Stand Analysis of an Invading Firetree (Myrica faya Aiton) Population, Hawaii

Abstract

Since 1971, the exotic firetree (Myricafaya) has been invading a native ohia tree (Metrosideros collina subsp. polymorpha Rock) habitat in the 1959 Kilauea Iki devastation area, Hawaii Volcanoes National Park. Ninetysix trees of the invading population were analyzed as to structural and fruiting characteristics. Data were collected from two permanent transects that were designed to provide for continued study of the fire tree and ohia community. Initial findings reveal that the present firetree spread depends on an outside seed source, and successful seedling establishment is dependent on favorable microhabitat conditions beneath ohia trees. As yet, no competitive replacement of ohia trees by fire trees has been observed. On the contrary, firetrees over 2 m tall that had grown up and into ohia tree crowns were exhibiting poor vigor. Additionally, there is a high positive correlation between fire tree loss of vigor and diameter increase beyond 4-5 em. Preliminary observations suggest that fire tree seed dispersal depends on birds, primarily, the exotic Japanese white-eye (Zosterops japonica).