OLYMPIA — A state panel on Wednesday took steps to ensure those who would log in landslide-prone areas do a lot more research on the safety of a site.

The state Forest Practices Board unanimously approved sweeping changes in guidelines used to identify unstable slopes where a dangerous landslide could occur.

Pages of new instructions, which took effect Wednesday, could require landowners and timber firms to gather volumes of additional scientific data about areas of planned timber harvests, to demonstrate to state officials that the safety of people living nearby is not compromised.

The revised guidelines are not binding. They are intended to assist those seeking a logging permit. Their adoption represents the board’s first significant action in response to the devastating landslide in March that killed 43 people.

After the vote, Dave Somers, a board member and chairman of the Snohomish County Council, said he was “frustrated it’s taken this long, but this is a good step. It greatly improves the information that will be required to make decisions about forest practices on unstable slopes.”

Wednesday’s action drew praise from Peter Goldman, director of the Washington Forest Law Center. He has said the state should ban logging in areas of glacial deep-seated landslides like the one near Oso until all locations are clearly identified and the potential risks are better understood.

“I think the board accomplished a lot today by focusing experts on the right things to look at in these really dangerous land forms,” he said. “If this had been on the table at the time of Oso, things might have been very different.”

Karen Terwilleger, senior director of forest and environmental policy for the Washington Forest Protection Association, convinced the board to make the guidelines “interim,” so they can be tweaked in coming months should problems arise as they are implemented. The guidelines would become final next August.

“We understand the importance of dealing with this issue now,” she said.

Somers and Goldman, in separate interviews, said the board now needs to begin reviewing how the information is used by the Department of Natural Resources staff members who decide whether to issue a permit.

“This focuses the people in the field to ask the right questions, but someone can still come up with the wrong answer,” Goldman said.

The Forest Practices Board is an independent state agency that develops rules for logging on public and private land. It includes representatives of the state departments of Ecology, Agriculture and Fish and Wildlife, and of a timber products union, a small forest landowner and a county government.

In May, it began to focus in earnest on how well rules were applied in areas with deposits of glacial sediment where deep-seated landslides have occurred in the past and are at risk of reocurring.

They wanted to pay extra attention to landforms where soils overlap with, or are near, groundwater-recharge zones — where water soaks into the ground and replenishes the aquifer. Studies show that when logging is done in recharge zones, more water is absorbed by the soil. Soggier soil is less stable.

Amendments to the board manual adopted Wednesday include a more-detailed description of the relationship between deep-seated landslides and recharge zones. It also includes more guidance on assessing past landslide activity on such a site and the risk of future earth movements.

In a public hearing prior to the vote, forest landowners and representatives of timber giants Weyerhaeuser and Sierra Pacific opposed adoption of the new guidelines.

They contended that the wording is too prescriptive and tantamount to regulations rather than guidance. Complying will be costly, they said, because reams of additional information will have to be gathered as part of the logging application process.

Ken Miller, of the Washington Farm Forestry Association, said landowners support the “well-intentioned goal” of ensuring logging isn’t conducted in areas where science shows there’s a great risk of landslides.

He said he feared that an “overreaction” to the Oso tragedy was pushing the board to act too quickly and could wind up creating a “disincentive” for forest landowners to log their land.

But a slew of environmentalists urged the board to act, saying the proposed changes will vastly improve the state’s ability to keep timber harvests out of areas where they could endanger human life and public resources.

Kara Whittaker, of the Washington Forest Law Center, implored members to adopt the guidelines without delay in “honor of the 43 men, women and children who perished in the Oso landslide.”

Goldman, in his testimony, said approving them will allow people living in or near landslide-prone areas to “sleep more safely at night.”

Jerry Cornfield: 360-352-8623; jcornfield@heraldnet.com.