For the purposes of defining the difference in the legalities I will define the two predominant areas as follows;
Private Riding Area
This area is a privately owned property where you have permission to ride either thru an agreement with the land owner or thru paying a fee to be allowed to ride. examples could be a friend or neighbours property or a pay per use facility/track.
On private land the requirements are at the discretion of the land owner. Typically there is no requirement for vehicle registration, license plates or liability insurance.
Public Riding Area
This area is publicly owned meaning it is crown land owned by the Province of Ontario or land owned by a municipality or conservation authority. Examples include Simcoe County Forest (County owned), Ganaraska Forest (Conservation Authority owned), Calabogie Area Forest (Province of Ontario Crown Land).
On public land the requirement is clearly spelled out in the Off Highway Vehicles Act and includes the requirement for vehicle registration, the presence of an on road or off road license plate permanently affixed to the motorcycle and valid liability insurance. Public riding areas also require all vehicles to have a spark arrested exhaust with a noise output of no more that 94 dbA as tested under SAE J1287.
From Ontario OHV Act
(2) No owner of an off-road vehicle shall permit it to be driven unless it is insured under a motor vehicle liability policy in accordance with the Insurance Act. R.S.O. 1990, c. O.4, s. 15 (2).
Production of evidence of insurance
(3) Every driver of an off-road vehicle who is not owner thereof shall, upon the request of a peace officer, surrender for inspection evidence that the vehicle is insured under a motor vehicle liability policy in accordance with the Insurance Act. R.S.O. 1990, c. O.4, s. 15 (3).
(4) Every owner of an off-road vehicle that is driven on land other than land that the owner occupies shall, upon request of a peace officer, surrender, for inspection, within seventy-two hours after the request is made, evidence that the vehicle was insured under a motor vehicle liability policy in accordance with the Insurance Act at the time it was driven. R.S.O. 1990, c. O.4, s. 15 (4).