You know the korokio. That tangled, twisted, almost angry-looking shrub that grows on rocky slopes and forest margins. Its branches zigzag like they can't make up their minds which way to go. Its leaves are small and tough, its flowers are bright yellow stars in spring, its red berries feed the birds. It is a survivor, a plant that thrives in harsh conditions, a living knot of botanical stubbornness. Now imagine that shrub bigger. Taller. Thicker. A korokio that grew to the height of a small tree, its branches so dense and tangled that you could not push through them. That was the giant korokio, and it was the guardian of the understorey. What made it special? Its structure. The giant korokio was not just a larger version of its living cousins – it was a different kind of plant. Its branches were thicker, more robust, forming an almost impenetrable thicket. Its leaves were larger, able to capture more light in the dim forest understorey. Its flowers were probably larger too – more visible to pollinators, more productive for the insects and birds that fed on their nectar. What did it do? It built the forest floor. In a mature lowland forest, the understorey is not empty space – it is a layered world of shrubs, saplings, ferns, and seedlings. The giant korokio would have been a dominant player in that world, forming dense thickets that provided shelter for small birds like the piopio and the bush wren. Its tangled branches offered protection from predators, nesting sites, and a place to hide. It also fed the forest. Its flowers provided nectar for insects and birds. Its berries – small, red, nutritious – were eaten by birds, which then dispersed its seeds across the forest. It was a keystone shrub, a foundation of the understorey community. Breeding? Slow. Korokio are not fast-growing plants. A giant korokio would have taken decades to reach full size. It reproduced by seed and probably by root suckers, forming clonal thickets that could persist for centuries. That strategy works when the forest is stable. It fails when the forest is logged. Why did it vanish? Forest clearance and logging. When Europeans arrived, they felled the lowland forests for timber and cleared the understorey for pasture. The giant korokio – a shrub that needed shade, moisture, and undisturbed soil – could not survive in open farmland. Its seeds could not germinate in grass. Its thickets could not regenerate after fire. The smaller korokio species survived. They are more adaptable, able to grow on rocky slopes, forest margins, and disturbed sites. They can tolerate sun and wind. They are the survivors, the scrappy ones, the plants that refused to give up. But the giant korokio is extinct. A few pressed specimens in a herbarium, a few fragments of wood in a peat bog, and the memory of a shrub that used to tangle the forest floor. We cleared its world. Then we wondered why the forest felt so empty.