View source for Biology:Chamaecyparis lawsoniana

{{Short description|Species of conifer}}
{{Speciesbox
| image = Chamaecyparis lawsoniana Dorena1.jpg
| image_caption = Old-growth stand of ''C. lawsoniana'' in California
| status = NT
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 13 November 2021">{{cite iucn |author=Farjon, A. |date=2013 |title=''Chamaecyparis lawsoniana'' |volume=2013 |page=e.T34004A2840024 |doi=10.2305/IUCN.UK.2013-1.RLTS.T34004A2840024.en |access-date=13 November 2021}}</ref>
| genus = Chamaecyparis
| species = lawsoniana
| authority = (A.Murray bis) Parl.
| range_map = Chamaecyparis lawsoniana range map 2.png
| range_map_caption = Natural range of Port Orford cedar
}}

'''''Chamaecyparis lawsoniana''''', known as '''Port Orford cedar'''<ref name=PLANTS>{{PLANTS | symbol =CHLA | taxon = Chamaecyparis lawsoniana| access-date = 22 March 2015}}</ref> or '''Lawson cypress''',<ref name=BSBI07>{{BSBI 2007 |access-date=2014-10-17}}</ref> is a [[Biology:Species|species]] of [[Biology:Conifer|conifer]] in the genus ''[[Biology:Chamaecyparis|Chamaecyparis]]'', family [[Biology:Cupressaceae|Cupressaceae]]. It is [[Earth:Native plant|native]] to Oregon and northwestern California, and grows from sea level up to {{Convert|1500|m|ft|-2|order=flip}} in the valleys of the Klamath Mountains, often along streams.

== Description ==
A large [[Biology:Evergreen|evergreen]] [[Earth:Tree|tree]], specimens mature up to {{convert|200|ft|abbr=on}} tall or more, with trunks {{convert|1.2|-|2|m|ft|0|abbr=on|order=flip}} in diameter, exceptionally {{Convert|8-9|ft|abbr=on}}.<ref name=":02">{{Cite book |last1=Arno |first1=Stephen F. |url=https://books.google.com/books?id=qDD4DwAAQBAJ |title=Northwest Trees: Identifying & Understanding the Region's Native Trees |last2=Hammerly |first2=Ramona P. |publisher=Mountaineers Books |year=2020 |isbn=978-1-68051-329-5 |edition=field guide |location=Seattle |pages=169–174 |language=en |oclc=1141235469 |orig-date=1977}}</ref> The [[Biology:Bark (botany)|bark]] is silver-brown, vertically furrowed, and {{Convert|15-25|cm|order=flip|frac=2}} thick near the base.<ref name=":02" /> The foliage is arranged in lacy, flat sprays with a feathery appearance,<ref name=":02" /> usually somewhat [[Glaucous|glaucous]] (i.e. blue-green) in color. The leaves are scale-like, {{convert|3|–|5|mm|in|frac=32|abbr=out|order=flip}} long, with narrow white markings on the underside, and produced on somewhat flattened shoots. The foliage gives off a rather pungent scent, not unlike [[Biology:Parsley|parsley]]. The seed [[Conifer cone|cones]] are globose, {{convert|7|–|14|mm|frac=32|abbr=out|order=flip}} in diameter, with 6–10 scales, green at first, maturing brown in early fall, 6–8 months after [[Biology:Pollination|pollination]]. The male cones are {{convert|3|–|4|mm|in|frac=32|abbr=out|order=flip}} long, dark red, turning brown after pollen release in early spring. The seeds fall quickly and can float on water.<ref name=":02" />

Old specimens lack branches near the base and often have dead tops. They can live up to about 600 years of age.<ref name=":02" />

