Written By kris Brown.

Posted on December 29th, 2021.

Share it!

Skidder bridge replacement job done at Siuslaw Model Forest. Thank you B&B Forest Products Ltd. of Cairo, NY!

Back in July 2021, B&B Forest Products Ltd. of Cairo, NY used their FastMat Drill to build a 20-foot portable skidder bridge to replace the rotten one at Siuslaw Model Forest. This was followed by what seemed like a continuous stretch of wet weather, capped off by a nor’easter in late October. Thankfully the sun came out in November, providing the opportunity to replace the old bridge. This blog documents how they did it. 

B&B logger Mike Fabian used a mini-hydraulic excavator with a swing boom – a CAT model 308E2 CR -- to drag the bridge panels from the roadside to the stream crossing site. This was a 4500-foot trip. The bridge panels had beveled edges underneath for smoother sledding along the ground.

3 preparing abutments

Mike Fabian navigates a hazard tree with the help of spotter Kyle Cunningham (wearing orange). Limbo! 

Once at the stream crossing, Mike was replaced in the mini-excavator by Ken Rockefeller. Mike and Kyle Cunningham cleared debris by hand while Ken removed the rotten bridge panels and laid them off to the side of the trail.

3 preparing abutments

Ken removes the rotten skidder bridge panels.

With the rotten bridge panels removed and laid aside, Ken then peeled back the duff at the top of the stream banks, exposing the old bridge sills, which is what the bridge panels rest on. As outlined in Vermont’s Best Practices for Using Portable Skidder Bridges, sill logs provide three major functions: 1) Stable bearing surface for the bridge panels; 2) Prevent bridge panels from being compacted into the ground, making removal easier; 3) Prevent the ends of the bridge from being frozen into the ground during winter logging. This reduces the potential for breaking during removal.

Note that this bridge will stay in place for as long as the cants are sturdy, serving as an example of forestry best management practices (BMPs) for water quality protection. Although this bridge will receive mostly foot traffic, it was designed, built, and installed to withstand skidder traffic. It’s the real deal! 

3 preparing abutmentsAt this point, Ken is nearly done preparing the area where the bridge panels will be placed. A sill log is visible in the foreground.

After a bit of clawing and packing with the excavator bucket, site preparation was complete, and it was time to drag the panels into place.

3 preparing abutments

Panel one being dragged into place. Notice the beveled edge on the underside of the panel. Also note that a shorter 17-foot cant near the panel’s center leaves a threaded steel rod exposed on each end. This allows for hooking on with a chain.

3 preparing abutments

Panel two.

3 preparing abutments

Panel three.

After a bit of nudging the panels around, they fit tightly together, and the bridge was in position perpendicular to the stream channel. Crossing the stream at a right angle is another example of a forestry BMP.

3 preparing abutments

Bridge installation complete.

The trail segment where the excavator was working was quite wet, which resulted in some soil displacement. Ken used the bucket to smooth out and add some drainage to the work site. 

3 preparing abutments

Ken remediates the work site while Connor Young and Kelsey West from CCE Columbia-Greene look on. 

Ken improved road drainage by re-opening several water bars on his way out. Mike and Kyle removed the Limbo hazard tree. In conclusion, B&B really helped Siuslaw Model Forest and the WAC Forestry Program by constructing and placing this portable skidder bridge free of charge. We can’t thank them enough for their generosity and excellent work to promote the use of forestry BMPs.

3 preparing abutments

Ken re-opening a water bar with the excavator bucket.

3 preparing abutments

A freshly re-opened water bar.

If you want to learn more about protecting your trails and streams during a timber harvest, check out MyWoodlot.com. If your logger needs a bridge, tell them to check out the WAC Forestry bridge loan program (details on application page 2), or contact B&B Forest Products, Ltd. of Cairo, NYand ask about having one built. 


Share it!