Chamaecyparis lawsoniana, known as Port Orford cedar or Lawson's cypress, is a species of conifer in the genus Chamaecyparis, family Cupressaceae. It is native to Oregon and northwestern California, and grows from sea level up to in the valleys of the Klamath Mountains, often along streams.

thumb|255px|Cypress cones of a Chamaecyparis lawsoniana.

Description

A large evergreen tree, specimens mature up to tall or more (exceptionally to ), with trunks in diameter, exceptionally . The bark is silver-brown, vertically furrowed, and thick near the base. of the Lawson & Son nursery in Edinburgh, Scotland, after whom it was named as Lawson's Cypress by the describing botanist Andrew Murray. The United States Department of Agriculture officially calls it by the name Port Orford cedar, Animal-facilitated spread is thought to occur, but is localized.

The United States Forest Service and Bureau of Land Management attempt to prevent Phytophthora spread through road closures, monitoring, research and education. Research has focused on determining the dynamics and mechanisms of spread, as well as attempts to breed resistant trees.

One solution against Phytophtera is known generically as Mancozeb and also commercially known as Dithane (C).

Commercial preparations of the parasitic fungus Pythium oligandrum are licensed for pest control, and documented to predate many species of Phytophthora.

Similar species

The extinct Eocene species Chamaecyparis eureka, known from fossils found on Axel Heiberg Island in Canada, is noted as resembling C. lawsoniana and C. pisifera.

The associated genus Calocedrus (incense-cedar) has thick orange-brown bark and the bark of Thuja plicata (western redcedar) is comparatively thin; both have different foliage than Port Orford cedar.

{| class="wikitable sortable"

|-

! Name !! Height (m) !! Spread (m) !! Shape !! Foliage Colour !! Ref.

|-

| 'Aurea Densa' || 1.5 || 1.0 || broadly conical || yellow-green ||

|-

| 'Chilworth Silver' || 2.5 || 1.0 || broadly columnar || silver-blue ||

|-

| 'Dik's Weeping' || 12.0 || 4.0 || columnar, weeping || blue-green ||

|-

| 'Ellwoodii' || 8.0 || 4.0 || columnar || grey-green ||

|-

| 'Ellwood's Gold' || 4.0 || 1.0 || columnar || yellow/grey-green ||

|-

| 'Ellwood's Pillar' || 2.5 || 1.5 || narrowly columnar || grey-green ||

|-

| 'Fletcheri' || 12.0 || 4.0 || columnar || grey-green ||

|-

| 'Gimbornii' || 2.5 || 2.5 || rounded || grey-green ||

|-

| 'Golden Wonder' || 20.0 || 4.0 || columnar || yellow-green ||

|-

| 'Grayswood Feather' || 4.0 || 1.5 || narrowly columnar || green ||

|-

| 'Green Globe' || 0.3 || 0.3 || rounded || dark green ||

|-

| 'Imbricata Pendula' || 8.0 || 4.0 || conical, weeping, pendulous || green ||

|-

| 'Kilmacurragh' || 12.0 || 4.0 || columnar || dark green ||

|-

| 'Lanei Aurea' || 8.0 || 2.5 || columnar || yellow-green ||

|-

| 'Little Spire' || 2.5 || 1.5 || conical || dark green ||

|-

| 'Minima Aurea' || 1.0 || 1.0 || conical || yellow-green ||

|-

| 'Minima Glauca' || 2.5 || 2.5 || rounded || blue-green ||

|-

| 'Pembury Blue' || 12.00+ || 8.00 || conical || blue-green ||

|-

| 'Pygmaea Argentea' || 2.5 || 1.0 || rounded || cream/blue-green ||

|-

| 'Stardust' || 4.0 || 1.5 || columnar || yellow-green ||

|-

| 'Summer Snow' || 2.5 || 1.5 || conical || cream/green ||

|-

| 'Triomf van Boskoop' || 25.0 || 8.0 || broadly columnar || grey-green ||

|-

| 'Wisselii' || 12.0+ || 4.0 || narrowly conical || blue-green ||

|-

| 'Wissel's Saguaro' || 6.0 || 1.0 || narrow, upright || blue-green ||

|}

Uses

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 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.

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.

<gallery>

File:LawsonsCypress.jpg|Foliage with cones: immature seed cones below, pollen cones above

File:Lawson cypress male cones.jpg|Male cones in spring with diagnostic red colour

File:Chamaecyparis lawsoniana.jpg|Mature female cones

File:Chamaecyparis lawsoniana imbricata pendula 01.jpg|Cultivar 'Imbricata Pendula', Rosemoor, Devon, UK

</gallery>

See also

  • Cedar wood

References

  • Snyder, Gary. 1999. "The Gary Snyder Reader". Counterpoint.

Further reading

  • Listed as Vulnerable (VU A1de+2e v2.3)
  • Siskiyou National Forest has posted precautions for persons entering areas with Port Orford Cedar populations ([http://www.fs.fed.us/r6/siskiyou/poc1.htm]).
  • Hunt, J. 1959. Phytophthora lateralis on Port-Orford-cedar. Research Note 172: 1–6. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station.
  • Torgeson, D. C., Young, R. A., & Milbrath, J. A. 1954. Phytophthora root rot diseases of Lawson cypress and other ornamentals. Oregon Agricultural Experiment Station Bulletin. 537: 1–18. Corvallis, OR: Oregon State College.
  • Zobel, D. B., Roth, L. F., & Hawk, G. M. 1985. Ecology, pathology, and management of Chamaecyparis lawsoniana. General Technical Report. PNW-184: 1–161. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station.
  • Jepson Manual treatment for Cupressus lawsoniana