Most of these forests are beech, primarily silver beech, and to a lesser extent mountain beech. Podocarp are also present at low altitude, in the less steep locations with deeper soil, such as valleys at the head of fiords. The most commonly represented species are rimu, miro, Hall's totara. Where it has not been modified by browsing animals, the understory is dense and varied, with many plants and shrubs, ferns and tree-ferns, and epiphytes. There is often a tangle of fallen rotting branches and tree trunks.
Mosses form deep cushions, covering the ground as well as tree trunks and branches.
However browsing animals, red deer and opossum especially, are now present in most areas of Fiordland National Park. They have proved to be the greatest factor of modification in the park by changing the aspect of the forest, eating undergrowth and trampling the mossy floor. Above it the vegetation is dominated by snow tussock grasslands, with many other alpine plants interspersed. Thirty five plant species are endemic to Fiordland, most of them above the treeline. Wildlife Forest Birds Fiordland is home to the only wild population of takahe in New Zealand.