Collapse: How Societies Choose to Fail or Succeed (20 page)

ing the early days of human settlement, Easter was not at all a barren waste
land but a subtropical forest of tall trees and woody bushes.

The first such method to yield results was the technique of pollen analysis (palynology), which involves boring out a column of sediment deposited
in a swamp or pond. In such a column, provided that it has not been shaken
or disturbed, the surface mud must have been deposited most recently,
while more deeply buried mud represents more ancient deposits. The actual age of each layer in the deposit can be dated by radiocarbon methods. There
remains the incredibly tedious task of examining tens of thousands of
pollen grains in the column under a microscope, counting them, and then identifying the plant species producing each grain by comparison with
modern pollen from known plant species. For Easter Island the first bleary-
eyed scientist to perform that task was the Swedish palynologist Olof Selling, who examined cores collected from the swamps in Rano Raraku's and
Rano Kau's craters by Heyerdahl's 1955 expedition. He detected abundant
pollen of an unidentified species of palm tree, of which Easter today has no
native species.

In 1977 and 1983 John Flenley collected many more sediment cores and
again noticed abundant palm pollen, but by good luck Flenley in 1983 also
obtained from Sergio Rapu Haoa some fossil palm nuts that visiting French
cave explorers had discovered that year in a lava cave, and he sent them to the world's leading palm expert for identification. The nuts turned out to be very similar to, but slightly larger than, those of the world's largest existing palm tree, the Chilean wine palm, which grows up to 65 feet tall and 3 feet in diameter. Subsequent visitors to Easter have found more evidence of the
palm, in the form of casts of its trunks buried in Mt. Terevaka's lava flows a
few hundred thousand years ago, and casts of its root bundles proving that
the Easter palm's trunk reached diameters exceeding seven feet. It thus
dwarfed even the Chilean palm and was (while it existed) the biggest palm
in the world.

Chileans prize their palm today for several reasons, and Easter Islanders
would have done so as well. As the name implies, the trunk yields a sweet sap that can be fermented to make wine or boiled down to make honey or sugar. The nuts' oily kernels are rated a delicacy. The fronds are ideal for
fabricating into house thatching, baskets, mats, and boat sails. And of
course the stout trunks would have served to transport and erect moai, and
perhaps to make rafts.

Flenley and Sarah King recognized pollen of five other now-extinct trees

in the sediment cores. More recently, the French archaeologist Catherine Orliac has been sieving out 30,000 fragments of wood burned to charcoal
from cores dug into Easter Island ovens and garbage heaps. With a heroism
matching that of Selling, Flenley, and King, she has compared 2,300 of those
carbonized wood fragments to wood samples of plants still existing today
elsewhere in Polynesia. In that way she has identified about 16 other plant species, most of them trees related to or the same as tree species still wide
spread in East Polynesia, that formerly grew on Easter Island as well. Thus,
Easter used to support a diverse forest.

Many of those 21 vanished species besides the palm would have been valuable to the islanders. Two of the tallest trees,
Alphitonia
cf.
zizyphoides
and
Elaeocarpus
cf.
rarotongensis
(up to 100 and 50 feet tall respectively), are
used elsewhere in Polynesia for making canoes and would have been much
better suited to that purpose than was the palm. Polynesians everywhere
make rope from the bark of the hauhau
Triumfetta semitriloba,
and that was
presumably how Easter Islanders dragged their statues. Bark of the paper
mulberry
Broussonetia papyrifera
is beaten into tapa cloth;
Psydrax odorata
has a flexible straight trunk suited for making harpoons and outriggers; the
Malay apple
Syzygium malaccense
bears an edible fruit; the oceanic rosewood
Thespesia populanea
and at least eight other species have hardwood suitable for carving and construction; toromiro yields an excellent wood for
fires, like acacia and mesquite; and the fact that Orliac recovered all of those
species as burnt fragments from fires proves that they too were used for
firewood.

