A: "In my experience, once municipalities see there's a neighborhood dispute, they decline to get involved," says Seattle attorney Ken Hart, of Larson Hart Shepherd.

Even if your local government will get involved, Hart thinks you need to do more.

"[Your situation] has gone past the point where you can rely on an agency or municipality to protect your interests in a timely fashion," Hart said. "The trees may be gone before they have time to act."

Since your neighbor shows no indication of backing down, you probably need legal muscle to sort this situation out and defend your interests. This means hiring a real-estate attorney experienced in handling boundary disputes.

Among other things, the attorney can help you research whether the neighbor might have a valid adverse-possession claim. Additionally, the attorney might be able to help you pursue a quiet title action -- basically, a lawsuit to clear the title of a specific problem -- to clarify the true boundary line.