Seeing the Rainforest

Stephen L. Talbott

From In Context #7 (Spring, 2002)

The following are some notes drawn from the rainforest sections of Andreas Suchantke’s book, Eco-Geography: What We See When We Look at Landscapes (Great Barrington MA: Lindisfarne, 2001).

When Andreas Suchantke walks through the Amazonian or African rainforest, he senses an entire lifeworld straining upward, seeking the light — almost, you might say, excarnating. The ecosystem has substantially detached itself from the earth, so that the walker finds himself traversing the forest's root zone. Giant, buttressing roots splay out from high up on tree trunks; the trees “seem to be standing on the earth rather than rooted in it. And, indeed, underground the roots hug the surface so closely that here and there they reemerge, coiling over the surface like great snakes” (p. 39). Everything you see immediately around you is root-like: “the hanging ropes of the lianas are scarcely distinguishable from the ubiquitous strangler fig and epiphyte tendrils, which are actually roots” (p. 40). (Epiphytes are plants growing non-parasitically upon other plants.)

Remove the thin layer of leaf debris on the forest floor, and you find an equally thin layer of rhizome-rich humus, which, if scratched away, reveals the sterile red soil immediately beneath. In the rainforest, Suchantke points out, the region of germination occurs less in the mineral-poor soil than upon it. The cycling of all important minerals occurs largely above ground. “Leaf litter and deadwood immediately fall prey to fungi, which live in such close symbiotic association with the shallow root systems of the trees that they prevent the nutrient cycles from dipping any lower and feed all decomposition products straight back into the upward nutrient stream of their host plants” (p. 112). Whatever does get into the ground is washed away by the heavy rains. “This explains why a tree can sprout only if the seed lands in the rotting remains of a fallen one” (p. 42).

Because of the continual loss of nutrients from the soil through leaching, the Amazonian rainforest would eventually face extinction if it were not for an unexpected nourishment borne on tradewinds from the northeast: mineral dust from the great sand storms of the Sahara desert.

The Earth's “death pole” [represented by the desert] is quite literally a key element in keeping the “vegetative pole” alive. This is a truly astonishing example of ecological interdependence. Here two of the Earth's large-scale ecosystems, geographically separate and widely differing in function, are seen to be so attuned to each other that their behavior can only be compared to that of organs within an organism. (p. 112)

Accordingly, the trees on Brazil’s east coast (nearest to the Sahara) are the most heavily laden with epiphytes — especially bromeliads, which lack roots and are therefore wholly dependent upon wind-borne minerals.

The curious “detachment” of the rainforest's root zone from the soil has implications for modern practice. When a tropical rainforest is cleared by burning, the mineral ash provides an immediate shot of fertility for the new crops, but the benefit is short-lived. The sun quickly burns up any remaining organic matter and the soluble minerals are leached out of the soil, leaving only insoluble iron and aluminum compounds that sometimes harden into a rock-like crust. The land is ruined. Unlike in a temperate forest, “to destroy the world above ground is to destroy everything” (p. 43).

A Separate World in the Sun

If the root layer of the rainforest is displaced upward, so, too, is the herbaceous layer. In a temperate forest the green herbs and flowers lie immediately above ground. But to see these in the rainforest you have to look upward to the “hanging gardens” in the forest canopy. There you will find all manner of epiphytes accumulating on branches, “together with a full complement of mites, springtails, and even earthworms.” Speaking of the African forest, Suchantke writes,

Ants, exclusively ground-dwellers in temperate forests, here prefer to build their nests in branches that stick out a little above the forest canopy. Many species of termites follow their example. With the grazing mammals the pattern is the same. Few are found on the ground, for example duiker, alone or in pairs, or the rare Bongo antelope, while large troupes of colobus monkeys swing through the high branches. Herbivorous apes are a characteristic phenomenon of tropical rainforests, and not only in Africa. In South Asia langurs (Presbytis) fill this role, in South America howler monkeys, as well as sloths. Particularly striking also is the fact that in both their mode of life and their physiology there are parallels between these inhabitants of the treetop meadows and the ruminants. (p. 42)

There is abundant bird life, too, high in the canopy. And “the birds share the scene with many species of frogs, which breed their tadpoles in the miniature ponds that form in the rosettes of bromeliads” (p. 110). In sum: whereas in temperate forests the layer richest in life processes and diversity of species is in or just above the ground, the tropical rainforests produce a corresponding layer in the canopy, high above ground level.

