Tree ferns are found on the mountains above 4000 ft.
The soil to the depth of many feet, and from it springs the most marvellous tangle of huge trees, shrubs, bushes, underwood, creepers, climbing plants and trailing vines, the whole hung with ferns, mosses, and parasitic growths, and bound together by rattans and huge rope-like trailers.
The vegetation is almost tropically luxuriant - palms, wild pineapples, and ferns growing profusely, and the valleys being filled with wild beans and patches of taro.
The relationship with Aepyornis of Madagascar is still problematic. Whilst the moas seem to have been entirely herbivorous, feeding not unlikely upon the shoots of ferns, the kiwis have become highly specialized wormeaters.
The ferns are most common in the midland zone and in the heavy timber forests.