Using Logs to Add Challenge
Source: IMBA Canada
Leave fallen logs on the trail. Some trail users view a fallen tree as a welcome challenge. Others see it as an insurmountable barrier and will go around, even if this requires leaving the trail. A shared trail must accommodate everyone and should offer a route without obstructions. The solution is to leave the log covering only part of the trail, allowing an unobstructed route to one side. This provides the option of passing over the log or skirting it (This will not work on narrow singletrack, however). Make sure there are good sight lines in both directions and that the route over the log is the more direct line. Try to keep the trail narrow. Don't use fallen logs to slow riders down. In fact, logs across the path may encourage cyclists to ride faster to jump them.
When is a log too large to be ridden? We've seen riders give trail workers grief for removing 3-foot high logs, so almost any size log can be in play. However, we've also seen erosion and multiple paths develop around the end of deadfall that obstructed the trail. One trailbuilding goal is to minimize our impact on the landscape. If fallen logs divert riders off the established tread, our impact increases.
Log ramps. A popular but misguided trail maintenance technique is to build a pile of logs to create a ramp up and over an existing fallen log. Our opinion is that these log piles are generally a bad idea. Most trails are shared use, and these flimsy ramps are a big obstacle to horses and hikers. One solution is to cut a gap and make the log pile optional. However, we've only seen three or four log piles out of hundreds that were well constructed. Throwing a bunch of rotting logs and twigs at an obstructing log and calling it trail maintenance is just being lazy. A well built log ramp will use at least 8-10-inch diameter logs. They may need to be fastened in place: use rope or wire, not dangerous spikes. Build them well, take pride in your work, and be sure to leave an easier option.
Log chokes. A series of logs staggered on either side of the trail can provide a narrow choke that enhances the ride. This strategy can slow users and add challenge. Make sure the narrowing flows naturally with the trail - otherwise people will find it annoying instead of interesting, and they may create a new route around it. Conflicts between mountain bikers and other trail users often are a result of the faster speeds that bikes travel. Just like traffic calming devices on roads, the best way we've found to slow cyclists is by narrowing the tread, creating tight points, and adding curves.
Balance beams. Logs placed lengthwise next to the trail can also provide a unique challenge. For some users the log will function as a balance beam, while others will use it as a bench to rest on. It's important to set these logs into the ground so they don't roll and to place them upslope of the trail where they won't impede drainage.
Log steps. Use large logs to construct short steps or drop-offs. This addition can challenge riders in an area without natural terrain difficulties. A six-inch-to-a-foot drop is appropriate for most users. Make sure the step fits with the overall flow of the trail. Use them in bike-length series in an area where riders won't be taken by surprise. Transitions are important: a tight turn following a step is awkward. Be sure to account for water flow.
Whether you're working with logs, rock, dirt - or all three - make sure to always to get permission before starting any trailwork.