The landform of the area is on Canoelands Ridge, a high, undulating, dissected plateau of Hawkesbury Sandstone with many steep gullies covered with dry sclerophyll forest, predominantly tall varieties of hardwood trees of the genus Eucalyptus.
The Blue mallee, or Blue-leaved mallee (Eucalyptus polybractea) is a small multi-trunked sclerophyll tree that grows naturally in western New South Wales and the Inglewood area in Victoria, Australia.
From 40,000 years ago, the crater was gradually occupied by sclerophyll vegetation such as Casuarina and Eucalyptus, with the transition being completed 26,000 years ago.
The vegetation on the Ngarrabullgan tabletop (plateau) has been described as wet sclerophyll forests, mainly of a bloodwood species of Eucalyptus, with a well-developed understory.
It is found in sclerophyll forest, associated with such species as Eucalyptus sieberi and Eucalyptus sclerophylla.
The vegetation is classified as wet sclerophyll forest with the dominant tree species the Mountain Ash, Eucalyptus regnans, the tallest flowering plant in the world.