Can you camp without a permit at Forbes State Forest motorized sites in winter?

No. Forbes State Forest's designated motorized, roadside campsites are not available at all during the winter closure period, with or without a permit. The Pennsylvania Department of Conservation and Natural Resources (DCNR) states that these sites are closed for the entire winter season, not just permit-restricted.

According to the official Forbes State Forest camping page, "Forbes State Forest campsites are closed for the winter season from the last day of regular rifle deer season to April 2 annually. Forest roads do not receive winter maintenance and are not plowed. Travel at your own risk and access is not guaranteed." Source: https://www.pa.gov/agencies/dcnr/recreation/where-to-go/state-forests/find-a-forest/forbes/camping

Outside of that closure window, motorized camping is only allowed with both a reservation and a permit. The same page notes that "Motorized, roadside campsites are available from April 2 to last day of regular rifle deer season," and that camping permits and reservations are required to stay at these sites at any time they are open. Source: https://www.pa.gov/agencies/dcnr/recreation/where-to-go/state-forests/find-a-forest/forbes/camping

So there is no version of the rule that allows permit-free motorized camping during the winter closure. The closure applies to the campsites themselves, and the surrounding forest roads used to reach them are not maintained or plowed in winter, which adds a practical access barrier on top of the regulatory closure.

Primitive backpack camping is handled differently year-round. DCNR explains that backpackers may camp without a permit if staying no more than one night in an allowed location, and a free permit is only needed for an emergency point of contact, for a campfire during the spring wildfire season, or for stays of more than one night in the same spot. That primitive-camping allowance is separate from the motorized, roadside campsite program and does not create an exception to the winter closure of the designated motorized sites. Source: https://www.pa.gov/agencies/dcnr/recreation/where-to-go/state-forests/find-a-forest/forbes/camping

Anyone planning a winter trip to Forbes State Forest should rely on primitive backcountry camping rules rather than the motorized fire-ring sites, since those sites remain fully closed until April 2 each year.