The morning of my second day in the Kalalau Valley, Isaac hands me a collapsible handsaw, shows me three dead trees, and tells me to split them. “These are guava,” he explains. “Java plum trees don’t burn well.” When I finish my work, I rinse my bandana in the stream. That afternoon we return to the beach via a path Isaac calls the “hippie highway.” It’s how those camping up valley get quickly to the ocean. About a quarter of a mile from the wate...