<I>Metrosideros polymorpha</I>

Vegetation succession on 4 recent (1852-1942) montane lava Rows on Mauna Loa, Hawaii, was remeasured 22 years after the first measurement in 1967. Colonisation patterns of vascular plant species were observed on a new lava flow (1984) which overwhelmed part of the earlier studied 1852 flow. An influx of adventive species, positively correlated with flow age, was noted at the remeasured sites; most were herbs and grasses that do not appear to interfere with the succession to Metrosideros- dominated forest.

Approximately 50,000 ha of native wet Metrosideros forest on the island of Hawai'i experienced a drastic reduction (dieback) of the tree canopy between 1954 and 1977. Two general hypotheses have previously been suggested to explain this phenomenon: 1) Metrosideros dieback has resulted from recently introduced pathogens, and 2) the dieback has naturally occurred previously in Hawai'i, and is related to plant succession under periodic conditions of climatic instability which effect the soil moisture regime.