I suspect no other relationship is more complex and fraught than that between humans and trees. I’ve been wanting for a long time to write something about it, but every time I try, I get overwhelmed. Where to begin?
For us humans, it indeed goes back to the beginning: Adam and Eve learned of their own humanity from a tree. Or if you prefer more scientific stories, our ancestors took a crucial step in speciating from other apes by descending from the trees. Since then we haven’t gone far from the tree, so to speak. We have eaten from trees, climbed trees, lived in trees, worshipped trees, studied trees, planted trees, bred trees, hugged trees, and saved trees. We have also, at various times, cut trees down for fuel, for lumber, to make paper, to make weapons, to clear farmland, to create subdivisions, because they threatened our infrastructure, because we didn’t like where they were growing, and for no reason whatsoever.
After hundreds of thousands of years of shared history, have we and trees come to understand each other better? Three stories I have come across recently suggest the answer is, it’s still complicated.
Life presents us all with certain problems, one of them being how to move ourselves from place to place. I submit that if you live in a compact, congested city, there’s really only one sane solution: ride a bicycle. Biking is carbon-neutral, it’s efficient, it’s outdoors, it’s exercise, it’s free, it’s fun. It’s a win-win-win-win-win-win.
But as I’m dodging morning traffic on my way to work in Washington, DC, I do find myself wondering, am I just fucking crazy? Could the health benefits from bike commuting possibly outweigh the risk of getting flattened by some latte-swilling, texting SUV driver? And even if I avoid that fate, what about the longer-term effects of the exhaust fumes I’m sucking in with every breath?
Since I am a science writer, I feel compelled to try to answer such questions with data. So it was troubling to find that one of the few sources providing data on the risks of different modes of transport puts biking near the top in deaths per journeys, miles traveled, or time spent in transit (apparently based on a 15-year old British survey). Only motorcycling, which is essentially bicycling at the speed of car traffic, proved more dangerous. U.S. data from a similar time period and cited in this paper tell a similar story.
It’s that magical time of year—after the big harvests and before the hard freezes—when apples at the farmers markets in my area burst with tangy goodness, when the last of the summer tomatoes and peppers mingle with luxurious piles of greens, roots, and winter squash, and when all seems right in the world.
So I admit I found it somewhat hard to believe, while admiring the overflowing stands at my local market last Sunday, that federal bureaucrats would want to make it harder for such enterprises to operate. But that is exactly what some small farmers and advocates are warning. They fear that food safety regulations proposed by the Food and Drug Administration would impose onerous costs on small produce growers, potentially driving many out of business altogether.
The once-mighty monarch butterfly migration—an extraordinary natural phenomenon that passes right through our neighborhoods and fields—has been reduced to a trickle. Where were you all summer, did you notice?
For how things used to be, here is Annie Dillard describing the event in Pilgrim at Tinker Creek, published in 1974:
The monarchs clattered in the air, burnished like throngs of pennies, here’s one, and here’s one, and more, and more. They flapped and floundered; they thrust, splitting the air like the keels of canoes, quickened and fleet. It looked as though the leaves of the autumn forest had taken flight, and were pouring down the valley like a waterfall, like a tidal wave, all the leaves of hardwoods from here to Hudson’s Bay.
Dillard seems to be describing a scene of almost unimaginable natural wealth. The world had such an excess of raw material that it could make monarch butterflies not by the ones and twos, but by the millions. Indeed, estimates of the number of monarchs that used to overwinter in Mexican fir and pine forests range up to a billion. In pictures, the trees seem to be literally dripping with butterflies.
We’ve all heard about the dangers of non-native plants: they outcompete natives; they carpet forest floors and smother roadsides; they cost us billions of dollars a year in control efforts. They’ve colonized huge swaths of the mid-Atlantic, where I live; I’ve written about them on this very blog. But is it possible that some introduced plants could prove beneficial in their new environments?
That’s certainly what Ariel Lugo thinks. Lugo, the director of the US Forest Service’s International Institute of Tropical Forestry, has long promoted a more catholic attitude toward plants of diverse origin. I recently visited him at the University of Puerto Rico’s Agriculture Experimentation Station in San Juan, where his office sits among groves of eucalyptus and bamboo—both of which humans introduced to the island. According to Lugo, the immigrant vegetation reflects the welcoming Puerto Rican spirit. “Here, we don’t persecute trees,” he says. “The federal government is the only one that persecutes trees.”
As far as Lugo is concerned, any species that can help his island recover from past environmental devastation—near complete deforestation, large-scale cultivation of sugarcane and other crops—is welcome. In 1992 he published a paper comparing the understories of pine and mahogany plantations with those in regrowing native forests. Lugo found that similar numbers of species were growing in both places, and that many of the understory plants in the plantations were native. Moreover, he found the older plantations were starting to give way to native overstory trees. “The study challenges the conventional dogma…and underscores the dangers of generalizing about all tropical tree plantations or all natural tropical forests,” he wrote. According to science writer Emma Marris, it took Lugo almost a decade to get his paper accepted.
As my devoted readers no doubt realize by now, I’m on a bit of a Rachel Carson kick. I wrote a blog post and produced a radio show about her last fall, and I’m working on an article about her for Johns Hopkins magazine (Carson got her master’s degree at Hopkins). Why this slight Carson obsession? It started with the 50th anniversary of Silent Spring, which got me wondering, as a science writer, how someone armed only with scientific knowledge and words could have such influence. I believe we science writers sometimes sell ourselves short in terms of what we can accomplish, especially in this age of disposable Web writing. Carson can remind us of the potential of writing for impact, not just for mouse clicks.
In 1953, Rachel Carson spoke at a symposium at the American Association for the Advancement of Science’s annual meeting. The topic was the sea frontier. Unlike the other eight panel members with whom she shared a stage, Carson was not a research scientist; she had until recently worked as a staff writer for the US Fish and Wildlife Service. (She was also the only woman on the panel).
At the conference she talked about the book she was writing, The Edge of the Sea, which would be based mainly on her observations, and less on the work of other scientists, as her previous books had been. Carson had scientific training, but it was her writing that earned her the speaking slot: her 1951 book The Sea Around Us had made her the nation’s most famous writer about the oceans and perhaps about all of science.
Although Rachel Carson spent almost her entire career writing about the sea, she is remembered today for her one book about things that happen on land. That book, Silent Spring, awoke the American public to the dangers of many common pesticides, and launched the environmental movement. But while the birth of environmentalism would not have happened exactly when it did and how it did without Carson’s advocacy, it would have happened: Americans would not have tolerated smoggy cities, burning rivers, and toxic chemical clouds for much longer. “I suspect that the audience [of Silent Spring] was close to an environmental awakening,” said Jane Lubchenco, a marine biologist and past head of the US National Oceanic and Atmospheric Administration, at a symposium dedicated to Carson at this year’s AAAS meeting. “No doubt [Carson] catalyzed it, but the ground was fertile.”