A new frontier: The wilderness above our heads

THE Crannell Giant, which had lived for 3,000 years near the Little River in Humboldt County, California, was felled by loggers in 1926. It contained about 70,000 cubic feet of wood, making it the biggest single organism ever recorded.

The largest tree alive today, the General Sherman, has about 50,000 cubic feet of wood. Its trunk is 27 feet thick at breast height. If it were cut into inch-thick planks a foot wide and they were laid end to end, the line would stretch for 125 miles. So claims Richard Preston in a new book. Subtitled “what if the last wilderness is above our heads”, The Wild Trees is a celebration of the world’s biggest trees and the dozen or so pioneering naturalists and tree-huggers who climb and study them. Described as “narrative non-fiction”, it reads like a novel, the adventures of its characters being interspersed with observations on the trees.

Some of Canada’s Douglas firs were taller than any tree alive today but all of the really big ones have been destroyed by loggers. Some of Australia’s eucalyptus regnans are giants but the blue whales of the plant kingdom are the redwoods which live along the west coast of the United States. Members of the cypress family, they first appeared about 280 million years ago, long before dinosaurs roamed the Earth. There are two species. The sequoia sempervirens, known as the California redwood, is the world’s bulkiest and heaviest tree. The sequoia giganteum, or coast redwood, is lighter but higher. Mature specimens, over 30 storeys high, are much taller than Dublin’s Millennium Spire. Some redwoods alive today may be 3,000 years old. Their exact ages can’t be determined; the inner core of an old tree dies, becoming hollow and tree-ring counting is not possible.

A redwood’s cylindrical trunk, devoid of branches for the first 200 feet or so, diverges into a multiplicity of smaller trunks towards the canopy. There may be 40 or more sub-trunks in a single tree. It takes two weeks for a drop of water to travel from the ground to the top of a redwood. Trees suffer strokes; if bubbles form in the channels feeding the crown, the flow of life-giving water is disrupted and everything above the embolism dies. But, if drawing up water is such a problem, why are redwoods so tall? The answer is that they have a trick up their sleeves; redwoods drink from the sky, taking moisture directly from the air into the leaves and exploiting the misty fogs which blow in from the Pacific. With such a lifestyle, it pays to be big.

During the 1980s, several eccentric individuals, most of them working independently, became obsessed with redwood trees. Some of these enthusiasts wanted to find the largest and tallest specimens. Redwood forests are impenetrable; many stands had never been visited, the only maps available being derived from aerial photographs. When a particularly big tree was located, it was virtually impossible to determine its height in the dense forest. However, another group of devotees were also searching for tall trees; they wanted to climb them. The specimen hunters needed the climbers to take tape measures up into tree canopies and, when the two groups combined their efforts, some remarkable discoveries were made.

The world of the tree-tops turned out to be a new frontier, an unexplored habitat, in many ways as unknown to science as the ocean floor. Lichens, mosses, fungi and a host of invertebrates have adapted to life on high. Even a species of mole and an amphibian live up there. Deposits of soil, metres thick, collect in the forks of giant trees, mini-ecosystems undisturbed for centuries.

Preston has met and interviewed most of the enthusiasts. His no-holds-barred account of the tree lovers’ personal lives is frank, almost to the point of voyeurism and some of the portrayals are not exactly flattering. The narrative reads like a thriller, with nail-biting accounts of dramatic ascents. Climbers would spend the night sleeping in hammocks tied between branches at the tops of trees. A giant, known as Telperion, was a candidate for the title of “world’s tallest tree”.

Although it was leaning dangerously and on the brink of falling, climbers ascended into its crown, remaining overnight at the top. Then a storm blew in from the Pacific, threatening to topple the stricken tree. Should the drenched climbers stay put in the swaying crown or make a precarious descent in the darkness where the slightest mistake would mean certain death?

On another occasion, a couple made love in the treetops, surely have the ultimate act of unsafe sex. They were married in due course; a minister of the Sufi Universalist Church climbed 200 feet into a tree to perform the ceremony.

* Richard Preston’s The Wild Trees, a fascinating account of obsessional behaviour and the world’s greatest trees, is published by Allen Lane, price £20 (€29).