Ceibo Near the Tiputini River, Ecuador 0¡38''10.2" S, 76¡08''39.5" W Moss has taken flight, lifting itself on wings so thin that light barely notices as it passes through. The sun leaves not a color but a suggestion. Leaflets spread and the moss plants soar on long strands. A fibrous anchor tethers each flier to the swarm of fungi and algae that coats every tree branch. Unlike their crouched and bowed relatives in the rest of the world, these mosses live where water has no skin, no boundary. Here the air is water.
Mosses grow like filamentous seaweeds in an open ocean. The forest presses its mouth to every creature and exhales. We draw the breath: hot; odorous; almost mammalian, seeming to flow directly from the forest''s blood to our lungs. Animate, intimate, suffocating. At noon the mosses are in flight, but we humans are supine, curled in the fecund belly of life''s modern zenith. We''re near the center of the Yasun'' Biosphere Reserve in western Ecuador. Around us grows sixteen thousand square kilometers of Amazonian forest in a national park, an ethnic reserve, and a buffer zone, connected across the Colombian and Peruvian borders to more forest that, seen through the lofty gaze of satellites, forms one of the largest green spots on the face of the Earth. Rain.
Every few hours, rain, speaking a language unique to this forest. Amazonian rain differs not just in the volume of what it has to tell-three and a half meters dropped every year, six times gray London''s count-but in its vocabulary and syntax. Invisible spores and plant chemicals mist the air above the forest canopy. These aerosols are the seeds onto which water vapor coalesces, then swells. Every teaspoon of air here has a thousand or more of these particles, a haze ten times less dense than air away from the Amazon. Wherever people aggregate in significant numbers, we loose to the sky billions of particles from engines and chimneys. Like birds in a dust bath, the vigorous flapping of our industrial lives raises a fog. Each fleck of pollution, dusty mote of soil, or spore from a woodland is a potential raindrop.
The Amazon forest is vast, and over much of its extent the air is mostly a product of the forest, not the activities of industrious birds. Winds sometimes bring pulses of dust from Africa or smog from a city, but mostly the Amazon speaks its own tongue. With fewer seeds and abundant water vapor, raindrops bloat to exceptional sizes. The rain falls in big syllables, phonemes unlike the clipped rain speech of most other landmasses. We hear the rain not through silent falling water but in the many translations delivered by objects that the rain encounters. Like any language, especially one with so much to pour out and so many waiting interpreters, the sky''s linguistic foundations are expressed in an exuberance of form: downpours turn tin roofs into sheets of screaming vibration; rain smatters onto the wings of hundreds of bats, each drop shattering, then falling into the river below the bats'' skimming flight; heavy-misted clouds sag into treetops and dampen leaves without a drop falling, their touch producing the sound of an inked brush on a page. The leaves of plants speak the rainÕs language with the most eloquence. Plant diversity here reaches levels unrivaled anywhere on Earth.
Over six hundred species of tree live in one hectare, more than in all of North America. If we survey an adjacent hectare, we add yet more species to the list. Every time I have visited, my anchor in this botanical confusion and delight is a Ceiba pentandra tree, a species that many local people call ceibo, pronounced SAY-bo. Twenty-nine paces take me around its base, steps that circle buttress roots radiating from the center, each root starting head high at the trunk, then sloping down into the forest. The trunk is three meters across, wider by half than the columns that support the Parthenon. Despite its impressive size, the tree is not nearly so ancient as the pines, olives, and redwoods that live in cold or dry climates and count their years in millennia. In the fungus- and insect-filled Amazon, few ceibo live more than a couple of hundred years. Ecologists estimate that this tree is between 150 and 250 years old.
The tree is large not because it is old but because young ceibo lance upward by two meters every year, sacrificing wood strength and chemical defenses for speed of growth. The ceiboÕs crown, its uppermost branches, form a wide dome that rises ten meters higher than the surrounding trees, themselves forty meters high, the equivalent of about ten stories in a human building. From a perch in the crown I see a forest canopy unlike that of relatively smooth-topped temperate forests. A dozen other ceibos grow between my eye and the horizon, each one a hummock protruding from the uneven, fissured surface created by the surrounding trees. The tree is a giant. An axis mundi? Perhaps, but the rain''s sound refutes any attempt to use a single idea to isolate the tree from its community. Every falling water drop is a tap against leafy drumskins. Botanical diversity is sonified, calling out under the drummer''s beat.
