Yea, you're right....calling would have been a waste of your time but coming on a forum two days later will stop the problem...

Who to call? Forest Service in Pomeroy - they have an enforcement officer, Garfield County Sheriff -they have some deputies on duty, Asotin County Sheriff - they too have some deputies on duty, WDFW -also have the ability to enforce the law....?
I am sure you are right and the one or two guys who are paid to patrol that area likely did not drive by the guy on the ATV at the moment he was riding around, but if people call and let them know there is a problem then maybe they can put a little emphasis patrol out earlier in the year and catch one or two of the people responsible a lot of damage is done.
I guess I see it as part of our (my) responsibility to be stewards of the land where we hunt, fish, hike, camp and enjoy. If we can't be part of the solution ourselves then we have one more person to complain about when things get ruined and they begin to take away accessibility to the rest of us.
