Paperbark

The paperbark is one of the most recognisable trees on the coast, and once you know it you will see it everywhere the ground goes soggy. The bark gives it away: thick, soft, spongy and pale, peeling from the trunk in papery sheets you can lift off in handfuls, layer upon layer like the pages of a sodden old book. The great swamp-former here is the broad-leaved paperbark, Melaleuca quinquenervia, which gathers into dense, pale-trunked stands in the wettest lowland hollows, often standing in water for months at a time. It is the tree that gives the swamps their name.

That habit of standing with its feet permanently wet is, for a tree, nearly as hard a trick as living in salt, and for a related reason: waterlogged soil is airless soil, and roots need to breathe. Where an ordinary tree would drown, the paperbark simply carries on, riding out long floods and the violent swing between drought and inundation that rules a floodplain. It is built for instability, for a world drowned one season and parched the next. That is the world the lowland wetlands offer.

On the sand country it pulls off a second trick. The water it stands in there is acid blackwater, leached from the peaty sand all around. The paperbark is one of the few trees at home in water no nursery would recommend.

The famous spongy bark earns its keep. Thick and soft and pale, shedding and regrowing freely, it insulates the living trunk against the fires that run the swamp margins in dry years. This is a tree built to be flooded, then dried, then burnt, then flooded again, and armoured for the whole cycle. It takes its own place in the wet, standing back from the open lily-water and the sedge on ground that stays damp but no longer drowns.

You do not appreciate the tree, though, until you are standing beneath one when it blooms. A paperbark in flower vanishes under creamy, bottlebrush-like spikes dripping with nectar, and when a whole swamp comes into blossom at once it lays on one of the largest free meals in the landscape. Lorikeets pour in by the screeching, tumbling flock. Honeyeaters work the spikes from first light. And after dark the flying-foxes arrive to drink, ferrying pollen between the trees and carrying the seed of the rainforest fruits they also feed on out to fresh patches of forest. Many of these nectar-feeders are nomads, ranging the country after whatever is in flower, so a swamp coming into bloom can summon animals from tens of kilometres away. The humble paperbark also runs a roadhouse.

The paperbark’s endurance has a limit. Along the low coast a slower shadow is gathering. As the sea rises and salt pushes up the floodplains, the lowest freshwater stands are expected to give way to mangrove and saltmarsh, a change already watched in northern Australia, where advancing salt has killed whole tracts of freshwater Melaleuca. The tree that has out-waited flood, drought and fire for so long meets, in the rising sea, the one flood it is not built for.