Most people probably know wood floats, but don't know how far it floats. Yet trees, in the form of driftwood, are the "Wooden Mariners" that were plying the Seven Seas long before the first human thought to take a ride on water.
I learned about seafaring trees as a boy in the late 1940s and early 1950s in western Oregon (USA), where I often visited the Pacific Ocean. The place I went to was a small, secluded beach tucked into an alcove at the base of a high, sandstone cliff, which had a narrow, mostly hidden trail leading from its top down through a dense pine forest and tall shrubs to the sandy beach. For years, a mountain of drifted trees and parts thereof lay between the base of the cliff and the beach, a seemingly impenetrable barrier over which I had to climb to reach the shore.
From whence did the trees come? How did they get to sea? How long did they travel as they circumnavigated the great waters? How did they end up here, in this great pile, this seeming graveyard upon which I now stand? Where will they go if they return to sea?
These are some of the questions I used to ponder because I also saw many a drifting tree being smashed into the rocky headlands again and again by wild waves, splintering their extremities before stranding them on a seaward-jutting premonitory. When next I visited the coast, however, they were gone. Yet seldom did I find such a mangled tree as one of these in the pile of driftwood on the beach, no matter how often I examined it.
Then, one year, the driftwood pile was gone—vanished without a trace, swept mysteriously away by a winter storm, never to return. Now past my mid-sixties, I still wonder where the driftwood trees went and what their fate was.
Besides working along the Pacific Coast for three years as a young man, I have, over the decades, crossed the Atlantic twice by ship, worked along the Mediterranean and the Red Sea, and have experienced the shores of the Indian Ocean and the Sea of Japan. But never, in all those miles of travel, have I seen the prodigious amounts of driftwood that accentuated my youthful sojourns to the shores of the Pacific Ocean, despite the fact that the ship's logs of early sea captains and the journals of explorers chronicled massive amounts of drifted wood upon many an ocean shore.
Where, I began to wonder as I traveled to distant strands, is all the driftwood that graced the memories of my childhood? Although it is today largely gone due to human interference with Nature's ancient connection between the forest and the sea, a few Wooden Mariners still ply the world's oceans as in the days of old.
Now I will tell you the seafaring part of their story. Borne on the floodwaters of rivers in near and distant lands, drifting trees, entrained in the currents of water and wind, travel the world's oceans, as they have done for millennia. In the north Pacific, for example, drifting trees that escape the inshore tidal currents enter the open ocean, where they may eventually contact the North Pacific Gyre. Once captured by this huge, circulating vortex, large trees can remain afloat for long periods and cover great distances to come ashore in such exotic places as the Hawaiian Islands. Other drifting trees that land on the shores of the Hawaiian Islands are indigenous to the Philippines, Japan, and Malaysia.
In olden times, the beached Douglas firs, western redcedars, and coast redwoods from the Pacific Northwest, of what today is the United States, were even integrated into the customs and rituals of the oceanic cultures. Ancient Hawaiians prized these huge trees because local chiefs preferred them for construction of their large, double canoes—once a symbol of wealth and power.
Meanwhile, on the eastern side of South America, seasonal floods carry drifting trees from the Amazon Basin into the Atlantic, where they begin a northward journey. There, trees from Pernambuco, a state in northeastern Brazil, and Campeche, a state in southeastern Mexico on the western part of the Yucatán peninsula, travel northward. Many come to rest on Jan Mayen, which is a fairly large island of Norwegian ownership lying north northeast of Iceland and east of Greenland. Others travel on. Wherever they land, these trees supply indigenous peoples near and above the Arctic Circle with tropical wood from which to build fires, shelters, and boats.
In other parts of the world, trees drift among islands and seamounts, where they "collect" a menagerie of species in their passing. In so doing, they act as floating islands that transport their assemblage of marine organisms hundreds of miles from their place of origin through weeks and months at sea. As a result of such travels, species from one place colonize another—an interchange that, in the march of centuries and millennia, has enriched the seas of the world. The seamounts of which I speak are submarine mountains that rise to more than 3,000 feet above the ocean floor, but whose summits remain at least 1,000 feet below the water's surface.
These Wooden Mariners in Nature's oceanic fleet also serve another purpose as they tack with wind and current around the world. They are the only solid, shade-producing structures in the open ocean, a function that draws many free-swimming fishes and other organisms to abide in their shadow as they float upon sunlit seas.
