Dieback of Norfolk Island pine in its natural environment

Summary

Concern has been expressed in recent years over the number of trees of Norfolk Island pine showing crown deterioration and ultimate death in its natural environment—an isolated small island, in the South Pacific Ocean, of great conservation and tourist value. An account is given of the history of the vegetation of the island since European settlement, with particular reference to its impact on the pine. Mapping, based on large-scale colour aerial photography, showed that almost one third of the remaining pine area was affected by dieback, most of it severely affected. It is likely that the dieback is the manifestation of serious ecological damage due to severe competition from introduced grasses and shrubs, overgrazing and nutrient depletion on land originally cleared for agriculture. Suggestions are made for further research.