Vegetation changes since early Maori fires in Waipoua Forest, Northern New Zealand

Abstract

The presence of abundant charcoal in sedimentary deposits is one of the key indicators of early Maori presence in New Zealand. However, it is often difficult to distinguish natural fire from anthropogenic. Studies of sedimentary charcoal and pollen in the Tarahoka clearing (or waerenga) in Waipoua Forest, where intentional burning is supported by the oral history of Te Iwi O Te Roroa, were undertaken with the belief that they would provide a level of detail, which could aid interpretation elsewhere. Vegetation plots and dendrochronological studies of trees on the clearing margins date the cessation of burning and subsequent invasion by woody plants. The radiocarbon and palynological results indicate that the clearing was created by fire ca. AD 1460. Although people were probably present to windward in the Waipoua valley before this time, they left no palynological signature at the study site. The date for the formation of the clearing agrees with others indicating population increase at this time, and with oral tradition for the arrival in the Waipoua valley of Manumanu 1, the ancestor of Te Iwi O Te Roroa. The maintenance of the clearing in seral vegetation by fire for >300 years supports the tradition that it was used as a kiwi ( Apterix australis) hunting site. During the period of European contact, fire intensity appears to have declined, while fire frequency may have increased, favouring the spread of bracken (rahurahu, Pteridium esculentum), an important food source. Intentional firing probably ceased ca. 1900, by which time the local Maori population was in decline and European gum-diggers were camped in the clearing. The postulated sequence of formation, use and abandonment of the clearing requires confirmation by investigation of similar nearby sites using the same combination of methods.