Green Island Eco Tour

Green Island: Eco Walk Self-Guided

Green Island Rainforest
Self-guided Rainforest Board Walk

At first glance, Green Island seems like a tiny and insignificant blob in the middle of the Coral Sea — it has a circumference of just 1.6km and only 25 people. Yet look a little deeper, and you’ll realize that it’s home to a thriving ecosystem.

The island is the only coral cay (of 300) on the Great Barrier Reef with a rainforest. It also boasts 100+ plant species, from coastal plants evolved to withstand the dry beach conditions to dense vines growing among the humidity and trees.

Not to mention the clear waters and breathtaking reef surrounding the island. No trip to the Cairns area or Great Barrier Reef is complete without stopping by to take it all in.

This guide contains a breakdown of the plant and wildlife species typically found in Green Island and what you can expect to see on a walk through the rainforest, along with useful facts and information.

Each number on the map represents a type of tree belonging to the island that you can expect to see on a walk. To learn more about each one, head to the section focusing on the corresponding number — or go to Green Island and follow the map’s route to visit for yourself.

A Quick Overview of Green Island

The Great Barrier Reef may contain more than 900 islands, but none is quite like Green Island. Most islands fall into either a coral cay (sandy) or a continental island (submerged parts of the continental shelf). Yet, although Green Island is a coral cay, it’s unique for hosting a rainforest, too.

Here are some quick facts about this unforgettable destination.

Location

Green Island is just 27 kilometres (or 16 miles) from Cairns, making it easy to head to the island for a day or two when staying or arriving at the mainland. It sits to the northwest of the reef surrounding it.

Size

Green Island contains an area of 12 hectares, almost eight of which contain its national park. It’s around 260 meters wide and 660 meters long.

In turn, the reef area surrounding the island is about 1,200 hectares, and the land lies around 4 meters above sea level.

Age

Although it’s impossible to give an accurate number for the age of Green Island, experts have suggested it could be around 6,000 years old. 8,000 years ago, the Ice Age destroyed all sand cays, so we know it must have formed at some point after this phenomenon.

Formation

Although we don’t know exactly when Green Island was formed, we know how sand cays took place. This type of island is built when waves push debris, shells, coral rubble, and sand onto the calm part of a reef flat, creating a sandy island (if the conditions are right).

Surprisingly, seabird droppings play a crucial part in this process — they help seeds sprout by providing nourishment and cementing the sand and debris in place. This process allowed the island to form and develop so many species.

Climate

As you’d expect, an island with a rainforest off the Cairns coast, Green Island has a tropical climate. It usually experiences its highest temperatures between November and April (23 °C–32°C) and its coolest temperatures from June to August (18°C–23°C) — plus a rainfall season from January to March.

Marine Life

There’s no shortage of plant life and marine species in the reef around Green Island — in total, there are more than 190 hard corals and 100+ soft corals.

One of the most notable habitats is seagrass beds, home to large sea turtles, dugong, and fish hiding from predators. The other principal habitat is a reef that goes from the shallows to the depths.

Protection

The reef surrounding Green Island is part of the Great Barrier Reef Marine Park. The island itself is a National Park, giving protection from the Australian government that limits certain areas’ activities. Both habitats are also a UNESCO World Heritage Area, awarding them extra safeguarding.

Birds Found on Green Island

Although most people would associate Green Island with sea life, it’s also home to a vast array of birds — there are over 50 species in total (around 38 seabirds, 38 shore and lord birds, and some migratory birds).

Here are six of the most common.

Torres Strait Pigeon

Torres Strait Pigeon

Also known as the Pied Imperial Pigeon, the Torres Strait Pigeon is a large dove. These migratory birds travel from Papua New Guinea to the Great Barrier Reef between September and March. Green Island is a favourite spot due to its prevalence of tropical fruit, with thousands arriving each year.

Buff Banded Rail

buff banded rail

As ground-dwelling birds with a well-camouflaged coat, spotting a Buff Banded Rail is no easy task (although you might have more luck noticing their small, fluffy chicks). The birds spend most of their time foraging through the ground for food using their feet.

