Lawson's cypress

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Lawson's cypress
Lawson's cypress tree (Chamaecyparis lawsoniana) leaves and cones

Lawson's cypress tree ( Chamaecyparis lawsoniana ) leaves and cones
Systematics
Class : Coniferopsida
Order : Conifers (Coniferales)
Family : Cypress family (Cupressaceae)
Subfamily : Cupressoideae
Genre : False cypress trees ( Chamaecyparis )
Type : Lawson's cypress
Scientific name
Chamaecyparis lawsoniana
( A. Murr. ) Parl. , 1868

Lawson's false cypress ( Chamaecyparis lawsoniana ) is an evergreen plant species from the genus of the false cypress ( Chamaecyparis ) within the cypress family (Cupressaceae). It was named after the Scottish botanist Peter Lawson . It is also called Oregon Cedar .

description

Habitus

Mature trees

Lawson's false cypress is an evergreen, single or multi-stemmed tree , which in its home country usually reaches heights of 50, rarely up to 65 meters and trunk diameters ( BHD ) of up to 300 centimeters, but in Europe it only reaches heights of 30 meters. It is the largest species of the genus of the false cypresses ( Chamaecyparis ). The maximum age is around 600 years. A characteristic of the species are the overhanging peak shoots and the fern-frond-like branches aligned in the same plane. The main branches are always directed downwards. Lawson's false cypress does not develop a taproot , but it is able to form sinkers on horizontal lateral roots.

Foliage

The very small, scale-like leaves are arranged opposite to one another and lie close to the branches. The size and shape of the leaves vary depending on the branch order and vigor. The edge blades are between 1.6 and 4 millimeters long and have free tips. The mostly diamond-shaped surface leaves only reach 70 to 90% of this size. They have a resin gland on the top. The inner leaves are covered by the outer leaves, which means that an x-shaped, white mark is created on the leaf-bearing branches. The leaves on the top of these branches are dark green, those on the underside light to gray-green. They stay on the tree for up to 3 years before they fall off.

bark

Tribes

The old trees have a dark red-brown bark that comes off in strips. It can be up to 25 centimeters thick near the ground.

Wood

The color of the white sapwood hardly differs from the creamy white heartwood . The annual rings are indistinct. The wood is very light and straight grain. It does not have any resin channels. The bulk density with a wood moisture content of 12% is 0.426 g / cm³. The wood is easy to work with and is extremely resistant to insects, fungi and caustic substances.

Flowers, cones and seeds

Female cones
Male cones
Seeds

Lawson's false cypress is monoecious ( monoecious ). Both the male and female cones are on the ends of the same branch. The male cones are carmine-red and 2 × 3 millimeters in size. The female cones are bluish to purple in color and spherical. They are around 5 millimeters in size. The spherical cones need 6 to 7 months to mature; they are then red-brown and have a diameter of 8 to 12 millimeters. They have eight to ten (rarely six to eight) cone scales with two to four seeds each. The chestnut seed is 2 to 5 millimeters in size; its irregularly shaped wing is at least as wide as the seed.

Chromosome number

The number of chromosomes is 2n = 22.

Lawson's cypress pollen (400 ×)

Distribution and location

The original distribution area ( primary area ) of Lawson's cypress is on the west coast of the USA - in southwest Oregon and northwest California . You can find them from 0 to 1950 m above sea level . The amount of precipitation is between 1,000 and 2,200 millimeters per year. It can withstand temperatures of down to −15 ° C and can handle heavy shading. Usually it forms pure stocks there. In Europe and New Zealand it also occurs as a neophyte.

Diseases and pests

Insect pests and diseases native to the natural range do little damage. Occasionally there are failures caused by bark beetles of the genus Phloesinus .

However, the introduction of the fungus Phytophthora lateralis in the 1950s has proven to be problematic. It attacks the fine roots and kills the cambium at the base of the trunk so that the tree wilts. There is no natural resistance and no possibility of chemical control.

Drought and winter cold are named as abiotic damaging factors. Young trees are sensitive to forest fires.

use

The light yellow, resin-free wood is used for boats, masts and furniture. In his home country it is also used in house building and for making arrows . In Europe, Lawson's cypress is planted as an ornamental tree and has been naturalized in many areas since the mid-19th century; meanwhile there are wild deposits. There are many varieties in culture.

Systematics

Cultivated forms (selection)

Lawson's false cypress hedge ( Chamaecyparis lawsoniana )

There are over 200 varieties on the market in Europe. Here is a selection:

  • 'Alumii': a very popular variety; it is about 3 to 4.5 meters high and grows narrowly columnar. The dense foliage is frosted blue.
  • 'Argentea Compacta': A dwarf form with variegated leaves.
  • 'Aurea': With golden yellow leaves.
  • 'Aurea Densa': With golden yellow leaves.
  • 'Blue Gem': with light blue leaves. grows 1.5 to 2 m in 10 years.
  • 'Croftway': The leaves are initially gray, later dark green.
  • 'Ellwoodii': Small in stature with a conical habit and blue-green leaves.
  • 'Erecta': This variety grows to about 10 meters tall; it grows narrowly conical. The leaves are light green.
  • 'Erecta Aurea': Similar to the 'Erecta' variety, but with bright yellow leaves.
  • 'Fletcheri': A slow-growing form with gray-blue leaves that are almost needle-shaped when young.
  • 'Glauca': With blue-gray leaves.
  • 'Golden Wonder': has golden yellow leaves all year round.
  • 'Green Globe': A dwarf shape only 45 centimeters high, which forms a dense, spherical cushion and has fine, dark green leaves.
  • 'Lane': A slender, columnar shape. The freshly sprouted leaves are initially lemon yellow and turn bronze to golden yellow in winter.
  • 'Lemon Queen': With pale yellow leaves.
  • 'Pembury Blue': A shape with overhanging branches and silvery-blue foliage.
  • 'Stewartii': A fast-growing form that grows 4 to 8 meters high. It has dense, overhanging branches and a striking golden yellow foliage that turns greenish yellow in winter.
  • 'Wisselii': This shape reaches heights of up to 25 meters. It grows slender, conical and has blue-green leaves.
  • 'Winston Churchill': A shape with a conical growth and golden yellow foliage.

literature

Individual evidence

  1. ↑ An illustrated manual of Pacific Coast trees By Howard McMinn, Evelyn Maino, HW Shepherd
  2. ^ Tropicos. [1]
  3. ↑ Rafaël Govaerts (ed.): Chamaecyparis. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved March 22, 2019.
  4. ↑ Dwarf and Small Growing Chamaecyparis lawsoniana ( Memento of the original from May 26, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.conifer.com.au
  5. ↑ biolib: Lawson's Cypress: Chamaecyparis lawsoniana (A. Murray) Parl.
  6. ↑ Michigan State University Extension Ornamental Plants plus Version 3.0 - 00000338 - 11/12/99: Chamaecyparis lawsoniana - Lawson Falsecypress ( Memento of the original from July 29, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / web1.msue.msu.edu
  7. ^ University of Delaware: College of Agricultural & Natural Resources: Botanic Gardens: Chamaecyparis lawsoniana

Web links

Commons : Lawsons False Cypress  - Album with pictures, videos and audio files