Eucalyptus diversicolor

Eucalyptus diversicolor, commonly known as karri,<ref name="FloraBase" /> is a species of flowering plant in the family Myrtaceae and is endemic to the south-west of Western Australia. It is a tall tree with smooth light grey to cream-coloured, often mottled bark, lance-shaped adult leaves and barrel-shaped fruit. Found in higher rainfall areas, karri is commercially important for its timber.

DescriptionEdit

Eucalyptus diversicolor is the tallest tree that grows in Western Australia.<ref name=CALM/> It is a tall forest tree that typically grows to a height of Template:Cvt<ref name=anps>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> but can reach as high as Template:Cvt,<ref name=FloraBase>Template:FloraBase</ref> making it the tallest tree in Western Australia and one of the tallest in the world.<ref name=AG>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=Stanford>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> As of February 2019, the tallest known living karri is just over Template:Cvt tall. A tree south of Pemberton, known as 'The Tyrant' is Template:Cvt tall and Template:Cvt in girth and contains approximately Template:Cvt of wood in its trunk and is thought to be the largest karri by wood volume.<ref>Template:Cite book</ref> A Eucalyptus diversicolor of Template:Cvt height and of Template:Cvt girth in Coimbra, Portugal, is the tallest reliably measured tree in Europe.<ref>Karri 'Karri Knight' in the Valle de Canas, Valle de Canas, Centro, Portugal, MonumentalTrees.com https://www.monumentaltrees.com/en/prt/centro/coimbra/4104_valledecanas/8314/ Template:Webarchive</ref>

Karri are an evergreen tree and typically have a heavy, widespread crown. The tree's trunk tend to be long and straight with a diameter of Template:Cvt making up about two thirds of the length of the tree.<ref name=useful/>

The trees root can reach depths of up to Template:Cvt.<ref name=seedvine/>

Karri do not form a lignotuber but do form epicormic buds located under the bark along the length of the stem.<ref name=euclid/><ref name=useful>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Trees are able to resprout from the buds after fire or other damage.<ref name=useful/>

The bark on the trunk and branches is smooth, grey to cream-coloured or pale orange, often mottled and is shed in larger plates, short ribbons or small polygonal flakes.<ref name="nsw" /><ref name="Euclid">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The bark sheds each year with the new white bark contrasting with the orange to yellow new bark contrasts against the recently exposed white bark. The bark becomes increasingly granulated with age.<ref name=euclid/> The bark is rich in tannins.<ref name=gardner>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The stems and branchlets are round in cross section, the branchlets have no oil glands in the pith.<ref name=euclid/>

The leaves on young plants and on coppice regrowth are arranged in opposite pairs, broadly egg-shaped to almost round, paler on the lower surface, Template:Cvt long, Template:Cvt wide and petiolate. The leaves tend to be more spreading than pendulous.<ref name=gardner/> Adult leaves are arranged alternately, glossy dark green on the upper surface, paler below, lance-shaped, Template:Cvt long and Template:Cvt wide on a flattened or channelled petiole Template:Cvt long. The leaves are penniveined, where the veins arise pinnately, in a feather like arrangement, from a single primary vein. The leaves are densely reticulated where the network of veins within the leaf is packed closely together. The prominent vein near the margin of the leaf is very close to the margin and runs almost parallel with it. The yellow oil glands within the leaves are situated in centre of the smallest unreticulated areas.<ref name=euclid/> The fine lateral nerves spread at a wide angle from the midrib.<ref name=gardner/>

The unbranched inflorescences are situated in the axils in small clusters on a common stalk. The flower buds are arranged in groups of seven in leaf axils on a rounded peduncle Template:Cvt long, each bud on a pedicel Template:Cvt long. The buds are oval, Template:Cvt long and Template:Cvt wide at maturity with a conical operculum. Flowering has been observed in January, April, May, August and December, and the flowers are white.<ref name=euclid/> The flowers have narrow cylindrical calyx tubes that slowly taper to the base into the pedicel. The many stamen form a continuous ring and has inflected white coloured filaments. The anthers at the end of the filaments have an oblong shape and open into a parallel longitudinal slits.<ref name=gardner/>

The fruit is a woody barrel-shaped capsule Template:Cvt long and Template:Cvt wide on a pedicel Template:Cvt long with three valves at or below rim level.<ref name="nsw" /><ref name="Euclid" />

The seeds found within the fruits have a flattened ovoid shape, are grey in colour with a length of Template:Cvt. The seeds are pointed at one end with a smooth back and a scar from where it was once attached to the placenta on the underside.<ref name=euclid/>

