Friday, March 28, 2014

Wet Weather Soil Study - A New Trail Management Tool?

*QWR’s, Don Amador, recently helped the FS’s wet weather management study lead, Roger Poff, with field research on the Mendocino National Forest.  QWR thanks Mr. Poff, a leading soil scientist, for sharing his overview of this important project with our readers.

Roger Poff Explains Soil Study to FS Resource and Recreation Specialists

Forest Service Wet Weather Management Studies – R. Poff

OHV traffic on trails under wet conditions can damage treads and drainage structures. Determining when to open or close OHV trails has been a challenge for trail managers. Some have used seasonal closures; others have used rainfall. Both of these approaches have limitations.

 Poff Takes Soil Moisture Reading at Sample Site 

The USFS is conducting field studies to develop an evidence-based method for opening trails based on direct measurements of trail condition. Four pilot studies are underway, in the Pozo area on the Los Padres NF, the Stonyford and Upper Lake areas of the Mendocino NF, and the Sugar Pine area on the Tahoe NF.

Don Amador Pre-Sample Test Ride at Data Collection Site 

The field studies involve measuring soil strength and soil moisture, and correlating these measurements with observed levels of trail damage. This information is used to predict the risk of trail damage at different levels of soil strength and soil moisture. This prediction of risk can then be used to develop threshold values to determine when to open or close trails.

Test Site Recon with Roger Poff

This method will not be a “magic bullet” to solve all the issues related to opening and closing trails under wet conditions. However, it will be an important tool in the trail manager’s toolbox for managing trails under wet conditions.

The field studies will be completed by October 2014.

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  1. Marin County Motorcycle Association has been using a soil moisture matrix we developed with a soils engineer to manage closures on our property for 20 years. It works pretty well overall but the key is to sample soils from different locations because they are not all the same. We also learned that opening trails with good sun and wind exposure first keeps our single track trails in the trees in better shape since they stay wet longer. I'm happy to provide a contact with our soils engineer if needed.

  2. has the USFS first confirmed with sound science that a statistically relevant cuase and effect relationship exists between soil moisture and types/classification of OHV pursuant to the over-arching CFR guiding the agency?