Rapa Nui National Park
The moai in the park are of varying height from 2 to 20 metres (6 to 65 ft). The volcanic rock formations quarried for sculpting are a distinctive yellow-brown volcanic tuff found only at the Ranu Raraku on the southeast side of the island. Some of the moai were also carved from red scoria. The ceremonial shrines where they are erected for offering worship are known as "ahu". Of impressive size and form, they are normally built close to the coast and parallel to it. Many unfinished moai are also found in the quarries. The production and transportation of the 887 statues are considered remarkable creative and physical feats. The moai have been under restoration since 1950. The period between 1837 and 1864 was a critical time when, for reasons that remain unknown, all the standing statues were toppled (probably during the tribal wars), although with little damage. Subsequently they were retrieved and returned to their original positions during the period of restoration.
Invasive plants have been introduced for livestock grazing. Forest fires are a common feature, threatening the remaining native plant species. Archaeological investigations indicate the terrain is subject to damage from erosion and the influx of tourists.Though declared a national park in 1935, the first management plan (by CONAF) was not implemented until the 1980s. As a result of inadequate funding, conservation was initially at a low level leading international conservation agencies to provide financial and technical support. Chile responded by setting up a Rapa Nui Monuments Board which enabled actions to be taken independent of the government.