PORTLAND (AP) — Oregon State University has disputed the findings of state geologists who said clearcut logging on OSU land led to a landslide that recently swept through homes and temporarily closed U.S. 30 near Clatskanie.

University officials asked the state Department of Forestry to review its logging practices on the tract of land owned and managed by OSU’s College of Forestry west of Clatskanie.

The College of Forestry also will conduct its own examination of slides from clearcuts to determine how much they contributed to the landslide last week.

The Oregon Department of Geology and Mineral Industries released on its Web site a step-by-step diagram of events that led to the landslide. It shows that two small landslides from OSU clearcuts during heavy rains two weeks ago clogged a culvert just downstream.

Those smaller landslides allowed mud and water to back up for a week behind an old railroad berm that finally burst, unleashing a much more catastrophic torrent below.

But Stephen Hobbs, executive associate dean of the OSU College of Forestry, said it was unclear whether the slides from OSU land clogged the culvert, or if it was clogged already.

Hobbs is in an unusual position because he is also chairman of the Oregon Board of Forestry, an appointed commission that oversees the Oregon Department of Forestry.

“I’m not sure we understand, and we may never fully understand, the sequence of events here,” he said.

Aerial photos in the diagrams show that the railroad berm was much closer to the initial slides than identified earlier, and that, when it broke, mud and water cascaded more than a mile to reach the highway.

But OSU officials Wednesday questioned the conclusions, downplaying the possibility that their logging activities played a role. The question highlights the long-running controversy surrounding the role of logging in clearcuts.

The clearcuts involved were within the Blodgett Tract, 2,440 acres donated to the College of Forestry in 1929 and now logged to produce revenue for the university.

One of the clearcuts involved up to 58 acres and was logged in 1992, and now has young trees growing on it. The other involved 19 acres and was logged in 2004, state records show.

The ages are important because studies by the Oregon Department of Forestry suggest that clearcutting increases the risk of landslides within the 10 years after logging.

Ted Lorenson, assistant state forester at the Department of Forestry, said the agency would also review its own actions to determine whether its staff properly assessed the risk of slides from the lands logged by OSU.

Even before last week’s slide, the Department of Forestry was already reviewing logging rules enacted after fatal slides during a major 1996 rainstorm. Assessments by agency staff have suggested the rules may not be reducing the risk of slides as intended.

Lorenson and Jason Hinkle, a department geologist who has examined the slide west of Clatskanie, said that review may now be expanded to include issues that emerged from last weeks slide.