That's a problem up here as well. If you want to ride you are pretty much doing it illegally. All the nice trails are in municipal boundaries and my community is changing the by-laws to prevent any kind of off-road vehicle use (this is being slipped in during the off season with little public notice, I pay more attention to local and provincial politics than average, but the month it was up for review completely slipped by me), and with recent changes in the petty trespass act for private land, there have been a lot of convictions so you don't want to risk the sections of trails that go over private land. There is lots of public land, but its all leased to oil and gas, and forestry companies who are almost impossible to get permission from either because they won't give it or there is no way of contacting the right person. Not to mention our new land use framework which is still being rolled out for the regions of the province.
Part of the problem is that a lot of the guys out there are leaving garbage not picking it up. It gives everyone a bad name. The other is that the type of equipment you run determines where you can go. There are a lot of nice snowmobile trails but unless you are part of the association and run a snowmobile (other vehicles with tracks don't count) I'm told you can't go on the trail because it is leased.
You can still ride in wildland provincial parks (and there are some really nice ones) as long as you are careful to stay only on existing trails and keep your registration/insurance up to date.
I make a point of only riding where I am supposed to, to try to keep good public will. But given all the guys that think atv use is about getting drunk on a trail and leaving garbage everywhere, I think its a lost cause. Too bad AATV's get blamed for it as well.