== Taxonomy ==
The species was first discovered (by European Americans) near Port Orford, Oregon, and introduced into cultivation in 1854 by collectors working for Charles Lawson FRSE<ref>{{cite book |url=https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf |title=Biographical Index of Former Fellows of the Royal Society of Edinburgh 1783–2002 |date=July 2006 |publisher=The Royal Society of Edinburgh |isbn=0-902-198-84-X |access-date=2017-03-28 |archive-url=https://web.archive.org/web/20160304074135/https://www.royalsoced.org.uk/cms/files/fellows/biographical_index/fells_indexp2.pdf |archive-date=2016-03-04 |url-status=dead}}</ref> of the Lawson & Son nursery in [[Place:Edinburgh|Edinburgh]], Scotland, after whom it was named as Lawson Cypress by the describing botanist Andrew Murray. The United States Department of Agriculture officially calls it by the name Port Orford cedar,<ref name="PLANTS" /> as do most people in its native area, but some botanists prefer to use the name Lawson cypress (or in very rare instances Port Orford cypress) instead. The name "Lawson's cypress" is widely used in horticulture.

== Distribution and habitat ==
The species is [[Earth:Native plant|native]] to southwestern Oregon and northwestern California, and grows from sea level up to {{Convert|1500|m|ft|-2|order=flip}}<ref name=":02" /> in the valleys of the Klamath Mountains, often along streams. It fares best at the north end of its range.<ref name=":02" />

== Ecology ==
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 so much so as competing species western hemlock and white fir.<ref name=":02" /> 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.<ref name=":02" />

=== Disease ===
In the wild, the species is seriously and uniquely threatened by a root disease caused by the oomycete pathogen, ''[[Biology:Phytophthora lateralis|Phytophthora lateralis]]'', accidentally introduced in the early 1950s following the fungus's arrival to the [[Place:Pacific Northwest|Pacific Northwest]] on nursery trees.<ref name=":02" /> 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 ''[[Biology:Phytophthora|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. lawsoniana'' in streamside populations are highly susceptible to ''P. lateralis'' infection. However, the rate of fungal spread through populations in dry upland areas appears to be slow. ''P. lateralis'' spreads through water via mobile spores ([[Biology:Zoospore|zoospore]]s). The fungus also produces resting spores ([[Biology:Chlamydospore|chlamydospore]]s) that can persist in soil for a long period of time. New infections generally begin when soil is transferred from an infected population to a non-infected population via water, human or animal movement.<ref name=":02" /> After initial infection in streamside populations, secondary spread via zoospores quickly infects all downstream individuals.

Human facilitated spread is thought to be responsible for most new, and all long-distance, infections. Soil on vehicle tires, especially logging trucks and other off-road vehicles, is considered the most pressing problem due to the volume of soil that can be carried and the traffic rate in and between susceptible areas. Spread on boots and mountain bike tires has also been suggested and probably contributes to new infections locally.<ref>{{cite news |last=Soden |first=Tabitha |date=October 19, 2015 |title=Roads in the Six Rivers National Forest close to prevent spread of root disease |newspaper=Times-Standard |location=Eureka, Calif. |url=http://www.times-standard.com/article/NJ/20151019/NEWS/151019809 |url-status=dead |access-date=8 September 2016 |archive-url=https://web.archive.org/web/20170820122530/http://www.times-standard.com/article/NJ/20151019/NEWS/151019809 |archive-date=20 August 2017}}</ref> 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 [[Chemistry:Mancozeb|Mancozeb]] and also commercially known as Dithane (C).
Commercial preparations of the parasitic fungus ''[[Biology:Pythium oligandrum|Pythium oligandrum]]'' are licensed for pest control, and documented to predate many species of ''Phytophthora''.<ref>{{cite web |last1=Plato Roberts |first1=Amy |title=Biopesticides Fact Sheet |url=https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-028816_07-May-07.pdf |access-date=10 February 2018 |publisher=epa.gov}}</ref>

=== Similar species ===
The extinct [[Earth:Eocene|Eocene]] species ''[[Biology:Chamaecyparis eureka|Chamaecyparis eureka]]'', known from fossils found on Axel Heiberg Island in Canada, is noted as resembling ''C. lawsoniana'' and ''[[Biology:Chamaecyparis pisifera|C. pisifera]]''.<ref name="Kotyk2003">{{cite journal |last1=Kotyk |first1=M.E.A. |last2=Basinger |first2=J.F. |last3=McIlver |first3=E.E. |year=2003 |title=Early Tertiary ''Chamaecyparis'' Spach from Axel Heiberg Island, Canadian High Arctic |journal=Canadian Journal of Botany |volume=81 |issue=2 |pages=113–130 |doi=10.1139/B03-007}}</ref>

