Trail-Building: Habitat Destruction by a Different Name
Michael J. Vandeman, Ph.D.
September 2, 2017

"Impacts on and along trails result from the trampling of hikers and pack stock and the effects of trail construction and maintenance. These impacts include the loss of vegetation and shifts in plant-species composition, exposure of bare mineral soil, soil compaction, and changes in microhabitats, including changes in draining and erosion. Where trail construction is carefully planned, most of these changes are of little concern; although pronounced. Most changes are localized and deliberate." Dawson and Hendee, 2009, pp. 423-4
"The study revealed that almost 80% of extinction research in the country focused on cute marsupials such as kangaroos and koalas, whereas not-so-adorable critters such as bats and rodents held only 11% of research time, despite making up almost half of the species examined."
     Scientists are generally honest, in what they say but not in what they choose to study. Despite a diligent search in one of the world's best libraries (the University of California, Berkeley), I wasn't able to find a single book or article on the harm done by trail-building. I notice that whenever I see a picture of a trail, I think "Oh, a trail so what?" It takes an effort of will to think about the wildlife habitat that was destroyed in order to build the trail. And the habitat destruction isn't restricted to the trail bed. As Ed Grumbine pointed out in Ghost Bears, a grizzly can hear a human from a mile away, and smell one from five miles away. And grizzlies are probably not unique in that. In other words, animals within five miles of a trail are inhibited from full use of their habitat. That is habitat destruction! If there were no trails, we would be confronted by our own destructiveness every time we entered a park. It is only because the habitat has already been destroyed for us, that we can pretend that we are doing no harm.
     So why do we build trails? It doesn't take much experimenting with cross-country travel to see that it is extremely difficult. There are many kinds of hazards biological (e.g. poison oak, poison sumac, poisonous snakes, etc.) and physical (e.g. blackberry thorns, cliffs, rivers, volcanos, etc.). It is extremely difficult to find a passable-, much less an efficient, route. It would be very difficult to communicate our location to emergency personnel, without trails. So it is unlikely that we will eliminate trails in the near future, except from areas designated off-limits to humans.
     That leaves only one option compatible with wildlife conservation: minimizing the construction, extent, and use of trails. For example, banning the use of off-road vehicles, such as bicycles, skateboards, and motorcycles would greatly reduce the use of the trails, the distance that people travel, and the harm done to the soil and the small animals and plants found on, under, or near the trails. Mountain bikers complain about being thereby "denied access", but of course they can still walk. They just can't easily travel as far as they can on a bike. On public land, especially, all trail construction should be thoroughly studied, and should be built only when officially authorized by the land manager, and only by thoroughly educated, authorized builders.
     By far the greatest threat to wildlife habitat in so-called "protected" areas would appear to be mountain biking. Motorized vehicles are generally not allowed in natural areas. The most destructive use of trails is mountain biking. Knobby tires are perfectly designed to rip up the soil. Mountain bikers, with rare honesty, call their riding "shredding". They also have a much greater range than hikers, and probably also equestrians. They also frequently ride illegally where bicycles are not allowed.
     All of this is well known. But what isn't so well known or understood is the mountain bikers' drive to build ever more trails. All park users seem to have a need for a certain amount of stimulation. A hiker or equestrian can satisfy that need on a relatively short trail, because they experience it fully, through all of their senses. They can stop instantly, and turn 360 degrees, seeing, hearing, smelling, touching, or tasting anything they choose. Mountain bikers, on the other hand, tend to ride fast, often as fast as they can, seeking what they call an "adrenaline rush". But even when riding slowly, the very nature of a bicycle requires one to focus almost 100% of his or her attention on the trail immediately in front of their front tire, or they will crash. The consequence is that they have to travel several times as far as a hiker, to have the same quantity of experience. And after riding the same trail a few times, they get bored with it and want to ride a new trail. And when they've ridden all their local trails, they begin demanding more trails to be built. Or, if their demands aren't met, they begin secretly building illegal trails, or building illegal "trail features" (jumps, berms, log bridges, teeter-totters, etc.). The rain-forests of North Vancouver are the iconic example (which destruction continues to this day), but it has been emulated by mountain bikers all over the world.
