Rainforest Layers, Amazon

As mentioned in the previous postcard, I am currently cruising alongside the river island Tupinambarana, which spans a massive 200mi (320km) in length. As the third largest island in Brazil, it'll take me a while to get to the end of it, but that'll allow me to admire the lush rainforest and marvel at the ecological diversity of the Amazon. Many indigenous communities have called the island home for generations and continue living a traditional way of life. The island teems with creatures, from gorgeous colourful birds to cheeky monkeys and adorable but very slow-moving sloths.

As I observe the forest from the riverboat's deck, I contemplate its structure, vegetation, and wildlife. Separated into four layers, the first one is the 'forest floor', which receives very little sunlight. The forest floor is covered in a thick layer of decomposing leaves and twigs, creating the perfect environment for fungi and small plants to grow. Large animals like tapirs and anteaters, including many insects and microorganisms, inhabit this area.

The next level is the 'understory layer', where sunlight is just starting to filter through the canopy. This layer is characterised by small trees, shrubs and vines. Plants such as bromeliads, palms and ferns have adapted to thrive in these low-light conditions. Up in the branches, toucans and parrots provide bursts of colour, boa constrictors coil and jaguars lounge, keeping a watchful eye.

The 'canopy layer' is where things change. Here the branches of the tallest trees overlap to form a dense canopy absorbing most of the sunlight. Interestingly, the canopy trees may look interlocked with each other, but in reality, they don't even touch, with the trees growing a few feet apart. This is thought to be a form of protection from tree-eating caterpillars and tree diseases. Canopy dwellers like monkeys and frogs must swing, climb, leap, glide or fly to close the gaps. Most of the trees in this layer reach 130ft (40m), with trunks wrapped in liana vines and epiphytes protruding from the sides or growing on branches.

The final level is the 'emergent layer', where trees 200ft (60m) tall push through the canopy into the full glory of sunlight and the full brunt of strong winds. The foliage on the trees is quite sparse around the trunk area, but they spread wide at the top, like an umbrella. Animals at this level, which typically include butterflies, birds, gliders and bats, must be able to fly or glide to manoeuvre between the branches. The Brazil nut tree is one of the emergent species found in the Amazon. If left undisturbed, the tree can live up to 1000 years. Its fruit, nutshell and seeds can weigh up to 4.4lb (2kg). It is an important food source containing several micronutrients providing various health benefits.

While each layer is distinct, as a whole system, they are interdependent and rely on each other for survival. Where the canopy layer regulates the amount of light and moisture reaching the ground, the understory provides a habitat for animals and plants that can't survive in bright environments. The forest floor is where everything decomposes, providing essential nutrients for new growth.

It is an incredibly complex ecosystem, so when I look at the jumble of vegetation, I don't see a jungle anymore. I see a well-organised environment where each plant and animal plays a vital role in survival.