The associated genus ''[[Biology:Calocedrus|Calocedrus]]'' (incense-cedar) has thick orange-brown bark and the bark of ''[[Biology:Thuja plicata|Thuja plicata]]'' (western redcedar) is comparatively thin; both have different foliage than Port Orford cedar.<ref name=":02" />

== Cultivation ==
''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 {{wipe|United Kingdom}} (UK) the following have gained the Royal Horticultural Society's Award of Garden Merit (confirmed 2017):<ref>{{cite web  | url= https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf | title = AGM Plants - Ornamental | date = July 2017 | page = 16 | publisher = Royal Horticultural Society | access-date = 24 January 2018}}</ref> 
{| class="wikitable sortable"
|-
! Name !! Height (m) !! Spread (m) !! Shape !! Foliage Colour !! Ref.
|-
| 'Aurea Densa' || 1.5 || 1.0 || broadly conical || yellow-green || <ref>{{cite web| title = ''Chamaecyparis lawsoniana'' 'Aurea Densa'
| url = https://www.rhs.org.uk/Plants/92923/i-Chamaecyparis-lawsoniana-i-Aurea-Densa/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Chilworth Silver' || 2.5 || 1.0 || broadly columnar || silver-blue || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Chilworth Silver'
| url = https://www.rhs.org.uk/Plants/93790/i-Chamaecyparis-lawsoniana-i-Chilworth-Silver/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Dik's Weeping' || 12.0 || 4.0 || columnar, weeping || blue-green || <ref>{{cite web
|url = https://www.rhs.org.uk/Plants/77528/i-Chamaecyparis-lawsoniana-i-Dik-s-Weeping/Details 
|title = ''Chamaecyparis lawsoniana'' 'Dik's Weeping'
|website = RHS Gardening |publisher=Royal Horticultural Society| access-date=2013-01-28}}</ref>
|-
| 'Ellwoodii' || 8.0 || 4.0 || columnar || grey-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Ellwoodii'
| url = https://www.rhs.org.uk/Plants/92331/i-Chamaecyparis-lawsoniana-i-Ellwoodii/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Ellwood's Gold' || 4.0 || 1.0 || columnar || yellow/grey-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Ellwood's Gold'
| url = https://www.rhs.org.uk/Plants/90200/i-Chamaecyparis-lawsoniana-i-Ellwood-s-Gold/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Ellwood's Pillar' || 2.5 || 1.5 || narrowly columnar || grey-green || <ref>{{cite web
| title = ''Chamaecyparis lawsonian''a 'Ellwood's Pillar'
| url = https://www.rhs.org.uk/Plants/43807/i-Chamaecyparis-lawsoniana-i-Font-Face-times-New-Roman-Ellwood-s-Pillar-FONT-Flolar/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 26 January 2018}}</ref> 
|-
| 'Fletcheri' || 12.0 || 4.0 || columnar || grey-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Fletcheri'
| url = https://www.rhs.org.uk/Plants/98546/i-Chamaecyparis-lawsoniana-i-Fletcheri/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Gimbornii' || 2.5 || 2.5 || rounded || grey-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Gimbornii'
| url = https://www.rhs.org.uk/Plants/91732/i-Chamaecyparis-lawsoniana-i-Gimbornii/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Golden Wonder' || 20.0 || 4.0 || columnar || yellow-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Golden Wonder'
| url = https://www.rhs.org.uk/Plants/94601/Chamaecyparis-lawsoniana-Golden-Wonder/Details
| website = RHS Gardening
| publisher = Royal Horticultural Society
| access-date = 17 July 2020}}</ref> 
|-
| 'Grayswood Feather' || 4.0 || 1.5 || narrowly columnar || green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Grayswood Feather'
| url = https://www.rhs.org.uk/Plants/95513/i-Chamaecyparis-lawsoniana-i-Grayswood-Feather/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Green Globe' || 0.3 || 0.3 || rounded || dark green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Green Globe'
