The people guarding the road to the forest were also strong magicians and Wallace even sensed a Battle Mage acting as a leader in each group.
The forest was still about two kilometers away from the town proper but the main road to the place was already heavily guarded by these magicians and soldiers. Also, he learned that several outposts were placed almost randomly to arrest those people trying to sneak in.
Apparently, the officials were aware that if someone tried to sneak into the forest, they wouldn't use the main road as they will be heavily checked.
These people would normally try to use another path only to be detected by these magicians.