OLYMPIA — The state Forest Practices Board on Wednesday expanded the guidelines used by forest-property owners to identify potentially dangerous landslide areas.

The move, opposed by several timber companies, comes nearly eight months after the landslide in Snohomish County that killed 43 people. Previous slope failures set the stage for that catastrophic slide, according to a report issued last summer, and officials have since been considering how to better identify potentially unstable areas and ensure public safety.

In May, the state Department of Natural Resources (DNR) declared that companies intending to log near potentially dangerous landslide areas must conduct geologic reviews before getting a state logging permit.

The guidelines agreed to Wednesday will replace old ones in a chapter of the Forest Practices Board manual, a supplement to official state rules. They are intended to define more comprehensively the causes of landslides and how to identify potentially dangerous areas, such as by looking for chaotic-looking drainage areas or pooling water in certain areas of valleys and hillsides.

Though they are not binding, the new guidelines use stronger language in suggesting loggers identify potentially dangerous areas.

“When planning timber harvest and construction activities, general practitioners ... need to determine whether potentially unstable slopes and landforms exist on or around the site of their proposed activities,” reads one section of the expanded guidelines. “If so, a qualified expert may be needed to perform additional analysis.”

The guidelines were developed by a panel of experts put together by the DNR after the Oso landslide. The panel met between July and the beginning of September to research, draft and edit the guidelines.

While the board voted unanimously to adopt the guidelines, several timber companies opposed it beforehand in public testimony. Opponents described the expansion’s language as poorly written, too broad in scope and sounding more like rules than guidance.

Kevin Godbout, who testified on behalf of forest-products company Weyerhaeuser against the expanded guidelines, said the new language sounds like rules. Godbout described them as “expensive, time-consuming and in most cases, unnecessary analysis.”

Mark Pawlicki, a spokesman for forest-products company Sierra Pacific Industries, said later in the day that because the expanded guidelines are so new, his company doesn’t know what impact they will have on logging operations.

“We just would like more time to have a look at this,” said Pawlicki.

As he declared his support for the new guidelines, board member Dave Somers dismissed the concerns of Godbout of the new language being tantamount to rules.

“I think the language in manual clearly says these are guidance,” said Somers, who is also chairman of the Snohomish County Council. “The manual is guidance; it always has been, it always will be.”

Environmental advocates praised the adoption of the expanded guidelines. Peter Goldman, director of the Washington Forest Law Center, called the vote a good first step toward preventing another disaster. But Goldman, who spoke at the meeting in support of the expanded guidelines, says enforceable rules are still needed.

Goldman described the new guidelines as a shift to a different way of thinking about land use.

“The approach has always been, ‘Do your best logging it, and keep your fingers crossed,’ ” he said. “And that’s what we’re moving out of.”

“Industry obviously sees a huge amount of ground out there that they’ve been logging to date, that now they’re going to have to do all kinds of documentation,” he added. “These are a bunch of folks who fight over dollars per acre; they don’t want to have to answer those questions.”

The Forest Practices Board is an independent state agency established by law in 1974 to adopt standards for, among other things, timber harvests and some tree-thinning. The board sought to alleviate the concerns of timber companies by approving the guidelines as interim ones until some differences are smoothed out.

But, “I’m not willing to delay action on the board manual,” said Aaron Everett, the board’s chairman, when declaring his intention to support the guidelines.

Material from The Seattle Times archives is included in this story.Joseph O'Sullivan: 360-236-8268 or josullivan@seattletimes.com. On Twitter @OlympiaJoe

Four weeks for 99 cents of unlimited digital access to The Seattle Times. Try it now!