Stewart Island is the southernmost of the three main New Zealand islan
ds, and is largely covered with Dacrydium cupressinum/hardwood forest.
Pollen analyses from three Holocene sites and a modern pollen rain su
rvey are presented. Stewart Island had a hardwood forest of Weinmannia
racemosa, Metrosideros umbellata, and abundant tree ferns from before
9000 BP to 5500-4500 BP when Dacrydium cupressinum and Prumnopitys fe
rruginea rose to dominate the forest reducing the abundance of Weinman
nia racemosa and greatly restricting Metrosideros umbellata. It is sug
gested that mild, cloudy climates during the early Holocene may have i
nhibited regeneration of podocarp trees, and that a change in climatic
regime in the mid to late Holocene brought sunnier, less cloudy condi
tions. Several woody species absent from the island but present on the
adjacent mainland (Phyllocladus alpinus, Nothofagus spp., Libocedrus
bidwillii) probably never grew there, and their absence is attributed
to failure to disperse and the limited time that suitable habitats hav
e been available.