Drones, physics and rats: Studies show how the people of Rapa Nui made and moved the giant statues – and what caused the island’s deforestation | Hugonweb Annotated Link Bibliography
The authors show that the Easter Island statues were moved by rocking them in the vertical position. Here is a video of researchers moving a mockup.
They also showed that deforestation had to do with the invasive rat population introduced by the Polynesian colonists. The rats ate seeds and kept trees from growing back after they were cut down by the colonists.