Forest Figs

Skyrail Nature Diary: October 2009

Did you know that one of the most important flowering trees in the Wet Tropics Rainforest is the fig?

In fact, according to the Wet Tropics Management Authority, figs are a "keystone species" of the World Heritage listed Rainforests, as they produce fruit at different times throughout the year, providing a reliable food resource for many birds and animals.

Globally, there are over 1,000 species of fig, 41 of which are found in Australia and 30 grow in Queensland’s tropical rainforests. At Skyrail, there are at least five different types of fig, three of which are now fruiting.

The Figwood (Ficus virgata) is a large tree, growing up to 30m high, and is found in rainforests from the Iron Range to Paluma Range. Its small fruits vary in colour from orange to red, to almost black, and are very popular with many rainforest birds, including Metallic Starlings.

The birds assist with seed dispersal across the forest, often depositing the digested seeds into the rainforest canopy and basket ferns. These seeds germinate high in the canopy, sending roots down to the ground, along the trunk of their host. Once established in the ground, these roots become larger, wrapping around the host tree, restricting its growth and competing for nutrients in the soil. Eventually, the Figwood will ‘kill’ its host and for that reason, it is also known as a ‘Strangler Fig’.

At Skyrail, the Figwood can be found at Lake Smithfield and in the rainforest regeneration corridor adjacent to Kuranda Terminal. These specimens are still young and were planted by Skyrail employees.

Another fig fruiting this month is the Septic Fig (Ficus septica), which can be seen at Skyrail’s Red Peak Station. This is a smaller species, only growing to about 15m high. It is one of the few figs whose fruit is not edible to humans.

Flowering and fruiting directly from its trunk and branches, the Septic Fig’s green to cream fruits are popular with Double-eyed Fig-parrots and Spectacled Flying-foxes. The plant’s common name refers to its sap, which if applied to raw flesh will cause the surrounding flesh to rot.

Finally, the Red Leaf Figs (Ficus congesta) at Barron Falls Station have large clusters of fruit. The green fruits can appear throughout the year and are a popular food source with the endangered Southern Cassowary.

This is a small fig, usually only growing to 6m high. Its hairy leaves have a sandpapery texture and start red, before turning green as they mature. This species can be found in rainforests from the Torres Strait Islands to Great Keppel Island.