Originally Posted by larryboy
That's kind of silly, I've never seen a motorized vehicle eat grass/weeds in one county and poop it out in another county...horses and elk do that..keep them out.
The soil (with contaminants) can get on your bike, then when it falls off or is washed off the noxious plant/weed/contaminant grows where it shouldn't. It's a pretty big issue in certain parts where I live (S. Oregon/N. California) where it kills trees at a significant rate. Not to hijack the thread, but just an FYI in case you really wondered. Port Orford Cedar Root disease is a big deal and is spread this way, and it is the reason why at certains times of the year certain areas become closed to motor vehicle traffic (when mud is slung).