Frequently Asked Questions about Mountain Biking Michael
Vandeman, Ph.D. March 5, 2004
1. Why do people mountain bike?
a. They say that using a bike allows them to get much
farther, in the same amount of time, than they can by
walking. They also maintain constant pressure on land
managers, to open more and more trails to bikes. Of
course, all of these trails are already open to them, if
they choose to walk. They also frequently claim that
closing trails to bikes "excludes" them from the parks.
This could only be true if they were unable to walk. Of
course, they are able to walk. There's nothing inherently
wrong with bicycling instead of walking; we all like to
save energy, when it's appropriate. Use of a bicycle to
replace automobile use is obviously beneficial. However,
by the same token, replacing hiking with mountain biking
is obviously not beneficial.
b. They are interested in the quantity of nature they can
see, rather than the quality of their experience. While
riding a bike, especially over terrain as rough as a
trail, one has to be constantly paying attention to not
crashing. That make it almost impossible to notice much
else. By contrast, a hiker feels the ground, hears all
the sounds and smells all the odors of nature and can
stop instantly, if he/she finds something interesting.
The brain thrives on stimulation. A biker has to travel
several times as far as a hiker, to get the same
stimulation as a hiker. (And, by the same token,
motorcyclists have to travel several times as far as a
bicyclist, and an auto user several times as far as a
motorcyclist, since they are enclosed in a metal box.)
c. They are interested in thrills. Riding a bike on a trail,
especially a trail containing many obstacles, or a trail
one is not familiar with, is very challenging. (But if
mountain biking is the high point of your week, as it
seems to be for many mountain bikers, you must be leading
a pretty dull life, off of the bike!)
d. They are interested in building mountain biking skills
and competing with other mountain bikers. The thrill of
racing drives people to spend more money on their bike,
and ride it harder and more often. Racing, up to and
including the Olympics, drives a lot of mountain biking.
Of course, it is also extremely harmful to the parks and
natural areas that are used for practice! It is hard to
think of any other (legal) use of public lands, other
than hunting, that is as harmful as mountain biking.
2. What is driving the sport of mountain biking? Besides
the attraction for participants, manufacturers and
retailers of mountain bikes and mountain biking
accessories, as well as "adventure" travel guides, make
a lot of money from promoting mountain biking. Even some
auto manufacturers (e.g. Subaru) promote and sponsor
mountain biking, and try to use its popularity to sell
more cars. The tourism industry also promotes mountain
biking, among other attractions.
3. What harm does mountain biking do?
a. Most obvious is the acceleration of erosion. Knobby tires
rip into the soil, loosening it and allowing rain to wash
it away. They also create V-shaped grooves that make
walking difficult or even dangerous. The mechanical
advantage given by the gears and ball bearings allow a
mountain biker to travel several times as fast as a
hiker. Given their increased weight (rider plus bike),
this results in vastly increased momentum, and hence much
greater horizontal (shearing) forces on the soil.
(Witness the skid marks from stops, starts, and turns.)
According to Newton, every action has an equal and
opposite reaction. Mountain bikes were built much
stronger than other bikes, so that they could withstand
the greater forces they were subject to on rough trails.
These same forces, therefore, are being applied to the
trails! To give a definite number, the winner of a 20-
mile race here in Briones Regional Park averaged 13 MPH
(the speed limit is 15 MPH -- where were the park
rangers?).
b. A hiker must be very careful not to accidentally step on
small animals and plants on the trail. For a mountain
biker, it is almost impossible to avoid killing countless
animals and plants on and under the trail. They have to
pay attention to controlling the bike, and can't afford
to look carefully at what is on the trail, especially
when travelling fast. And even if they happen to see, for
example, a snake, it is hard for them to stop in time to
avoid killing it. A hiker, when crossing a creek, will
try to avoid getting wet, by crossing on stepping stones
or logs. Mountain bikers, on the other hand, simply ride
right through the creek bed, crushing any animals or
plants that happen to be there. Mountain biking magazines
are full of photos of mountain bikers throwing up spray,
as they barrel through creeks. Not only do bikes destroy
animals and plants as they ride across streams, they ride
through streams stirring up sediment. The sediment in the
water interferes with the oxygen uptake by aquatic life,
for example, killing fish- and frog eggs. Young fish,
insects, amphibians, and aquatic microorganisms are
extremely sensitive to sediment in water.
c. Bikes also allow people to travel several times as far as
a hiker. This translates into several times the impacts,
both on the trail and on the wildlife (to say nothing of
the other trail users). Existing parklands are already
inadequate to protect the wildlife that live there. When
they are crisscrossed by mountain bikers and legal or
illegal trails, their habitat becomes even more
inadequate. Mountain bikers frequently advertise rides of
20-50 miles or more. Have you ever tried to walk that far
in a day? In other words, allowing bikes in a park
greatly increases human presence in that park and drives
wildlife further from the resources that they need to
survive, including water, food, and mates.
d. Due to their width and speed, bikes can't safely pass
each other on narrow trails. Therefore, policies that
permit mountain biking also result in more habitat
destruction, as trails are widened by bikers (or by
hikers and equestrians jumping out of their way).
e. Knobby mountain bike tires are ideal for carrying mud,
and consequently exotic plants, fungi, and other
organisms from place to place, resulting in the spread
of exotic invasive species, such as weeds and Sudden
Oak Death.
