As a fair-weather walker I frequently find myself on routes that have suffered from erosion due to the large numbers of people hiking along them. I wish to cause the least possible amount of further problems of this sort and I wondered what was the best way? Ought I to stick to the worn path, minimising the extent of the damage, or bypass the badly-affected areas, minimising the intensity of the erosion. Or is there some other better way?
The only real way to stop erosion is of course not to walk on them at all - but that's not really a viable solution per se!
Realistically, I'd stick to the marked, worn path. Most people will do that anyway, so you'll be treading on well worn ground which has two main advantages over trudging elsewhere:
The organisation responsible for maintaining such routes will generally only maintain the marked, well worn path - and it makes their life easier having to maintain one as oppose to a bunch of other ad-hoc worn paths that have appeared all over the place.
You'll generally cause much less damage by sticking to an already-eroded path than trudging elsewhere.
There's no real hard and fast rule of course and some people's strategies may differ. The other thing to remember is that a lot of erosion is seasonal, and therefore not as bad as you might think - in summer for instance, paths tend to get eroded a lot, but in the less popular walking seasons they're often repaired and recover.
The Leave No Trace (LNT) principles actually cover footpath erosion and give specific guidelines to minimize the impact of hikers on trails.
First and foremost, travel on the trail.
Concentrating travel on trails reduces the likelihood that multiple routes will develop and scar the landscape. It is better to have one well-designed route than many poorly chosen paths.
Second, choose where you tread on a basis of durability. How much will the ground you are walking on be affected by your footsteps?
In order of most to least durable:
Snow/Ice: these will melt and/or be snowed over before the season is over, effectively leaving zero trace of you ever being there (if there is enough snow).
Rock, sand and gravel: These are not easily affected by footprints and are considered highly durable. Prioritize rocks whenever possible to lower your impact on the trail!
If you have to step on vegetation, choose durable plants to step on. Big roots are fairly resilient, and dry grass will survive being walked on, whereas flowers and moss will quickly suffer. Avoid vegetation whenever possible, especially on steep slopes where the effects of off-trail travel are magnified.
Cryptobiotic crust (this is the first time I heard about this): according to the LNT guidelines linked above, blackish crust on sand is a tiny community of organisms that help retain moisture and protects from erosion, so, like moss, it is especially destructive to step on it. In the case of moss, avoid stepping on it because it is especially slow to grow back.
Water/mud holes: go through those mud holes, not around. Avoiding the muddy areas, alongside every hiker before and after you, only widens the trail and affects all the vegetation around it. Even if you don’t have waterproof footwear, remember that shoes dry overnight while erosion can take years to recover!
I have no direct evidence to support this, but I believe that wearing minimalistic shoes like moccasins or Vibram toe shoes reduces trail damage, as does learning to walk and run barefoot.
Soft-soled shoes conform to the terrain rather than gouging in. You also learn to walk with less impact when wearing this kind of shoe.
Going barefoot, even if not while actually hiking, teaches one not to twist, drag, or skid his feet as this will cause blisters. Once learned this smoother motion should carry over to hiking as well, at least in soft shoes that are conducive to the stride.
When walking on sidehill tread cut into a slope, walk closer to the uphill side when possible rather than towards the downslope, which can cause the tread to creep downhill over time.
Do not cut switchbacks, as this wears paths between the properly constructed tread that allows water to bypass water control devices and flow at a faster rate, causing erosion.
When possible, step over water control features like waterbars, drainage dips and checksteps rather than standing on them and wearing them down or knocking them loose. This isn't always possible, and many are constructed to handle traffic across them.