MEDFORD — The U.S. Forest Service has proposed that nearly 3,500 miles of roads be available for highway-legal and off-highway motorized vehicles in the Rogue River-Siskiyou National Forest.

The agency’s draft plan also would designate two “motorized play” areas in the High Cascades Ranger District.

The draft plan is part of a nationwide effort to establish a designated and managed system for motorized use on national forests because increased off-highway vehicle use has caused user conflicts and resource damage.

A decision is expected in September, followed by the release of motor vehicle use routes in the forest by the end of the year, said Steve Johnson of the Forest Service.

Routes not on the maps will not be open to public motor vehicle travel, he said.

“The maps will show where you can go in a wheeled, motorized vehicle,” he said.

“Right now, everything is open unless it is posted as closed,” he said. “The change will be that everything is closed unless posted as open.”

Steve Croucher, president of the Motorcycle Riders Association, said the group will look at the plan.

“We would like to see what kind of corridors and routes are available to us,” he said. “Connectivity is a big issue with us.”

Rich Nawa, an environmental activist working with the Siskiyou Regional Education Project in Josephine County, said the agency should reduce off-highway vehicle use on what are known as serpentine trails, rich in botanical diversity.

“That’s where it needs to be emphasized. That would allow it to be done in places where the impact is relatively low. The serpentine areas need to be managed for non-motorized recreation.”

A 45-day public comment period on the plan begins Saturday. Six open houses are scheduled to review the environmental document and take public comments.

There are 5,914 miles of road and 1,155 miles of trails, including 170 miles of trails for motorized vehicles on the 1.8 million-acre forest.