Lawson's cypress

A large evergreen tree, specimens mature up to 50 m (160 ft) tall or more (exceptionally to 81 m (266 ft)), with trunks 1.2–2 m (4–7 ft) in diameter, exceptionally 3.65 m (12.0 ft). The bark is silver-brown, vertically furrowed, and 15–25 centimetres (6–10 in) thick near the base. The foliage is arranged in lacy, flat sprays with a feathery appearance, usually somewhat glaucous (i.e. blue-green) in color. The leaves are scale-like, 3–5 millimetres (1⁄8–3⁄16 in) long, with narrow white markings on the underside, and produced on somewhat flattened shoots. The foliage gives off a rather pungent scent, not unlike parsley. The seed cones are globose, 7–14 millimetres (9⁄32–9⁄16 in) in diameter, with 6–10 scales, green at first, maturing brown in early fall, 6–8 months after pollination. The male cones are 3–4 millimetres (1⁄8–5⁄32 in) long, dark red, turning brown after pollen release in early spring. The seeds fall quickly and can float on water. Old specimens lack branches near the base and often have dead tops. They can live up to about 600 years of age.

The species is native to southwestern Oregon and northwestern California, and grows from sea level up to 1,500 metres (4,900 ft) in the valleys of the Klamath Mountains, often along streams. It fares best at the north end of its range.

The thick bark provides resistance to wildfires, and the species regenerates well on disrupted land in a variety of soils, but requires consistent moisture. It is shade tolerant, but not as much so as competing species western hemlock and white fir. The old-growth population near Coos Bay, Oregon, was wiped out by logging and wildfires in 1867–1868, and again by fire and root disease in 1936.

Disease. In the wild, the species is seriously and uniquely threatened by a root disease caused by the oomycete pathogen, Phytophthora lateralis, accidentally introduced in the early 1950s following the fungus's arrival to the Pacific Northwest on nursery trees. This disease is also a problem for horticultural plantings in some parts of North America. The tree is sometimes killed, though less often, by other species of Phytophthora. Phytophthora lateralis infection begins when mycelium, from a germinated spore, invade the roots. The infection then spreads through the inner bark and cambium around the base of the tree. Spread up the trunk is generally limited. Infected tissue dies and effectively girdles the tree. Large trees are more likely to be infected than small trees due to larger root areas (although all trees at the edges of infected streams will eventually succumb). However, large trees can often live with the infections for a longer duration (up to several years). C. …

The species was discovered by Euro-Americans in the 1850s. The wood is light yet has great strength and rot resistance, even after long exposure to salt water. Its properties resemble those of yellow-cedar, but was historically more available in the region. On shores lacking docks, logs were transported via high-line cable directly onto ship decks. It was valued for boatbuilding. The species was important to Oregon's lumber industry until the 1950s when it was crippled by disease. It was preferred for storage battery cell separation, Venetian blinds, and other uses. Quality specimens eventually began to be shipped almost exclusively to East Asia, where it is highly valued. Large amounts have been exported to Japan where it is used in making coffins, shrines, and temples. Its lumber is known for its highly fragrant ginger aroma, caused by an oil which repulses decay and insects, including termites; this oil has been used as an insecticide. Due to the straightness of its grain, it is also one of the preferred woods for the manufacture of arrow shafts. It is also considered an acceptable, though not ideal, wood for construction of aircraft. The wood is considered more than acceptable for use in stringed instruments. Its fine grain, good strength and tonal quality are highly regarded for soundboards in guitar making.

Chamaecyparis lawsoniana thrives best in well-drained but moist soils, in a fairly sheltered position in full sun. Several hundred named cultivars of varying crown shape, growth rates and foliage color have been selected for planting in parks and gardens. In the United Kingdom (UK) the following have gained the Royal Horticultural Society's Award of Garden Merit (confirmed 2017):