By the turn of the millennium in 1000 ad, the population was still rising and a statue-carving culture had developed. The statues were carved in Easter Island’s lone quarry and then transported to desired locations using logs as rollers. The forest stock would have been down to perhaps two-thirds of its original level and the islanders probably would have regarded as apocryphal any claims that the island was once fully forested. However, this much loss of forest cover would have begun to reduce rainfall (because low clouds could pass overhead more easily) and would also have reduced the capacity of the soil to retain water. These trends continued for the next several hundred years. The peak population (of probably between 10,000 and 14,000), the greatest intensity of statue carving, and the virtual elimination of the forest stock all occurred in the neighborhood of 1400 ad.
The subsequent 100 years on Easter Island must have been very difficult. Statue carving declined and soon ceased entirely. A new weapon, almost certainly used for hand-to-hand combat, enters the archaeological record at this time. Chickens were moved into fortified enclosures, much of the population moved into caves, and there is evidence of cannibalism from this period. The population began to decline steadily. The population was apparently still decreasing in the 18th century, because the 1774 population estimate by Cook was significantly less than Rogaveen’s estimate of 50 years earlier. In addition, Cook noted that many of the statues had been pushed over on their faces, but no such phenomenon was observed by Rogaveen. It seems likely that the middle of the 18th century was a turbulent time on Easter Island. As has been frequently observed, the Easter Island civilization temporarily surpassed its limits and crashed devastatingly.