Rainforests
From the mist-shrouded forests of the border ranges to the stunted scrubs of Cape York Peninsula, Queensland has the most diverse rainforests in the world.
Rainforest is dense, moisture-dependent vegetation where a variety of shade-tolerant plants grow beneath an almost closed canopy.
As Earth's most diverse ecosystem, rainforest is home to more than half the world's plant and animal species and is a valuable resource for cultivated plants, drugs and medicines.
Every broad rainforest type is found in Australia - the driest inhabited continent on earth. While rainforest makes up five percent of the country's forest, it covers only two million hectares or 0.3 percent of the continent.
Queensland is the only state where every rainforest type is represented and most of the country's remaining rainforest is found here.
But half the world's rainforest has been destroyed. It now covers less than 10 percent of the earth's land surface.
If this vital ecosystem is to survive, remaining areas of rainforest must be protected.
Rainforest history
Most of Australia's vegetation was rainforest when the country broke away from the ancient supercontinent of Gondwana about 50 million years ago.
As Australia drifted towards the tropics and conditions became drier, the Gondwanan rainforests almost disappeared.
Grasslands and woodlands took over from rainforests. But scattered rainforest pockets remained in refuges on mountain tops and in protected valleys.
In the two centuries since Europeans came to Australia, half the rainforest has been cleared for farms, mines, plantation forests, towns and resorts.
Today, rainforest is scattered along the east coast, in western Tasmania, and small pockets across north Australia from Cape York to the Kimberleys. Most of Australia's rainforest - well over one million hectares - is in Queensland.
Rainforest types
Rainforests can be grouped broadly by climate into five major rainforest types - tropical, subtropical, dry, warm temperate, and cool temperate.
Queensland is the only place in the world with all types. Rainforests in Queensland range from evergreen (leaves always present) to semi-deciduous (trees lose leaves during the dry season).
But classifying rainforest by climate is too basic. Scientists prefer to classify rainforest on the basis of the leaf size of canopy trees and on the complexity of the forest's structure. Leaves less than 2.5cm long are termed nanophyll; between 2.5-7.5cm microphyll; 7.5-12.5cm notophyll; and 12.5-25cm mesophyll.
Soil fertility and the presence of plant forms such as buttresses and palms determine a rainforest's structural complexity. Simple forests have a single canopy and few plant forms. Complex rainforests have several layers and most or all plant forms.
Tropical rainforest
Most rainforest remaining in Australia is tropical. Tropical rainforest is either evergreen or semi-deciduous.
In Queensland, tropical rainforest grows in patches in coastal areas north of Mackay, and in Cape York Peninsula.
The wet tropical rainforests between Townsville and Cooktown are Australia's richest forests. More than 200 animal species live here. Most depend on rainforests for survival and about a quarter are found nowhere else in Australia.
In tropical rainforest, the leaf size of canopy trees tends to decrease as you go higher.
Lowland rainforest typically contains woody vines, fan palms, epiphytic ferns and strangler figs and more deciduous trees than upland forests.
Upland forests on fertile soils are more complex. They have more layers and species, buttressing, tree ferns, climbing vines, and mosses. On less fertile soils, the forests are simpler with fewer species, little or no buttressing, and fewer layers.
Subtropical rainforest
Most of Australia's remaining subtropical rainforest is in Queensland. Like tropical rainforest, these forests are lush and attractive, containing palms, strangler figs, buttressed trees, large vines and epiphytes. They have two or three tree layers and many canopy species.
In south-east Queensland, large stands of complex notophyll vine forest grow on basaltic soils on mountains. Notophyll vine forest is more widespread and grows on moist mountain tops and gullies and on coastal sands at Cooloola and Fraser Island.
Dry rainforest
Dry rainforest remnants are scattered across northern Australia and throughout eastern Queensland.
These forests lack the lush quality normally associated with rainforest and grow where soils are poorer and rainfall less reliable.
Dry rainforest usually has two tree layers, a diverse canopy, small leaves, large woody vines, and thorny or spiny shrubs. Ground ferns and epiphytes are fairly rare.
Trees such as hoop pine, lace-bark tree and teak often emerge above the dry rainforest canopy. Rainforests with emergent pines, once common on more fertile soils along the coast and inland, have been largely cleared for agriculture and hoop pine plantations.
Low microphyll vine forest/thicket grows between Brisbane and Toowoomba, along the central Queensland coast and further inland.
Warm temperate rainforest
Warm temperate rainforest is found on coastal ranges in south-east Queensland and in New South Wales.
Growing at higher altitudes on less fertile soils, warm temperate rainforest has two tree layers and less variety in the canopy layer. The fairly uniform canopy may contain emergent hoop or bunya pine, eucalypts or brush box.
Notophyll leaves are most common. Wiry vines, smaller epiphytic ferns, orchids, tree ferns, ground ferns and lichen-covered tree trunks are typical. Plank buttresses, stranglers and palms are uncommon.
