Historian studies vital role trees play in our big cities
WASHINGTON In the leafy Connecticut Avenue corridor in Washington, big old street trees are saying a slow farewell to a growing season. Some 60-foot oaks attest to years — even decades — of knowing stressful conditions in tight root boxes, and they should be admired for their survival skills alone.
I say a slow farewell because this year many trees seem to be reluctant to let go of their leaves. I’m talking about trees where the entire canopy of foliage remains firmly attached in mid-december, albeit in fall coloration.
Sonja Dumpelmann, a landscape historian at the University of Pennsylvania, was recently in her native Germany and noticed the same phenomenon while riding the train to Weimar. In the Cleveland Park neighbourhood, we found the leaves still clinging — in the case of a sweetgum, they were just changing from green to yellow.
What gives, we asked? Neither of us knew, but we live in strange times when shifting natural cycles seem bound up with unpredictable patterns of weather and climate.
One thing seems certain: The need for street trees is only going to get greater. They shade, they cool, they grab carbon from the atmosphere. Oh, and they can be beautiful if spared the butchery of life with the aerial power line. A 2015 study confirmed people who live in the shelter of mature trees are healthier than folks in neighbourhoods that don’t have them.
Even before the age of climate change, the value of the urban forest was understood.
Dumpelmann tracks the history
of the modern street tree in her book Seeing Trees, a deep, scholarly dive into urban society’s need for — and relationship with — trees that sought to return the natural world to the concrete jungle.
Her focus is on two great sylvan cities — New York and Berlin — but she gives a nod too to Washington, the first city in the United States to implement a street-tree planting program, she writes. By 1912, the capital had almost 280 miles of double plantings of street trees — about 100,000 trees and, crucially, a program of annual replacement.
Around the same time, civicminded tree lovers in New York were pressing the city to create an urban forestry agency to plant and care for street trees, Dumpelmann writes, especially in poor and tenement neighbourhoods in need of better sanitation.
The effort was led by a physician, Stephen Smith, and other figures, the sculptor Augustus Saintgaudens
and financier J. Pierpont Morgan among them. Smith had written an influential paper equating the lack of trees and summer heat with childhood mortality.
Today, the citizens and civic leaders of both Washington and New York embrace the urban forest with enthusiasm and resources. Public, private and non-profit partnerships have led to a resurgence of tree planting. In New York, the city launched a program in 2007 to plant one million trees, a task that was finished in 2015.
Trees were not always hugged like this. Older folks will remember the decline of American cities in the postwar decades, and in Washington, the city’s tree canopy withered as people abandoned the urban core for the suburbs. “Disinvestment” in communities, Dumpelmann says, “automatically meant disinvestment in the urban forest.”
Now, ironically, the sprucing up of the streetscape often precedes the gentrification of low- and moderate-income neighbourhoods.
“These are the big questions we need now to resolve,” she told me. “How do we see to it that everybody has access to nature and is not displaced when trees are planted?”
Some of the most poignant images from the book are of tree-planting efforts in Berlin and Kiel in the years after the Second World War, when both cities were still in ruins. One photo is of schoolboys planting saplings in Kiel in 1948 against the backdrop of a bombedout building. The children and the young trees speak to a future being built out of a horrific immediate past.
Other pictures show the replanting of Berlin’s famous boulevard, Unter den Linden, against the backdrop of mountains of rubble. The avenue by then was in Soviet control. Many of the postwar trees declined before reunification and have since been replanted.
During the Cold War, the communist authorities created a model, tree-lined boulevard in East Berlin named Stalinallee, which became part of a greening competition between the city’s two camps.
The East’s tree-planting frenzy of the early 1950s didn’t necessarily play out decades later in the form of a mature urban forest, though. Many died or declined as a result of excessive road salting and the use of gas lamps, which had the effect of poisoning plants.
Street trees can be alarmingly short-lived, so the mature oaks on Connecticut Avenue deserve to be cherished. But it is uplifting, too, to see a number of young trees in Cleveland Park getting established — beyond the sapling stage and on their way to healthy adolescence.
“This isn’t scientifically proven,” says Dumpelmann. “But I think if people care about trees, they also tend to care about people.”