Making moai, too, must have used huge numbers of trees. Flenley believes Easter Island is an amazing example of total deforestation, sparked by obsession. The Islanders' cult of ancestor worship cost many of them their lives. Soil erosion with no trees severely hit farming. And there were no canoes in which to escape. Trapped in a hell of their own making, the Islanders turned on each other.
Back from the brink
But if a violent, even cannibalistic, society had emerged in the 1600s, why did the Dutch in 1722 report fields of yams and healthy, fit people? The key to the recovery lies at a place called Orongo, a cliff between a volcano and a small offshore islet. There, carvings in the stones from just after the catastrophe show a birdman.
Historical accounts describe a contest between tribes - the challenge, to swim across a mile of sea and climb a cliff to bring back a bird's egg. Whichever tribe won got first call on the Island's diminishing resources. In place of warfare there was an orderly distribution of food.