Behind every autumn leaf lies a chemical shift-chlorophyll fading, carotenoids glowing, anthocyanins rising-that turns survival into spectacle. Every autumn, landscapes across much of the world ...

This is the time of year when Nicole Hughes gets constantly distracted by the fall foliage as she drives around North Carolina. "I'm always looking," says Hughes, a biologist at High Point University.

Fall is in full swing in Oregon. The tips of trees are transforming into a palette of yellow, orange and red hues and cooler weather signals the change of seasons. Contrasted by the state's vast ...