| url = https://www.rhs.org.uk/Plants/94045/i-Chamaecyparis-lawsoniana-i-Green-Globe/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Imbricata Pendula' || 8.0 || 4.0 || conical, weeping, pendulous || green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Imbricata Pendula'
| url = https://www.rhs.org.uk/Plants/43652/i-Chamaecyparis-lawsoniana-i-Imbricata-Pendula/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Kilmacurragh' || 12.0 || 4.0 || columnar || dark green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Kilmacurragh' 
| url = https://www.rhs.org.uk/Plants/52803/i-Chamaecyparis-lawsoniana-i-Kilmacurragh/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date=21 January 2018}}</ref> 
|-
| 'Lanei Aurea' || 8.0 || 2.5 || columnar || yellow-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Lanei Aurea'
| url = https://www.rhs.org.uk/Plants/66124/i-Chamaecyparis-lawsoniana-i-Lanei-Aurea/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Little Spire' || 2.5 || 1.5 || conical || dark green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Little Spire'
| url = https://www.rhs.org.uk/Plants/52219/i-Chamaecyparis-lawsoniana-i-Little-Spire/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date=21 January 2018}}</ref> 
|-
| 'Minima Aurea' || 1.0 || 1.0 || conical || yellow-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Minima Aurea'
| url = https://www.rhs.org.uk/Plants/95050/i-Chamaecyparis-lawsoniana-i-Minima-Aurea/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Minima Glauca' || 2.5 || 2.5 || rounded || blue-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Minima Glauca'
| url = https://www.rhs.org.uk/Plants/93292/i-Chamaecyparis-lawsoniana-i-Minima-Glauca/Details
| website = RHS Gardening| publisher = Royal Horticultural Society | access-date=21 January 2018}}</ref> 
|-
| 'Pembury Blue' || 12.00+ || 8.00 || conical || blue-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Pembury Blue'
| url = https://www.rhs.org.uk/Plants/99620/i-Chamaecyparis-lawsoniana-i-Pembury-Blue/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Pygmaea Argentea' || 2.5 || 1.0 || rounded || cream/blue-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Pygmaea Argentea'
| url = https://www.rhs.org.uk/Plants/94470/i-Chamaecyparis-lawsoniana-i-Pygmaea-Argentea-(v)/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Stardust' || 4.0 || 1.5 || columnar || yellow-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Stardust'
| url = https://www.rhs.org.uk/Plants/99380/i-Chamaecyparis-lawsoniana-i-Stardust/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date=21 January 2018}}</ref> 
|-
| 'Summer Snow' || 2.5 || 1.5 || conical || cream/green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Summer Snow'
| url = https://www.rhs.org.uk/Plants/93460/i-Chamaecyparis-lawsoniana-i-Summer-Snow-(v)/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Triomf van Boskoop' || 25.0 || 8.0 || broadly columnar || grey-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Triomf van Boskoop'
| url = https://www.rhs.org.uk/Plants/100019/Chamaecyparis-lawsoniana-Triomf-van-Boskoop/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Wisselii' || 12.0+ || 4.0 || narrowly conical || blue-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Wisselii'
| url = https://www.rhs.org.uk/Plants/93565/i-Chamaecyparis-lawsoniana-i-Wisselii/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date = 30 January 2018}}</ref> 
|-
| 'Wissel's Saguaro' || 6.0 || 1.0 || narrow, upright || blue-green || <ref>{{cite web
| title = ''Chamaecyparis lawsoniana'' 'Wissel's Saguaro'
| url = https://www.rhs.org.uk/Plants/51664/Chamaecyparis-lawsoniana-Wissel-s-Saguaro/Details
| website = RHS Gardening |publisher=Royal Horticultural Society| access-date=21 January 2018}}</ref> 
|}