Osprey

Osprey

The Osprey is a large, formidable bird that uses its sharp talons to catch fish and its legs to carry prey away — they can cope with a load up to two kilograms! There’s a mating pair on the island that has remained there for years.

Reef Heron

Reef Heron

There are both white and grey reef herons, but they’re the same species. The birds are known as ambush hunters, meaning they wait for their prey by the water then pounce suddenly, using their beaks to attack.

Ruddy Turnstone

Ruddy Turnstone

As migratory shorebirds, Ruddy Turnstones stay at Green Island between September and March each year, among various other destinations in the Great Barrier Reef. They use their beaks to “turn stones” and find food, giving them their name.

Silvereye

Silvereye

The Silvereye is a tiny bird that makes equally tiny nests out of coconut fibres and grasses. As the name suggests, their eyes have an unusual silver look that really pops out against the yellow on their heads. Fun fact: they remain with their first mate for life if they’re successful at raising their young together.

1.    Octopus Bush

Octopus bush

Start your walk as you arrive at the Helipad by the beach and head down the southern walking track. At the end of the path, you’ll find the first plant of note: the Octopus Bush (Messerschmidt argentea).

It’s a small, round plant — in fact, its roots are generally bigger than the shrub you can see above the ground. This expansive root system doesn’t only support the Octopus Bush but also cuts down on erosion.

Leaves

  • Thick and strong
  • Contain fine, silvery hairs (prevent damage from sea spray)
  • Crowded at the end of branchlets

When and How It Flowers

  • Flower sporadically
  • Tiny white flowers in clusters
  • Look similar to octopus arms.

Fruits and Seeds

  • Also, yield fruit sporadically.
  • Tiny, fleshy fruits
  • Found inside hairy lobes that turn black when ripe

What It’s Used For

  • Leaves are edible when young.
  • Timber can make firewood.
  • Leaves can be used for handling food.

2.    Cardwell Cabbage

Cardwell Cabbage

As you return to the southern walking track and follow it back toward the Helipad, you should soon set your eyes on the Cardwell Cabbage (Scaevola sericea).

Sometimes called the Sea Lettuce, this bushy shrub stands 2–3 meters above the ground and is known for its extensive and dense foliage.

Leaves

  • Rounded tips
  • Light green with a shiny coating
  • Sometimes curled (they reflect sunlight to stop water evaporating)

When and How It Flowers

  • Flower sporadically
  • Petals form “half flowers.”
  • Small and white

Fruits and Seeds

  • Sprout small fruits
  • Fruits are green when raw and white when ripe.
  • Contain hard stones inside

What It’s Used For

  • Leaves are edible when young.
  • Fruit juice can treat sore eyes, tinea, and sores.
  • Heated leaves have medicinal use on swollen joints.
  • Stems can be hollowed and made into pipes.

3.    Cheesefruit

Cheesefruit tree

Continue along the path, then turn to the left at the first opportunity. Here, you’ll have the chance to spot three beautiful plants, starting with the Cheesefruit Tree (morinda citrflora) —a small, thin tree with no end of leaves.

Leaves

  • Smooth texture
  • Dark green
  • Shiny
  • Pointy tips and strong veins

When and How It Flowers

  • Flower between July and December
  • Sprout white tubular flowers
  • Each flower is around 1 centimetre long.

Fruits and Seeds

  • Yield fruit between July and December
  • Each fruit has one seed.
  • The fruit has a strong smell but is edible.

What It’s Used For

  • Tea made of fruit can help with diarrhea.
  • Raw fruit rubbed on the body can treat flu, colds, or fever.
  • Leaves can be used to wrap food in
  • Roots used for weaving

4.    Casuarina

Casuarina Tree

 

Not far away from the Cheesefruit Tree, you’ll find our next plant. Just look toward the beach, and you’ll see the Casuarina — sometimes called the Whistling Pine (due to the sound the wind creates) or She-Oak (early settlers believed it was similar to their native oak but inferior, so they gave it a female name).

