The extraordinary process of photosynthesis not only harvests the sun’s energy but primitive life forms, billions of years ago, created the very soil these plants depended upon. The foliage, roots and fibre of these plants all contained carbon compounds that decomposed and combined with minerals from eroded rocks to create our soils.
A rapidly warming climate, as well as the appropriateness of trees to different gardening styles, is highlighting the importance of Australian rainforest trees in our gardens. Many people can't see the rainforest for the Eucalypts - but there are scores of other native trees from the forests of the east coast (such as the Great Dividing Range which stretches from the Daintree all the way down to Gippsland) that deserve a place in most gardens.
These rainforest trees have proven themselves for over 150 years in all our mainland botanic gardens as outstanding air conditioners, making gardens habitable (Moreton Bay Figs, Red and White Cedars, Araucarias, Hills Fig, Flame Tree and Flindersia australis to name but a few).
Unlike eucalypts, which also have evergreen foliage, our rainforest trees have lush green, rather than khaki-green, coloured foliage and their leaves are horizontal, providing a denser shade with summer temperatures 5-8 degrees cooler than those under eucalypt trees whose leaves hang down to avoid the sun.
These trees provide free air conditioners in your garden, and should be included in all future plantings, because summer temperatures are forecast to rise up to 5°C, and well above 45°C.
Many gardeners want to plant ‘the bush’ in their backyards and, of course, that is perfectly fine ... if they accept that they will be creating a hotter summer garden compared to those planted with deciduous or rainforest evergreens.
Both eucalypts and Radiata pines are downright dangerous on a hot day by, in effect, pumping up ground water and turning it into inflammable, kerosene-like fuel on days over 40°C.
Clive Blazey (2017).