What rescues the group from the trees in which they are hiding?

It depends on the context and specific situation of the story. There are several potential scenarios and factors that could contribute to rescuing the group from the trees. Here are a few possibilities:

1. Another group or individual may come across them. This could be fellow survivors, search parties, or even law enforcement officers. They are alerted to the group's presence and provide assistance by helping them get down safely or offering a way out of the area.

2. Helicopters or drones might be deployed for search and rescue purposes. These aerial vehicles locate the group in the trees and lower rescue ropes or extendable ladders to help the group descend to safety.

3. A natural event, such as heavy rain or flooding, forces them out of the trees. The rising water levels or uncomfortable conditions make it necessary for the group to leave their hiding spot and find an alternate route or shelter.

4. An animal attack could startle the group or chase them out of the trees. This might include predatory animals, such as wolves or bears, or even aggressive smaller creatures like bees or wasps. The threat of an attack pushes the group to leave their perch and seek safer ground.

5. They discover a hidden path or escape route that leads them away from the trees. While exploring their surroundings or trying to find a way out, the group stumbles upon a hidden trail or road that eventually leads them to safety.

Remember, these are just a few possibilities, and the actual rescue method would depend on the specific context and intentions of the story.