11 January 2021
I travelled to Australia in 2018 and was immediately struck by the country’s diverse forests comprising tropical mangroves, ancient Gondwana rainforest and extensive bush-lands. Australia is home to some of the largest, rarest and oldest trees on the planet. However, they have come under increasing human and environmental threat, as evidenced by the devastating forest fires in 2019 and 2020.
Australia’s forests provide essential habitats for a wide range of species, thereby creating diverse ecosystems. One of the most iconic species in Australia with national significance is the koala, which relies on eucalyptus forests for its survival.
Eucalyptus trees comprise 80% of the forests in Australia. Their stringy leaves are highly toxic to most animal species, yet koalas have adapted to rapidly flush out the toxins. Eucalypts are an essential component of a koala bears’ diet and water source as koalas consume between 200 and 500 grams of their leaves per day (click for reference). However, the issue is that they are quite picky creatures! Koalas only eat from a handful of eucalyptus tree types, despite there being approximately 900 hundred available species across Australia (see map below)!
When I visited the Koala Hospital in Port Macquarie, staff spoke to me about the challenges they faced finding fresh leaves to feed the injured koalas. They have since set up a project to plant koala food trees including Tallowood, Swamp Mahogany and Forest Red Gum and are asking for donations from the public (click for reference).
Although eucalyptus trees offer huge value to koalas, they are problematic as they intensify forest fires. Not only do their leaves contain flammable oils, but their burning bark can also be carried by the wind across large distances, igniting new fires. This process of spotting has the potential to start fires 30km ahead of the main blaze which is a significant challenge for firefighters (click for reference). Nevertheless, there is some hope as eucalyptus trees have evolved to generate strategies to recover from fires. Many eucalyptus trees produce seeds when they come into contact with fire so they are able to regenerate. This also prevents other species becoming dominant and taking over the area. In addition, many deciduous trees in Australia such as Ash, Hawthorn and Honey Locust can tolerate extremely dry conditions as they have a high moisture content. Storing water in their leaves enables these deciduous species to act as a fire retardant, thus reducing the spread of forest fires.
The forest fires in 2019 and 2020 were highly destructive, destroying over 18 million hectares of forest. As a result, koalas’ habitats have come under increasing pressure as their already limited food supply has been depleted. This loss of habitat was particularly pertinent in New South Wales (NSW) in 2020 where blazes spread across five million hectares and affected 24% of koala habitats (click for reference).
The environment minister of Australia declared that 30% of koala bears in NSW were killed during the forest fires (click for reference) and WWF branded it one of the “worst wildlife disasters in modern history” (click for reference). This is a huge loss to an endemic species and what’s more, koalas may face extinction by 2050. Such alarming statistics, in addition to the threat of housing developments, agricultural land clearance and logging, highlights the need to conserve and maintain Australia’s forests and remaining koala populations.
This could be achieved through the creation of National Parks which are formally protected areas where threats can be managed and mitigated. For example, the Great Koala National Park in NSW has been proposed following the 2020 bush fires and is supported by the Gumbaynggirr people (click for reference).
Alongside habitat creation, Australian forests perform vital environmental functions including carbon mitigation, soil stabilisation and air pollution removal. Forests make up 17% of Australia’s land area and contribute to 3% of the forests world-wide (click for reference). Therefore, they have both a national and global importance for carbon sequestration.
Australia’s forests are clearly of cultural and national significance, offering economic, social and environmental benefits. However, it is important to note that trees are an essential part of life worldwide, not just in Australia! We need to care for, manage, maintain and replenish our trees if we are to envisage a world where these benefits don’t cease to continue.