North Coast environmental groups have followed through on their threat to sue Cal Fire over its approval of a 400-acre logging operation within the floodplain of lower Gualala River.

The lawsuit, filed last week by Forest Unlimited and Friends of Gualala River, alleges state forestry officials failed to meet mandated safeguards and follow state environmental laws when they gave the go-ahead last month to the so-called “Dogwood” project, near the coast along the Sonoma-Mendocino county line.

The groups called out planned road building in the river floodplain, claiming such plans were exempted from state logging rules without adequate explanation from Cal Fire.

“Normally it (floodplain) would be protected,” said Peter Baye, with Friends of the Gualala River. The group is considering seeking an injunction to halt the harvest, which began more than a week ago.

Cal Fire officials were not available to comment, but Henry Alden, forest manager for Gualala Redwood Timber LLC, which owns the land, said the environmental groups misconstrued details of the harvest. The new forestry rules, adopted last year, don’t prohibit roads in floodplains, but rather limit their use, he said.

In addition, the timber company isn’t building new roads, he said, but is using existing ones and skid trails to carry out the harvest. The area has been logged multiple times in the past and is composed primarily of second-growth redwood trees, some a century old, Alden said. There are fewer than a dozen old-growth redwoods within the timber harvest plan and they will remain standing, he said.

The environmental groups’ lawsuit escalates a campaign they began against the logging project last year, after Gualala Redwood Timber Inc. purchased more than 29,000 acres of mixed redwood and Douglas fir timberland straddling the Sonoma/Mendocino county line and sought to advance the timber harvest plan created by the previous owner.

Cal Fire and timber company officials say the plan, which calls for selective logging on 330 acres of the 404 acres included in the harvest plan, provides sufficient protections for the environment. Under state forest practice rules, the 13 largest trees on each acre must be left standing, with setbacks from the river of 30 feet.

The operation must maintain 80 percent canopy cover within 150 feet of the water. It also requires a buffer area that screens logging operations from nearby Gualala Point Regional Park at the river’s mouth.

You can reach Staff Writer Glenda Anderson at 707-462-6473 or glenda.anderson@pressdemocrat.com. On Twitter @MendoReporter