Young Casuarinas look thin and flimsy, but they become thicker and taller as they grow, sometimes reaching impressive heights. They also have an extensive root system beneath the ground.

Leaves

  • The greenery on the tree is actually made of small, thin branches (not leaves)
  • Leaves are small spikes that are barely visible.
  • Help to stop moisture loss.

When and How It Flowers

  • There are male and female flowers.
  • Female flowers swell into small cones.
  • Male flowers shed pollen.

Fruits and Seeds

  • Yield no fruit
  • Seeds are small and winged.

What It’s Used For

  • Spears and woomera pegs can be made from timber.
  • Inner bark and sapwood can cure a sore mouth or toothache.

5.    Goats Foot

goats foot

Close to the Casuarina by the beach, you’ll find the next species of I interest: the Goats Foot (ipomoea pes caprae). This species grows in a tuber and is a close relative of the sweet potato.

The plant plays a crucial role in preventing erosion on exposed beaches, and it’s actually the first plant many people notice when they arrive at the island. However, as the purple petals tend to stick out above the sand and make them easy to spot, they’re less conspicuous if the flowers aren’t out.

Leaves

  • Have an oval shape
  • Indent in the middle

When and How It Flowers

  • Flower sporadically
  • Mauve/purple colour
  • The flowers have a trumpet shape.

Fruits and Seeds

  • Yield fruit between May and August
  • Contain four seeds

What It’s Used For

  • Heated leaves can treat sores.
  • Boiled leaves can treat aches and stings.
  • Root is edible

6.    Pandanus

Pandanus

As you return to the main path and walk toward the jetty, you’ll see the Pandanus (pandanus tectorius). Other names for this tree include the Walking Tree (from a Polynesian myth about male and female trees walking toward each other using their root systems) or the Screw Palm (because it grows upwards in a spiral).

The tree has roots that extend from fairly high up the trunk, giving a distinctive look that helps give the tree balance. It also contains cells to deal with excess salt and dormant roots that can add extra stability if necessary. These unusual features have no doubt helped to inspire the old myths about the plant.

Leaves

  • Long, thin leaves
  • Resemble a palm
  • Contain thorns

When and How It Flowers

  • Yield male and female flowers on different plants
  • Small and white flowers

Fruits and Seeds

  • Yield fruit between June and October
  • Edible but only with careful preparation
  • The fruit resembles a pineapple and contains various segments.
  • Have a woody base with seeds

What It’s Used For

  • Can make fibres from leaves to weave into ropes and baskets
  • Fruit kernels are edible and can be used to make bread.
  • Treats diarrhea, colds, mouth sores, and more
  • The skinned core can make rafts.

7.    Beach Hibiscus

Beach hibiscus

Further along, the main path lies the Beach Hibiscus (hibiscus tilliaceus), a plant that can grow between 5–8 meters high. These shrubs tend to pop up close to the beach’s sandy part, acting as a barrier that shields taller trees from the wind.

Leaves

  • Dark green
  • Smooth on the upper side, hairy below
  • Heart-shaped
  • Pointy tips

When and How It Flowers

  • Flower sporadically
  • Only bloom for 24 hours at once
  • Flowers are yellow in bloom but turn red as they die.
  • Dark purple in the centre

Fruits and Seeds

  • Yield seeds from January to April
  • Hairy capsules with kidney-shaped seeds inside

What It’s Used For

  • Roots, leaves, and shoots are eligible.
  • Can make jam from buds
  • Inner bark and sapwood are antiseptic.
  • Bark fibres make string, ropes, and more.
  • Wood makes spears, fire sticks, and more.

8.    Beauty Leaf

Beauty leaf

Keep approaching the jetty, and you’ll find the Beauty Leaf (Calophyllum inophyllum), a plant known for its attractive greenery.

The plant grows on short but wide trunks, with extensive branches that spread over into the beach. It’s also incredibly resilient, weathering salt and even cyclones. You may also find some green ants nearby, as they often use the leaves to make their nests.

