Few things spark controversy among trail maintenance organizations like broaching the subject of blowing leaves off hiking and mountain biking trails. As predictable as the change of seasons, each Autumn I can count on various Facebook feeds, chat rooms and discussions over beers at the local brewery turning to should you or shouldn’t you blow leaves off the trails? My initial answer to the question is definitive, “It depends.”
Arkansas gets a pretty heavy-duty leaf fall each year from pine in the lower elevations of the southern part of the state to the various oak, birch, hickory, and walnut as well as others of the highlands. Blowing the leaves off the trails can create an easy-to-see trail through the woods making it harder to get lost. It exposes roots and rocks that could be trip hazards to hikers and trail runners and allow mountain bikers to easily navigate better lines and ride faster. These are generally short-lived benefits particularly if blowing is done earlier in the season before all the leaves have fallen. Either way, it’s generally not necessary on a well-trafficked trail as the process of hiking and cycling tends to pack them down and move them although to a less severe degree.
- Blowing leaves can leave a trail “unprotected” as this video from New Jersey illustrates very well. While Arkansas does not have as intense a Winter as New Jersey, I’m sure most cold-weather trail users in Arkansas have seen the issues with “frost heave” on the trails as seen in the video.
- Another issue is that under dry conditions, most backpack blowers are capable of not only removing the leaves from the trail but also the precious dirt that lies between rocks and roots. By removing this fine dirt the leaf blowing inadvertently exposes more of the rock and roots above the dirt level (in actuality, dropping the dirt level while leaving the rocks and roots). This creates a rougher trail by further degrading it.
- Finally, under moderate rainfall, leaves protect the trail from direct water giving time for the dirt under the leaves to gradually absorb much of the water before it can run down the trail creating ruts and mud holes.
So What’s the Answer?
Occasionally blowing leaves off the trail is not a horrible thing. I’m a proponent of doing it for events like trail runs where hidden obstacles can be dangerous, but even on these occasions, it may be time to talk to the event organizer if there might be a better time for doing the event. Maybe even blowing the leaves back on the trail when the event is over is appropriate.
Here are some tips if you are going to do some leaf blowing
- Remember that if you are going to be blowing leaves off the trail, do not leave a wall of leaves along the edge of the trail, this can cause water to channel on the trail and degrade it through erosion.
- Don’t try to get every, single leaf off the trail, get enough off to expose hazards, but those new backpack blowers are strong and if you point it in the dirt, it will move the dirt.
- Only blow those areas where it is really necessary. A hard pack dirt section of a trail lacking rock and root hazards doesn’t need the blowing.
- Don’t blow during dry conditions. When the dirt is dry, it’s lighter and thus more prone to flying away with the leaves. A good rule of thumb is if any counties in your area are under a burn ban, don’t blow trails. (probably a good idea to keep the use of gas-powered equipment out of burn ban areas, too) Check for local burn bans here.
Charles Williams, the Trail Adoption Coordinator for Friends of Arkansas Singletrack in Northwest Arkansas, did an experiment on this:
I raked a 100-yard section right out of the trail on SBAT and Moonshiner’s Holler on the Back 40 system. Same exact trail surface, backslope, etc. And I monitored it all winter. Folks….there’s NO argument to be made, the sections that had leaf cover….held up MUCH better. It wasn’t even close in fact, DESPITE me wanting it to be the opposite result!
Leaving the leaves on the singletrack XC trails will go much further toward having a place to ride when we start encountering freeze/thaw, than blowing them. I proved it to myself.
The leaves help insulate the ground from the ambient air temps. It allows the ground temp to be nearer the surface (which in AR remains just under 60* most of the year…think of caves), so when it does get below freezing, it can’t freeze as deeply into the topsoil layer. It’s the deeper freezes that expand the soil and create the mushy peanut butter surface. Limit those…and the trails just hold up better over the long run.
But…you could literally ride down those sections and have soft trail where it was clear, and firm trail where the leaves were. It seems like the leaves would hold moisture, and make it worse…but they don’t.
On flow trails where speed is needed…blow the leaves. BUT…just be aware that if we get a good freeze-thaw cycle going, we have to concede that they may be closed for weeks at a time given the right circumstances. We can’t have knuckleheads out there rutting them up. WHICH IS WHY I think it’s critical that we leave the XC trails alone, so it helps us to have a place to ride and to guide tourists toward!
None of that precludes the possibility that we have a long enough cold spell with enough moisture to still have a cycle on ALL of the trails because we saw that 3-4 years ago. But…the leaves help!
My final word would be to assess the trail needs and put aside your own riding or running comfort for the long-term sustainability of the trail. Ask yourself if what you are doing is for the benefit of the trail. Are you sacrificing years of riding a great trail for a couple of months of clean, highly visible trail? Should you leaf blow the trail, well, it depends.