Sydney Blue Gum
Sydney Blue Gum

Eucalyptus saligna, is a large Australian hardwood (flowering) tree common along the New South Wales seaboard and into Queensland, which can reach a maximum of 65 metres (213 feet) in height. It is a common plantation timber in Australia and South Africa.

Commonly known as the Sydney blue gum or simply blue gum, Eucalyptus saligna was described by English naturalist James Edward Smith in 1797, and still bears its original name. It has been classified in the subgenus Symphyomyrtus, Section Latoangulatae, Series Transversae (eastern blue gums) by Brooker and Kleinig. Its two closest relatives are the flooded gum (Eucalyptus grandis) and the mountain blue gum (E. Deanei).

Eucalyptus saligna grows as a straight and tall forest tree, growing to heights of 30 to 55 (or rarely 65) m (100–210 ft) tall with a dbh of 2 or even 2.5 m (7–10 ft). The trunk has smooth pale grey or white bark with a long (1 to 4 m high) 'skirt' of rough brownish bark at the base. The dark green leaves are arranged alternately along the stems and are 10–17 cm (4-6.5 in) long by 2–3 cm (0.8-1.2 in) wide. The white flowers appear from December to February, and are arranged in groups of seven to eleven in umbellasters.

Eucalyptus saligna is generally found within 120 km (75 mi) of the coastline in its range from the New South Wales south coast to Maryborough in central Queensland. To the northwest, it is found in disjunct populations in central Queensland; Eungella National Park, Kroombit Tops, Consuelo Tableland, Blackdown Tableland and Carnarvon Gorge. It grows in tall forests in more sheltered areas, on clay or loam soils, and alluvial sands. It is a component of the endangered Blue Gum High Forest ecological community in the Sydney region.

Eucalyptus saligna regenerates by regrowing from epicormic buds on the trunk and lower branches after bushfire. Trees live for over two hundred years. The Grey-headed Flying Fox (Pteropus poliocephalus) eats the flowers, the koala (Phascalarctos cinereus) eats the leaves, and Crimson Rosella (Platycercus elegans) eats the seed.

The wood of this species is heavy (about 850 kg/m3), fairly hard, coarse, even textured and reasonably easy to work. It is used for general building construction, panelling, and boat-building, and is highly prized for flooring and furniture because of its rich dark honey colour.