Rainforests

Rainforest is the most diverse land-based ecosystem on earth. It is dense, moisture-dependent vegetation where a variety of shade-tolerant plants grow beneath an almost closed canopy. 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. Half the world’s rainforest has been destroyed, it now covers less than 10% of the earth’s land surface.

Rainforest is scattered along Australia’s east coast, in western Tasmania, and small pockets across north Australia from Cape York to the Kimberley. Most of Australia’s rainforest—over 1 million hectares—is in Queensland.

Queensland’s rainforests range from evergreen (leaves always present) to semi-deciduous (trees lose leaves during the dry season). From the mist-shrouded forests of the Border Ranges to the deciduous thickets of Cape York Peninsula, Queensland has significant rainforest diversity.

Rainforests of northern Queensland

Rainforests are often grouped broadly by climate (tropical, subtropical, dry, warm temperate, and cool temperate).

Soil fertility and the presence of plant forms such as buttresses and palms determine a rainforest’s structural complexity. Simple forests have a single tree layer and few plant forms. Complex rainforests have several layers and most or all plant forms.

In tropical Queensland, rainforests are either evergreen or semi-deciduous. There are significant areas north of Mackay, and between Townsville and Cooktown where Australia’s richest rainforests are found. More than 200 vertebrate animal species live here. Most depend on rainforests for survival and about a quarter are found nowhere else in Australia.

The leaf size of canopy trees tends to decrease as you go higher in altitude. Lowland rainforest typically contains a greater variety of plants including woody vines, fan palms, epiphytic (a plant that grows on another plant) ferns and strangler figs than upland forests. Upland forests on fertile soils are more complex. They have more tree 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 tree layers.

Rainforests of southern Queensland

Rainforests in South East Queensland have 2 tree layers and less species variety in the canopy layer. The fairly uniform canopy may contain emergent hoop or bunya pine, eucalypts or brush box. Wiry vines, smaller epiphytic ferns, orchids, tree ferns, ground ferns and lichen-covered tree trunks are typical.

The rainforests on the cool mountain tops along the McPherson Range on the Queensland and New South Wales border have few species, 1 or 2 tree layers, and a fairly dense canopy. The 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.

Dry rainforest

Dry rainforest remnants are scattered across northern Australia and throughout eastern Queensland. These forests lack the lush appearance normally associated with rainforest and grow where rainfall is less reliable. Low microphyll (a leaf with only one vascular bundle and no complex network of veins) vine forest/thicket grows between Brisbane and Toowoomba, along the central Queensland coast and further inland.

Dry rainforest usually has 2 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 bottle trees, hoop pine, lace-bark tree and Crow’s ash 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 plantations.

Rainforest features

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 survive in waterlogged soils or helps them transport more sap and nutrients.

Epiphytes

Epiphytes grow on another plant for support or anchorage. They include orchids, ferns (such as elkhorns and staghorns), lichens, and mosses.

Lianas

Lianas are climbing vines which grow from ground roots but use other plants for anchorage as they climb towards light.

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.

Palms

Palms have woody stems, no branches and surface roots at the trunk base and usually grow in moist locations 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 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 rainforest biodiversity.

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.

Protecting rainforests

About 70% 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 K'gari (formerly 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.
• Clean your boots beforehand to avoid introducing soil pathogens.
• Remember, everything is protected. Don’t pick, break or remove any plants.
• Don’t feed native animals. Feeding is harmful and may lead to aggressive behaviour.
• 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.
• Only use fuel stoves when cooking in rainforests. Nutrient recycling is critical in a rainforest so gathering leaf litter and dead branches for fires can cause damage.
• Don’t use soap, toothpaste, sunscreen or detergent in waterways. They pollute the water and harm aquatic animals.