Hazel, holly and yew are the understorey trees beneath soaring beeches and magnificent Douglas firs.

The trampling of human feet made most suburban woodlands I knew barren, but here the understorey was thick with life.

Unlike a possum, they can't climb up the tree so they're eating the seedlings and smaller saplings in the understorey, he said.

Around us a soft breeze, its understorey laced with a tang of salt and seaweed, beneath a sweeter overtone of thrift, or sea pinks.

These pests and predators have destroyed the canopy and understorey of the ngahere, and attacked threatened species to the point of local extinction, she said.