Karri | |
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Climbing a famous karri tree - the Gloucester Tree | |
Scientific classification | |
Kingdom: | Plantae |
(unranked): | Angiosperms |
(unranked): | Eudicots |
(unranked): | Rosids |
Order: | Myrtales |
Family: | Myrtaceae |
Genus: | Eucalyptus |
Species: | E. diversicolor |
Binomial name | |
Eucalyptus diversicolor F.Muell. |
Eucalyptus diversicolor, commonly known as the karri, is a eucalypt native to the wetter regions of southwestern Western Australia.
The tree grows to over 80 metres making it one of the tallest trees in the world. It has white to cream bark that turns brown as it matures and is shed. The whitish trunk beneath takes on a patina of colours from white to grey to deep brown. The trunk is without secondary trunks, but occasionally a twin trunk occurs where two trunks of the same diameter grow up from the seedling stage. Mature trees branch only from the top third of the trunk. The leaves are dark green on top and lighter underneath, and grow to a length of 90–120 mm and 20–30 mm broad. The cream-colored flowers occur in groups of seven, each flower measuring about 18–28 mm in diameter. Flowering occurs in spring and summer. The fruits are squat and barrel-shaped, with numerous small dry seeds. The fruit is up to a centimeter long.
The botanical name diversicolor means “separate colours” and refers to the difference between the top of the leaf and its underside while the common name is derived from the Aboriginal name for the tree.
The soil in which karri grow 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.
Karri occurs only within the High Rainfall Zone of the South West Botanical Province of Western Australia. It mostly occurs within the Warren biogeographic region, but there are some outlying populations, of which the most notable is in the Porongorup Ranges.