Trial maintenance would be necessary even if bikes were not allowed on the trails. However, bikers pump much more money into the forest and local economies than they pull out. 22,000 trial passes were issued. Trail access is indeed the key issue at hand. Erosion concerns are of little significance and can be effectively curbed.
Economic concerns hold no merit.
The hikers believe that since they were there first, they should have exclusive rights to land paid for and maintained by the tax payers of the state of Wisconsin. In order to maintain their position of dominance, they resort to spreading propaganda about the environment and financial costs. In the birth place of the Mountain Bike, Marin Co CA, the hatred is the highest. Many horse riders feel it is their duty to attempt to throw bikers. On a local level, hikers are not quite so spiteful but there is still tension.