I always thought a phone tree was:
Definition: Give the message and move on. Your business, family, church or club may deal with emergencies and celebrations better if you build a phone tree. A phone tree organizes your people to help you contact all of them. You might use a phone tree to warn employees of a road closure, to introduce new members, or for reminders on upcoming meetings or parties. Virtually everyone has a phone, so well-built phone trees succeed.
Read more: How to Build a Phone Tree | eHow.com