I live in a quiet residential neighborhood on the outskirts of a city in Indiana. In similar neighborhoods, often carved out of reclaimed farmland, each lot might feature a couple of trees that were planted relatively recently. Somewhat unusually, my yard contains more than a dozen trees in the backyard, plus a small woodlot behind it that remained during development of our neighborhood. As a child, I grew up with several friendly trees in my yard (apple, black walnut, redbud, sycamore, silver maple) that I enjoyed playing beneath or climbing, and I am happy to be surrounded by so many trees now: two hickory trees, three young buckeyes, six sugar maples of various ages, one towering Chinquapin oak, one mature ash that we hope we’ve saved from the emerald ash borer (an insect that is decimating ash trees in our area), one magnolia, an awkwardly placed river birch, and a blue spruce that would prefer a little more sun. We had to say goodbye to an elm that became sick and died a few years ago. The indentation in the ground where its trunk once stood occasionally gives rise to spectacular fairy rings of small mushrooms after a good soaking rain. Birds, squirrels, chipmunks, raccoons, opossums, and the occasional fox spend time in our yard. In the summer, spiders, butterflies, fireflies, and cicadas find homes among my trees and perennials. When the wind picks up, the sounds of leaves fluttering or branches swaying in the backyard are noticeable. Over the years, I have learned to appreciate the pleasures, benefits, responsibilities, and occasional hazards of living with trees.

Buckeye trees in my yard in summer.

Buckeye seeds from last fall’s harvest.

Because of my general appreciation of nice trees, with some curiosity I added The Songs of Trees, a new book by David George Haskell, to my summer science reading list after hearing positive reviews about it this spring. Plants are not generally considered popular literary characters, or even interesting fodder for non-fiction writing. Many people tend to relegate plants to the background of life, if they notice them at all. Yet trees, so abundant in many parts of the world, tower over us and our infrastructure, so they are difficult to ignore. I was curious to see how Haskell would treat his chosen subject matter. (As an aside, children’s literature does occasionally feature trees as main characters: The Giving Tree, by Shel Silverstein, The Lorax, by Dr. Seuss, and Chicka Chicka Boom Boom, by Bill Martin, Jr. and John Archambault immediately come to mind, the first two stories having played influential roles in my own childhood.) Having read recently about relationships among microorganisms and people and other animals (see my earlier blog post), I also was intrigued about the accompanying theme of interspecies communities implied by the book’s subtitle, “Stories from Nature’s Great Connectors.”

The Songs of Trees consists of a series of interconnected chapters, each featuring a different kind of tree. We are taken on a journey around the world to strikingly different habitats to meet a representative tree species from that area and learn about its life history and its ecological and/or human partners, including Haskell himself through repeated visits he made to particular trees. The title of the book refers in part to actual sounds of trees–acoustic patterns recorded by Haskell using specialized equipment in and around the trees–but also observations by Haskell about the sounds and other sensory input he experienced while simply hanging out in the presence of trees. He also expands the idea into metaphorical “songs” established in complex ecological communities and by the inclusion of trees and tree products into different human societies and activities. It is a quiet book of carefully chosen prose that seems to honor the perceived stoicism of trees.

Dead log on display at a park near my home. The width of this tree, lying on its side, is as tall as a person. What stories could it tell?

Writing about nature has a long history, of course. As it turns out, tomorrow (July 12) marks the 200th birthday of Henry David Thoreau, who is famous for essays and books about nature, wilderness, and human society in the United States. (The U.S. Postal Service has even issued a stamp in his honor.) He promoted mindful appreciation of natural spaces, such as his retreat at Walden Pond, as essential for the human spirit (see this link to the New York Times for an essay on Thoreau’s legacy). The writings of Thoreau, as well as other American naturalists and early environmental conservationists such as Aldo Leopold, John Muir, Edward Abbey, and many others have been studied and discussed by generations of students and nature-lovers alike, seeking to understand our relationship as humans with our habitats.

Haskell, decades removed from these early writers, now promotes the mindful appreciation of trees themselves and their diverse habitats around the world. He encourages readers to consider trees and their interdependent ecological partners on their own terms, as living, breathing–even beautiful–organisms that exist along a timescale on Earth that is very different from our own. Haskell also reflects on how much people benefit from the presence of trees and likely underappreciate their contributions. Many scientific studies over the years have examined the ramifications of global concerns such as deforestation. Losing trees in large quantities from existing habitats can destabilize soils, weather, and natural and human communities. But how much of a difference do the individual hickory trees in my backyard make in my life, or in the quality of my neighborhood? In my corner of the city, they feed and shelter wildlife, likely improve the air quality and temperature, probably lowered my blood pressure a bit when I had strung a hammock between them, and provide friendly shade. Raking all those leaves in the fall is also good exercise, if a bit of a pain! Anecdotally then, it would seem that the trees in my yard also have value to people beyond their intrinsic worth of simply being alive, but scientists like to measure these parameters and report on the data.

Toward the conclusion of his book, Haskell includes an important modern addition to the naturalist’s repertoire by considering trees in urban settings, such as my backyard, or lining the sidewalks of a bustling urban center, rather than just in more sparsely populated natural areas (such as those Thoreau promoted in Walden). Urbanization is a shifting trend among human societies: more than half of all people now live in cities, in a marked change from past social patterns, and will continue to increase in the decades to come (see this site from the United Nations for more information and trends). In considering how to create sustainable cities (especially in the wake of climate change), understanding how trees, wildlife, and people coexist in urban habitats has become a new priority among many urban planners and ecologists. Including trees and other green spaces is also an important area of research into urban public health and epidemiology. For example, Adam Roger’s recent article in WIRED magazine, “All the Trees Will Die, and Then So Will You,” highlights a research study on insect and fungal infections of potentially millions of trees in California and how their die-off could impact human illness and mortality in urban areas. The presence of individual trees, tree cover as a whole, and other green spaces can positively impact air quality, rainfall and temperature, and overall quality-of-life factors associated with healthier people. Considering the natural history of not only wild trees and forests, but also our urban species, can expand our understanding of plant biology, the effects of climate change on plants, and how plants benefit urban communities.

Trees along a paved nature trail in one of my local city parks. Trees add aesthetic and ecological benefits for human and nonhuman residents of cities.

If you’re curious about Haskell’s descriptions of trees, I would encourage you to read a brief article he wrote for Scientific American’s blog site, “10 Ways to Listen to Trees,” which will give you a condensed version of some of his ideas. You can also get a preview of the book in Haskell’s post on NPR’s 13.7 Cosmos and Culture web page, “Life is the Network, Not the Self.” I came across two other articles about trees while I was preparing to read Haskell’s book, which feature examples of others who are “listening” to trees and what they’re discovering about interspecies communities:

• “Soil Microbes May Be Orchestrating Tree Migrations,” by Brittany Patterson for Scientific American, about scientific research on microbes, climate change, and the range of tree growth in the future;
• “The World Told Through the Eyes of the Ginkgo Tree,” (Smithosonian.com) which includes a podcast about the ancient history of ginkgos and their modern relationship with humans, who rescued them from near-extinction.

After you’re done reading, consider heading out to your favorite wild space or park–or just take a walk down the street and see what’s growing. Feel free to give a tree a hug, or maybe just a restrained nod of acknowledgment. Maybe you’ll make a new friend. In the meantime, I’ll be out on my back porch, relaxing among my tree neighbors.