Composition and structure of forest overwhelmed at Pureora, central North Island, New Zealand, during the Taupo eruption (c. AD 130)

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Abstract
The composition and structure of forest at Pureora, overthrown and buried by pumiceous tephra during the c. AD 130 Taupo eruption, are deduced from identification of plant macrofossils. A tall, dense podocarp forest was dominated by rimu (Dacrydium cupressinum) and tanekaha (Phyllocladus trichomanoides), with occasional matai (Prumnopitys taxifolia) , miro (Prumnopitys ferruginea), kahikatea (Dacrycarpus dacrydioides) and totara (Podocarpus totara). Understorey plants included toro (Myrsine salicina), horopito (Pseudowintera colorata), Neomyrtus pedunculata, Metrosideros diffusa, crown fern (Blechnum discolor) and Leptopteris superba. Poorly drained sites were dominated by kahikatea, rimu, tanekaha, Astelia grandis, Gahnia xanthocarpa and kiekie (Freycinetia baueriana ssp. banksil) with rare bog pine (Halocarpus bidwillil) and kaikawaka (Libocedrus bidwillil)' The classification and ordination techniques applied indicated that the forest was basically of one type with minor variations reflecting drainage conditions and topography. Comparison with present-day forest revealed some major differences. Matai and rimu dominate the tall podocarp forest of adjacent Pikiariki Ecological Area, and tawa (Beifschmiedia tawa), mahoe (Melicytus ramijlorus ssp. ramijlorus), kamahi (Weinmannia racemosa) and Asplenium bulbiferum s.s. are common in the understorey or ground cover but were not recorded in the buried forest. Kiekie, Gahnia xanthocarpa and kaikawaka, on the other hand, are absent from present-day forest in the Pureora district. These species were probably casualties of the volcanic devastation, unable to return because of one or a combination of factors, including improved soil aeration, drainage and fertility, and possibly a deterioration in climate.