     If this were a matter of a few sites or a few trails, it wouldn't be too significant. But it's not restricted to one area. Mountain bikers, apparently ignorant of conservation biology, have destroyed thousands of square miles of wildlife habitat, and show no signs of slowing down or recognizing the harm that they are doing. IMBA (the International Mountain Bicycling Association) has been promoting mountain biking tourism, claiming that mountain biking brings economic benefits to communities that embrace it, of course ignoring the economic value of the intact ecosystems they are destroying. The mountain biking infrastructure is called "epic trails", "ride centers", "bike parks", etc. They bait their demands with offers of volunteer trail-building and trail maintenance. (But, of course, their vision of a good trail (lots of humps, twists, and turns) is quite different from what the other trail users want.)
     In the San Francisco Bay Area, projects were created to build two huge trails -- the Bay Trail and Ridge Trail -- each several hundred miles long, circling the bay near the water and along the ridgetops. The community enthusiastically voted for these projects, waxing poetic about all the "new opportunities" to "connect to nature". Actually, no new habitat was created, and the trail construction (which still continues) destroyed an enormous amount of habitat. Nevertheless, I never heard anyone complain about this. People seem to think that trails somehow thread their way through the wilderness harmlessly, without touching it.
     Haven't we already destroyed far too much wildlife habitat? Isn't it time we started telling the truth about trails and our construction and use of them?
Here are a few examples of the destructiveness of trail construction and use (for an online copy of this paper, where you can click on the links and won't have to type them, see
100 Seconds of Trail Destruction with Matty Miles:
(Can you imagine what would happen to you if you happened to be on this trail?!)
Mountain bike trail building:
Illegal mountain bike trail construction, Hop Ranch Creek Squamish BC May 27,2014:
IMBA promotes trail-building:
"Saturday is National Public Lands Day
Get connected with your local IMBA chapter or club to see if it is hosting a volunteer trail day this Saturday. Trails don't build some love for the places you love to ride!
Dig In Applications Open Through October 6
IMBA is currently accepting applications for its new Dig In Campaign - a grant program that directly supports local IMBA chhapters [sic] with actionable trail projects. The project list will be published in early October so stay tuned to see what's happening near you."
Vancouver's North Shore All Built Illegally! (The video is 51 minutes long, but every minute is worth watching. Very enlightening!):
IMBA wants to create 500 more miles of trail!:
669 miles of mountain biking trail:
San Francisco Bay Trail: 500 miles:
Bay Area Ridge Trail: 375 miles, growing to 500 miles:
Long-distance trails in the United States:
The Lost Sierra to gain 300 news miles of trail:
Examples of Destructive Trail-Building:
Illegal Trail Building in Whistler (I am in no way implying that legal trail building is acceptable! They both destroy wildlife habitat!):
Glorification of illegal trail building:
IMBA: "IMBA is currently accepting applications for its new Dig In Campaign, a grant program that directly supports local IMBA chapters with actionable trail projects. We are committed to growing access for mountain bikers and increasing the pace of new builds in the U.S." "It takes a village: that statement of wisdom is particularly true in the mountain bike community, where volunteers, experts and funders must come together to make great places to ride happen. In Wausau, WI, the Central Wisconsin Offroad Cycling Coalition (CWOCC), an IMBA chapter, recently completed a multi-year project that resulted in a pumptrack, four bike-optimized downhill trails of varying difficulty and a beginner-friendly loop, all designed by IMBA Trail Solutions."
"How To Build A Legit DH Bike Trail":
Glorifying trail-building and mountain biking:
Day in the life of a Trail Builder: the upbeat background music clearly indicates the mountain bikers' attitude: trail building legal or illegal is fun and has no moral implications
Building a Mountain Bike Flow Trail:
10 Ways to Make Your Mountain Bike Trail Awesome! Part 1:
10 Ways to Make Your Mountain Bike Trail Awesome! Part 2:
Build a Mountain Bike Trail:
Trail Building:
OUR DIRT: Mountain Bike Trail Building Documentary: no speed limit, will hit anything in the trail; too fast to appreciate anything; no knowledge of biology or conservation.
Don't forget this one. This is what "rock armored" mountain bike trails turn into during heavy rains:
