Forget what the adage says. You may not be able to cross that bridge when you come to it. Especially if it's a log bridge over a stream in the Rogue River-Siskiyou National Forest.
Sixteen trail bridges on the High Cascades, Siskiyou Mountains and Wild Rivers ranger districts have been closed because of safety concerns.
Siskiyou Mountains Ranger District: Butte Fork bridge on Butte Fork Trail No. 957; Knox Gulch bridge on Middle Fork Trail No. 950; Marble Gulch bridge on Middle Fork Trail No. 950.
To see a copy of the closure order, which includes maps showing bridge locations, see the national forest website at www.fs.usda.gov/rogue-siskiyou.
The lion's share of the closed foot bridges are single logs which are decaying and could collapse, explained forest bridge engineer David Scovell, who conducted the bridge inspections.
"Many of the bridges were constructed in the early 1990s utilizing untreated, native, log stringers," he said. "The anticipated service life of native logs is 15 to 20 years before decay sets in and they are no longer safe to use."
Closure of 15 foot bridges was announced late Thursday. Many of the bridges on the list have been removed, and signs have been placed at appropriate trailheads warning of the bridge closures.
A 16th log bridge, over Squaw Creek near Squaw Lake in the Siskiyou Mountains district, was also removed late this summer after it was determined to be a safety hazard. It is not on the recent closure list.
"Some of these bridges are in pretty remote areas and don't get a lot of use," said Scovell, who inspected 50 of the bridges in 2010 and another half-dozen this year. There are a few more than 100 foot bridges in the forest.
Log bridges were often used in the past because they could be created from a tree near the stream, Scovell said.
"In most sites where there are log stringers, it is difficult to get anything else in there," he said. "They were very common throughout the Northwest. They would find a tree that would work, then just cut it down."
But after less than two decades, the untreated log bridges succumb to rot and bug infestation, he reiterated.
"The ends are usually the worst," he said. "With the log bridge at Squaw Creek, about three feet from each end was turning to dust."
Many of the log bridges on the west side of the forest are in better shape because they are made from treated lumber, he noted.
No decision has been made on the future of the closed bridges, said Brian Long, recreation staff officer for the Siskiyou Mountains district.
"It's primarily based on funding," he said. "We are going to identify which ones have the highest priority. We have a couple of different options, including rerouting trails and fording streams in some areas."
Meanwhile, other similar spans in the forest are currently in good shape, he said.
Reach reporter Paul Fattig at 541-776-4496 or email him at firstname.lastname@example.org.