Growing a community’s sense of ‘heritage’: a former mataī forest from SW Ōtautahi Christchurch and its nitrogen status, 860–1430 CE

Abstract

ABSTRACTAs in many places, heritage narratives in Ōtautahi Christchurch remain focused on colonial times. To expand these narratives, we examined three subfossil mataī (Prumnopitys taxifolia) excavated along a 700 m arc during residential subdivision earthworks. Characterisation used δ15N, radiocarbon, and ring width measurements. Conventional (uncalibrated) radiocarbon ages were 1222 BP (calibrated median 856 CE), 932 BP (1148 CE) and 545 BP (1425 CE). Mean δ15N values of +1.0 ± 1.1‰ (±SD) were similar to nearby alluvial forest remnants, with no discernible change through the 550-year sampling interval. Ring widths in three trees from the 545 BP site were 0.58 ± 0.12 mm, half that of present day mataī from humid West Coast forests at a similar latitude. The 545 BP site included a burnt stump, and stumps with longhorn beetle (Cerambycidae) larval galleries that occur only in already dead trees. We conclude that the forest was slow growing and mesotrophic but dynamic due to periodic flooding, ending with fire around 1430 CE and inundation of the dead standing forest years or decades later. We are now using traditional and social media and artists to disseminate the narrative of a former mataī forest ‘beneath our feet’ through schools, community groups, and in public facilities.KEYWORDS: Cerambycidaecommunity engaged researchhuman impactNew ZealandpodocarpPrumnopitys taxifoliaSamalasstable isotope AcknowledgementsJo Golden (Christchurch City Council) facilitated retrieval of the material that underpinned our work, and carver John Robertson found the fire-damaged stump. Sarah Bury, Julie Brown, and Josette Delgado carried out stable isotope sample preparation and analysis. We are indebted to the university academics who gave their expertise and moral support to the project. Peter Almond (Lincoln University) advised us on the sedimentary history of our study site, and he and Matiu Prebble (University of Canterbury) shared information about their project on another subfossil wood discovery nearby. Rod Wallace (University of Auckland) identified the 932 BP and 1222 BP wood samples. John Marris (Lincoln University) identified potential sources of the larval cavities in the 545 BP disc, discussed potential sources of the radial cavities in the >5.4 m stem with his entomologist network, and provided relevant literature. Richard Holdaway (University of Canterbury) linked the 1256 CE ring width hiatus to the Samalas LVE. Finally, we acknowledge with thanks the substantial input from journal editors and three anonymous reviewers.Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingFunding for the 932 BP and 1222 BP radiocarbon analyses came from Waipuna Halswell-Hornby-Riccarton Community Board via Discretionary Response Fund grant 61207 to Halswell Residents Association. Richard Holdaway included the 545 BP radiocarbon analysis in a project funded by the Brian Mason Science and Technical Trust (grant 2019/08).