The person who pored through 6,433 bones of birds and other verte
brates from early middens at Anakena Beach, probably the site of the first human landing and first settlement on Easter, was zooarchaeologist David
Steadman. As an ornithologist myself, I bow in awe before Dave's identifica
tion skills and tolerance of eye strain: whereas I wouldn't know how to tell a
robin's bone from a dove's or even from a rat's, Dave has learned how to dis
tinguish even the bones of a dozen closely related petrel species from each
other. He thereby proved that Easter, which today supports not a single
species of native land bird, was formerly home to at least six of them, in
cluding one species of heron, two chicken-like rails, two parrots, and a barn
owl. More impressive was Easter's prodigious total of at least 25 nesting
seabird species, making it formerly the richest breeding site in all of Polyne
sia and probably in the whole Pacific. They included albatross, boobies, frigatebirds, fulmars, petrels, prions, shearwaters, storm-petrels, terns, and
tropicbirds, attracted by Easter's remote location and complete lack of

predators that made it an ideal safe haven as a breeding site
—until humans
arrived. Dave also recovered a few bones of seals, which breed today on the
Galapagos Islands and the Juan Fernandez Islands to the east of Easter, but it is uncertain whether those few seal bones on Easter similarly came from
former breeding colonies or just vagrant individuals.

The Anakena excavations that yielded those bird and seal bones tell us
much about the diet and lifestyle of Easter's first human settlers. Out of
those 6,433 vertebrate bones identified in their middens, the most frequent
ones, accounting for more than one-third of the total, proved to belong to
the largest animal available to Easter Islanders: the Common Dolphin, a porpoise weighing up to 165 pounds. That's astonishing: nowhere else in
Polynesia do porpoises account for even as much as 1% of the bones in
middens. The Common Dolphin generally lives out to sea, hence it could
not have been hunted by line-fishing or spear-fishing from shore. Instead, it
must have been harpooned far offshore, in big seaworthy canoes built from
the tall trees identified by Catherine Orliac.

Fish bones also occur in the middens but account there for only 23% of
all bones, whereas elsewhere in Polynesia they were the main food (90% or
more of all the bones). That low contribution of fish to Easter diets was be
cause of its rugged coastline and steep drop-offs of the ocean bottom, so
that there are few places to catch fish by net or handline in shallow water.
For the same reason the Easter diet was low in molluscs and sea urchins. To
compensate, there were those abundant seabirds plus the land birds. Bird
stew would have been seasoned with meat from large numbers of rats,
which reached Easter as stowaways in the canoes of the Polynesian colonists.
Easter is the sole known Polynesian island at whose archaeological sites rat
bones outnumber fish bones. In case you're squeamish and consider rats
inedible, I still recall, from my years of living in England in the late 1950s,
recipes for creamed laboratory rat that my British biologist friends who
kept them for experiments also used to supplement their diet during their
years of wartime food rationing.

Porpoises, fish, shellfish, birds, and rats did not exhaust the list of meat sources available to Easter's first settlers. I already mentioned a few seal records, and other bones testify to the occasional availability of sea turtles
and perhaps of large lizards. All those delicacies were cooked over firewood
that can be identified as having come from Easter's subsequently vanished
forests.

Comparison of those early garbage deposits with late prehistoric ones or
with conditions on modern Easter reveals big changes in those initially

bountiful food sources. Porpoises, and open-ocean fish like tuna, virtually
disappeared from the islanders' diet, for reasons to be mentioned below.
The fish that continued to be caught were mainly inshore species. Land
birds disappeared completely from the diet, for the simple reason that every
species became extinct from some combination of overhunting, deforesta
tion, and predation by rats. It was the worst catastrophe to befall Pacific is
land birds, surpassing even the record on New Zealand and Hawaii, where to be sure the moas and flightless geese and other species became extinct
but many other species managed to survive. No Pacific island other than
Easter ended up without any native land birds. Of the 25 or more formerly breeding seabirds, overharvesting and rat predation brought the result that
24 no longer breed on Easter itself, about 9 are now confined to breeding in
modest numbers on a few rocky islets off Easter's coasts, and 15 have been
eliminated on those islets as well. Even shellfish were overexploited, so that
people ended up eating fewer of the esteemed large cowries and more of
the second-choice smaller black snails, and the sizes of both cowry and snail
shells in the middens decreased with time because of preferential over-
harvesting of larger individuals.

