After heavy rains triggered fatal landslides in 1996, Oregon rewrote its rules on where logging can happen in landslide-prone areas.
Oregon law now clearly states that you can't log in areas with where logging could trigger a public safety risk from a certain type of landslide.
That is -- the type of landslide that sends a thin layer of soil washing down a slope and taking everything on the surface along with it. Removing trees from steep slopes can raise the risk of that kind of landslide. John Seward's job with the Oregon Department of Forestry is to avoid that risk.
Seward: "There's a link between harvesting and shallow, rapid landslides. You can't necessarily point to any landslide and say it was caused by logging but our objective is to prevent logging from exacerbating those kinds of sites."
But the landslide in Oso was a different kind of landslide. It's called a deep-seated landslide. It happened on terrain with a long history of landslides -- and where loose soil extended much deeper into the side of the slope.
Peter Goldman is the director of the Washington Forest Law Center. He says Washington has rules restricting logging above these kinds of landslides – in places known as ‘recharge zones.’ Logging in these drainage areas allows more water to flow into the landslide area below. And that can lead to a slide.
But Goldman says Oregon doesn't have rules restricting logging in these types of areas.
Goldman: "So, based on my initial review, there's nothing in Oregon that technically would have stopped the logging of a recharge area such as what occurred up in Snohomish County."
Seward says that's true. Oregon's rules are designed to address the more direct connection between logging and removing tree root systems that hold shallow soils in place.
Seward: "In terms of harvesting with those kind of deep-seated landslides like that, they're well beyond the rooting depth of any tree."
But Seward says the geology on the slope above Oso is different from anything in Oregon because it was created by glaciers that didn't come down that far south.
Seward: “In Oregon we don't have that particular landform, so therefore we don't have rules that address that particular situation because it doesn't apply here."
Oregon does have deep-seated landslides, though. Seward says even though Oregon rules don't restrict logging above those deeper landslide areas per se, they do allow him to use his judgment to recognize active landslide areas and restrict logging to protect public safety.