Cupressus macrocarpa (Monterey Cypress, Macrocarpa; syn. Callitropsis macrocarpa (Hartw.) D.P.Little) is a species of cypress endemic to the central coast of California. In the wild, the species is confined to two small populations, near Monterey and Carmel. These two small populations represent what was once a very large forest on the west coast. The surviving trees from this forest are as old as 2000 years.
It is a medium-sized evergreen tree, which often becomes irregular and flat-topped as a result of the strong winds that are typical of its native area. It grows to heights of around 10-25 m, and its trunk diameter reaches 0.6 m, rarely up to 1 m or more. The foliage grows in dense sprays, bright green in color. The leaves are scale-like, 2-5 mm long, and produced on rounded (not flattened) shoots; seedlings up to a year old have needle-like leaves 4-8 mm long. The seed cones are globose to oblong, 20-40 mm long, with 6-14 scales, green at first, maturing brown about 20-24 months after pollination. The pollen cones are 3-5 mm long, and release their pollen in late winter or early spring.
Along with other New World Cupressus species, it has recently been transferred to the genus Callitropsis, on genetic evidence that the New World Cupressus are not very closely related to the Old World Cupressus species.
Monterey Cypress has been widely cultivated away from its native range, both elsewhere along the California coast, and in other areas with similar cool summer, mild winter oceanic climates. European distribution includes Great Britain (including the Isle of Man), France (including the Channel Islands), Ireland, Greece, Italy, Portugal, and Sicily. It is also found in western Oregon, and New Zealand, where it is naturalized) as an ornamental tree, and occasionally as a timber tree. It has also been grown experimentally as a timber crop in Kenya.
In New Zealand, where it is almost always referred to as Macrocarpa, it is most frequently grown as a shelter tree on farms, usually in rows or shelter belts. When growing in better conditions than it receives in the wild, it often grows much larger, with trees to over 40 m tall and 3 m trunk diameter known.
When planted in areas with hot summers (e.g. interior California away from the coastal fog belt), it has proved highly susceptible to cypress canker, caused by the fungus Seiridium cardinale, and rarely survives more than a few years; this disease is not a problem where summers are cool.
A number of cultivars have been selected for garden use, including 'Goldcrest', with yellow-green, semi-juvenile foliage (with spreading scale leaf tips), and 'Lutea' with yellow-green foliage.
The foliage is slightly toxic to livestock, and can cause miscarriages in cattle.
In New Zealand, the timber was used for fence posts before electric fencing became popular. Sawn logs are used, by many craftspeople, some boat builders, and small manufacturers, as a furniture structural material and a decorative wood because of its fine colours. It is also a fast, hot burning, albeit sparky (therefore not suited to open fires), firewood.