(Patrick Moore, a co-founder of Greenpeace, is president of Greenspirit, an environmental consultant to government and industry.)

It has become a principle of the environmental movement to insist that wood and paper products be certified as originating from sustained, managed forests. Movement members even created their own organization, the Forest Stewardship Council, to make the rules and hand out the certificates.

Lord help those who don't fall in line, as big-box retailers and builders discovered when Greenpeace and the Rainforest Action Network became their judge and jury--hanging corporate reputations from the rafters with the TV cameras rolling.

Many corporations felt compelled to accept restrictive buying policies for wood and paper products to demonstrate loyalty to the cause. This appears politically correct on the surface. Yet, as with so many environmental issues, it's not that simple, and the result may damage the environment rather than improve it. The environmental movement's campaign to force industry into accepting it as the only judge of sustainable forestry is pushing consumers away from renewable forest products and toward nonrenewable, energy-intensive materials such as steel, concrete and plastic.

Anti-forestry groups such as the Sierra Club and Greenpeace make endless and unreasonable demands restricting forestry practices. This is mainly why the Forest Stewardship Council has certified less than 2% of the wood and paper produced in North America.

Meanwhile, the same environmental groups won't acknowledge that some regions--such as California--already comply with government regulations that meet or exceed guidelines imposed by the Forest Stewardship Council.

Wood is the most renewable and sustainable of the major building materials. On all measures comparing the environmental effects of common building materials, wood has the least impact on total energy use, greenhouse gases, air and water pollution and solid waste.

So why isn't the environmental movement demanding that the steel and concrete industries submit to an audit for "sustainability"? Where's the green steel, concrete and plastic? These materials are nonrenewable, require vast amounts of energy to manufacture and recycle and are contributors to greenhouse gas emissions.

Why shouldn't steel and concrete manufacturers be required to reduce energy consumption and greenhouse gas emissions or face boycotts, demonstrations and restrictions? Why does the environmental movement stand silent in the face of promotional campaigns by steel and concrete interests that leverage mythical environmental claims against wood for their own commercial benefit?

Because emotive images of forests sell memberships.

The environmental movement has unfortunately led the public into believing that when people use wood, they cause the loss of forests. This widespread guilt is misplaced. North America's forests are not disappearing. In fact, there is about the same amount of forest cover today as there was 100 years ago, even though we consume more wood per capita than any other region in the world. Isn't this proof positive that forests are renewable and sustainable?

When we buy wood, we are sending a signal to plant more trees to satisfy demand. If there were no demand for wood, landowners would clear away the forest and grow something else instead.

We have powerful tools at our disposal to reduce carbon dioxide emissions and the threat of climate change. Grow more trees, and then use more wood as a substitute for materials like steel and concrete that are responsible for excessive emissions in the first place.

If the environmental movement would recognize this one fact, it would turn its anti-forestry policy on its head and redirect membership dollars to where they are most needed--promoting sound environmental choices.