Collapse_ How Societies Choose to Fail or Succeed - Jared Diamond [61]
The most dangerous part of the operation was the final tilting of the statue from a very steep angle to the vertical position, because of the risk that the statue’s momentum in that final tilt might carry it beyond the vertical and tip it off the rear of the platform. Evidently to reduce that risk, the carvers designed the statue so that it was not strictly perpendicular to its flat base but just short of perpendicular (e.g., at an angle of about 87 degrees to the base, rather than 90 degrees). In that way, when they had raised the statue to a stable position with the base flat on the platform, the body was still leaning slightly forwards and at no risk of tipping over backwards. They could then slowly and carefully lever up the front edge of the base that final few degrees, slipping stones under the front of the base to stabilize it, until the body was vertical. But tragic accidents could still occur at that last stage, as evidently happened in the attempt to erect at Ahu Hanga Te Tenga a statue even taller than Paro, which ended with its tipping over and breaking.
The whole operation of constructing statues and platforms must have been enormously expensive of food resources for whose accumulation, transport, and delivery the chiefs commissioning the statues must have arranged. Twenty carvers had to be fed for a month, they may also have been paid in food, then a transport crew of 50 to 500 people and a similar erecting crew had to be fed while doing hard physical work and thus requiring more food than usual. There must also have been much feasting for the whole clan owning the ahu, and for the clans across whose territories the statue was transported. Archaeologists who first tried to calculate the work performed, the calories burned, and hence the food consumed overlooked the fact that the statue itself was the smaller part of the operation: an ahu outweighed its statues by a factor of about 20 times, and all that stone for the ahu also had to be transported. Jo Anne Van Tilburg and her architect husband Jan, whose business it is to erect large modern buildings in Los Angeles and to calculate the work involved for cranes and elevators, did a rough calculation of the corresponding work on Easter. They concluded that, given the number and size of Easter’s ahu and moai, the work of constructing them added about 25% to the food requirements of Easter’s population over the 300 peak years of construction. Those calculations explain Chris Stevenson’s recognition that those 300 peak years coincided with the centuries of plantation agriculture in Easter’s interior uplands, producing a large food surplus over that available previously.
However, we have glossed over another problem. The statue operation required not only lots of food, but also lots of thick long ropes (made in Polynesia from fibrous tree bark) by which 50 to 500 people could drag statues weighing 10 to 90 tons, and also lots of big strong trees to obtain all the timber needed for the sleds, canoe ladders, and levers. But the Easter Island seen by Roggeveen and subsequent European visitors had very few trees, all of them small and less than 10 feet tall: the most nearly treeless island in all of Polynesia. Where were the trees that provided the required rope and timber?
Botanical surveys of plants living on Easter within the 20th century have identified only 48 native species, even the biggest of them (the toromiro, up to seven feet tall) hardly worthy of being called a tree, and the rest of them low ferns, grasses, sedges, and shrubs. However, several methods for recovering remains of vanished plants have shown within the last few decades that, for hundreds of thousands of years before human arrival and still during the early days of human settlement, Easter was not at all a barren wasteland but a subtropical forest of tall trees and woody bushes.
The first such method to yield results was the technique