E.Template:Nbspdiversicolor is relatively fast growing, particularly compared to other Eucalypts,<ref name=CALM/> and can grow Template:Cvt each year for the first five years of its life. It reaches maturity after 10 to 15 years.<ref name=seedvine/>

The species has a haploid chromosome number of 12.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

TaxonomyEdit

Eucalyptus diversicolor was first formally described in 1863 by the botanist Ferdinand von Mueller in his book Fragmenta Phytographiae Australiae.<ref name=APNI>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="F.Muell.">Template:Cite book</ref> The type specimen was collected in 1860 by the botanist Augustus Frederick Oldfield near Wilson Inlet, the location given, in Latin, is In Australiae regionibus depressioribus quam Maxime austro occidentalibus, ubi Blue Gum-tree vocatur.<ref name=nsw>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="Mueller1863" />

The holotype is held at Royal Botanic Gardens Victoria, syntypes are held at Cambridge University Herbarium, Royal Botanic Garden Edinburgh and Royal Botanic Gardens, Kew.<ref name=euclid>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The botanical name diversicolor is taken from the Latin word diversus meaning to turn apart and color or "separate colours" and refers to the difference between the top of the leaf and its underside.<ref name=anps/><ref name=euclid/> The common name is derived from the Noongar name for the tree karri pronounces ka-ree.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Karri is a part of the Symphyomyrtus subgenus, all of which have two opercula on the buds and have four rows of ovules. It is not closely related to any other members of the subgenus and is the sole species in the section Inclusae. The defining feature of this section is having inflexed stamens, flattened ovoid seed shape, enclosed valves of the fruit and the lack of pith glands in the branchlets. Although it has no closely related species it has some affinity with tall Eucalypts found the wet forests of eastern Australian including [[Eucalyptus saligna|E.Template:Nbspsaligna]] and [[Eucalyptus grandis|E.Template:Nbspgrandis]] all of which have discolorous adult leaves and seeds with a flattened-ovoid shape.<ref name=euclid/>

Distribution and habitatEdit

File:Eucalyptus diversicolor distribution.png

Distribution

The climate over the range of the tree is mildly temperate with small variations in humidity and temperature with frosts only occurring on rare occasions.<ref name=CALM/> Karri occurs only within the High Rainfall Zone of the South West Botanical Province of Western Australia which receives Template:Convert of rain per year, mostly in winter.<ref name=fpc>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It mostly occurs within the Warren biogeographic region, but there are some outlying populations including the Porongorup Ranges, Mount Manypeaks, Torbay, Rocky Gully all along the south coast and Karridale and Forest Grove to the north west<ref name=fpc/> and the Leeuwin-Naturaliste Ridge to the south of Margaret River to the west of the main belt.<ref name=gondwana/>

The heart of the karri forest is found near Nannup and Manjimup through to Denmark.<ref name=gondwana>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The total area covered by karri forest is less than Template:Convert which is about one fifth of its virgin growth.<ref name=AG/> The nearest tall tree forests are some Template:Convert to the east in Tasmania and Victoria.<ref name=AG/>

Karri has been introduced to parts of Africa including; Kenya, Tanzania and the Canary Islands.<ref name=kew>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The species is considered invasive in South Africa where it is a problem in the Western Cape region and is locally known a karie. It commonly invades clearings, fynbos, water courses and road sides often out competing local species and is spread easily by seed dispersal.<ref name=Invasive>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

EcologyEdit

Karri is regarded as one of the six forest giants found in Western Australia; the other trees include; Corymbia calophylla (Marri), Eucalyptus gomphocephala (Tuart), Eucalyptus jacksonii (Red Tingle), Eucalyptus marginata (Jarrah) and Eucalyptus patens (Yarri).<ref name=seed>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name=pfaf>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Some karri specimens are thought to reach an age of up to 300 years.<ref name=AG/> The soil in which the species grows is often poor, and the tree tends to flower after fire to take advantage of the nutrients released by the combustion of forest litter. The soil is classified as karri loam. Though low in some minor nutrients it is admired for its depth and pasture-growing properties. The depth of the soil is several metres and thought to be created primarily from the bark shed by the tree, which collects at the trunk base to a depth upwards of six metres in mature trees. The karri supports an extensive ecosystem which is connected to the granite outcrops of the lower south-west and the many subsequent creeks and rivers created from runoff. Karri generally dominate in the deep valleys between granite outcrops surrounding the creeks and rivers.

