Sclerophyll - Australian Bush

Australian Bush

Most areas of the Australian continent able to support woody plants are occupied by sclerophyll communities as forests, savannas or heathlands. Common plants include the Proteaceae (Grevilleas, Banksias and Hakeas), tea-trees, Acacias, Boronias, and the Eucalypts.

The most common sclerophyll communities in Australia are savannas dominated by grasses with an overstorey of Eucalypts and Acacias. Acacia (particularly mulga) shrublands also cover extensive areas. All the dominant overstorey Acacia species and a majority of the understorey Acacias have a scleromorphic adaptation in which the leaves have been reduced to phyllodes consisting entirely of the petiole. Many plants of the sclerophyllous woodlands and shrublands also produce leaves unpalatable to herbivores by the inclusion of toxic and indigestible compounds in an attempt to maintain these long-lived leaves. This trait is particularly noticeable in the eucalypt and Melaleuca species which possess oil glands within their leaves that produce a pungent volatile oil that makes them unpalatable to most browsers. These traits make the majority of woody plants in these woodlands largely unpalatable to domestic livestock. It is therefore important from a grazing perspective that these woodlands support a more or less continuous layer of herbaceous ground cover dominated by grasses.

Sclerophyll forests cover a much smaller area of the continent, being restricted to relatively high rainfall locations. They have a eucalyptus overstory (10 to 30 metres) with the understory also being hard-leaved. Dry sclerophyll forests are the most common forest type on the continent, and although it may seem barren dry sclerophyll forest is highly diverse. For example, a study of sclerophyll vegetation in Seal Creek, Victoria, found 138 species.

Even less extensive are wet sclerophyll forests. They have a taller eucalyptus overstory than dry sclerophyll forests, 30 metres or more (typically Mountain Ash, Alpine Ash, Messmate Stringybark or Manna Gum), and a soft-leaved, fairly dense understory (tree ferns are common). They require ample rainfall — at least 1000mm (40 inches).