Banksia serrata and the closely related Banksia aemula are generally a smaller but very distinctive tree species found on well drained sites. A perimeter of Hawkesbury Sandstone vegetation The Hawkesbury Sandstone areas of the Lower Blue Mountains, the Woronora Plateau and Hornsby Plateau surround Western Sydney. Vegetation here ranges from open-forests in gullies to woodland on ridges and heath on sites with very shallow or poorly drained soils. Species are generally quite different from those on the Cumberland Plain. The sandstone areas include those along the Georges River from Holsworthy to Wedderburn, along the Nepean River at Bents Basin, and Fairlight.
Conservation needs The future of Western Sydney's vegetation is linked to development and change.
Vegetation has also been destroyed by extensive sand and gravel extraction. As the population density of Western Sydney continues to grow, bushland remnants are increasingly threatened by the expansion of suburban areas. Unfortunately little attention has been paid to the vegetation of Western Sydney because it is less spectacular than the colourful Hawkesbury sandstone vegetation. Western Sydney bushland is characterised by remnants of eucalypt woodland on clay soils, derived from Wianamatta Shale. The native flora is quite different from that of the surrounding Hawkesbury Sandstone.