Defenders of the Earth

MTBs erode the soil more than walkers or horses, right?

Not so, according to scientific research, which says that booted feet and hooves cause more damage. And with Wales beginning a debate on changing the law to let mountain bikers loose on footpaths, we thought it was time to scratch beneath the surface of what really causes soil erosion.

What does the science say?

The short answer is, not very much. But the little research that has been done suggests wheels do less damage than you’d think. Way back in 1994, John Wilson and Joseph Seney at Montana State University compared erosion from hikers, horses, motorbikes and off-road bikes on Montana trails.

They watered the trail to simulate wet weather and each group passed over the ground 100 times. And they found… not much. There was no statistically significant difference between hikers and mountain bikers, but horses and motorcycles did cut up the trail.

Then Aussies Luke Chiu and Lorne Kriwoken conducted a physical impact study in Wellington Park, Tasmania, published in 2013. Again, there was no difference between the level of impacts caused by mountain bikers and walkers.

Finally, Jeff Marion from the US Geological Survey looked at 125km of trail in the Big South Fork National River and Recreation Area, Tennessee and Kentucky, comparing equestrian, walking, mtb and ATV trails. And lo and behold, mtb trails had the least erosion, and computer modelling showed they suffered the least soil loss, too. So far so good…


Watch how to brake properly to avoid eroding the trails


Trails in Wales are fair game, then?

Not exactly. Chiu and Kriwoken’s Tasmania research also found that when a trail was wet, very steep or riders skidded more, erosion was worse. In fact, water could be the biggest trail destroyer of all, according to the Montana research, eclipsing the impact of either wheels or feet.

What it all means

So what are the implications for Right to Roam access and letting mountain bikers share paths with walkers?

Some trails are undoubtedly going to need more maintenance to stave off erosion. Some bridleways might need less maintenance, however, because mountain bikers won’t be limited to a fraction of trails and can spread out instead.

Really it’s education and signage that’s needed most, helping different user groups understand access restrictions and become more tolerant of one another.

Works cited:

Wilson, John, and Seney, Joseph, Erosional impact of hikers, horses, motorcycles, and off-road bicycles on mountain trails in Montana, Mountain Research and Development, Volume 14, Issue 1, p. 77-88, DOI: 10.2307/3673739, Published Feb 1994

Chiu, Luke, and Kriwoken, Lorne, Managing Recreational Mountain Biking in Wellington Park, Tasmania, Australia, Annals of Leisure Research, Volume 6, Issue 4, 2003

Olive, Nathaniel D., and Marion, Jeffrey L., The influence of use-related, environmental, and managerial factors on soil loss from recreational trails, Journal of Environmental Management, Volume 90, Issue 3, p. 1483-1493, DOI: 10.1016/j.jenvman.2008.10.004,
Published Mar 2009

  • Fluff

    Ted
    At a guess, that source may have been Mark McLure (in Oldham) or his predecessor (Oliver ?)- chairs of IMBA – who undoubtedly would have had access to that info.

  • Tim Parkin

    Just to add a bit of interest. We’ve got a lovely steep path at the back of the house on which you can’t cycle but mountain bikers sometimes do. I haven’t seen any ‘more’ damage from mountain bikers skidding that was caused by our nieces and nephew skidding down in their wellies. However, when the local hunt came down with their ‘environmentally friendly’ horses, the track was so churned up we couldn’t use it for a couple of months…

  • slam69

    Also the evidence is clear to see. Look at a local trail and a local footpath, which has the most damage? The local trails in our woods have been there for 30 years and are 300mm wide and half the time over grown. Step sideways a few feet and theres a stoned footpath 2 1/2 metres wide and no vegetation.

  • slam69

    you beat me to it

  • slam69

    Just to thrown something else into this, a Fatbike does even less damage with its wide foot print, spreading the bikes weight over a larger are = less pressure.

  • isawtman

    The Dirty Truth is that Mountain Bikes can go twice as far as a hiker. I don’t think any of those studies take that into account. All they are looking at is the damage on a certain plot of land that they ride a mountain bike over time and time again to estimate the damage. Plus, mountain bikes do a different type of damage than hiking. So that compound with hiking damage does a greater damage to the trail. Mountain bikes can create long thin channels that funnel water down the trail instead of off the trail.

  • Kevin LaRoe

    add fat bikes and we are causing even less damage!!

  • Mercutio

    I dug up the citations, since apparently they can’t be bothered to (nor did they get the correct year of publication for one of them). Of course, there may very well be other studies out there that disagree, and they’re simply not mentioning them. I also can’t vouch for whether they’re accurately summarizing the findings of these studies; I have plenty of other papers to read without adding more to the pile just for kicks.

    Wilson, John, and Seney, Joseph, Erosional impact of hikers, horses, motorcycles, and off-road bicycles on mountain trails in Montana, Mountain Research and Development, Volume 14, Issue 1, p. 77-88, DOI: 10.2307/3673739, Published Feb 1994

    Chiu, Luke, and Kriwoken, Lorne, Managing Recreational Mountain Biking in Wellington Park, Tasmania, Australia, Annals of Leisure Research, Volume 6, Issue 4, 2003

    Olive, Nathaniel D., and Marion, Jeffrey L., The influence of use-related, environmental, and managerial factors on soil loss from recreational trails, Journal of Environmental Management, Volume 90, Issue 3, p. 1483-1493, DOI: 10.1016/j.jenvman.2008.10.004,
    Published Mar 2009

  • http://www.WinterParkFatBikeSeries.com Jim

    And, now we should add another aspect to the discussion… Fat tires have substantially changed the argument, at least scientifically. 4.8″ tires rolling at 5 psi (tubeless) are very efficient and put 1/15th the pressure on the ground than any hikers toes do. With mid-fat 2.8-3.0 getting more common, maybe defining mtb to be 2.4+ is a reasonable start and then specifying sensitive areas as 4.0+ ONLY (no hikers). The last category will certainly start a valuable discussion, even if it never gets passed.

  • Paul Richardson

    Lightweight article with nothing to back it up – erosion patterns are a much more complex subject than this article suggests. However, it does identify the most active agent in most erosion and that’s water. If the suppositions in the article are to be substatiated then there needs to be some proper evidence based research behind it because, as public sector budgets are slashed, it will have a big impact on trail maintenance.

  • Ted Liddle

    I remember seeing similar evidence at a Lake District National Park presentation about 15 years ago possibly produced by a Manchester source. I will try to check this out.

  • Chris Killer

    Wheres the link to the science?