ABSTRACTThis paper examines the floristic changes that occur following human disturbance in mid-montane forest in the Wau area in Papua New Guinea. The study was restricted to a 1600–2400 m altitudinal range on Mt Kaindi, with disturbed forest, and Mt Missim, with undisturbed forest. Special attention was given to the status ofNothofagus pulleiwhich is locally dominant on Mt Kaindi.A major change in floristic composition was observed between 1800 and 2000 m. The abundance and species

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... of ferns and mosses above 2000 m characterizes the floristic differences.Nothofagus pulleiwas found to be a pioneer species with a long life-span, one which does not regenerate under its own cover. There were no other important floristic differences betweenNotho-fagus-dominated forest and mixed mid-montane forest.Nothofagus pulleilocally dominates the canopy and thereby suppresses the growth of other trees.