Chainsaw massacre

By Fred Pearce THE US and Canada have seriously overestimated how much timber they can harvest without harming their forests, claims a leading international science agency. Despite urging other countries to log sustainably, neither country has reliable data on the size of its own forests, how much timber grows in them or how much can be removed before biodiversity suffers. The US harvests more than 500 million cubic metres of timber a year. The government’s Forestry Service says this amount could be increased by more than 40 per cent by 2040. But a report published on the Internet this week by the International Institute for Applied Systems Analysis in Austria concludes that this increase will be possible only if serious environmental damage is done, or if protected areas are violated. For example, the plan would lead to serious deforestation in southern states such as Georgia and Mississippi. “Both the US and Canada are urging other countries to manage their forests in a sustainable way, but they do not have their own house in order,” says Sten Nilsson, the author of the report and one of the world’s leading analysts of forestry data. The problem, he says, is that national data on wood supplies take no account of government commitments to maintain tree cover, protect against erosion and sustain biodiversity in forests. Forestry scientists simply work out how much timber is growing and assume it can all be harvested. Nilsson describes the situation in Canada as “desperate”. Official statistics still refer to a 1985 study of timber growth. He believes it overestimates growth by as much as 40 per cent in some provinces and that the rate of harvesting in Canada is now approaching twice the rate of replanting. Nilsson also points out that while plundering its own forests, Canada has been “a driving force in funding model forests in a number of countries in order to illustrate how sustainable forest management should be carried out”. Thomas Schmidt, a research scientist at the US Forest Service’s experimental station in St Paul, Minnesota, helped provide data for the report. He admitted this week that US statistics on timber do not consider many factors—such as economics, accessibility and environmental restrictions—that affect the amount available for harvest. Schmidt told New Scientist that he expected “some anger” within the agency about the findings. But they would be hard to contradict, he said, since the authors had an excellent reputation and many of the figures used in the report were the agency’s own. “We need to raise our standards,” he says. Nilsson says his data also cast new doubt on the recent claim that American forests are absorbing a large proportion of the carbon dioxide emissions from the US ( Science, vol 282,
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