Editor’s Note: This article previously appeared in a different format as part of The Atlantic’s Notes section, retired in 2021. It’s autumn, the season for leaves, nuts, needles, and other arboreal ...

What purpose does a fallen leaf serve? Its time as beautiful fall foliage has ended. It’s no longer claimed by the tree that grew it, and now it simply sits on the ground. Does that make it garbage? I ...

Although the chemistry of autumn colours is well understood, there is an ongoing and lively debate among scientists about why trees evolved their vivid autumn colours in the first place. Driving north ...