Cool temperate rainforest
Cool temperate rainforest is found from cool mountain tops along the McPherson Range on the Queensland and New South Wales border, and south to Tasmania.
In southern Queensland, this forest type has few species, one or two tree layers, and a fairly dense canopy.
In cool temperate forests, trees tend to be covered in mosses, lichens and ferns. Leaves of canopy trees are small. Stranglers, palms, plank buttresses, large vines and epiphytes are rare or absent. Ground ferns and tree ferns are common.
Rainforest plants
Buttresses
Buttresses are distinctive flanges at the bases of large rainforest trees. Trees are buttressed only in tropical and subtropical forests. Buttressing probably helps trees breathe in waterlogged soils or helps them take up nutrients from shallow soils.
Epiphytes
Epiphytes grow on another plant for support or anchorage. They live on rainwater washed down tree trunks, and nutrients from animal droppings and rotting leaves.
Orchids, ferns (such as elkhorns and staghorns), lichens, and mosses are epiphytes. Orchids and ferns are common in subtropical and tropical forests while mosses and lichens grow mainly in cool temperate rainforest.
Lianas
Lianas are climbing vines which grow from ground roots but use other plants for anchorage as they climb towards light. They get extra nourishment from rainwater and rotting plants trapped in trunk crevices.
Strangler figs
Starting from seed dropped in humus high in a canopy tree, the strangler fig sends down prop roots which thicken, interlace, join and gradually strangle the host tree to death.
This process can take 500-1000 years.
Cauliflory
In tropical forests, a cauliflower-like mass of flowers and fruit grows directly on trunks and main branches of some trees.
Birds, fruit bats and possums help this plant type spread by pollinating flowers and spreading seeds.
Palms
Palms with woody stems, few or no branches, and surface roots at the trunk base usually grow in moist spots in the rainforest.
Where can I see rainforest?
You can see rainforest in many national parks in Queensland.
Some parks have facilities for bushwalking; others are suitable only for keen, experienced walkers.
If you would like to know more about rainforest, check with your local Queensland Parks and Wildlife Service office.
Threats to survival
Weeds (such as rubber vine and lantana), fire, feral animals (pigs, dogs and cats), clearing for residential development, and visitor pressures (vandalism, erosion and littering) threaten remaining rainforests. Burning is particularly destructive and must be minimised.
Many parts of Queensland rainforest have been declared as national park. But this does not guarantee their survival.
Fragmented rainforest is particularly under threat. Private landholders who have rainforest habitat on their property can help conserve this special ecosystem and the many plant and animal species living within it.
Natural processes can also affect rainforests. Growth, maturity and death form a never-ending cycle. Change can be rapid when a cyclone, strong wind, flood, landslip or tree clearing disturbs a forest.
Although regeneration is fast, a rainforest might not recover fully from a major disturbance for hundreds of years.
Protecting rainforests
A quarter of Queensland's protected rainforest is in national parks and three-quarters in state forest.
About 70 percent of Queensland's rainforest is found in north Queensland. Much of this is protected in the Wet Tropics of Queensland World Heritage Area. Subtropical rainforest on coastal sand at Fraser Island also has World Heritage status.
Subtropical and temperate rainforests along the Queensland and New South Wales border now form part of the Gondwana Rainforests of Australia World Heritage Area.
How you can help
- Stay on walking tracks. Delicate ground cover plants are easily trampled.
- Use only a fuel stove. Nutrient recycling is critical in a rainforest so gathering leaf litter and dead branches for fires can cause damage.
- Remember, everything is protected. Don't pick, break or remove any plants.
- Leave the rainforest as you found it. Take your rubbish home with you. Buried rubbish uncovered by forest animals can harm them.
- Leave your pets at home. They are not allowed in national parks and can chase, scare and kill animals.
- If you camp within the park, disturb the forest floor as little as possible. Don't cut timber for tent poles or clear plants around your campsite.
- Don't feed native animals. Feeding is harmful and may lead to aggressive behaviour.
- Don't use soap, toothpaste, sunscreen or detergent in waterways. They pollute the water and harm aquatic animals.
Protecting yourself
When you walk in a rainforest, please follow these guidelines.
- Take a warm coat. Little sunlight penetrates the forest so it can be cool.
- Take wet weather gear. Rain can fall at any time.
- Wear personal insect repellent. Use salt or heat to remove leeches.
- Stay clear of cassowaries in north Queensland rainforests; they can be aggressive.
- Avoid snakes. Snakes usually attack people only when they are threatened. If bitten, apply a pressure bandage over the entire bite and immobilise that body part. Seek immediate medical attention.
- Check for scrub ticks after a walk in dry rainforest. Apply insect repellent or methylated spirit to kill the tick, then remove with tweezers.
- Always carry a map and compass, and let the Ranger or friends know your travel plans. Take adequate food, clothing and equipment for extended stays.
Last updated: 20 September 2007