A dense understorey is found in karri forest areas which retains moisture over the hot summers. Associated trees and shrubs found in the understorey include the peppermint (Agonis flexuosa), karri sheoak (Allocasuarina decussata), karri wattle (Acacia pentadenia) and karri oak (Chorilaena quercifolia). A diverse assemblage of flowers and smaller plants – around 2,000 plant taxa – make up the mosaic of habitats within the karri forests.<ref name=gondwana/>

The tree has a complex floral cycle and it takes four to five years from the production of flowers to the seeds being released. The production of seed is dependent on a multitude of variables including tree density, availability of pollinators, soil moisture, genetics, nutrients and fire.<ref name=CALM>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

PollinatorsEdit

Most Eucalypts achieve pollination through insects and birds rather than wind. Insects are far less active through the colder winter months so bird pollination is thought to be more important. The trees are often visited by nectar feeding birds, particularly Purple-crowned lorikeets. The lorikeets have a wide range and are quite active during winter and are thought to be dominant pollinators and able to cross pollinate over larger distances.<ref name=CALM/> Karri is a source of pollen for honeybees (Apis mellifera). The pollen has a protein content of 23.4% and provides sufficient amino acids for the nutrition of A.Template:Nbspmellifera. The content of some of the amino acids are; 3.84% proline, 2.07% glutamic acid, 1.72% lysine, 1.22% cystine, 1.91% aspartic acid, 1.50% leucine, 1.11% alanine and 1.11% valine.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

UsesEdit

File:Deanmill karri logs on train.jpg

Deanmill karri logs on train

File:Karri log in Primer of Forestry Poole 1922.png

'Log and fallers.' Poole, C. E. L., Primer of Forestry 1922

The wood has a green density of around Template:Convert with an air-dried density of about Template:Convert.<ref name=fpc/> The heartwood of Karri is a red colour and closely resembles Jarrah heartwood. Bushmen used to tell the two timbers apart by burning a splint of wood, Karri would leave a white ash and Jarrah would leave a grey to black coloured ash.<ref name=gardner/> Timber from Karri is suitable for construction work. It is a little more dense than Jarrah but is much stronger. Karri wood is not as termite resistant as that of Jarrah.<ref name=gardner/> The tree has been logged since the settlement of Western Australia with logging towns appearing throughout the range of the tree and producing hardwood timbers, mostly for construction purposes, for the first 150 years since settlement.<ref name=gondwana/> The first Karri timber to be felled for export was at the isolated population around Leeuwin, which became known as Karridale. The virtues of the wood were promoted in the 1920s by the state conservator of forests, Charles Lane-Poole, who noted the colonists' preference for other timber as its vulnerability to white ants made it a poor choice for fence posts and railway sleepers. The timber found uses in the state for wagon spokes and wooden pipes, and in England it was found suitable for scantlings by the national railway and telegraph arms by the postal services and was listed among Lloyds shipbuilding timbers as possessing great strength over large lengths.<ref name="Lane-Poole1922">Template:Cite book</ref>

Fire lookouts were established in the forests using the tallest Karri trees, giving the foresters a commanding view of the landscape. The idea of using karri trees in this way was first suggested in 1937 by a young forester, Don Stewart, who later became Conservator of Forests. The first of these was built on a large marri (Corymbia calophylla) at Alco, near Nannup. Eight lookouts were established in the forests between 1937 and 1952. Spotter planes are now used and some of the trees are now used as tourist attractions.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="Pemberton">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Karri wood is a beautiful mahogany colour, lighter in colour than jarrah. It is used extensively in the building industry, particularly in roofs for the length and knot-free quality of the boards. The wood is also used for flooring, furniture, cabinetry and plywood. The heartwood is golden to reddish brown, often with an orange or purple cast, and tends to darken with age. It has an interlocked grain with a uniform medium-coarse texture.<ref name=wood>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> It has the reputation of being termite-prone, although it is nowhere near as susceptible to these insects as pine. It is durable against rot. It is also an excellent furniture wood.

Some of the main streets of early Sydney were paved with blocks of Karri but have been long since covered by asphalt. The wood was also sent to London for the same purpose.<ref name=Stanford/>

Karri honey is widely sought after for its clarity, light color and delicate flavor.<ref name=gardner/> In 1952 it was estimated that 25% of honey produced in Western Australia was produced in Karri forests. Tourism to this area is also supported by the Karri. Main honey flows occur every four to five years with even larger flows every fifteen years or so.<ref name=gardner/>

The species is commercially available and sold in seed form. It germinates readily and prefers a protected sunny position, but is known to be both drought- and frost-sensitive.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Although too large for most suburban gardens they are suitable in plantations. Seeds will germinate in three to four weeks and have germination rates of 84%.<ref name=seedvine>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>