New Zealand Journal of Botany abstract
A history of Kaiparoro clearing and the limits of Nothofagus in the
northern Tararua Range, New Zealand
G. M. ROGERS
Manaaki Whenua - Landcare Research
Private Bag 3127
Hamilton, New Zealand
M. S. McGLONE
Manaaki Whenua - Landcare Research
P.O. Box 69
Lincoln, New Zealand
Abstract Kaiparoro clearing is a 40 ha enclave of
tussock grassland within forest, straddling a rounded peneplain remnant in the
northern Tararua Range. The grassland occurs at an unusually low altitude
compared with other North Island red tussock grasslands. Charcoal and pollen
from a peat bog suggests that fire created the clearing and helped maintain
open vegetation throughout its 3500+ year history. There appear to be no
edaphic constraints on forest occupation of most of the site. Before the
clearing was created, tussock grasses were probably confined to small riparian
peat bogs within low forest on the peneplain surface. Rates of shrub invasion
of the tussock clearing by Dracophyllum longifolium, Leptospermum
scoparium, and Olearia colensoi are slow. A fire return-period of
<400 years would be sufficient to perpetuate the open or non-forest
vegetation. Kaiparoro coincides with the modern-day distributional limits of
Nothofagus in the northern Tararua Range. The pollen record indicates
that Nothofagus has had a delayed population growth there in the
Holocene relative to the main population centre further south. Similar trends
for Nothofagus at other provincial limits in its distribution are
evident elsewhere in New Zealand. Pollen results from Kaiparoro and similar
sites adjacent to Nothofagus boundaries, suggest that Nothofagus
is non-competitive under humid, mild, low-insolation climates.
Keywords Tararua Range; palynology; pollen analysis; late
Holocene; peat bog; fire; paleoclimate; Nothofagus; beech
New Zealand Journal of Botany, 1994, Vol. 32: 463-482
0028-825X/94/3204-0463 $2.50/0 (c) The Royal Society of New Zealand 1994
PDF file of entire paper: medium quality (1840K); (scanned from paper original: notes about this process)
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