The University of Michigan requires that dogs must be kept on a leash. There are signs posted at the entrances informing walkers of the rules and it is the caretaker's job to enforce the rules. The University of Michigan Police can be contacted if there are issues.
Be considerate of the other people using Stinchfield Woods including researchers, students, hikers, clubs, organizations, youth groups, athletic teams, etc. by keeping your dog on a leash. An editorial found on Ann Arbor.com explains the frustration experienced by people who come in contact with dogs off a leash. Please help preserve the integrity of current research being conducted, protect the safety of all other people and dogs, safeguard your dog from coming in contact with herbicides or being hit by a car, and respect the rules of the University of Michigan.
I encourage you to politely ask dog owners to leash their dogs if you feel uncomfortable or threatened.