The great gradient (reef to range)

Here is a forty-minute drive that doubles as a time machine and a field guide. Point the car down the hill from Maleny to Mooloolaba and, before your coffee has gone cold, you will have crossed more than three hundred million years of rock and passed through every major ecosystem the Sunshine Coast holds. Most people make this drive thinking about lunch. Learn to read it instead, and you will have understood the entire place.

Start at the top, in the deep green hush of the Blackall Range rainforest, on rich chocolate-red basalt soil. Point the car downhill and within minutes the rainforest thins and surrenders to tall eucalypt forest, the canopy lifting and opening. Lower still, the country flattens into old floodplain — cane paddocks now, with the occasional lonely forest red gum left standing in a field like the last guest at a party nobody told it had ended. Cross the river and the very ground changes its mind and turns to sand: paperbark swamps in the hollows, flower-strewn wallum heath on the rises, then the dunes, and finally the mangroves and open water of the river mouth, where the tide breathes in and out, twice a day, forever.

Six worlds, one short drive — and they are not an accident. They are a single, ordered sequence, and the thing that lines them up is not the rain (most of the gradient gets a decent drink) but the ground itself: how deep the soil runs, how many nutrients it holds, and where the water sits or slips away. Rich basalt on the cool, wet range grows rainforest; hungry sand on the warm coast grows heath; mixed sedimentary ground between them grows the open eucalypt forest nine people in ten picture when you say “the Australian bush.”

And here is the part that makes the rule worth learning: it plays at every scale beneath the great slope. Climb almost any hill and you will find the gradient repeated in miniature — dry, fast-draining slopes growing open forest, damp gullies a few steps away growing wet forest toward rainforest. Walk the Cooloola dunes and it is there again, laid out through time rather than up a slope, the forest shrinking to low heath as the sand ages and its phosphorus drains away. Once you have the rule, you never quite look at a hillside the same way again. You see instead a set of answers to a single question the land is forever being asked — what will grow here, given this rock, this soil, this water — and you find that you can very often read the answer before you have taken a step.