f. Mountain biking is driving the very young and old off of
the trails and hence out of the parks. Even able-bodied
hikers and equestrians fear for their safety, and don't
enjoy sharing the trails with bikes. (The mountain bikers
claim that they are simply being selfish and "unwilling
to share", but actually they have no problem sharing
trails with mountain bikers; it is only their bikes that
are a problem!)
g. Mountain bikes, which are obviously built to go anywhere,
teach children and anyone else who sees them that the
rough treatment of nature is acceptable. This undoubtedly
has a negative effect on people's treatment of nature.
h. In order to mitigate bike-caused erosion, park managers
have been resorting to extreme measures -- even in some
cases putting a plastic matrix or other exotic material
under the trail (e.g. in Pleasanton Ridge Regional
Preserve, near Pleasanton, California)! It's hard to
imagine that this will have a beneficial effect on the
park and its wildlife….
i. Allowing mountain bikes in a park greatly increases the
damage to the trails, damage from "bootleg" (illegally
created) trails, and the problems of conflicts between
trail users, and hence the cost of maintaining the park.
Considering how tight park budgets are, we can't afford
the extra costs of policing, and repairing the damage
from, mountain biking.
4. Mountain bikers claim that their sport has no greater
environmental impact than hiking. Is that true? If you
read the "studies" that make that claim, you find that
they don't really compare the impacts of hiking and
mountain biking, but only the impacts per foot. If, for
a moment, we assume that the studies are correct in
their having equivalent impacts per foot, it would still
follow that mountain biking has far greater impact per
person, since mountain bikers typically travel so much
farther than hikers. Besides overlooking distances
travelled, those "studies" almost all ignore impacts on
wildlife. And they don't study mountain biking under
normal conditions -- only at a very slow speed.
Actually, the comparison with hiking is irrelevant. It
would only be relevant if we planned to allow only one
of the two, and were considering which of the two is
more harmful. In fact, no one is considering banning
hiking. We are only considering adding mountain biking.
Therefore, the only relevant question is, "Is mountain
biking harmful"? (Of course, it is!) There is only one
truly scientific study that I know of that compares the
impacts of hiking and mountain biking. It found that
mountain biking has a greater impact on elk than hiking
(Wisdom, M. J., H. K. Preisler, N. J. Cimon, B. K.
Johnson. 2004. Effects of Off-Road Recreation on Mule
Deer and Elk. Transactions of the North American
Wildlife and Natural Resource Conference 69: in press.
Wisdom et al. 2).
5. Where should mountain biking allowed? A couple of role
models for wildlife protection are Yosemite National
Park and East Bay Municipal Utility District (in
Alameda and Contra Costa counties, California). They
both restrict bicycles to paved roads, where they
can't do much harm. Somehow bicyclists have managed to
enjoy their sport for over a hundred years, without
riding off-road.
6. What should the policy be on trails? Closed to bikes,
unless marked open. Signs that say "No Bikes" are
quickly and repeatedly ripped out of the ground by
mountain bikers.
7. Isn't it discriminatory to allow hikers and equestrians
on trails, but not mountain bikers? Mountain bikers love
to say this, apparently because they think it will gain
them some sympathy. The truth is that mountain bikers
have exactly the same access to trails that everyone
else has! It is only their bikes that are banned. If
mountain bikers were really being discriminated against,
they could easily go to court to gain access. However …
they already have access to every trail in the world!
8. Don't I have a right to mountain bike on all public
lands? I am a taxpayer! The public has the right,
through its elected representatives, to restrict how
land is used. A federal court has already ruled that
there is no right to mountain bike. It is a privilege,
and any land manager who gives a good reason (such as
safety or protecting the environment) can keep bikes off
of trails (see
home.pacbell.netmtb10.htmOpen ↗).
9. Don't mountain bikers do some good things, like trail
construction and trail maintenance? Trail construction
destroys wildlife habitat both directly (by killing
plants and animals) and indirectly (by reducing the size
of the intervening "islands" of habitat). Moreover,
mountain bikers favor trails that are "twisty"
(sinuous), bumpy, and full of obstacles that provide
thrills for mountain bikers. Such designs increase
habitat destruction (by lengthening the trail) and make
the trails less useful for hikers and equestrians. Trail
maintenance sounds good, until you realize that it would
hardly be necessary, if bikes weren't allowed there. The
mountain bikers are the main reason why trail
maintenance is necessary! Trails used only by hikers
require hardly any maintenance. Therefore, admitting
bicycles to a park greatly increases its cost of
maintenance. Nothing is really "free", including trail
construction and maintenance. (How does the saying go?
"Beware of Trojans bearing gifts"?)
10. But don't mountain bikers provide added safety, by being
able to quickly summon help in the event of an
emergency? I would rather trust in a cell phone, than a
speeding mountain biker. Besides, natural areas are
already one of the safest places you can be. In over 50
years of hiking and backpacking, I have never witnessed
any situation requiring emergency aid. Most people go to
natural areas partly for solitude. If we wanted to be
around large, fast-moving pieces of machinery, we would
stay in the city!
===
I am working on creating wildlife habitat that is off-limits
to humans ("pure habitat"😉. Want to help? (I spent the
previous 8 years fighting auto dependence and road
construction.)