/ 3 February 2005

Listening to the trees

The chain saws that are beginning to rip through the primeval forests at the heart of Africa are not only depleting the region of trees that can never be replaced. They are also destroying the branches on which global biodiversity depends.

The fate of the vast forest expanse will be discussed at a regional summit meeting in Brazzaville, the capital of the Congo Republic, this weekend.

What comes out of this six-nation meeting is of vital interest not only to the region but to the rest of the world.

The 2,6-million square kilometres of forest covering Cameroon, Central African Republic, Congo Republic, Democratic Republic of Congo, Equatorial Guinea and Gabon is one of the world’s two lungs. The Amazon forest is the other.

It is often thought of as virgin forest, unaffected by human activity, but this is becoming less true by the day. Most of the area is covered by secondary forest resulting from land-clearing for agriculture and above all, in recent decades, from logging.

”To reach the primeval forest you have to travel days by car and then on foot,” said French botanist Francis Halle, an emeritus professor from the University of Montpellier who took his study to the tops of the trees in what was known as the Canopy Raft project.

”You cannot identify a primeval forest from the air or from a satellite because the images do not permit making a distinction between the species,” he said. ”But on the ground, you know in five minutes whether it is a primeval forest. If one species is dominant, the forest is secondary.”

Halle believes that not more than 10% of the African forest, and perhaps as little as three percent, is primeval, yet it contains twice as many plant, insect, bird and animal species as the vast area of secondary growth.

Even the primeval forest is not immutable. Halle’s studies of pollen fossils, and the observations he has made on an inflatable raft perched among the tree tops shows that long before man started attacking, the forests went through various periods of glaciation, heat, aridity and humanity.

As a result, distinct zones have formed in the forest, each with their own distinctive flora and fauna, Halle said.

For example, zones in Gabon and Equatorial Guinea conserve about a thousand plant types that are not found elsewhere. The gorillas that form distinctive tribes in those countries indicate that localised areas of primeval forest followed different patterns of growth.

When the big trees of the primeval forest fall, their place is taken by plants that are greedier for light and moisture. The animals that live off the fruit and leaves of the old forest either adapt, or are driven to extinction by other species.

The human tribes of pygmies that have lived in the forest from time immemorial in harmony with nature also are disappearing. The industrial and agricultural exploitation of a forest that was never intended for such purposes are causing changes of unprecedented rapidity and amplitude.

Halle, who knows these forests as well as anyone, says he has never been a pessimist by nature.

But now, he says, ”I’m terribly pessimistic” as he seeks to prevent the ecological disaster that has followed deforestation in many other tropical areas such as Haiti or Madagascar, and the disappearance of species that may be vital to human medicine, nutrition and even survival. – Sapa-AFP