HONOLULU (KITV) - The brush fire on the slopes of Mauna Loa on the Big Island is just five-percent contained, and it's more than doubled in size. So far, it's burned more than 3,200 acres.

It started Sunday at Keauhou Ranch, and is now spreading toward the Kipuka Ki Special Ecological Area, a rare old-growth native forest-home to threatened and endangered native plants and animals.

The cause of the fire is still under investigation.