Because of all the damage done to our mountain slopes from too much trail building, they are building debris flow basins in our creeks, here -- but the authorities won't stop the mountain biking... It is costing us millions of dollars....
Here is more from British Columbia:
Delta, BC... (Illegal trail damage to riparian area)
This trail build was legitimate, but shows the damage done by too many people trail building, and pulling huge roots out, in a stupid kind of challenge race to see which team can build the most trail in the shortest time. Pure mayhem at work here (all through pristine area of forest, destroying the ground cover, and digging borrow pits to collect dirt and rocks to pack on the trails): (at the .24 mark, you can see a guy just tear out a large tree root...) "When Arc'teryx challenged MEC to a trail building competition, we jumped at the chance to get dirty... plus we couldn't resist a little friendly competition. So on November 17, dozens of MEC staff and supporters met up with the NSMBA to dig, grub and mine for gold on the North Shore. Our goal was to build more trail than Arc'teryx over a few hours."
Unauthorized bike trail damages pristine habitat in Forest Park:
Tracking the environmental impact of mountain biking in bushland:
Mountain bikers are also degrading forests and thereby contributing to global warming:
The damage mountain bikers do on Fromme Mtn. Seems one builder, MW, who left the NSMBA hasn't gone away (still digging on the North Shore) -- and the NSMBA continues to give a thumbs up to this sort of digging and building:
More trenches dug in the name of "sustainable" mountain biking...:
and this is what they dug up the forest to build (video of the jump structure in action):
How many buckets of gold dirt [mineral soil] and borrow pit digging was required to pack all that dirt on the eroded mtb trail on Mt. Fromme?:
This is what the NSMBA bragged about last year... How much more this year? For your trail building files/paper to show how devastating this all is:
Pleasanton Ridge Illegal Trails - Park Ranger Helicopter Incident 1-27-12 (NICA coaches taking high school mountain bikers on an illegal ride, in violation of their own "rules"; note the nasty comments from the mountain bikers):
Robert Moor: Only a single sentence negative on trails: "[W]e leave the most destructive trails, I think, of any group of animals" p.160
Proof That High School Mountain Bike Racing Is Environmentally Destructive:
Trees are falling, due to erosion exposing their roots:
Intact forests are the key to fresh water: (click on each photo with cursor to see the story behind the illegal trail building.... some of it at night time, hiding under darkness.) This is now celebrated and applauded.... wrong became a right, overnight... This is how mountain bikers won CMHC... This is the sordid history of mountain biking on our North Shore...
So much digging for dirt to pour over their ever eroding and compacted trails. The riding style seen in the last part of this video is the reason why the trails become that way, eroded and compacted. Anyone who tries to paint this MTB sport as benign as hiking, etc. needs to watch this until their eyes pop out!:
Illegal trail building a vexing problem for public land managers:
An example of how a mountain biker role model rides:
Illegal mountain biking on Mount Royal is damaging its ecosystem, experts say. Repeatedly crossing the mountain's soil loosens tree roots, affects Laurentian flora:
North Shore Mountain Biking Association Rationalizes Its Illegal Trail-Building:
Illegal trail-building in Kelowna, BC:
Endangered bees caught in middle of plan to add mountain biking trails in Minnetonka, MN:
Habitat destruction by mountain bikers using heavy equipment on Bowen Island, BC:
Photo showing the extra habitat destroyed by a winding vs. straight trail:
A 2,000-km biking trail set to open in the Balkans:
Proposed system calls for 30 miles of new routes; seen as economic boon:
"Impacts of Off-Road Recreation [specifically, mountain bike trail-building] On Public Lands Habitat":
Landers: Urging mountain bikers onto a sustainable track:
Profiting from habitat destruction (trail-building):
In Duluth, it costs about $45,000 to build one mile of trail:
Mountain bikers build illegal trails first, then ask permission only if they get caught!: The same thing happened in both Victoria, BC and LaSalle, Ontario. Kids built dirt jumps in parks without permission. The cities razed them and the mtb kids whined...
It's not trails that disturb forest birds, but the people on them
"We believe protected areas with forbidden access are necessary and important, and that new trails into remote forest areas should not be promoted. Visitors to existing forest trails should be encouraged to adhere to a 'stay on trail' rule and refrain from roaming from designated pathways." "Mountain bike riders are currently the park's most destructive user group.'' Parks Officials: Stay Off "Rogue" Trails Ireland Is Being Blanketed in Newly-Built Singletrack Mountain Bike Trails

