Intensive dryland farming on the leeward slopes of Haleakala, Maui, Hawaiian Islands: archaeological, archaeobotanical, and geochemical perspectives

Polynesians settled and farmed the leeward, relatively arid slopes of Haleakala Volcano beginning about AD 1400. Archaeological investigations at two sites revealed dense concentrations of conical impressions in a subsurface 20cm cinder layer that was previously undisturbed, interpreted as resulting from cultivation practices involving digging sticks. Ethnographic accounts of Hawaiian sweet potato and dryland taro cultivation techniques provide details on the use of such digging sticks. By puncturing this cinder layer, farmers created a loamy mixture of ash and cinder suited to root crop development. Archaeobotanical analyses suggest an intensive, short-fallow regime: macroscopic wood charcoal was absent (therefore no fallow sufficient for secondary re-growth of dryland forest) and evidence of disturbance-tolerant, weedy species is abundant. Geochemical analyses relying on stratigraphic relationships show that cultivation depleted nutrient levels in the digging-stick impressions, through harvest and leaching losses. Our findings provide evidence for repeated and intensive use of a landscape under a system of dryland cultivation. Keywords Polynesia; Hawai'i; dryland agriculture; digging stick; nutrients; geoarchaeology.