Continue to wait
No sense in rushing things, lets see if the stranger turns up.
What happens next...
You manage to jimmy your way into one of the large oaks and conceal yourself from the path. You are not sure if the stranger saw you do this or not. You sit quietly for a minute but have lost track of them.
Leave the tree
Perhaps you overreacted, leave the tree and continue walking.
Search your bag
Maybe you have something with which you can defend yourself.