Environmentally Determined Deforestation

UCLA biogeographer Jared Diamond and U. of Hawai‘i anthropologist Barry Rolett have published an article in Nature (23 September 2004) about pre-European deforestation on Pacific Islands. Those familiar with Diamond's Guns, Germs, and Steel (W. W. Norton, 1996) will not be surprised that environmental determinism plays a major role.

The pair, whose collaboration started after Diamond visited Hawai‘i as part of UH's Distinguished Lecture Series in 2000, coded Pacific islands for the amount of deforestation and forest replacement based on the observations of early European visitors. They used four types of statistical analysis to weigh nine variables. Predisposing islands to deforestation are

• low rainfall (which slows plant growth and increases risk from fire)
• higher latitudes (where cooler temperatures slow plant growth)
• age (because soil nutrients are lost over time)
• distance from sources of material that replenish soil nutrients (volcanic ash fallout and Central Asians dust)
• low elevation (mountains rains provide water and capture atmospheric dust, and streams carry nutrients to the lowlands)
• small and isolated [Arrgh! They mean "small size and isolation"!] (limiting diversity of tree species and inaccessible areas and reducing trading and raiding as options for obtaining resources)

While they don't dismiss the impact of Polynesian societal practices on deforestation, Rolett and Diamond conclude that Easter Island's collapse had less to do with improvident actions than the fragile environment. They hope to see their analysis further refined and extended to other societies and locations.