== Uses ==
The species was discovered by Euro-Americans in the 1850s. The [[Biology:Wood|wood]] is light yet has great strength and rot resistance, even after long exposure to salt water.<ref name=":02" /> Its properties resemble those of [[Biology:Cupressus nootkatensis|yellow-cedar]], but was historically more available in the region.<ref name=":02" /> On shores lacking docks, logs were transported via high-line cable directly onto ship decks. It was valued for boatbuilding.<ref name=":02" /> The species was important to Oregon's lumber industry until the 1950s when it was crippled by disease.<ref name=":02" /> It was preferred for storage battery cell separation, Venetian blinds, and other uses.<ref name=":02" /> Quality specimens eventually began to be shipped almost exclusively to [[Place:East Asia|East Asia]], where it is highly valued.<ref name=":02" /> Large amounts have been exported to {{wipe|Japan}} where it is used in making coffins, shrines, and temples.<ref>Snyder 1999 pg. 225</ref> Its [[Engineering:Lumber|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 [[Biology:Insecticide|insecticide]].<ref name=":02" /> Due to the straightness of its [[Engineering:Wood grain|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.<ref>Kroes, Watkins, and Delp: Aircraft Maintenance and Repair, sixth edition, page 66, McGraw Hill, 1993</ref>

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.<ref>{{cite web |title=Port Orford Cedar tops |url=http://www.lmii.com/products/mostly-wood/tops-tonewood/port-orford-cedar |publisher=Luthiers Mercantile International, Inc.}}</ref>

==Gallery==
<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 ==
* [[Biology:Cedar wood|Cedar wood]]
== References ==
*Snyder, Gary. 1999. "The Gary Snyder Reader". Counterpoint. {{ISBN|1-887178-90-2}}
{{Reflist|30em}}

== Further reading ==
{{Refbegin}}
* {{cite iucn |author=Farjon, A. |date=2013 |title=''Chamaecyparis lawsoniana'' |volume=2013 |page=e.T34004A2840024 |doi=10.2305/IUCN.UK.2013-1.RLTS.T34004A2840024.en |access-date=13 November 2021}} 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]).
*{{cite journal | doi = 10.1890/0012-9658(2002)083[3167:SOAIPO]2.0.CO;2 | author = Jules, E. S. | author2 = M. J. Kaufmann | author3 = W. Ritts | author4 = A. L. Carroll | name-list-style=amp| year = 2002 | title = Spread of an invasive pathogen over a variable landscape: a non-native root rot on ''Chamaecyparis lawsoniana'' | journal = Ecology | volume = 83 | pages = 3167–3181 | jstor = 3071851 | issue = 11 }}
*Hunt, J. 1959. [http://www.fs.fed.us/pnw/pubs/journals/pnw_os_rn-172.pdf ''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.
*{{cite journal |author1=Roth, L. F. |author2=Trione, E. J. |author3= Ruhmann, W. H. |name-list-style=amp| year = 1957 | title = ''Phytophthora'' induced root rot of native Port-Orford-cedar | journal = Journal of Forestry | volume = 55 | pages = 294–298}}
*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.
*{{cite journal | author = Trione, E. J. | year = 1959 | title = The pathology of ''Phytophthora lateralis'' on native ''Chamaecyparis lawsoniana'' | journal = Phytopathology | volume = 49 | pages = 306–310}}
*{{cite journal |author1=Tucker, C. M. |author2=Milbrath, J. A. | year = 1942 | title = Root rot of ''Chamaecyparis'' caused by a species of ''Phytophthora'' | journal = Mycologia | volume = 34 | pages = 94–103 | jstor = 3754945 | issue = 1 | doi = 10.2307/3754945 }}
*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.
* {{FEIS |last=Uchytil |first=Ronald J. |date=1990 |type=tree |genus=Chamaecyparis |species=lawsoniana}}
{{Refend}}

== External links ==
{{Commons and category}}
*[https://web.archive.org/web/20160401103242/http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?157,160,170 Jepson Manual treatment for ''Cupressus lawsoniana'']
*[https://web.archive.org/web/20160930173554/http://conifercountry.com/conifers/Cup/poc/index.html ConiferCountry ''Chamaecyparis lawsoniana'']

{{Taxonbar|from=Q161360}}

[[Category:Chamaecyparis|lawsoniana]]

{{Sourceattribution|Chamaecyparis lawsoniana}}