Between Earth and Sky: Our Intimate Connections to Trees
Nalini M. Nadkarni
336 pages, hardcover: $24.95.
University of California, 2008.

Between Earth and Sky sets out to describe the many ways in which trees sustain us. When author Nalini Nadkarni was a girl in suburban Maryland, after school she would climb one of the eight maples in her family's yard. Those early days spent up high — climbing, playing and reading — had a profound effect on her, which she shares throughout this unique book.

After graduating from college, Nadkarni was pulled in several professional directions.  She studied dance in Paris and almost took to the stage professionally before committing to science. She is now a highly regarded ecologist at Evergreen State College in Washington, but her varied interests remain evident throughout this book, which draws on science, poetry, fine art and even psychology.

Nadkarni builds on Abraham Maslow's famous "hierarchy of needs," which starts with physical basics like shelter and moves up to abstract notions like self-actualization. This theory helps explain what really matters to humans, and Nadkarni uses her own version of it to show how trees meet many of our most vital needs. "From the first glimmers of humanity's dawn," she writes, "we have evolved with trees." Even now, millennia later, when synthetics have replaced many wood products and most people live among skyscrapers, not redwoods, we still feel "affinities" to trees, she says.

You might expect the author to speak only of the spiritual or aesthetic elements of trees — the reflections of a treehugger walking in the woods. But true to her "needs" framework, Nadkarni starts with basic scientific information about trees and such seemingly mundane things as the use of wood in making our houses and paper products. She then moves on to the "higher" elements, such as health, play, spirituality and mindfulness.

Interdisciplinary work is often risky; an author who mingles science with poetry, personal stories and even theology goes out on a limb. Some readers may find this aspect of Between Earth and Sky to be a stretch. Most, though, will be intrigued by Nadkarni's play of ideas. Nadkarni has been climbing trees for many years, and she understands the balance and skill required to take risks so far above the ground.