The declining vigour that has been noticed in sugar
maples and red spruce, both important commercially for
Eastern Canada, will spread to other trees.
Canada and the United States have pledged to cut
emissions of sulphur dioxide, the main gas that causes
acid rain, by about 50 per cent from the peak levels
of the late 1970s and early 1980s. The task force
says the cut should be closer to 90 per cent.
Canada has gone beyond its target, still precipitation
is often 10 times more acidic than unpolluted rain
water, according to the report.
"Despite the emissions reductions, the problem of
devastated forests, lakes, streams and ecosystems
due to acid rain has not been solved," the report
says. "A growing body of evidence shows that without
significant additional cuts in acid rain forming emissions
many of the problems associated with acid rain will
persist for many, many decades."
Environmentalists say governments need to place
tougher regulations on coal-fired power plants and
metal smelters, two of the big sources of acid rain
Ontario, for instance, has pledged to cut its remaining
discharges of sulphur dioxide by a further 50 per
cent by 2015, but even this might not be enough.
"There is no jurisdiction in Canada that has committed
to what is needed in emission reductions," said John
Wellner, a spokesman for Pollution Probe, a Toronto
Achieving a big cut in emissions will be expensive.
A study two years ago by the federal and provincial
governments estimated that a 75-per-cent cut would
cost $2-billion annually.
Much of the cost would be borne by coal-fired power
plants, which have the technology to cut their discharges
dramatically, but at a high price. Ontario Power Generation
is proposing new technology to cut nitrogen oxides,
another acid gas, from some of its stations at a cost
"I don't see us looking at 75 per cent to 80 per
cent [reductions] because it's well beyond our contribution
to the environmental impact," said John Earl, a spokesman
for the utility.
But the report says the reduction targets instituted
in the 1980s and early 1990s were made without the
benefit of new research showing how sensitive the
environment is to this threat.
Atlantic salmon in Nova Scotia, which spend their
early years in fresh water streams before migrating
to the ocean to mature, are suffering an enormous
loss of habitat, the report says.
A review of 49 Nova Scotia rivers that historically
supported salmon found populations extinct in 14 and
severely affected in 20. "Loss of salmon is correlated
with increased acidity," the report notes.
Watersheds in Quebec and Ontario continue to sustain
large amounts of damage from acid rain, with a loss
of fish and aquatic communities in an estimated 30,000
Acid rain also damages trees, making them less able
to resist insects, disease and drought.
Red spruce, the provincial tree of Nova Scotia,
is severely affected. The report says that since the
1960s, more than half of the large canopy red spruce
in the Adirondack Mountains of New York and Green
Mountains of Vermont have died.
In Ontario and Quebec, the productivity of hardwood
forests dominated by sugar maples is declining because
soil nutrients are leached from the ground by acid
Although most of the research on tree decline has
focused on sugar maples and red spruce, the report
says acid rain injures other species.
White birch and mountain paper birch are in decline
along the Bay of Fundy, probably because of acid fog,
which is common in the area.
The report says that, at current rates of acid deposition,
forest soils in the U.S. southeast will not have enough
reserves of calcium to support the growth of merchantable
timber within 80 to 150 years.