Rainforest Understorey
Rainforest Understorey at
Chambers Wildlife Rainforest Lodges
The Understorey
- The forest stratum between the forest floor and the canopy is called the
understorey.
- It supports many plant species including the rainforest trees, ground ferns, tree
ferns, zamias, cunjevois, cordylines or palm-lilies, native bananas, palms, climbing
plants and epiphytes.
- Epiphytes (lichens, mosses, ferns and orchids) use trees for attachment purposes
only, and do no hurt their host. Their roots absorb moisture from rainwater as it runs
downs tree trunks, and nutrients from rotting vegetation trapped by the epiphytic
structure itself or from crevices in the tree.
- Large tree branches in the understorey support many ferns such as the Bird’s
Nest, Elkhorn, Staghorn and Basket Fern. These can reach great sizes and provide excellent
catchment areas for falling leaves and plant debris. This rotting plant material then
provides the fern with nutrients while supporting a miniature community of its own.
Insects and other small creatures thrive in these damp aerial micro-habitats and frogs and
reptiles commonly shelter within the foliage.
- Tropical rainforests in high rainfall and cloudy areas support the greatest
abundance and diversity of epiphytic ferns, as most prefer shady situations beneath the
canopy.
- Most orchids also grow in shady conditions as epiphytes in the understorey. There
are about 150 species that have been recorded in the Wet Tropics, with at least 25percent
of them being endemic to the region.
- Their brightly coloured flowers help attract insect pollinators such as wasps, bees,
moths and butterflies. Many have similar structures – three inner petals and
three outer sepals. Usually one petal is larger and acts as a landing platform for the
pollinator.
- Hundreds of tree trunks of all shapes, sizes and colours can be seen in the
understorey, their bark often decorated with epiphytic lichens and mosses giving it a
mottled appearance. Trunks may be smooth, ridged, furrowed or noticeably bumpy.
- There are also many palm trees that are found in the Wet Tropics, several of them
endemic. One is the Atherton Palm found only in rainforest above 800m altitude, and
another is the majestic palm found only in dense upland regions.
- The Lawyer Vine (Wait-a-While) is a palm without a large woody trunk. It is a
climber with long wiry stems that have hooks growing out and upward from axils of the
leaves to help grip as a climbing aid.
- There are many other climbing plants that can be seen in the understorey too. The
seeds of climbing plants germinate on the forest floor, and the successful seedlings grow
up (with the support from a host tree) towards the light they need to survive until
maturity.
- Many animal species are supported by the diversity of plant life in the
understorey. Some of the understorey invertebrates are moths, butterflies, bees, ants,
flies, preying mantids, stick insects, beetles, crickets, cicadas and spiders. These are
preyed upon by skinks, geckos, monitors and birds (eg. robins, fantails, scrubwrens,
gerygones, shrike-thrushes and treecreepers). Other birds such as pigeons and bowerbirds
build their nests in sites amongst the understorey.
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