Teacher background information

For Aboriginal and Torres Strait Islander Peoples, science has long been an integral aspect of everyday life for procuring resources, manufacturing implements, developing technologies and managing the environment. Prior to colonisation, resources required for all aspects of life were procured from the environment; different geographical regions encompassing a community’s Country or Place produced different resources. Ongoing access to resources requires careful and considered management of the environment to ensure ecosystem balances are maintained and the continuation of plant and animal species within the environment is ensured. Plant matter is a source of natural material that has long been harvested by Aboriginal and Torres Strait Islander Peoples in the manufacture of tools, weapons, musical instruments, clothing, cosmetics and items for paintings. Bark from trees is used in the construction of shields, watercraft, blankets, clothing and canvases for painting, branches are used to manufacture musical instruments, and fruits and berries provide dyes for cosmetics and body adornment. These components have been sustainably harvested by Aboriginal and Torres Strait Islander Peoples for millennia; sustainable collection of plant materials has ensured their survival and maintained access to these resources. This elaboration provides students with the opportunity to consider how Aboriginal and Torres Strait Islander Peoples incorporate their scientific knowledge of plants to maintain an environmental balance and sustainably source materials for a variety of purposes.

Plants have long been an important resource for Aboriginal and Torres Strait Islander Peoples as a source of natural materials for: the construction of tools, weapons and musical instruments; the manufacture of clothing; and cosmetics and artworks. It is important to note that while in contemporary times the term artwork is used to describe Aboriginal and Torres Strait Islander Peoples’ paintings and illustrations, for many Aboriginal and Torres Strait Islander Peoples this term is oversimplified. Artworks hold much more significance than mere aesthetic value and play a critical role in providing a record of information and material for teaching purposes.

In contemporary Australian society, wood is harvested from both commercial forest plantations and old growth forests, to provide timber predominantly for the building industry and for products such as wood pulp for paper and paperboard products. In the commercial forest industry, the entire tree is cut down to access all the resources. The industry is partly sustained through the re-planting of trees or the establishment of new plantations. By contrast, Aboriginal and Torres Strait Islander Peoples carefully harvest desired materials from trees ensuring the survival of the plant for continued access to resources. The scientific understanding of the requirements for growth and survival of trees is well understood by many Aboriginal and Torres Strait Islander Peoples and has long informed ongoing Caring for Country/Place practices.

In botany, trees are defined as a perennial plant, that is, a plant that lives longer than two years, that generally has roots, a trunk, elongated branches and leaves. The roots of a tree function to anchor it to the ground and gather nutrients and water from the soil that are transferred to other parts of the tree. The trunk of a tree transports water and nutrients from the roots to the aerial parts of the tree and carries compounds generated by the photosynthetic processes of the leaves to other parts of the plant. Trees grow through a process of cell division and expansion that takes place in an area of the trunk known as the cambium. The trunk of many trees, including angiosperms such as Eucalyptus spp., have an outer layer of bark that is composed of dead cells. This outer layer of bark provides a protective layer to the phloem, the living inner tissue of the trunk, that transports the products of photosynthesis, such as sucrose, through the plant. Removal of the phloem results in death of the tree as it can no longer transport sucrose and other products of photosynthesis from the leaves to the roots of the tree. Aboriginal and Torres Strait Islander Peoples have knowledge and understanding of this aspect of botany and carefully harvest material from trees to ensure that the phloem is not destroyed and the tree can survive.  

For millennia, the outer bark of hardwood trees has been carefully harvested by Aboriginal and Torres Strait Islander Peoples for the construction of canoes, shields, tools and implements, and for painting. The removal of bark can cause damage to the cambium, the region of cell division in the tree trunk. The cells of the cambium that are exposed to air after removal of the outer bark dry out and die, and growth ceases. This can result in the formation of a scar on the still-living tree. The presence of scarred trees across southern and eastern Australia attests the application of in-depth botanical knowledge by Aboriginal Peoples in the sustainable harvest of bark as a resource. The Alyawarre People of the central desert region in the Northern Territory cut the outer bark from the ghost gum (Corymbia aparrerinja) to manufacture winnowing trays that are used in processing resin. Separate pieces of bark are carefully cut from opposite sides of the tree at different heights to ensure the tree will not die. Construction of bark canoes by the Wonnarua Peoples of the Hunter Valley Region is evidenced by scarred trees in the area. Canoes were constructed in the region as a mode of transport on the river, particularly during times of flood. One scarred tree in the region is believed to be more than 100 years old, and shows scars where the bark has been carefully removed from either side of the trunk. The regular elongated shape of the scar, with parallel sides and curved ends suggests the bark was removed for the construction of canoes. Similarly, an example of a ‘canoe tree’ remains at Lanyon, on the outskirts of Canberra, on Ngunnawal Country. Bark that has been taken from a Eucalyptus blakeleyi forms a long canoe scar, approximately 2.5 x 0.4 metres, on the south-west side of the tree facing the Murrumbidgee River. The tree is alive and healthy and is protected by a small fence.

The Yolŋu Peoples at Yirrkala in east Arnhem Land in the Northern Territory use stringybark as a surface for painting. The bark is cut from the tree during the wet season, taking advantage of the ambient moisture and seasonal presence of sap to facilitate its removal. Only the outer layers of the bark are removed, ensuring the survival of the tree and continued access to the bark for this purpose. Yolŋu Peoples have applied scientific knowledge in the production of bark canvases over millennia, an example of the sustainable management of living things in the environment. The Dyirbal Peoples of the north Queensland rainforest region sustainably harvest bark from the banana fig (Ficus pleurocarpa) to manufacture blankets. The bark is collected from high up in the tree (up to 12 metres has been recorded) likely to prevent damage to the root system and ensure survival of the tree. Two horizontal incisions are made around the entire circumference of the tree, followed by a single vertical cut to join them. Careful removal of the bark results in a large single sheet of material that is the processed to create a soft, lightweight blanket.

