Tiny, gas-filled beads of volcanic ash with a scaly surface. Scientists have identified a new type of volcanic ash that erupted from a volcano in central Oregon roughly 7 million years ago.

Ash trees are dead or dying because of the little iridescent green beetle; The emerald ash borer's small size – no bigger than a cooked grain of rice – belies its destructive power.

Wood ash contains calcium, magnesium, and potassium among a dozen or more important nutrients. “They vary widely with the types of trees being burned,” Gaskin said.