Presented here are results of field survey, sedimentology and pollen and starch analysis of sediment cores from two different environmental settings in the Tolaga Bay catchment, New Zealand. One of the sites is an inland floodplain paddock with ditch‐like features (which appear to be mainly horse‐drawn plough lines), the other a back‐dune wetland adjacent to the beach. The former is capped with a thick alluvial layer deposited during Cyclone Bola (1988) and has a layer of reworked 1.7 ka Taupo Tephra. Both sites show evidence of large‐scale prehistoric deforestation, and reveal starch grains similar in appearance to Polynesian‐introduced sweet potato (Ipomoea batatas) and European‐introduced potato (Solanum tuberosum), suggesting cultivation of these crops.