An Intense Monotony of Green

There is in all this, Suchantke notes, a remarkable paradox: “The earth's most luxuriant vegetation grows on the most infertile of soils” (p. 111). Just how luxuriant is brought home when you realize that, while rainforests account for only 3 percent of the earth's land surface, they contain almost one-third (29 percent) of terrestrial plant biomass. This mass includes a tremendous quantity of carbon (now being released into the atmosphere with the destruction of the forests) and also acts as a “gigantic saturated sponge” for water. The root systems catch much of the daily rainfall, and absorb the snow melt coming out of the mountains. The Amazon catchment area alone contains nearly one-fifth (18 percent) of all the fresh water flowing into the earth's oceans. The enormous quantity of water held by the biomass and released steadily into the atmosphere through transpiration has the same moderating effect as a large body of water, damping temperature extremes and keeping the air moist (pp. 96-97).

The vegetative lushness of the rainforest can present itself to the traveler as depressingly one-dimensional. The green leaf prevails — so much so that one can walk for hours without any change of scenery. “Finding a blossom provides very welcome relief for senses saturated by the endless monochrome of the lush foliage” (p. 100). Most blossoms, however, occur in the epiphytic layer overhead, close to the light. And even here, careful inspection reveals that the brightly colored parts are often sepals or bracts, while the blossoms themselves remain small and inconspicuous:

The blossom itself cannot attain its full expression; it is drawn down into the vegetative leaves and “swallowed.” It would seem that blossoms cannot compete with the vegetative vitality of the lower leaves; many trees only blossom once they have shed their leaves!

Some visitors find this unquenchable vegetative force oppressive. “Even scientists who have come to do research on the rainforest have been known to develop such a phobia against it that no power on earth would induce them to visit it a second time. They have the feeling of being trapped, smothered by its rampant vitality” (p. 108).

The oppressive feeling of being hemmed in that we experience in the rainforest comes not from any lack of space, but from being cut off from the light and enveloped in a vegetative realm of intense, mute, unconscious growth. Subjective as such an impression might be, it points to a real, objective danger to which anyone from more temperate parts who stays for any length of time in a rainforest is prey. The brooding closeness of the atmosphere, which persists even at night, and the eternally repeated daily alternation between dizzying heat and torrential rain dull the mind and smother all activity. A slow, inexorable fall into inertia sets in, leading ultimately to a complete disintegration of personality. Conrad's “Mistah Kurtz” is not the only one to have suffered this fate. Not for nothing are many areas of tropical West Africa called “the grave of Europeans.” (p. 40)

Suchantke relates the vegetative intensity of the rainforest to the relative scarcity of higher animal forms in the understory of the forest. In higher animals there begins to form an interior “reflective” space that is opposite to the vegetative pole—a space where growth forces are stopped and turned inward, toward sentience and consciousness. And, in any case, the protein-poor forests could not support an extensive, high-level food chain. It required the light-filled savannas to make possible the great herds of mammals evident on the African plains.

Clearing the Forest

European culture, Suchantke writes, would have been unthinkable without the clearing of the forests and the beginnings of agriculture.

Although it may be “politically incorrect” to say so, we should not be deceived by the modern city-dwellers' romantic attitudes. There is a strong desire to “go back to nature” and the forest is made the idealized focus of this longing, but the fact remains that the forest, in its natural state, provides no adequate basis for human culture of any scale, and has always been alive with dangers of one kind or another. (This earlier experience is reflected in myths and fairy tales, where the forest is always a hostile place, foreboding and full of demons and wild animals; in the forest you are likely to lose your way.) The clearing of the forest was the legitimate outward expression of an inner need human beings had to make the landscape their own, to tame the power of wild nature and set their cultural stamp on the land.

But the healthy impulse in all this gave way (in Europe as elsewhere) to ecological devastation, and Suchantke now worries that the biosphere itself may not be able to survive the current wholesale destruction of the world's forests. His own aim is to understand the forests as a necessary preliminary for a wiser human engagement with them — an engagement that would bring out their ancient virtues and help them to evolve in directions consistent with their own “striving.”

With this in view, he points to a few promising ventures in rainforest-human partnership. And he speaks of much more in this book as well, including savannas and deserts, the Great Rift Valleys of Africa and elsewhere, the ecology of New Zealand, and the role of “juvenilization” in evolution. The book is a stimulating addition to the growing literature of a new, qualitative science.