The giant palm, and all the other now-extinct trees identified by Cather
ine Orliac, John Flenley, and Sarah King, disappeared for half a dozen
reasons that we can document or infer. Orliac's charcoal samples from
ovens prove directly that trees were being burned for firewood. They were
also being burned to cremate bodies: Easter crematoria contain remains of thousands of bodies and huge amounts of human bone ash, implying mas
sive fuel consumption for the purposes of cremation. Trees were being
cleared for gardens, because most of Easter's land surface except at the high
est elevations ended up being used to grow crops. From the early midden abundance of bones of open-ocean porpoises and tuna, we infer that big
trees like
Alphitonia
and
Elaeocarpus
were being felled to make seaworthy
canoes; the frail, leaky little watercraft seen by Roggeveen would not have
served for harpooning platforms or venturing far out to sea. We infer that trees furnished timber and rope for transporting and erecting statues, and
undoubtedly for a multitude of other purposes. The rats introduced acci
dentally as stowaways "used" the palm tree and doubtless other trees for
their own purposes: every Easter palm nut that has been recovered shows
tooth marks from rats gnawing on it and would have been incapable of
germinating.

Deforestation must have begun some time after human arrival by
a.d.
900, and must have been completed by 1722, when Roggeveen arrived

and saw no trees over 10 feet tall. Can we specify more closely when, between those dates of 900 and 1722, deforestation occurred? There are five types of evidence to guide us. Most radiocarbon dates on the palm nuts themselves are before 1500, suggesting that the palm became rare or extinct thereafter. On the Poike Peninsula, which has Easter's most infertile soils and hence was probably deforested first, the palms disappeared by around 1400, and charcoal from forest clearance disappeared around 1440 although later signs of agriculture attest to continued human presence there. Orliac's radiocarbon-dated charcoal samples from ovens and garbage pits show wood charcoal being replaced by herb and grass fuels after 1640, even at elite houses that might have claimed the last precious trees after none was left for the peasants. Flenley's pollen cores show the disappearance of palm, tree daisy, toromiro, and shrub pollen, and their replacement by grass and herb pollen, between 900 and 1300, but radiocarbon dates on sediment cores are a less direct clock for deforestation than are direct dates on the palms and their nuts. Finally, the upland plantations that Chris Stevenson studied, and whose operation may have paralleled the period of maximum timber and rope use for statues, were maintained from the early 1400s to the 1600s. All this suggests that forest clearance began soon after human arrival, reached its peak around 1400, and was virtually complete by dates that varied locally between the early 1400s and the 1600s.

The overall picture for Easter is the most extreme example of forest destruction in the Pacific, and among the most extreme in the world: the whole forest gone, and all of its tree species extinct. Immediate consequences for the islanders were losses of raw materials, losses of wild-caught foods, and decreased crop yields.

Raw materials lost or else available only in greatly decreased amounts consisted of everything made from native plants and birds, including wood, rope, bark to manufacture bark cloth, and feathers. Lack of large timber and rope brought an end to the transport and erection of statues, and also to the construction of seagoing canoes. When five of Easter's little two-man leaky canoes paddled out to trade with a French ship anchored off Easter in 1838, its captain reported, "All the natives repeated often and excitedly the word
miru
and became impatient because they saw that we did not understand it: this word is the name of the timber used by Polynesians to make their canoes. This was what they wanted most, and they used every means to make us understand this . .." The name "Terevaka" for Easter's largest and highest