Plant science for plant people.

Oak trees share their food with beech trees in a drought. Researchers watching a temperate forest found that carbon, the sugar trees build from sunlight, moves between species underground through fungi threaded among their roots, and the sharing speeds up threefold when the trees are stressed. A forest behaves less like a competition and more like a neighborhood pooling resources in a crisis.

That same quiet cooperation shows up everywhere this week. Rosemary plants chewed on by insects release invisible airborne chemicals, and their neighbors start preparing defenses before any bug arrives. Tomato plants grafted onto hardier rootstock pass the toughness on to their seeds, and to their seeds' seeds. And in cities, even modest tree cover, around 15 percent, cuts heat-related deaths dramatically; plane trees and lindens are especially generous with their shade.

Plants don't endure alone, and most of the help they pass each other happens on timescales or wavelengths we can't see.