 As required by regulatory authorities, buffer zones have been further developed around rivers to prevent erosion and maintain animal habitats, but the Eel River, the region's major waterway, has been considerably damaged as a result of more than 150 years of logging activity, not all of which is the result of PALCO operations.In 1999 PALCO agreed to American activist Julia Butterfly Hill's requests to create a buffer zone around a 600-year old-growth redwood named Luna in exchange for leaving the tree, as she had been living in it for just over two years.Though someone vandalized the tree during the process, it survives to the present.