GRANTS PASS, Ore. — A watchdog group is challenging the environmentally friendly “green lumber” certification for Plum Creek Timberlands, one of the nation’s biggest landowners and timber producers.

The Center for Sustainable Economy, based in Lake Oswego, Oregon, filed the complaint Thursday with a nonprofit group that verifies whether timber producers follow standards for environmentally responsible logging, including replanting after harvest, protecting water and biological diversity, and complying with environmental laws and regulations.

The complaint covers Plum Creek logging in Oregon’s Coast Range, citing 11 civil citations over the past six years for violating state logging regulations, including four citations for exceeding the clear-cutting limit of 120 acres. The complaint includes Google Earth images showing landslides in areas stripped of trees by Plum Creek.

“The fragmentation caused by large clear-cuts is a driver of extinction for wildlife dependent upon interior forest conditions and one of the most damaging ecological impacts associated with forest operations in Oregon,” the complaint said.

The company also was cited for failing to protect riparian zones along fish-bearing streams, allowing logging road drainage into a stream and failing to notify state regulators of changes in logging operations.

Seattle-based Plum Creek said in a statement that it was aware of the complaint and reviewing it.

“Plum Creek is committed to practicing sustainable forestry where ever we operate,” company spokeswoman Kathy Budinick said in an email. “There is an established process in place for handling such complaints, and we will engage fully in the process to understand and address this complaint.”

On its website, the company states prominently that all its timberlands are certified by the nonprofit Sustainable Forestry Initiative.

The complaint demands that the Sustainable Forestry Initiative immediately suspend certification for Plum Creek in Oregon and investigate the company’s logging practices throughout the country.

Besides giving companies a way to green up their image, certification can have economic benefits. Some state and federal agencies are required to buy products that are certified as sustainable, and some businesses and retailers have sustainability policies. The Home Depot Inc., for example, says on its website that it sells only lumber certified by the Forest Stewardship Council, the other major certification body.

The timber industry started the Sustainable Forestry Initiative, but it has since become an independent nonprofit certifying more than 240 million acres of private forests. Outside auditors certify that companies conform to standards for environmentally responsible logging.

Chris Lunde, harvest manager for Blakely Tree Farms LP in Seattle, oversees compliance with Sustainable Forestry Initiative standards in Oregon. He confirmed receiving the complaint, the first in his seven years in the position.

Plum Creek has 45 days to respond, and the complaint will be taken up by an outside auditor, initiative spokeswoman Elizabeth Woodworth said.

John Talberth, president of Center for Sustainable Economy, said the group believes the Oregon violations are part of a larger nationwide problem.

“We think this is the tip of the iceberg, definitely in Oregon, but probably in other states as well,” he said. “As we know, regulations protecting state and private forest lands are far weaker than those for federal lands, and have far less citizen oversight.”