Botanic Gardens Trust, Sydney, Australia

Tropical rainforests

Australia’s most luxuriant rainforests are between Cooktown and Mackay in Queensland. These Tropical Rainforests support the greatest density of plants and animals of all Australian rainforests. In the northern Queensland are members of at least a quarter of all Australian plant genera! That includes over 90 per cent of all our epiphytic orchid species and over half the ferns. Vast numbers of all shapes and sizes are in turn dependent on this botanical diversity.

Characteristic features of tropical rainforests include:

  • at least three storeys of trees forming an uneven, non-uniform canopy
  • many different tree species contributing to the canopy
  • predominance of large, often compound leaves with drip tips that drain water off the leaf so preventing lichens and liverworts growing on them
  • thick woody vines which interlace the overlapping crowns of rainforest trees
  • plank buttresses which provide support for the trees in shallow soils
  • high density and diversity of large vascular epiphytes, such as orchids, aroids and ferns. Epiphytes depend on other plants for physical support, but collect their moisture and nutrients from the surrounding air and litter that they collect
  • massed flowers and fruits produced directly on the trunk of many trees, an arrangement known as cauliflory or stem flowering
  • plants such as palms, strangler figs, lawyer vines, large-leaved epiphytic climbers and large-leaved ground herbs

Tropical Rainforests
Features of Tropical Rainforests