Families from different Language Groups came together at Yarralumla (ACT) and gathered bogong moths from Birragai in the lands of the Ngunnawal People. When the moths were smoked out of the caves, they tumbled to the bottom of the cleft. A fine net made from Pimelia spp. fibre captured the insects. Pimelia spp. is a shrub that grows to a height of approximately one metre and provides the resources to make the bogong moth nets. The bark of the bush is stripped, allowed to dry, and then weighed down with stones under water for several days until the non-fibrous portions have partly rotted. It is then taken out of the water and allowed to dry until it becomes crisp, and beaten with sticks and/or stones until the fibre is freed. This process is undertaken by women; the final product is a strong material that can be spun into the finest thread to construct bogong moth nets.

The didjeridu, a wooden musical wind instrument long manufactured by some Aboriginal Peoples, was crafted prior to colonisation by sustainable harvesting of tree material. Conjecture surrounds the origin of the word ‘didjeridu’. Many consider that it is not a traditional language word; rather, it is believed to have been introduced after European colonisation as an onomatopoeic description of the sound the instrument makes. Didjeridus are crafted from a variety of trees including species of Eucalyptus and Acacia. Trees are investigated to find a hollow branch or fallen log; attack by insects or physical damage to a tree branch can cause a hollow to form and expose the inner layers of the trunk. This can expose the inner bark to microorganisms and insects, thus causing the decay and decomposition of the inner bark tissue, while the outer bark layers remain intact. Aboriginal Peoples select such branches or logs for the construction of sound instruments as a sustainable means of obtaining the desired material. Aboriginal and Torres Strait Islander Peoples have long applied careful consideration to the sustainable harvest of bark for a range of purposes; this demonstrates ecological knowledge and understanding and ensures continued access to the resources.

Other components of plants have long been sustainably harvested by Aboriginal and Torres Strait Islander Peoples; for example, fruits, flowers and berries are used to produce cosmetics. The Kuku Yalandji Peoples of far north Queensland harvest the fruits of the cassowary pine as a source of red pigment, while the Erubam Le Peoples of Erub Island in the Torres Strait use the scarlet flowers of the hibiscus as a red pigment to stain body tints. The Noongar Peoples of south-west Western Australia use resin from the balga (Noongar language term for grass tree) as a yellow paint that is smeared on skin, while the Bardi Peoples of the west Kimberley region use yellow pigment from iling (Bardi language term known in English as caustic bush (Grevillea pyramidalis)).

Grass trees (Xanthorrhoea spp.) have long been a culturally important species for many Aboriginal Peoples across Australia and knowledge of the life cycle of these plants, and when components can be harvested for use, is well understood. The plant provides material for many purposes including resin, food, nectar, fibre, and wood to construct implements and weapons, as well as firemaking. Noongar Peoples of south-west Western Australia have documented at least 28 different uses for the plant. The growing tip of the stem is edible, although it is rarely consumed as its removal destroys the plant completely, and therefore the opportunity to produce further resources. The long, straight spike of the grass tree dries and detaches during the plant’s lifecycle and has been used by Aboriginal Peoples for many purposes. It can be used for the construction of lightweight spears, as a torch or as a drill stick to create fire. The Noongar Peoples use the dried flower stem of the grass tree (balga) as a torch. Many First Nations Peoples, including the Yirrganydji and Yidinji Peoples of the Cairns region, the Cammeraigal Peoples of the Eora Nation in the region now known as Sydney, some Tasmanian Aboriginal Groups, and Ngunnawal people of the Canberra region, used the dried stem of the grass tree as a drill stick for starting fire.

Resin is produced at the leaf base of some species of grass trees. Aboriginal Peoples have long sustainably collected and used this resin in many different applications: as a waterproofing agent on canoes and water-carrying vessels such as coolamons; as an adhesive to fix axe heads onto handles and spear tips on spear shafts; and to repair other implements. Colonists in the early 20^th century recognised the commercial value of grass tree products and exploited the resin for use in wood polish and varnish, photographic light filters, textile colouring and medicines. A lack of sustainable resin harvesting procedures resulted in widespread destruction of grass trees through large scale removal of entire plants. Several species of native grass trees are now protected by special regulations under government legislation.

This elaboration provides students with the opportunity to learn how Aboriginal and Torres Strait Islander Peoples use science in many aspects of daily life. For millennia, Aboriginal and Torres Strait Islander Peoples have worked scientifically to understand the complexities of the environment, and the living things within their Country or Place. Scientific knowledges regarding physiological processes, the life cycles of species, habitat requirements, food webs and ecosystem interdependencies provide the foundation for the sustainable harvest of environmental resources. Prior to colonisation, the procurement of natural materials from the environment was crucial for many aspects of daily life including the construction of tools, weapons, sound instruments and surfaces for painting, for body adornment and cosmetics and in the manufacture of clothing and bedding. Scientific knowledge of the environment and the living things within it ensured that these essential materials were sustainably harvested, providing ongoing access to the resources. Much of this important knowledge remains in Aboriginal and Torres Strait Islander communities where sustainable harvesting practices continue today.