The Bureau of Land Management has issued a new national plan for off-road vehicles that greatly expands the definition of the word "vehicle." From now on, it includes mountain bikes, in-line skates and other nonmotorized vehicles as well as those powered by something other than human arms and legs.

The strategy would not close any roads or trails, nor would it automatically limit the use of nonmotorized vehicles to established routes. What it would accomplish is to give land managers a tool for restricting such travel in instances when it causes resource damage.

Those who are accustomed to biking freely throughout the territory that is now Canyons of the Ancients National Monument are understandably concerned that their recreation will be curtailed. Any new limitations on land use are viewed with emotions ranging from suspicion to outrage.

The premise behind this new plan is a sensible one, though. It makes a great deal of sense to allow or restrict activities based on the impact they create on public lands, rather than to lump all motorized vehicles in one class, all nonmotorized modes of transportation in another, and assume that they affect the land in the same way.

Four-wheel-drive vehicles, motorcycles and dune buggies allow drivers to move very fast over large amounts of terrain; that’s what makes them so potentially damaging. Those modes of transportation with smaller wheels are not wholly benign, however. They concentrate weight in a very small area, very quickly wearing a groove into the ground. Water begins to follow that groove and erosion begins. Because they’re narrower and lighter than motorized vehicles, they can be used in — and potentially damage — many more places.

Non-wheeled transportation should not be exempt either. A pack string can be pretty unfriendly to the environment if the person leading it isn’t paying close attention. We’ve all seen waterholes trampled to mudbogs by hooved animals (some of them loosed by recreational users who didn’t bother to close a gate), and delicate tundra soil crushed by careless hikers. Campfire rings, holes left by pothunters, random dumping grounds — there are a lot of scars on our public lands.

If this new strategy is a move toward carefully assessing results rather than unilaterally restricting entire classes of use — including grazing, extractive industries, transportation and utility corridors, as well as recreation — it’s a good thing.

If it really does allow more consistency across the West, it may ease the popular perception that some restrictions have been both arbitrary and punitive.