My guess is that anywhere else she's off-leash she either is more familiar with the area (i.e. near the house or her regular exercise route) or, being out of the woods, is more open so she can see you at much greater distances. Alternatively, if you are at home when she won't come back then she is probably confident she knows where to find you when she feels like coming back. If you'd like to improve her recall, start by calling her from the end of her leash and give her praise and/or a treat when she comes. Slowly work out further until she figures out that when her name is called she will get a reward. I for one am not big on treat training alone, most dogs thrive on the praise and will come just for that, but to start with the treats do add a very nice incentive.