High Quality Content by WIKIPEDIA articles! The Blue Gum High Forest of the Sydney Basin Bioregion is one of six main indigenous forest communities of Sydney, Australia. It has been classified as critically endangered, under the New South Wales government`s Threatened Species Conservation Act 1995. The principal canopy trees in this forest community are Sydney Blue Gum and Blackbutt which are usually seen between 20 and 40 metres tall. 180 species of indigenous plants have been identified at Dalrymple-Hay Nature Reserve.