Rainforests of NSW

The rainforests of NSW

Hotspots of biodiversity, rainforests are characterised as areas with a continuous closed canopy of broadleaved evergreen trees. This results in a protected understorey that is shady with small temperature fluctuations. Soils are moist and air movement is minimal. Understory plants have adapted to low light and include ferns, vines, strangler figs, epiphytes, moss and lichens.  They provide habitat to a diverse range of animals many of which have specialised interactions between rainforest plants and other animals.  Rainforests develop in areas where three essential physical factors are met:

• adequate moisture

• fertile soils

• protection from fire.

The evolution of rainforests in Australia

The supercontinent of Gondwana was once covered in rainforest. Australia, a fragment of this continent broke off and drifted north approximately 40 million years ago. The climate became warmer, drier, the soils less fertile and as a result eucalypts evolved creating a more fire-prone landscape. Climatic changes continued and Australia became cooler and more arid leading to the development of mixed forests, deserts and grasslands. Over time rainforests evolved and contracted to areas of adequate moisture, soil fertility and protection from fire.

Rainforests once covered much of Australia. Today rainforests cover only 0.25% of the continent, 17% of which occurs in NSW.  

Spatial distribution of rainforests in NSW

The rainforests of NSW are located in a series of discontinuous patches along the eastern edge of the state. These 'islands' separated by fire prone eucalypt forest, agricultural lands and urban areas range from covering large tracts of land to being contained within small gullies. 

They are located in the subtropical and warm temperate climate zones based on the Koppen classification method. This method uses native vegetation as the climate indicator. Other climate classifications maps are based on temperature and humidity, and rainfall. View the maps at the Australian Bureau of Meteorology.

The subtropical zone encompasses coastal NSW on the mid north coast from 32º  south latitude to the Queensland border. This climate experiences warm humid summers and mild winters with higher rainfall in the summer season. 

The  warm temperate zone follows the coast from 32º latitude to 34º latitude, south of Wollongong. This zone experiences warm summers and cold winters and has traditionally experienced uniform rainfall.  

The location of rainforests can be identified by:

• using data collated by the Australian Government Department of Agriculture, Water and the Environment (ABARES). Spatial data can be viewed using Native forest - data visualisation. Select rainforests and NSW to view the distribution and forest attributes.

• The NationalMap. This online tool provides access to spatial data from Australian government agencies. Select 'add data' and type in Forests of Australia 2018 to view the dataset and view rainforests. 

Activities

1. Outline the subtropical and warm temperate climate zones of NSW.

2. Explain the climatic factors  which influence these climate zones.

3. Describe the spatial distribution of rainforests in NSW.

4. Explain the influence of the Great Dividing Range on rainforest location. 

The nature of rainforests in NSW

Rainforest types

In subtropical and temperate NSW, rainforests have evolved over time and space in unique ways. The complex interactions between the atmosphere, hydrosphere, lithosphere and biosphere create diversity within and between different rainforest ecosystems. In NSW there are four main types of rainforest, or vegetation class, each defined by their biophysical characteristics; topography, climate, soil, plant structure and species composition. These are

• subtropical

• warm temperate

• cool temperate

• dry rainforest

Additional rainforest types include littoral rainforests and the Oceanic forests of Lord Howe Island.

Wet tropical rainforests are not located in NSW.

Rainforest features - unique characteristics

Rainforest forest types are classified by vegetation structure and composition. Structure refers to the layers of a forest and plant height. Composition refers to the type of plant species found within a vegetation community. 

Rainforests:

• have tree dominated vegetation. Trees make up more than 50% of the biomass of the vegetation.

• have a canopy cover of greater than 70%.

• have a crown cover made up of more than 50% of rainforest species.

• are dominated by rainforest species such as ferns, vines and epiphytes and trees with buttress roots.

• have few or no eucalypt species. 

Forest transitions

In areas where there are high levels of moisture, soil fertility and protection from fire, rainforests develop and thrive. As moisture and soil fertility decline and exposure to and experience of fire increases, the forest will transition to wet sclerophyll forest. In wet sclerophyll forest, rainforest species are found within the understory, however, eucalypt species dominate the canopy. As the land becomes even drier the forest transitions to dry sclerophyll forests. Sclerophyll vegetation has hard, tough and often spiky leaves such as eucalypts, wattles and banksias. 

Activities

1. Access the NSW Department of Planning Industry and Environment Rainforest Overview and NSW National Parks and Wildlife Service Under the Canopy PDF to describe the structural and compositional features of the four main types of rainforest. 

