Forests in northern nations such as Russia and Canada are worth US$250 billion a year because of services they provide by purifying water or soaking up greenhouse gases, a researcher said on Tuesday (26/09).

Mark Anielski, an ecological economist based in Edmonton, Canada, urged governments to follow suit and place value on natural services rather than go on treating them as free. "We only realise what nature is worth when its gone," he told Reuters of a study he presented to a forestry congress in Canada about the value of forests in Alaska, Russia, the Nordic nations and Canada.

It estimated that services provided by intact forests in filtering water and waste, providing habitats for animals and plants, capturing greenhouse gases and attracting tourists were worth about US$250 billion a year. He said his estimates ranged from US$145-$300 billion.

"This natural capital should be in the balance sheets of nations," he said. Such valuations would help preserve forests, for instance, and discourage logging of trees that were not replaced by new plantings. Trees store carbon dioxide, the main greenhouse gas blamed for global warming, as they grow.

The study estimated that environmental services provided by Canadas forests alone were worth about 93 billion Canadian dollars (US$83 billion) a year and that each hectare of forest was worth 160 Canadian dollars (US$143.4).

"If these ecosystem services were counted in Canada, they would amount to roughly 9 percent of GDP," he said. Countries including Sweden, Austria, Switzerland, Greece and Algeria have annual gross domestic product (GDP) of around US$250 billion. Under conventional accounting, governments can spur short-term GDP growth by axing forests for building materials or pulp. The valuations suggested by Anielski would show up longer-term risks, ranging from erosion to loss of habitats.

Other scientists are also trying to put values on natural services, ranging from mangroves to peat marshes. A UN report in January, for instance, said that coral reefs were worth $US1,000-6,000 per hectare per year -- because of services ranging from fisheries to tourism. Some scientists question the validity of assumptions underlying such estimates.

Anielski said forests could also help to counter global warming, widely blamed on a build-up of heat-trapping gases emitted by burning fossil fuels in factories, power plants and cars. "The forests and peatlands store an estimated 67 billion tonnes of carbon in Canada alone," he said, adding this was almost eight times the amount of carbon produced by human activities worldwide in 2000.
(Por Alister Doyle, Planet Ark, 27/09/2006)