The understory is the area of the forest one admires at eye-level… from the floor to about 3-meters up. In high standing forests, with colossal trees over 50 meters tall, two central protagonists tell a unique story of interrelationship: tree trunks and light shafts.
In the shade
We are reminded of a Baroque-style temple as we walk through the rainforest’s gates, into the threshold of godly nature found beyond the borderline tangles. The bustling sound of the outside world suddenly muffles into a busy hush-hush silence. And a feeling not too unlike walking on creaking colonial hardwood floors suddenly makes us feel hollow inside, as we take each step over the moist leaves that lay like a carpet beneath our feet. Instead of gold leaf, of course, we have the glistening green colors of exuberant vegetation, highlighted by vibrant heliconias and orchids and the sculptural shapes of twisted lianas, hanging lichens and clinging bromeliads.
A fortunate fern receives light.
But what is most akin to this general ‘religious’, ‘cathedralesque’ feeling inside the rainforest is the fantastic effect of Renaissance chiaroscuro that dominates the understory. It’s a shady, shadowy place, fabulously layered with countless columns of trees (any comparison with a church suddenly falls grossly short when juxtaposed to the rainforest’s infinite breadth). But what is ironic is that these tall forests aren’t that tangled from our view down below. The height of trees and the successive dome-like roof they provide, a roof that stretches thousands of kilometers, and is obvious evidence of aggressive competition for light up in the canopy, renders what goes on 50 meters below a dark, mysterious world.
Only very resilient species of plant life – which there are – can survive. One of the very special understory encounters is the walking palm. This plant, in a very creature-like way, literally paces up and down the shady forest in search of light, quickly growing new appendage roots in the direction it wishes to go (where it suspects trickles of light will be found), while losing the ‘hind’ roots that would otherwise hold it in place. It can move some 50 meters a year! The trickles of light, by the way, can be minimal, almost non-existent. And there are many plant species that have adapted to these situations. But the understory, like all rainforest environments, is a most versatile ecosystem in and of itself.
Black agouti.
And then there was light
One of the most important events in the rainforest, even more earth shattering and life changing than what to us would be a volcano erupting near our hometown, is a tree-fall. When a monstrous kapok tree, for example, crashes to the ground, it creates, in a matter of seconds, an enormous gully of light. This gush of life-giving power reverses the entire dynamics of the forest understory, and in record time, shrubs, weeds, and low forest denizens, that had been unable to conquer the dark for decades, begin to sprout, creating spectacular tangles that multiply exponentially. Fruit flies horde the dead tree’s fermented sap and bulky beetles and other colorful insects conquer the fallen trunk, to them a veritable mountain worth colonizing, to lay their eggs.
Bats and birds come in to feed and disperse seeds and before you know it, more weeds grow and flower.
The activity becomes unparalleled and continues so for years. With all the different species of animals and plants that make up any given area in a place like Yasuní, every tree-fall will lure a different, unique set of species—including those that specialize in these conditions. Fierce competition for survival will ensue and in about 80 years, we will have, once again, a dark world of quiet and calm.
Understory protagonists
Understory animals usually keep a close connection to the forest-floor. When trees fall, however, animals from the higher strata also descend to get in on the action. In tune with the mystery and darkness of this part of the forest, most understory dwellers present a camouflaged appearance. Antbirds have adapted to prey on creatures that try to escape army ant swarms that charge through the forest. Jungle Cats (five species in Yasuní) present a camouflaged appearance to hide from their prey, as do tree boas, which are bright green and disguise well at their leafy hangouts (while snakes that lurk the ground are brown). To this, add larger mammals like anteaters, giant armadillos, tapirs or peccaries and countless bat species that may be found sleeping on a fallen trunk.
