Most will disappear within decades, impairing the planet's ability to protect water, wildlife, the carbon cycle and even human life, the study, released yesterday in Nairobi, concludes.

Canada, with its expanse of virgin boreal forest, plays a key role in preserving these crucial planetary systems. The report calls for this country and the other 14 national stewards of the world's most important forests to agree to take care of them.

"Short of a miraculous transformation in the attitude of people and governments, the Earth's remaining closed-canopy forests and associated biodiversity are destined to disappear in the coming decades," says the study's foreword, written by Klaus Toepfer, the executive director of the United Nations Environment Program.

The study is the first comprehensive global snapshot of how much forest cover is left on Earth. Scientists examined satellite photographs of all the world's forests, figured out how many had enough density to support wildlife, then examined pressures that could destroy those ecosystems.

The report found that roughly 21 per cent of the planet's land area -- or 2.9 billion hectares -- is covered with what it calls closed-canopy forests, meaning that 40 per cent of the forest's trees are interlocked. That's a proxy for a forest ecosystem, untouched or replanted, healthy enough to support wildlife and protect watersheds.

Most of the forests are in just 15 countries. Russia has the greatest area of canopy forests, followed by Canada and Brazil. Together, the three countries have nearly half the canopied forests in the world.

Also on the list are the United States, Democratic Republic of Congo, China, Indonesia, Mexico, Peru, Colombia, Bolivia, Venezuela, India, Australia and Papua New Guinea.

The report says the forests in these countries are so important that "the international community, in co-operation with these 15 national governments, should develop a comprehensive forest strategy for conservation and management of the remaining closed forests."

Only a small percentage of these canopy forests are protected. Globally, there are formal bans on tree removal in just over 9 per cent. The proportion ranges from about 20 per cent in South America to less than 4 per cent in Europe and Asia. In North and Central America, it is only 7.4 per cent.

A diverse range of threats put forests across the globe at risk, including poverty-stricken families who need wood to survive and multinational logging companies out for a quick profit.

About half the closed-canopy forests in Asia are under moderate to high threat from logging. Another major threat in Asia is its population growth: The forested land is expected to be needed to grow food.

The goal of the UNEP study is to pinpoint where conservation funds can be spent to protect forests most worth saving. Nick Nuttall, a spokesman for UNEP, said yesterday the organization is counting on steps taken during climate-change convention negotiations in Bonn last month.

There, the world's most powerful governments agreed to spend money on transferring new technology to developing countries in a bid to reduce the need to burn fossil fuels. That money, in turn, could be aimed at the countries that have forests that matter most.

Closed forests

Closed forests are a clear indication of a healthy ecosystem beneath the trees. The grey areas on the map indicate closed forests in North America. These are areas where 40 per cent or more of tree crowns are interlocked.

The global picture

Just over 20 percent of the world's land mass lies under covered forest. The data below illustrates the top five countries and their share of the total:

Russia                                23.3%

Canada                                12.8%

Brazil                                12.6%

United States                          8.2%

Democratic Republic of the Congo       4.0%

Copyright © 2001 Globe Interactive

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