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Study says Pollution-Hit Trees Growing at One-Third Former Pace

January 31, 1987

TORONTO (AP) _ Trees in heavily polluted areas of Canada are growing as little as one- third the rate they did before the 1950s, and acid rain is partly to blame, a government forestry consultant said Friday.

″There is a direct link (with acid rain) near heavy pollution sources, such as a big smelter,″ said Leo Sayn-Wittgenstein, president of Dendron Resource Surveys Ltd. of Ottawa, which is completing a study for the Canadian Forestry Service on tree growth this century.

″The decline starts about 1950-1960 and has been there ever since,″ the consultant told The Associated Press.

He said damage to 3,000 trees examined from Nova Scotia to Ontario was milder in less-polluted areas. Disease, climatic changes and budworm and other insects also contributed to the stunted growth, he added.

The three-year study follows Canada’s protests to the United States this month over President Reagan’s failure to launch an agreed five-year, $5 billion cleanup of emissions thought to cause acid rain over Canada. Acid rain in formed mostly from sulfur dioxide from power plants and smelters, and nitrogen oxides from vehicles.

In his annual economic report to Congress on Thursday, Reagan repeated his view that ″scientific uncertainties″ on the cause and effect of acid rain pollution make it unwise to press ahead with a costly cleanup program.

The Canadian Embassy in Washington reacted sharply to Reagan’s position. Some 800,000 Canadian jobs are linked to the forestry industry.

″It’s killing our lakes. There is a growing body of scientific evidence to suggest it’s hurting our forests as well, and we want something done about it,″ said embassy official Jim Wright.

Deputy Prime Minister Don Mazankowski told Parliament Friday that acid rain will figure prominently at the April summit in Ottawa between Reagan and Prime Minister Brian Mulroney.

Canada claims that 50 percent of the acid rain that falls on its central and eastern provinces is caused by U.S. industry and vehicles, and that the problem has killed 1,200 lakes with another 40,000 in danger.

Mulroney’s government has pledged to cut Canadian sulfur dioxide emissions in half by 1994.

Sayn-Wittgenstein said of his tree-growth research, ″The decline since the 1950s was quite marked. It is not unusual to find trees growing at half the rate.″

In what he called the ″worst-case plots,″ trees were growing only one- third as fast as they did 40 years ago.

″It’s a warning,″ he said, recalling the speed of destruction linked to acid rain in the coniferous forests of Europe.

Dr. Carl Winget, research director for the Canadian Forestry Service, warned against drawing too many conclusions from the tree-growth study and said the overall slowdown may be more like 6 percent than 66 percent.

He said there clearly is acid rain damage, but it is more difficult to pinpoint in forests than in lakes, where fish die and acid levels can be measured.

″The real danger of acid rain is the long-term effect on soil productivity,′ ′ he said, and scientists are still collecting data on that.

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