Will clear-cutting forests increase global warming? That's a contentious issue as California, which is seeking to slash its carbon footprint, wrestles over rules to manage the state's private forests.

The Center for Biological Diversity, a Tucson-based environmental group, this week filed lawsuits against the California Department of Forestry and Fire Protection in seven California counties to halt logging plans for 5,000 acres across the Sierra Nevada and Cascade regions. The group contends that the agency approved the projects without properly analyzing carbon emissions and climate consequences under the California Environmental Quality Act.

"Clear-cutting is an abysmal practice that should have been banned long ago due to its impacts on wildlife and water quality," said Brian Nowicki, the group's California climate policy director. "Now, in an era when all land-management decisions need to be fully carbon-conscious, there is no excuse to continue to allow clear-cutting."

Sierra Pacific Industries, the timber company that is proposing the logging, responded that its harvesting would result "in a net sequestration rate of carbon dioxide that far exceeds any emissions that might occur." California requires that clear-cut areas be replanted, so that although logging results in emissions of some of the carbon stored in those trees, replanted areas would eventually compensate.

"This out-of-state organization . . . won't be happy until they have taken away every forest-related job in California," said Mark Pawlicki, director of corporate affairs and sustainability for Sierra Pacific. "The plaintiffs do not understand forestry, and they do not understand carbon sequestration."

Dave Bischel, president of the California Forestry Assn., an industry trade group, said that the logging plans "provide significant data on the carbon sequestration benefits," adding that 40% of the state's sawmills have closed since January 2000, boosting rural unemployment.

Forests act as carbon sinks, absorbing carbon dioxide from the atmosphere through photosynthesis and storing it in the trunks and leaves of trees and in shrubs and soil. Forestry experts say the state's 14 million acres of private timberland could be managed to sequester twice as much carbon as they do now. But the technicalities of how to accomplish that are a matter of bitter dispute between environmental groups, state agencies and the timber industry.

California is poised to adopt a cap-and-trade plan this year that would allow timber companies to calculate the extra carbon they obtain through changing their management practices, and then sell carbon credits or "offsets" to polluting industries, such as utilities and refineries, which are required to cut their carbon dioxide output. Several environmental groups, including the Environmental Defense Fund and the Natural Resources Defense Council, worked with the industry to fashion the rules adopted by the California Air Resources Board to govern forest offsets. But the environmental community is split, and the Center for Biological Diversity is demanding that the board rescind the rules for failing to account for their environmental effects.

The lawsuits were filed in superior courts in Amador, Calaveras, El Dorado, Modoc, Shasta, Tehama and Trinity counties. "By continuing to rubber-stamp Sierra Pacific Industries' clear-cutting plans, the Department of Forestry is chopping a gigantic hole in the credibility of California's climate policy," Nowicki said.

He added that in August, Sierra Pacific withdrew plans to log more than 1,600 acres after the Center for Biological Diversity filed lawsuits over the greenhouse gas effect. Several dozen new Sierra Pacific plans are pending.

margot.roosevelt @latimes.com