2. Explain how and why cool temperate rainforests can be located in a warm temperate climate zone.

3. Compare and explain the differences between temperate rainforests and the wet tropical rainforests of Queensland.

4. Define the term sclerophyll.

5. Explain the difference between rainforests, wet sclerophyll and dry sclerophyll forest types.

The importance of rainforests

The rainforests of NSW:

• are areas of enormous biodiversity containing half of all Australian plant species including unique and ancient plant families

• provide habitat to the state's most threatened plant and animal species

• are a refuge for animals in times of fire

• are a link to our evolutionary history containing living species that have been traced to ancient fossil records from Gondwana and Indo-Malaysia

• have physical, cultural and spiritual connections for Aboriginal Peoples

• contain places of exceptional natural beauty and aesthetic importance

• are places of outstanding heritage value and include the World Heritage listed Gondwana Rainforests of Australia

• have economic importance for tourism

• have yet to be fully explored.

The Gondwana Rainforests of Australia World Heritage Area

The Gondwana Rainforests of Australia was inscribed on the World Heritage List in 1986 with an extension in 1994. It includes 40 reserves from Brisbane in south east Queensland to Newcastle near the NSW Central Coast. They include  the most extensive areas of subtropical rainforest in the world, large areas of warm temperate rainforest and the majority of Antarctic beech cool temperate rainforest. 

It represents outstanding examples of major stages of the Earth’s evolutionary history, ongoing geological and biological processes, and exceptional biological diversity. 

Management 

53% of rainforests in NSW are managed as nature conservation reserves and 28.5% are privately owned. 

Nature conservation reserves are publicly owned and are managed by state and territory government agencies. They are formally reserved for environmental, conservation and recreational purposes, including national parks, nature reserves, state and territory recreation and conservation areas.

28% are managed by Indigenous co-managed ownership and management.

Activities

1. View the YouTube video NSW Parks: Uncle Mark Flanders shares his Gumbaynggirr Culture at Dorrigo National Park (01.00min) . List the connections Gumbaynggirr Peoples have with Country.

2. Explain the importance of Dorrigo National Park to the Gumbaynggirr Peoples.

3. View the YouTube video Discover Gondwana Rainforests (0.57min) to identify reasons why you think these rainforests are managed and protected as World Heritage. 

4. Learn more about why the Gondwana Rainforests of Australia were inscribed onto the UNESCO World Heritage List.

5. Explain the need to protect rainforest ecosystems. In your answer categorise your reasons into maintaining genetic diversity, utility values, intrinsic values and heritage values. 

Conducting fieldwork

Fieldwork is an essential component of geography. It provides students a pathway for active research when investigating geographical phenomena. 

Complete the following activities to guide fieldwork in the investigation of rainforest characteristics and functioning.  

Key fieldwork inquiry questions:

• How do the four components of the biophysical environment interact to form a rainforest ecosystem?

• What fieldwork methodologies and equipment can be used to investigate rainforest ecosystems?

• How will our results be recorded?

• How do we draw conclusions?

For further assistance in conducting fieldwork contact:

• NSW Department of Education Environmental and Zoo Education Centres

• NSW National Parks and Wildlife Service

Pre-work 

Prior to fieldwork identify the location of your rainforest ecosystem using digital maps. 

1. Access Six Maps to view topographic maps and legend. The topographic map will provide opportunities to read contours, create cross sections and analyse  the influences topography has on the ecosystem. 

2. Access weather and climate information from the Bureau of Meteorology.

3. Explain how the location is influenced by the dynamics of weather and climate. 

Measuring abiotic factors

Abiotic factors are important to measure as they are the primary determinant of species abundance and distribution. In rainforest ecosystems the interactions within the atmosphere, hydrosphere and lithosphere that occur under the canopy lead to its unique character. The maintenance of the understorey microclimate is essential for proper functioning. 

To investigate the nature and functioning of rainforest ecosystems measure the abiotic factors in a rainforest ecosystem and one other ecosystem such as dry sclerophyll forests for means of comparison.

1. View the gallery of images to identify the equipment and methodologies used to measure and record abiotic factors. 

2. Predict the differences between the abiotic factors in a rainforest and with one other environment. Explain the unique conditions that exist in rainforests.

Measuring biotic factors

The living components within an ecosystem all interact and play an important role in shaping the environment. 

An investigation of vegetation structure and composition informs an understanding of the nature of rainforest ecosystems.  The interactions between species explains the proper functioning of the system. Land managers are able to determine rainforest stress by measuring and recording biotic factors. 

1. View the gallery of images to describe the methodologies used to measure and record biotic factors.

2. Identify secondary sources that support biotic investigations in the field.

3. Explain how fieldwork informs our understanding of ecosystem functioning. In your answer explain rainforest productivity in the production of biomass and in energy flows.

4. Explain the importance of ethical fieldwork practices.