The fossil bones do not tell much about the environment in which T.rex lived. Bones are preserved in stream beds, flood plains, ponds, lakes and other regions were sedimentation can cover and protect the bones. In order to best determine the environment at the time of T.rex, late Cretaceous 83-65 million years ago, you need to look at the plant fossil record. This is a problem because plants require different preservation conditions than the bones do and this makes correlating plants evidence with dinosaurs difficult.