New Zealand Journal of Botany abstracts

---

Aranuian (post-glacial) pollen diagrams from the Tongariro region, North Island, New Zealand

M. S. McGlone

Botany Division, DSIR, Private Bag, Christchurch, New Zealand

W. W. Topping

Joint Sciences Department, Ambassador College, Pasadena, California 91123, U.S.A.

Abstract Retreat of glaciers on the Tongariro Volcanoes began before 14 000 yr b.p. By 14 000 yr b.p., podocarp-hardwood forest had begun replacing the previous scrub and grassland communities. We recognise three major post-glacial pollen zones.

(i) 14 000-10 000 yr b.p. Podocarpus spicatus forest was dominant. Annual temperatures may have been only 2-3 °c lower than present, but the climate was substantially drier.

(ii) 10 000-5 000 yr b.p. Dacrydium cupressinum forest was dominant and the climate much wetter and milder than present.

(iii) 5 000 yr B.P.-present. Return of Podocarpus .spicato-dominant forest, increase of Nothofagus, and a general trend away from the mild climates of (ii) to a more drought- and frost-prone climate.

The present pattern of Nothofagus forest on the Volcanic Plateau originated during the last glacial maximum when forest was confined to small relict areas. The development of milder climates, and the post-glacial expansion of podocarp-hardwood forests kept the Nothofagus forest confined to small, scattered localities. Only in the last 5 000 years has there been significant expansion of Nothofagus forest, but the large rhyolitic eruptions of the last 3 500 years have tended to delay this spread.

Received 21 March 1977
New Zealand Journal of Botany, 1977, Vol. 15: 749-60. 749

PDF file of entire paper: medium quality (5080K); (scanned from paper original: notes about this process)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page