Celebrate tropical ecosystems this Tropical Tree Day

By Claire Laws 14 November 2023

Each year we come together to celebrate National Tree Day on the last Sunday in July. Did you know we also celebrate Tropical Tree Day on the first Sunday in December? Early December coincides with the beginning of the ‘wet’ season in places like northern Western Australia, the north of the Northern Territory and northern Queensland, making it a great time for planting seedlings. 

This year, Tropical Tree Day is Sunday 3rd December. So, to get into the spirit, we wanted to give some love to our wonderful tropical ecosystems and shine a light on some amazing groups working to protect them. 

The tropical zone is located between the latitudes of 23.5°N (the Tropic of Cancer) and 23.5°S (the Tropic of Capricorn) and is characterised by a hot, humid and wet climate.  

Australia’s tropical zone covers far north Queensland, the northern part of the Northern Territory and north of Broome in Western Australia. Although these regions are always hot, they have distinct ‘wet’ and ‘dry’ seasons - most rain occurs during the ‘wet’ season which occurs during what most Australians call summer. 

Tropical ecosystems

For most people, the first thing that comes to mind when thinking of the tropics is a tropical rainforest. Whilst rainforests are iconic, there are also many other types of vegetation communities and ecosystems in the tropics – such as mangroves, heathlands and grasslands. Australia’s tropical regions are dominated by rainforest and grassland ecosystems.  

Most of Australia’s tropical rainforests are found in far north Queensland, in what is known as the Wet Tropics World Heritage Area. It is important to highlight that tropical rainforests are not the only type of rainforest. For example, there are also subtropical rainforests (QLD and NSW), warm temperate rainforests (NSW and VIC) and cool temperate rainforests (TAS, VIC). The different rainforest types are defined by their latitude, temperature and rainfall. They are also home to unique assemblages of plants and animals. 

Australia's tropical rainforests

You’re probably familiar with Australia’s largest tropical rainforest – the Daintree Rainforest, located between Cairns and Cooktown within the Wet Tropics World Heritage Area. However, did you know that the Daintree Rainforest is the oldest lowland tropical rainforest on Earth? The Daintree is estimated to be at least 80 million years older than the Amazon Rainforest (which is the world’s largest tropical rainforest). 

The Kuku Yalanji people have a long connection to the Daintree, which is of significant cultural importance – if you’re interested to learn more about the connection First Nations Australians have with the Daintree, you can visit the Mossman Gorge Cultural Centre. 

Plants and animals

Many of the world’s tropical ecosystems are biodiversity hotspots – which means they a rich in plant and animal life (most of which is found nowhere else) and are also facing destruction. In each hectare of tropical rainforest, it is estimated there are between 40 to 100 (or more) different tree species. 

Although tropical rainforests cover less than 3 per cent of the planet, they are home to over half of the world’s terrestrial animals. About 80 per cent of all species ever recorded are found in tropical rainforests – it is clear these ecosystems are vital habitats that we must help protect. 

The tropical rainforests of Australia’s Wet Tropics World Heritage Area are home to more than one quarter of all Australian marsupial species, 58 percent of all Australian bat species and 40 percent of all Australian bird species. This is despite the Wet Tropics only comprising 0.2 per cent of Australia’s total land mass – incredible! 

Some animals who call the Wet Tropics home, that we think are particularly cool, are the southern cassowary and two species of tree kangaroo (known as Lumholtz’s tree kangaroo and Bennett’s tree kangaroo). The tree kangaroos, who have been described as a cross between possum and kangaroo, live high in the tree canopy so, unlike the kangaroos most of us are familiar with, they’re not easy to spot.  

The southern cassowary is Australia’s largest flightless bird – females can weigh over 70 kilograms! Cassowaries are crucial for maintaining the health and diversity of tropical rainforests, by spreading seed long distances in their dung.  

And not to be left out, the plants are also super cool - check out the ancient plant known as the ‘Green dinosaur’, which is one of the rarest and oldest flowering plants. Then there are the many fascinating adaptations tropical rainforest plants have evolved to thrive in their environment – such as the pointed leaves of canopy plants called ‘drip tips’, which allow rain to run off the leaf surface and into the vegetation and soil below. 

Ecosystem services

As well as providing habitat for the amazingly diverse plants and animals that call them home, the world’s tropical rainforests provide crucial ecosystem services – a fancy name for the many benefits that nature provides to humans. Some of the benefits humans derive from healthy tropical rainforests include clean air, fresh water, climate regulation, medicines, and food.  

Threats to the world's tropical rainforests

Like many of our natural environments, tropical rainforests currently face several threats. Key threats include deforestation and fragmentation (especially for development and agriculture) and climate change (which is altering temperature and rainfall patterns within tropical environments). 

In Australia, we are lucky much of our tropical rainforests are protected in reserves or World Heritage Areas. However, Australia’s tropical environments still need our help. Below, we introduce some groups from the National Tree Day community who are working to protect Australia’s tropical ecosystems. 

Brettacorp Inc.

Working in far north QLD’s Cassowary Coast region, Brettacorp Inc. is revegetating and rehabilitating degraded lands using the Miyawaki method and is creating habitat for threatened species like the southern cassowary and mahogany glider.  

Daintree Life

Dave and Connie from Daintree Life are passionate about providing education to help protect the magical Daintree Rainforest. Working with landowners, businesses, government and the community, they’ve set a goal to plant half a million trees by 2030.  

Rainforest Rescue

Rainforest Rescue has been working to protect and restore rainforest across Australia, not just in the tropics, since 1999. With a particular focus on the Daintree Rainforest, they’ve been able to increase biodiversity and connectivity within this important tropical habitat. 

If you live in northern Australia and want to get involved in Tropical Tree Day, there may be some plantings happening near you. Otherwise, there’s no need to wait until National Tree Day next year to get involved – every day can be tree day!  

Visit the National Tree Day website to learn more about how you can get involved (even at home) on any day of the year. We can all help boost our local biodiversity whilst reaping the wellbeing benefits that come from connecting with nature. 

Claire Laws
Claire joined the Planet Ark team in 2021. With a background in Environmental Science and a Masters in Environmental Law and Sustainable Development, Claire is keen to build on her previous work in ecological research and be part of Planet Ark's actions-based approach to environmental protection.