a band of ranch land on mauna kea's lower slopes was formerly "acacia koa" – "metrosideros polymorpha" (koa-ōhia) forest. its destruction was driven by an influx of european and american settlers in the early 19th century, as extensive logging during the 1830s provided lumber for new homes. vast swathes of the forest were burned and cleared for sugarcane plantations. most of the houses on the island were built of koa, and those parts of the forest that survived became a source for firewood to power boilers on the sugarcane plantations and to heat homes. the once vast forest had almost disappeared by 1880, and by 1900, logging interests had shifted to kona and the island of maui. with the collapse of the sugar industry in the 1990s, much of this land lies fallow but portions are used for cattle grazing, small-scale farming and the cultivation of eucalyptus for wood pulp.