Every species has its rain sound, revealing the varied physicality of leaves of the ceibo tree and the many other species that live on and around its massive form. The expansive leaflets of flying moss tick under the impact of a drop. An arum leaf, an elongate heart as long as my arm, gives a took took with undertones that linger as the surface dissipates its energy. The stiff dinner-plate leaves of a neighboring plant receive the rain with a tight snap, a spatter of metallic sparks. A rosette of lance-shaped leaves sprouts from the tip of a Clavija shrub, each leaf twitching as the rain smacks the surface. The sound is flat, tup, with none of the urgency of less yielding leaves. The leaf of an Amazonian avocado plant sounds a low, clean, woody thump. These sounds come from the ceibo''s understory plants, species that root themselves under the spreading branches and amid the duffy soil around the trunk.
The water that strikes the understory has already passed across many leaves above. In the treetops most leaves have forms characteristic of the tropics: smooth surfaces ending in sharp tips or filaments. These "drip tips," combined with slick leaf surfaces, gather water, drawing it into large teardrops. As tears swell on the leaf tip, the water becomes a lens, refracting light so that an inverted image of the forest appears within. The drop has only a thin tip to hold, so every few seconds the leaf releases the accumulated water, then another lens bulges, flashing its image before falling away. The leaf thus sheds water, drying itself and slowing the growth of moisture-loving fungi and algae. These drip tips in the upper levels of the forest enlarge the already-giant raindrops, sending them down to understory plant skins. Larger leaves gather the most water and drip fastest, so the rhythms of the understory are born in the diversity of leaf shapes in the ceibo''s crown.
The myriad sizes, shapes, thicknesses, textures, and pliancies of the leaves below add texture to the sound. Even the litter sings with a vigor that I have not encountered elsewhere. This ground sound is the clack and tick of thousands of spring-wound clocks, each releasing its tension with a tschak unique to the woody muddle of the decomposing surface. In the ceibo''s crown, botanical acoustic diversity is present, but it is more subtle. Drops are smaller and create a sound like river rapids in the leaves of the many surrounding trees, obscuring variations in the sounds of individual leaves. Because I''m standing high up in the branches of an emergent tree, a tree that arches over all others, the sound of the river rapids comes from beneath my feet. I feel inverted, like an image in a teardrop, disoriented by hearing forest rain under my soles. My ascent, up a forty-meter series of metal ladders, has carried me through the rain layers: The sounds of rain on litter and understory plants fade a meter or two above the ground, replaced by the spare, irregular spat of drops on sparse leaves, stems reaching up to the light, and roots drilling down.
At twenty meters up, the foliage thickens and the rapids begin. As I climb higher, the sounds of individual trees push forward, then recede, first a speed-typist''s clatter from a strangler fig, then rasping drops glancing across hirsute vine leaves. I top the rapids'' surface and the roar moves below me, unveiling patters on fleshy orchid leaves, greasy impacts on bromeliads, and low clacks on the elephant ears of Philodendron. Every tree surface is crowded with greenery; hundreds of plant species inhabit the ceibo''s crown. Human contrivances to keep away water are useless here and dull the ears. Rain jackets may repel falling drops, but their plastic magnifies the tropical heat and sweat soaks from within. Unlike many other forests, there is so much acoustic information revealed by the rain here that the crack, puff, or smack of drops on woven polyester, nylon, and cotton become an aural barrier and distraction. The yielding, lightly textured surface of human hair and skin is silent, or nearly so.
My hands, shoulders, and face answer the rain with feeling, not sound. When Western missionaries arrived here, they insisted that their colonized, evangelized subjects wear clothing. An unintended effect of this stricture was to reorient ears toward the self and away from the forest, partly closing the door to acoustic relationship with plants and animals. My conversations with members of the Waorani, the local indigenous culture, have almost without exception included unsolicited comments about the awkwardness and constraint of the clothes required when visiting town. The Waorani.