Here in our ancient land we have evidence of the oldest rocks formed in the first cooling of the earth's crust. We have the oldest fossil evidence of life yet found. And some of the Australian landforms are so little changed that when we photograph them now we are recording them much as they were 200 million years ago. We can stand in awed silence in rainforests whose ancestors were here 60 million years ago, and feel their mystical antiquity, and be humbled in the knowledge that their green, lovely world predates the arrival of humans on this planet by about 58 million years.
Eucalypts
The special character of the Australian flora is due mainly to the dominance of eucalypts. No other comparable area of land in the world is so completely dominated by a single type of vegetation as
Australia is by its gumtrees. Australia's eucalypts are well adapted to the conditions in which they live. Their small, hard, leathery and spiny leaves are an adaptation to low-nutrient soils and dry Conditions. Plants whose leaves are adapted in this way are referred to as sclerophylls. Eucalypts dominate in the better-watered regions that is, those that receive at least 300 millimetres per annum.
Wet sclerophyll forests
Eucalypt species are dominant in wet sclerophyll forests but absent in rainforests. They generally occupy moist gullies and the southern aspect of hillsides in areas with relatively high rainfall. The jarrah forests of Western Australia are prime examples of this forest type.
Dry sclerophyll forests
Dominated by eucalypts, the dry sclerophyll forests are the ‘Australian bush' as most of us knows it. This vegetation type has specifically evolved to suit the low-nutrient soils, to withstand drought and to regenerate after fire.
Eucalypt woodlands
Australia's woodlands are a combination of eucalypts and grasslands the mix of which is determined by the local conditions of aspect, soil and topography.
