E. marginata subsp. marginata
E. marginata subsp. thalassica
Eucalyptus marginata is one of the most common species of Eucalyptus tree in the southwest of Western Australia. The tree and the wood are usually referred to by the Aboriginal name Jarrah. Because of the similar appearance of worked jarrah timber to the Honduras mahogany tree, jarrah was once called Swan River mahogany after the river system that runs through Perth.
The tree grows up to 40 metres (130 ft) high with a trunk up to 3 metres (9.8 ft) in diameter, and has rough, greyish-brown, vertically grooved, fibrous bark which sheds in long flat strips. The leaves are often curved, 8–13 centimetres (3.1–5.1 in) long and 1.5–3 centimetres (0.59–1.2 in) broad, shiny dark green above and paler below. The species' scientific name marginata refers to the light-coloured vein on the border around its leaves. The stalked flower buds appear in clusters of between 7 and 11; each bud has a narrow, conical bud cap 5–9 millimetres (0.20–0.35 in) long. The flowers are white, 1–2 centimetres (0.39–0.79 in) in diameter, and bloom in spring and early summer. The fruits are spherical to barrel-shaped, and 9–16 millimetres (0.35–0.63 in) long and broad.
The bark of this Eucalyptus is not shed in patches as it is with many others, but splits into fibrous strips. Jarrah trees are also unusual in that they have a lignotuber, a large underground swelling which stores carbohydrates and allows young trees to regenerate after a fire. Because they are deep-rooted, as much as 40 metres (130 ft), jarrah are drought resistant and able to draw water from great depths during dry periods.
Jarrah is an important element in its ecology, providing numerous habitats for animal life - especially birds and bees - while it is alive, and in the hollows that form as the heartwood decays. When it falls, it provides shelter to ground-dwellers such as the chuditch (Dasyurus geoffroii), a carnivorous marsupial.
Jarrah has shown considerable adaptation to different ecologic zones - as in the Swan Coastal Plain and further north, and also to a different habitat of the lateritic Darling Scarp.
Jarrah is very vulnerable to "dieback", the oomycete Phytophthora cinnamomi, which causes root-rot. In large sections of the Darling Scarp there have been various measures to reduce the spread of dieback by washing down vehicles, and restricting access to areas of forest not yet infected.
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