There is this popular notion that the ancient inhabitants of Easter Island (also known as Rapa Nui) completely destroyed their own environment, long before the arrival of Europeans. By annihiliating the island's forests through slash-and-burn agriculture and the erection of the moai statues, they are thought to have wrecked the island's original ecosystem, thus committing "environmental suicide". With only very little remaining in the way of resources, the Rapanui supposedly killed and even ate each other, until only a very small number of them remained when Europeans first set foot on the island.
However, I have recently come across a book which makes a very persuasive case that, in fact, ancient Easter Islanders may not have committed environmental suicide after all. This book is Beverly Haun's Inventing Easter Island (2008).
First of all, Haun points out that, if you have a look at the sources for most articles and books on the alleged Easter Island catastrophe, they tend go all the way back not to eighteenth-century eyewitness accounts, but, rather, books written in the Nineties and Noughties—often, Jared Diamond's Collapse: How Societies Choose to Fail or Succeed (2005) or Richard Wright's A Short History of Progress (2005). Books like these often say their sources are eighteenth-century witness accounts, or traditional Easter Island lore, or archaeological evidence, but a bit of detective work reveals that, in fact, eighteenth-century accounts tend to be distorted to support the authors' arguments, and other pieces of "evidence" offered are also not as sound as they may seem at first. An example: Wright says that Captain Cook described the few Easter Islanders he came across as "small, lean, timid and miserable", but Haun (2008: 245-247) shows that Wright's source is not Cook himself, but Flenley and Bahn, in The Enigma of Easter Island (2003), and the latter don't say where exactly it is that Cook uses these words. It turns out the phrase appears nowhere in Cook's papers. Another example: Diamond says that there is a cave known in Rapanui language as Ana Kai Tangata, which he translates to "man eat cave". However, etymological research shows that, in fact, Ana Kai Tangata could also be translated as "cave where men eat", or even "cave where tales are told" (kai means both "to eat" and "to tell"). Not only that, but the name of the cave may simply refer to the fact that the mouth of the cave is so large that it looks like it is eating whoever enters it, and it is also possible that it was named after Kai Tangata, a legendary Polynesian chief known throughout the Eastern Pacific (Haun 2008: 252).
The list of examples like these could go on. There's also Wright's assertion that Easter Islanders ate their own dogs, despite the fact that archaeologists have never unearthed dog remains on the island—most likely, if the original settlers tried to bring dogs with them, they probably did not even survive the voyage (Haun 2008: 242-243).
However, it is still possible that Easter Island did lose some or most of its trees as a result of human settlement. One thing that does come up in eighteenth-century sources is the island's lack of trees. Sedimentary pollen deposits and large root boles embedded in hardened lava flows suggest that the island once had decent forest coverage, but George Forster, who travelled to the island on Captain Cook's ship in 1777, wrote that "there was not a tree upon the island, which exceeded the height of ten feet" (Haun 2008: 238). Ancient Easter Islanders would have used wood for building both boats and cooking fires, but also funeral pyres, as they were the only prehistoric Polynesians to cremate their dead. Also, the first settlers deliberately introduced an edible species of rat, Rattus exulans, which is likely to have had a significant impact on the environment—centuries-old gnawed seed rinds found in caves suggest that the rats quickly made short work of the island's trees, which grew too slowly to recover properly (Haun 2008: 243). Interestingly, though, it seems unlikely that the island's moai statues necessitated much wood: for one thing, it's possible that no wood at all was needed, just three ropes and eighteen men; secondly, even if wood was required, Haun (2008: 245) points out that, of the almost 900 moai found, 397 were never transported beyond their original quarries, which means wood was never required to move them, while the 500 or so statues which were moved, were created over a span of 600 years. This suggests that, on average, only one moai per year needed logs to be transported and erected.
If they did experience or cause environmental change, the islanders successfully adapted to it. To see how, and read some actual eighteenth-century descriptions of Easter Island and its inhabitants, including Captain Cook's thoughts on their potatoes, please head over to the original post.