rain forest

[First paragraphs...]
A study of the history of the development of grassland in New Zealand is also a study of a prolonged interaction between native and introduced plants in which there has usually been a strong and deliberately guided bias towards the supremacy of the introduced plants. Because much of the native vegetation does not meet the requirements of the farmer, he has tried to replace this with plants that do so.

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.