By Sharon Go
Text-only version

Some people think of trees as non-living sentinels that just embellish the World around us. Others think of them as a way of making quick cash. But in truth, they are much more then most would imagine.

Although there are basically 2 kinds of rainforests (tropical and temperate), when people see the word "rainforest", they immediately think of the Amazon. Hopefully, that thought will not soon become a legend...

The Perfect Place to Grow...

Tropical rainforests are fast growing; most of which are around 100 000 years old which is young considering the abundance of Life and diversity to which it hosts. This accelerated speed to which the forest grows is due to excellent climatic conditions such as high levels of humidity, intense sunshine, high temperatures and precipitations that are relatively stable.

The Strata Principal

The tropical rainforest is characterized by it's layered structure to which in each strata, we find that the plants and animals that inhabit there have adapted perfectly to the particularities of that layer. There are 3 main divisions:

• The forest floor
• The understory
• The canopy

The forest floor receives very little light due to the competition for sunlight by most of the other plants and trees found in the understory and in the canopy. But that doesn't stop Life from continuing... Plants of the forest floor (such as ferns) have adapted to this condition: they need very little sunlight, and would probably not withstand exposure to direct light anyway. Their leaves are disposed in a way to catch as much sunlight as possible, and yet allowing their lower leaves to get some too. This is done thanks to a fan-like disposition of their leaves or simply by adding holes to them. Unique insects (like the Giant Tarantula) thrive in this strata of the forest. They too have adapted to the lack of light by means of dark coloration and camouflage. There are several mammals that also live in this part of the forest such as capybaras (the largest rodent on Earth) and jaguars. Although they are spotted, jaguars in this area usually have darker pelts, making them look almost entirely black.
There are 2 types of soils in the Amazonian rainforest, the highlands and the floodplains. In the highlands, the soil is fairly poor and fragile. The organic litter layer is thin. There are very few minerals and nutrients in the soil, since they are either almost immediately absorbed by the rapidly growing vegetation or washed away to the floodplains of the forest by seasonal rains. Most of the trees develop their roots horizontally and not vertically like trees of the temperate regions. Once the vegetation is removed, the soil rapidly dries up and is unsuitable for farming or any type of agriculture. Unfortunately, most people don't know this yet and continue to move further into the forest when the soil dries out. And once the upper part of the rainforest is cut... it's gone forever.
In the floodplains, yearly floods make the Amazon River swell like an anaconda who just ate a caiman! Along the Amazonian basin, the soil is extremely fertile since all the minerals and nutrients washed away from the highlands are found here. Sometimes, seasonal inundation would reach a high of several meters for weeks or even months at a time! The species of this area develop particular habits: the Tambaqui is a fruit-eating fish that usually fasts in ponds during dry season and gorge themselves with fruits when the water is high. The fruits pass through the Tambaqui's digestive system and the seeds are spread out in the fish's excretions. (eww... )
Water is thus a very important part of the growth of the Amazon, or any other living systems in the World. There are actually three types of waters in the Amazon: muddy waters, clearwaters and blackwaters. Muddy waters are rich in sediment. Most fish or mammals (The bôto dolphin lives here too!) have little need of their eyes in these dark waters so they have poor vision. Clearwaters come from old, torn-away mountains. They are usually nutrient and sediment-poor. Blackwaters, on the other hand, have little sediment but are dark in coloration. These waters are among the purest on Earth. They attribute their dark coloration due to it's sandy soils. This type of water is too poor in microorganisms to easily decompose organic matter. Organic chemicals which would normally bind to clay soil have no affinity for sand. So this organic overload then seeps through the soil and swept away to other streams and rivers, making them almost black.

The understory hosts some of the most beautiful and exotic flowers on Earth: orchids. These belong to the family of plants called epiphytes, they do not need soil to grow on. They extract their nutrients from the humidity in the air and they usually nest on trees. Yep, they basically just sit there. Some plants, like the tillandsia (a bromeliad) do not even have roots, they have little hairs on their "leaves" that capture moisture in the surrounding air. They kind of look like white, frilly hair hanging from the trees. They too need little light. Unlike vines, they are not parasitic. Monkeys such as the Golden Lion Tamarin live in this part of the jungle. It's beautiful golden coloration made it subject to human greed and fashion. Now, an endangered species, it hangs in the balance of existence and non-existence.

Peaceful and serene looking, the canopy is in fact a battlezone for sunlight. It's a fight to the death to see who grows high enough, fast enough and abundant enough to survive and conquer a specific space of the jungle. Vines were once thought to strangle trees since many dead trees were found to be tightly wound with vines. But nowadays we know that the latter will compete for sunlight by climbing along tree trunks until they reach the top, where they will then open up their leaves, creating a kind of umbrella, and steal the light from it's host. Needless to say, the host withers and dies, leaving only the twisted structure of hardened vine. In the canopy, the air is actually dry and windy. The sun is vicious and unforgiving (don't forget the suncreen!!). But the view is breathtaking and unforgettable. To lose such a sight will indeed be a greater lose than we think...