Mount Ninderry

Pull off near Yandina and look up at Mount Ninderry, and you are looking at a survivor. Three hundred and four metres of steep, rocky peak stands alone above the flat lowland, bare stone breaking through the scrub near the top, nothing else nearby its equal. It looks, reasonably enough, as though something shoved it up out of the plain. Nothing did. Ninderry is the hard, unbroken heart of an old volcano, a plug of silica-rich rhyolite that cooled solid in the throat of the North Arm Volcanics and never rotted. It stands high for one reason: everything around it, being softer, has quietly gone. Grain by grain the plain washed to the sea, hundreds of metres of it over millions of years, while the tough core refused to wear and was left holding the sky. The Glass House peaks and Mount Coolum tell the same story — no mountain was ever raised here, only a stump the land wore itself away from.

On the great slope of this coast, height means wealth: the high basalt range at the top holds the cool, deep-soiled, rainforest end of the country. So you climb Ninderry half-expecting a green, dripping summit — and get nothing of the kind. Hard silicic rock weathers grudgingly and yields only a thin, stony, quick-draining soil with almost nothing in it. That ground grows tough, open eucalypt forest, not rainforest, and on the bare rock pavements up top a low, wind-scoured scrub that roots in the cracks and hangs on out of sheer obstinacy. The leaves are hard and grey. That is the sclerophyll leaf, a soil report you can read at a glance. Height does not buy you a rainforest. Soil and shelter do, and this peak has neither to spare.

The dry, sun-blasted slopes carry the open forest, and you can read them tree by tree. Grey gum sheds its bark in apricot patches; tallowwood stands beside it, and between them they offer some of the best koala browse in the open forest. Grey ironbark waits in armour, a baked black coat that lets the living wood beneath ride out a grass fire. Under a black she-oak, cones litter the ground, splintered like cracked pistachio shells — the work of the glossy black-cockatoo — while the tree fertilises the poor rhyolite with nitrogen its root bacteria pull from the air. Grass-trees a century old at head height wait, resin-packed, for the smoke that cues them to flower.

Slip off the exposed face into a gully on the shaded southern flank, and within a few paces the world changes. Soil washes in and deepens, the air cools and stays damp, and the open woodland closes into something taller and dimmer. Flooded gums rocket fifty metres and more out of the gully floor, among the tallest eucalypts alive, standing over piccabeen palms and bracken. This is wet sclerophyll, edging toward rainforest. The contest runs under your feet. Those giants cannot reproduce in their own shade, while the palms and rainforest saplings crowding the floor hardly need the sun. Left undisturbed, the shade wins; only a fire reaching up the gully every few decades resets the board and lets the gums seed again. Same hill, two worlds. The difference is written in where the soil lies deep and the water lingers.

That two-in-one richness is why one small reserve carries some four hundred native plant species. The same rock that outlasted a mountain was too steep and stony to be worth clearing or logging, so much of the bush up there is remnant, self-sown, old.