Nalini Nadkarni has spent two decades climbing the trees of Costa Rica, Papua New Guinea, the Amazon and the Pacific Northwest, exploring the world of animals and plants that live in the canopy and never come down; and how this upper layer of the forest interacts with the world on the ground. A pioneering researcher in this area, Nadkarni created the Big Canopy Database to help researchers store and understand the rich trove of data she and others are uncovering.

Nadkarni teaches at Evergreen State College in Olympia, Washington, but her work outside the academy is equally fascinating -- using nontraditional vectors to teach the general public about trees and the ecosystem. For instance, she recently collaborated with the dance troupe Capacitor to explore the process of growth through the medium of the human body. In another project, she worked with prison inmates to grow moss for the horticulture trade, to relieve the collecting pressure on wild mosses. The project inspired in her students a new reverence for nature -- and some larger ecochanges at the prison.

She's the author of Between Earth and Sky: Our Intimate Connections to Trees.