Australian rainforests are classified based on the physiognomic and structural features rather than a species-based floristic approach. Leaf size is a primary descriptor of forest type with the major sub-divisions of mesophyll, notophyll and microphyll found in the rainforests of the Wet Tropics. Mesophyll is the largest leaf size category, with a blade length of greater than 12.5cm, notophyll leaves are greater than 7.5cm, while leaf blades of less than 7.5cm are classified as microphyll.
Mesophyll rainforest types generally occur in very wet to
moist lowlands and foothills, typically below 400m,
although variants may also be found in upland localities.
Mesophyll rainforests include all those forest types where
mesophyll sizes dominate the sun exposed canopy leaves.
View the mesophyll rainforests Fact Sheet here.
In general, palm leaf rainforests are distinctive
categories of mesophyll rainforests, with a conspicuous
and significant proportion of the upper strata (canopy
layer) comprising either feather or fan leaf palms. It
should be noted that palm leaf size is not used in the
classification of rainforests.
View the Palm Leaf rainforests Fact Sheet here.
Notophyll rainforests are the most extensive rainforest
formation in the bioregion. A vast array of structural and
floristic variation is encompassed within the formation,
including complex and simple structural associations,
evergreen, semi-evergreen and semi-deciduous types,
and variations in stature from very tall closed forest to
vine thickets with canopy heights of less than 9m.
View the notophyll rainforests Fact Sheet here.
Microphyll rainforest and thicket types include all
rainforest communities where the dominant canopy leaf
size is less than 7.5cm in length. In the tropics, microphyll leaves generally indicate an
environmental stress, whether this stress is exposure
(wind and salt), limiting edaphic conditions and/or
climatic influences. These stresses also prevent the
development of complex structural features.
View the microphyll rainforests Fact Sheet here.