Leaves

  • Exude poisonous sap
  • Dark green
  • Shiny but leathery
  • Closely parallel veins run from the centre to the bottom of the leaf.

When and How It Flowers

  • Flower between November and February
  • White flowers with yellow stamens
  • The scent is strong and fragrant.

Fruits and Seeds

  • Yield fruit between May and August
  • The fruit is pale yellow when ripe.
  • Hang in small bunches
  • The fruit looks like a small brown ball when dry.

What It’s Used For

  • Laxative
  • Nut oil for lighting (but it’s poisonous)
  • Oil can be turned into soap.
  • Treats body pain (with a mix of nut kernels and red pigment)

9.    Strangler Fig

Strangler Fig

Just before you reach the jetty, you’ll see the Strangler Fig (ficus virens) to the left of the path. It’s also known as a Banyan Tree. It’s one of the larger species on the island and can grow up to 30 meters tall while spreading aerial and prop roots.

The deciduous tree grows in the hollow of other trees after birds leave seeds to gather nutrients from leaf litter. Eventually, the Strangler Fig will sprout its roots to the ground, growing more as it receives water and nutrients. It eventually surrounds the host tree it grew within until that tree is choked and dies — that’s why it’s a “strangler.” The host then leaves behind nutrients that maintain the fig for years.

Leaves

  • Oblong-shaped
  • 6–14 centimetres long
  • Dark green
  • Shiny, smooth, and leathery

When and How It Flowers

  • Tiny flowers
  • Flowers grow within fleshy receptacles
  • Figs must be pollinated by fig wasps, which need to reproduce inside figs.
  • Yield fruit often since wasp has a short life cycle and needs fig to survive.

Fruits and Seeds

  • Yield fruit from March to September
  • Dark purple fruits
  • Each fruit contains a seed.
  • Fruits are 3–6 centimetres long.

What It’s Used For

  • Edible fruits
  • Can make nets, baskets, and more from the bark on aerial roots

10.   Fish Poison

Fish Poison

Passing the jetty, you’ll soon find another tree on your right: the Fish Poison (Pongamia pinnata). The deciduous tree, also known as Indian Beech, can grow anywhere between 5 and 20 meters high.

The name says it all with this one. It’s one of the various trees that are traditionally used to stun and catch fish.

How? After grating the inner bark and roots and placing them in the sea, a chemical reaction lowers the oxygen level available, forcing the fish to float to the surface of the water. It might sound cruel, but it’s undoubtedly effective. The stunned fish can still be released after they’ve been stunned.

Leaves

  • Dark green
  • Shiny
  • Thin
  • Pointy tips
  • Distinct vein formation

When and How It Flowers

  • Flower between September and November
  • Petals are light blue or pale pink.
  • Flower in clusters

Fruits and Seeds

  • Yield seeds between June and October
  • Oblong pods with seeds inside

What It’s Used For

  • Stunning and catching fish

11.  Coconut Palm

Coconut Palm

Shortly after the Fish Poison lies the Coconut Palm (cocos Nucifera), on the same side of the path as the last stop. These looming trees can grow up to 25 meters tall and have thin, segmented trunks. Plus, they do an excellent job of withstanding difficult conditions, particularly cyclones.

Although coconut trees aren’t native to Green Island (European botanists planted them in the nineteenth century to provide for shipwrecked sailors), there are certainly plenty about now. Originally, they probably came from the Indonesian archipelago and are part of the wider palm family.

Leaves

  • Large leaves
  • Have a feather-like appearance

When and How It Flowers

  • Small white flowers
  • Grow from the top of the trunk (so they’re hard to spot from the ground)

Fruits and Seeds

  • Yield coconuts
  • Typically produce their first crop after five or six years.
  • Continue to produce crops for up to fifty years.
  • Coconuts are typically 45 centimetres long and 20 centimetres wide.
  • Contain half a litre of liquid and lots of oil
  • Fruits contain a single nut.

