The great gradient (reef to range)

Here is a forty-minute drive that doubles as a time machine. 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 the trip thinking about lunch. Learn to read it instead and the coast stops being a pleasant jumble of scenery and starts to make sense.

Start at the top, in the deep green hush of the Blackall Range rainforest, where the soil under your boots is a rich chocolate red and the air fogs your sunglasses the moment you step out of the car. Roll downhill and within minutes the rainforest thins into tall eucalypt forest, the canopy lifting and the light pouring in between the trunks. Lower still the country flattens into old floodplain, cane paddocks now, dotted here and there with a lone forest red gum, the last of a forest otherwise long gone. Cross the river and the ground itself turns to sand: paperbark swamp in the hollows, flower-strewn wallum heath on the rises, then the dunes, and at last 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. To a newcomer they look like six unrelated places flung together like passengers on a delayed train. They are nothing of the kind. They form a single ordered sequence, and it is the ground that lines them up, not the rain. Basalt at the top carries the rainforest, sand at the bottom carries the heath, and the mixed ground between them carries the gum forest. Why that should be so is a rule worth a chapter to itself. What matters on the road is that it holds the six worlds in their order, top to bottom, again and again.

There is a neat symmetry to the run. It begins in the richest soil of all and ends in the richest water, the mangrove-and-seagrass estuary that feeds the coast’s fisheries, with the poorest, hungriest ground of the lot, the wallum, improbably wedged between the two. The sequence runs rich to poor to rich, and finishes with more life packed into it than it started with.

The drive is the grandest performance of the rule. It is not the only one. Climb almost any of the region’s hills and the gradient turns up again in miniature. On Mount Ninderry, behind Yandina, the thin, dry, fast-draining soil of the exposed slopes grows open, grassy, fire-loving eucalypt forest, while a few steps away, in the gullies where deeper soil gathers and the air stays damp, the same hill grows tall wet forest edging toward rainforest. Two worlds on one small mountain, sorted by which way the ground faces and where the water pools. Walk the Cooloola dunes and it appears yet again, laid out this time through time rather than down a slope, the forest shrinking to low heath as the sand ages and leaches. Even the two banks of a single creek can carry two different worlds, if one is basalt and the other sand.

That is the real reason to learn the sequence. One stretch of road hands you a grammar that reads at any scale, from the whole coast down to the patch of ground beneath your boots.