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Abstract
In mixed stands with Agathis australis (kauri), Nothofagus truncata (hard beech) has frequently been described as not regenerating and appearing unhealthy. Hypotheses proposed by other authors to explain the dynamics of these stands that would lead to these observations include 1) the two species replace each other reciprocally, 2) a climate change‐induced replacement of N. truncata by A. australis is occdng, and 3) N. truncata acts as a long‐lived ‘’nurse” for A. australis. These hypotheses were investigated by conducting stand structural analyses in the Hapuakohe Ecological District. The basal area of each species was not positively comelated with the density of saplings and seedlings of the other species, which does not support the reciprocal replacement hypothesis. N. truncata was not less abundant than A. australis and was regenerating at some sites, thus not supporting the theory of replacement induced by climate change. N. truncata was generally younger or of similar age to A. australis, suggesting that N. truncata does not act as a “nurse”. Stand age structures suggest that both species establish in stan& initiated by forest disturbance. Eighty‐six percent of the N. tnncata were healthy. me poor health of N. truncata Mer north may be caused by the senescence of relatively even‐aged cohorts, extrinsic factors, or a result of the health of N. truncata declining as it nears its northern limit.