P.M.
My first thought when reading this is that your neighbor does charge you a small fee (and it sounds VERY small) for the services she renders for you. In some cultures, favors are done unasked, but there is an automatic assumption that the recipient will do something in return. It's a traditional means of building or strengthening community relationships, and of allowing poorer folks to "share the wealth" of those with more, even if modestly.
So I find myself wondering whether you've ever tried to find some material way to show your amazing neighbor your appreciation. If not, her taking things might be a small indication of resentment, or simply taking the "reciprocal" part of the transaction into her own hands. I'll bet that would stop if you were to give her some payment or gifts for her generosity.
If that's not comfortable for you, you can tell her that you don't want her favors. That may not endear you in the neighborhood, however.