Managing Resources

The Oregon Legislature has introduced bills to preclude all logging on steep slopes due to the tragedy in Douglas County earlier this winter. Overlooked was a nearby slide on unlogged lands that was just as severe, but in which no lives were lost.

Slides in old logged areas are more noticeable, but a tally done last fall in Washington's Gifford Pinchot National Forest showed that there were as many slides on "virgin" forests as on logged areas.

If we are to reduce the severity of landslides, perhaps we should look more closely at the wind-thrust factors. In Canada, a study shows that thinning and removing of risk trees may reduce slide damage as much as 50 percent. At Breckenridge ski area in Colorado, the vibration of trees started a slide on slopes where cleared areas of equal slope did not move. In Yosemite, an aftermath of a huge slide showed that the wind thrust factor was responsible for more extensive damage away from the steep slopes.

Before making an extreme change in forested areas, it would be desirable to test slopes on Oregon lands, thinning some slopes or selectively logging the mature trees. The remaining trees would continue to grow with deeper roots. This would prove or disprove the contention that after a dozen years the clear-cut tree roots are a hazard.

Sustained forest resources are important to the Northwest, and if we can at the same time reduce landslide damage by as much as 50 percent through selective harvesting, all will benefit.

DICK BEHM Wood products consultant Vancouver, Wash.