In the eastern Pacific, for example, yellowfin tuna and skipjack tuna, as well many other free-swimming forms of life, aggregate around large driftwood. Small yellowfin and skipjack are among the main species associated with driftwood in other oceans, which indicates its importance in their life histories. Yellowfin even time their migration to the continental shelf to coincide their spawning with the onset of monsoon rains and the resulting floods that carry new supplies of driftwood to the sea just as the young tunas are hatching from their eggs. The association of juvenile yellowfins with large driftwood is likely important in the successful recruitment of new members into the breeding population.
In addition to single trees navigating the open ocean, there were, once upon a time, flotillas of trees that, flushed during seasonal storms from such rivers as the Ganges, Congo, Orinoco, and Amazon, often traveled fifty to a hundred miles from shore. These flotillas were in the form of "wood islands" complete with live trees and shrubs growing upon them, among which dwelled serpents, small mammals, and birds. The vegetation received nourishment from the soil that formed while the "islands" were still in the silt-laden waters of their rivers of origin, where they were initially attached to the shore. Once at sea, however, a white beach began to encircle the margin of each raft wherever it was touched by the washing of waves and rays of the tropical sun. Some of these islands even imperiled ships, according to a sailor from centuries past, because they were large enough to be mistaken for solid ground, when in fact, they were in rapid motion.
This unpredictable danger to ships on the open seas, as well as the inconvenience of wood islands anchored in navigable rivers, became a battle cry for their destruction, a battle that was inadvertently aided by deforestation close to rivers on which the logs could be floated to mills. Today, I doubt an island of drifted trees would be allowed to form in a navigable river, were there even enough wood to create one.
Whereas these flotillas have long disappeared into the halls of navigational history because they interfered with contemporary shipping, to say nothing of deforestation, single, drifting trees are still captured by wind and current in the open seas. Yet they, too, ultimately disappear, but where do they go?
At length, drifting trees become waterlogged and sink to the ocean floor—an act that dispels a common textbook misconception in marine biology. Namely, the ocean's bottom is almost devoid of life except for the communities of bacteria and other animals that live around deep-sea, hydrothermal vents through which hot water issues in the ocean's floor. Such vents are thought of as islands of deep-ocean biological diversity.
That notwithstanding, each drifted tree that becomes waterlogged and sinks is also an island of deep-ocean biological diversity that represents carbon of terrestrial origin—a vital element in the deep-ocean food web. Wood at the interface of water and bottom sediments supplies both energy in an energy-scarce environment and a source of habitat diversity. It's not surprising, therefore, that a single, waterlogged tree on the deep-ocean floor is the focus of abundant life and intense activity. Here, deep-sea, wood-boring bivalves, living in waters ranging from depths of approximately 6,000 to 11,500 feet, rely on the sunken trees as food.
These woodborers quickly invade the sunken trees, wherein they grow rapidly, which means a once-drifting tree in the North Atlantic can become infested with a dense population in approximately three months. Such dense populations convert a sunken tree into fecal pellets that settle to the ocean floor and there attract a surprising variety of bottom-dwelling animals.
The conversion of a sunken tree into a readily available source of detritus supports the development of a complex, local community of bottom-dwelling organisms. The piles of fecal pellets, which are finely ground fragments of wood, can attract more than forty species of other deep-sea invertebrates. Chemical enrichment of the deep-ocean floor, as a result of disintegrating wood and the accumulating fecal pellets, contributes to the development of a rich, intricate fauna.
While I still don't know the origin or the routes of travel that brought driftwood to my childhood shore, at least I know what probably happened to most of it that escaped into the open ocean, there to travel at the whim of wind and water. These Wooden Mariners, whose lives begin as seeds somewhere in the sacred forests of the world, end their journeys either stranded on a distant shore, where they become part of human culture, or they reside for a time on the ocean bottom, where they feed the creatures of the deep.
While the Wooden Mariners of old plied the seas of the world in such numbers that the ocean deep was constantly supplied with the food of their bodies, that supply is rapidly dwindling and becoming more sporadic as the world's forest are ravaged to feed the insatiable coffers of industry. What will happen to the ocean ecosystem if the deep-sea, wood-dependent creatures become extinct?
To maintain healthy oceans as part of the global commons, which is the birthright of every human being, we must begin now to reconnect forests and the sea. To affect such a reconnection will require consciously, purposefully growing large, old trees to become the Wooden Mariners of the future, while allowing today's Mariners to carry out their prescribed function. Can such a thing be done? Of course it can! It is, after all, only a choice on the part of today's adults. The caveat is: whatever choice we make becomes our bequest, our legacy to all generations of the future because they must live with the consequences of our choices as their increasingly irreversible circumstances. This being the case, how shall we choose?
This essay appeared in "Trees for Life, 2007 Engagement Diary" of The Parks, Findhorn Bay, Forres, Scotland.
©chris maser 2006. All rights reserved.