrades with mixed evergreen forest or montane coniferous forest. Sargent Cypress is associated with Redwood (Sequoia sempervirens) Douglas Fir (Pseudotsuga menziesii) forest and North Coast forests in Mendocino County, California. In some areas it is associated with Yellow Pine (Pinus ponderosa and P. jeffreyi) forests, closed-cone coniferous woodlands, and pine-cedar-cypress pygmy forests. Sargent Cypress occurs sympatrically with MacNab Cypress (C. macnabiana) in Lake County, California, where it is larger and tends to occupy lower slopes than MacNab Cypress.
Reproduction is exclusively from seed. Staminate cones are produced on trees that are 6 to 7 years old. Ovulate cones are produced on trees that are 5 to 6 years of age or older. The cones require 2 years to mature and contain about 100 seeds each. When cones are closed they persist on the tree until opened by the heat of a fire or from desiccation due to age. Seeds are shed gradually over several months after the cones are opened. Detached cones will open, but they rarely result in seedling establishment, usually due to lack of a suitable seedbed. Seed dispersal is primarily by wind and rain. Seeds require bare mineral soil for germination and establishment. Seedling mortality is high on shaded sites with abundant litter because of damping-off fungi as seedlings are sensitive to excessive moisture. Seedlings are shade intolerant and survive best in full sunlight. Most chaparral species are less able to compete on serpentine soils where Sargent Cypress is often found.
Sargent Cypress is a fire-adapted, fire-dependent species. It has slightly fire-resistant bark and serotinous cones, although its low branching habit makes it susceptible to crown fires. Reproduction is generally restricted to burned sites. The serotinous cones persist on the trees for years, often remaining closed for over 8 years. Cone opening is erratic, slow, and almost negligible except when cones are exposed to extreme heat; then it is rapid and uniform. When opened by the heat of a fire, the seeds fall on exposed mineral soil, with most seeds falling in the first few months. Fires that occur in late summer and fall and are followed by winter rains ensure seed dissemination on bare mineral substrates and moist conditions for germination. In southern California, Sargent Cypress trees generally reach cone-bearing age before another fire occurs.
Severe fires can kill Sargent Cypress. Their thickets are conducive to crown fires, which usually kill most trees in the burned area, although fire may be patchy. Some large trees could survive surface fires; however, most large trees in burned areas are located on bare or rocky sites that may have been left unburned. Cones open as the resin melts and boils. Rapid charring of the thick cone scales extinguishes the flames, leaving seeds unburned. Sargent Cypress commonly forms thickets of dwarfed trees following chaparral fires.
Sargent Cypress is largely restricted to serpentine soils. Using cypress wood to fuel the furnaces used to extract mercury from serpentine soils has reduced California's cypress forests.
Although young plants are not seen as desirable grazing for cattle, trampling by livestock can be detrimental to seedlings. Fire soon after trampling may eradicate an entire cypress grove.
Sargent Cypress commonly forms thickets of dwarfed trees following chaparral fires. Fires occurring too frequently in Sargent Cypress groves may destroy them, as reproduction could be eliminated before it had a chance to produce cones. Conversely, fire suppression could threaten the species too.
Seedlings are susceptible to damping-off fungi. Sargent Cypress is moderately susceptible to Cypress Canker (Seirideum cardinale), which can kill trees. Mistletoe (Phoradendron bolleanum/pauciflorum) often forms dense clusters on bushy Sargent Cypress trees in Marin County, California.
|Conservation Actions:||Substantial proportions of the major areas of occupancy are on public lands where the natural vegetation is more or less protected under legislation. Management of fire, such that it allows fires to occur with frequencies and intensities approaching natural conditions, is crucial to the conservation of this species.|
|Citation:||Farjon, A. 2013. Cupressus sargentii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 09 March 2014.|
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