Trees with smoother bark are better at repelling attacks by mountain pine beetles, which have difficulty gripping the slippery surface, according to a new study by the University of Colorado Boulder.

Clockwise from top left: (1) Two lodgepole pines growing side-by-side with notably different bark textures, (2) a rough-barked limber pine that has been attacked by bark beetles, (3) a limber pine ...

It’s a crisp autumn morning, and the forest trail glows with golden light filtering through turning leaves. Naturalist-led groups gather along woodland paths to talk about seed pods, bark textures, ...