What It’s Used For

  • Coconut oil is a moisturizer and protects the skin from the drying tropical climate.
  • Flesh from the coconut is edible.
  • Milk from coconut is drinkable and nutritious.
  • The husk is a mosquito repellant when burned.
  • Strands from husk can be used for sewing.

12. Beach Almond

Beach Almond

Walk a little further along the path and take the third path to your left. As you reach the end of the walkway and see some picnic tables, you’ll find the majestic Beach Almond (Terminalia arenicola).

When growing in the rainforest, these trees have a long, thin trunk and then sprout out into blooming canopies — but when they grow by the beach, they’re shorter and thicker to compensate for the high winds.

Although it’s known to some as the “Dead Dog Tree,” this name originates from the tree’s sickly smell rather than any deadly tendencies. If anything, the Beach Almond is a victim in the rainforest — it’s often a target of strangler figs (which kill their host trees) and mistletoe (which also steal nutrients and water from other trees).

Leaves

  • Dark green
  • Have a pear shape
  • Pointy tips
  • Between 10–20 centimetres long

When and How It Flowers

  • Flower between November and February
  • Emit strong, “rotten” smell.
  • Small, white flowers
  • Pollinated by flies

Fruits and Seeds

  • There are nuts in the seeds.
  • Seeds contain juicy pulp — resembles fruit and attract fruit bats.
  • Often evidence of fruit bats below the tree.

What It’s Used For

  • Nuts are edible and nutritious (high levels of protein and thiamin)
  • Can make purple/pink dye from the fruit pulp

13. Bloodwood

Bloodwood tree

Return to the main path and take the first turn to your left to reach the Bloodwood Tree (macaranga tanarius). Thanks to its heart-shaped leaves, the tree has also been given the name “Bleeding Heart.”

Although the tree can only reach 8 meters in height, it grows extremely quickly.

Leaves

  • Dark green
  • Soft texture
  • 20–15 centimetres long
  • Heart-shaped

When and How It Flowers

  • Flower between November and January
  • Yellow/green flowers that grow in bunches
  • Separate trees for male and female plants

Fruits and Seeds

  • Yield fruit in January and February
  • Shiny black seeds
  • Yellow/green fruit in a capsule

What It’s Used For

  • Can make twine from the bark
  • Birds can eat the fruit (but humans can’t)
  • Leaf ash a traditional cure for inflated stomach
  • Can wrap food with the leaves
  • Firesticks and fishing spears made from wood

14.  Coral Tree

Coral Tree

Last but not least, a little further along the main path, we have the Coral Tree (erythrina variegate), just before the Marineland Melanesia.

Also called the Flame Tree, this species is actually a legume — just like beans and peas. But you wouldn’t think it has much in common with kidney beans when you look at this huge tree with its extensive route system and thick trunk.

The species is found throughout the island except for exposed beaches, where it struggles to grow.

Leaves

  • Smooth
  • Made up of three lobes (the middle one is the largest)

When and How It Flowers

  • Flower from July to November
  • Drop leaves in September or October
  • Grow large red flowers after shedding leaves
  • Attract pollinating insects and nectar-feeding birds when bare

Fruits and Seeds

  • Yield fruit from August to October
  • Seed pods that resemble are beans there for most of the year.
  • Red seeds found inside the pods

What It’s Used For

  • The bark is waterproof and can be used for canoes.
  • The inner bark can be a disinfectant.
  • Seedling roots are edible when roasted.
  • Can make seeds into necklaces and jewellery

That’s the end of the trees, but you don’t have to finish your walk quite yet! There are plenty more species and plants to look out for, so why not continue to the Interpretive Boardwalk?

Time to Plan Your Visit

This is just a snippet of what Green Island has to offer. In addition to the fantastic trees and birds you’ll see on the boardwalk, an island is a great place for water activities and marine life — as you’d expect for an island that lies within the Great Barrier Reef area. Or simply relax on the breathtaking beach and enjoy the local amenities.

Find out everything you need to know to plan your trip on Visit Green Island — from ferry trips to tours to accommodation, and we take care of it all.

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