Under a bill proposed by the Cabinet, authorities would place caps on the amount of carbon dioxide - a major greenhouse gas - that major industries are allowed to emit annually. The legislature is expected to approve the bill soon, officials say.

Shen Shih-hung, head of the Environmental Protection Administration, told lawmakers that companies may choose to grow trees, which can absorb carbon dioxide, on Taiwan or in mainland China and other countries to offset some of their gas emissions and reach the targets.

"Carbon dioxide emissions cause warming globally, not just confined to Taiwan," he said.

Some industries say they cannot find enough land to plant trees on Taiwan, a densely populated island of 23 million people.

Officials say oil refineries, power plants, and steel, chemical and plastics factories together accounted for more than 50 percent of the 268 million tons of greenhouse gases produced by the island in 2007.

Taiwan has pledged to gradually cut its greenhouse gases so its 2016 total will not exceed the 2008 level.

The government says it will plant 148,000 acres (60,000 hectares) of forests in the next few years to help reach that goal.

Taiwan did not sign the Kyoto Protocol, an international treaty on cutting greenhouse gas emissions.

But as a major trader, Taiwan wants to contain its greenhouse gases to prevent other countries from imposing barriers on its products on environmental grounds.