Illegal trail-building in the White Mountains National Forest:
"Sam Evans-Brown: If youve ever been walking and turned onto a trail that suddenly is zig-zagging, maze-like through the woods, winding crazily through the trees and doubling back on itself thats a mountain bike trail. Theyre super frustrating to walk on, because they take forever to get anywhere. Mountain bikers dont want views or point-to-point trails, they want corners, and obstacles to get over, and downhills and to ride their bikes until theyre tired and wind up back where they started. And they want it close to home which means often these trails were built in whatever woods were nearest by no matter whose they were."

“Support our stewardship efforts—maintaining and building 700 miles of backcountry trail across the state isn’t easy. Do your part.” 600-mile Lost Sierra Route would connect Truckee to Lassen

Recreationists in denial illegally constructed mountain bike trails:
Trail building is an integral part of being a mountain biker:

Organizations that promote trail-building:,,,,,,,,,,,,,


Trails Can Harm Natural Resources:,involves%20cutting%20down%20mature%20trees

Dawson, Chad P. and John C. Hendee, Wilderness Management Stewardship and Protection of Resources and Values. Golden, CO: Fulcrum Publishing, 2009.
Ehrlich, Paul R. and Ehrlich, Anne H., Extinction: The Causes and Consequences of the Disappearances of Species. New York: Random House, 1981.
Errington, Paul L., A Question of Values. Ames, Iowa: Iowa State University Press, 1987.
Flannery, Tim, The Eternal Frontier -- An Ecological History of North America and Its Peoples. New York: Grove Press, 2001.
Foreman, Dave, Confessions of an Eco-Warrior. New York: Harmony Books, 1991.

Forman, Richard T.T., Daniel Sperling, John A. Bissonette, Anthony P. Clevenger, Carol D. Cutshall, Virginia H. Dale, Lenore Fahrig, Robert L. France, Charles R. Goldman, Kevin Heanue, Julia Jones, Frederick Swanson, Thomas Turrentine, and Thomas C. Winter, Road Ecology. Island Press, 2002.
Grumbine, R.E., Ghost Bears. Covelo, CA: Island Press, 1992.
Hilty, Jody A., Annika T. H. Keeley, William Z. Lidicker Jr., and Adina M. Merenlender, Corridor Ecology - Linking Landscapes for Biodiversity Conservation and Climate Adaptation. Washington, D.C.: Island Press, 2019.
Knight, Richard L. and Kevin J. Gutzwiller, eds. Wildlife and Recreationists. Covelo, California: Island Press, 1995.
Louv, Richard, Last Child in the Woods -- Saving Our Children from Nature-Deficit Disorder. Chapel Hill, N.C.: Algonquin Books of Chapel Hill, 2005.
Moor, Robert (, On Trails. New York: Simon & Schuster, 2016.
Newsome, D., C. Davies, "A case study in estimating the area of informal trail development and associated impacts caused by mountain bike activity in John Forrest National Park, Western Australia". Journal of Ecotourism. 2009 Dec 1; 8(3):237-53.
Noss, Reed F. and Allen Y. Cooperrider, Saving Nature's Legacy: Protecting and Restoring Biodiversity. Island Press, Covelo, California, 1994.
Reed, Sarah E. and Adina M. Merenlender, "Quiet, Nonconsumptive Recreation Reduces Protected Area Effectiveness". Conservation Letters, 2008, 19.
Stone, Christopher D., Should Trees Have Standing? Toward Legal Rights for Natural Objects. Los Altos, California: William Kaufmann, Inc., 1973.
Vandeman, Michael J.,, especially,,,,, and
Ward, Peter Douglas, The End of Evolution: On Mass Extinctions and the Preservation of Biodiversity. New York: Bantam Books, 1994.
"The Wildlands Project", Wild Earth. Richmond, Vermont: The Cenozoic Society, 1994.
Wilson, Edward O., The Future of Life. New York: Alfred A. Knopf, 2002.
[NOTE: This paper can be found at, where you can follow the above links without having to type them.]