(IPS) Scientists announced on Monday that they had found the world's richest lowland forest but warned the area could disappear within three years because of logging.

A tropical lowland forest on the Indonesian island of Sumatra harbours twice as many plant species per area as any other lowland forest in the world, according to results of a field survey.

''No published records are available anywhere that show similar levels of plant species elsewhere in the world's lowland forests,'' said Andrew Gillison, author of the report and head of the Australia-based private sector Centre for Biodiversity Management, which conducted the survey with the World Wildlife Fund (WWF), a Swiss-based international advocacy group.

Tropical forests have long been known to hold the planet's richest terrestrial biological diversity. But this 1,600 sq km tract of forest, known as Tesso Nilo, was found to contain an extraordinary wealth of flora, said Gillison. In just one 200 sq m plot, researchers found 218 vascular plant species, or plants with a system of vessels to transport sap.

This was nearly twice the highest previous number of 114 species recorded using the same measuring technique elsewhere in Sumatra, he said. It was also much higher than tropical lowland forests in 19 other countries, including biologically-rich nations like Brazil, Cameroon, Malaysia, Papua New Guinea, Peru, and Thailand, WWF said in a statement.

''In short, no lowland forest known to science comes close to matching the hyper-richness of species diversity in Tesso Nilo, also home to a wide range of wildlife including elephants, tigers, gibbons, and even tapirs,'' according to WWF.

The new findings focused new urgency on saving the forest block that is being cut for timber and pulp by small-scale illegal loggers and international corporations, said Claude Martin, director-general of WWF.

The Tesso Nilo is one of Sumatra's single largest remaining blocks of lowland forest, a type of forest so endangered that the World Bank predicted last year it would be gone entirely by 2005. Gillison said that even that forecast could be too optimistic. Tesso Nilo, he warned, may be gone in less than three years.

''Giant tress were literally falling down around us as we took measurements and counted plants,'' said Gillison.

Concerned about the loss of elephant habitat, WWF asked the government of Indonesia in October 2001 to set aside almost 200,000 of the Tesso Nilo forest as a protected area. Since then, the number of illegal logging vehicles and camps inside the forest has been steadily increasing, said the environmental group.

Meanwhile, said WWF, the Indonesian company Riau Andalan Pulp and Paper (RAPP), began clear-cutting Tesso Nilo in order to convert the land into pulp and acacia plantations for pulp.

RAPP has told WWF that its logging was legal but researchers said it was unclear whether the company had official permission, since the government of Indonesia declared a moratorium on any natural forest conversion in 2000. Martin said clear-cutting has continued despite Indonesian foreign ministry announcements in December and January that illegal logging will not be tolerated.

Chris Barr, a forest policy scientist at the Indonesia-based Centre for International Forestry Research (Cifor), said that Indonesian timber and pulp companies were only part of the problem. He said the economic reforms driven by the International Monetary Fund (IMF) and World Bank in the aftermath of Indonesia's 1997-98 financial meltdown have encouraged speculative investment in the forest sector and have increased timber harvesting by debt-ridden Indonesian pulp and paper companies.

Bank and IMF officials have acknowledged that some things could have been done better but they dispute the environmentalists' conclusions.

In signing an IMF emergency financing package in 1998, the Indonesian government committed itself to a course of export-led growth. The package also included a number of policy reforms aimed specifically at restructuring Indonesia's forestry sector.

However, said Barr, the World Bank's proposed reforms largely overlooked expansion of Indonesia's pulp and paper industries and timber plantation efforts.

''This lack of attention is paradoxical given that over US$12 billion has been invested in these industries since the late 1980s and Indonesian pulp mills consumed over 100 million sq m of wood from natural forests between 1998 and 1999,'' said Barr.

Environmentalists have also blamed export credit lending agencies based in Europe, Japan and North America for encouraging deforestation in Sumatra by supporting Indonesian pulp and paper facilities without requiring any environmental safeguards or assessments.

The Indah Kiat pulp and paper facility, for example, consumes 200 sq km of old-growth tropical forest per year because its accompanying tree plantations are not yet mature, according to Stephanie Fried, a scientist at Environmental Defense, a New York-based advocacy group.

The Indah Kiat mill, which is owned by the company Asia Pulp and Paper, was financed through a US$500 million investment package supported by Canadian, Finnish, Swedish, and Spanish export finance institutions, said Fried, who has conducted research in Sumatra. German and US agencies also provided loans and guarantees to the project under separate arrangements.

Over the past 12 years, Indah Kiat has deforested 278,000 hectares, an area the size of Luxembourg, according to Cifor.