It’s hard to be a maple: How climate change is remaking D.C.’s treescape

The old tree had survived plenty.

Branches tangled in power lines. Dogs doing what dogs do. Bikes and scooters and more careening into it.

But hotter summers and milder winters had weakened the tree. Its leaves browned early, branches snapped. Its foliage thinned. Then, last winter, a truck veered off the road and into its trunk, and the maple that for decades had stood on the side of a busy road in the nation’s capital fell.

“That tree was here before I got here,” said Tom Hester, who has lived in the Cleveland Park neighborhood since 2000. “I felt bad for it, because it couldn’t catch a break; it just kept getting damaged over the years. Until that was it.”

It was gone.

Urban development and climate change have contributed to the annual loss of thousands of D.C. trees and threaten the long-term survival of some of the region’s native tree populations. Analysis of data by The Washington Post found that in order to expand the tree canopy — a longstanding priority for D.C. — humans with the city’s Urban Forestry Division have mostly given up on trying to preserve certain species of trees, and instead have prioritized ones they believe will fare better amid unceasing construction, temperature fluctuations and long-term climate shifts.

Those decisions will hasten a dramatic and long-term change in the District’s treescape that also stands to impact bird and insect populations, the ability of the region to endure floods and extreme heat and even the vibrant foliage D.C. is known for in the fall.

Even the most modest ecological projections show that D.C. could see permanent species shifts by the end of the century.

That means trees that have thrived for hundreds of years in the region may vanish by 2100, and new varieties will settle in. Some of those changes are already underway — and people who care deeply about the trees in this region have begun to notice.

“There will be a tremendous sadness when certain species of trees can no longer make it here,” said Melanie Choukas-Bradley, a naturalist and the author of several regional nature books, including “City of Trees: The Complete Field Guide to the Trees of Washington, D.C.”

In the nearly 50 years that Choukas-Bradley has gotten to know D.C.’s trees, she has watched many of them die — of natural and human-driven causes. As climate change worsens, she said, she is bracing for more losses to come: “Seeing species of trees you’ve known for years start to disappear, it’s very painful. It’s like losing a friend.”

To get a better sense of what species may vanish over time, and which may explode in number, The Post analyzed D.C. and federal data to determine what types of trees are being favored by city arborists and landscapers and what trees are vanishing in the nation’s capital.

Threats to D.C.’s tree goals

Known nationally for its public green space, D.C.’s most postcard-worthy views show off its distinctive treescape: Pink and white cherry blossoms in the spring. Golden ginkgos in the fall. Manicured federal parks and tree-lined city streets.

According to the nonprofit Trust for Public Land, which has named D.C. the best big-city park system in the country for five years running, 99 percent of the District’s nearly 700,000 residents live within a 10-minute walk of a park.

All told, an estimated 2 million trees live in the District. Among those, roughly 200,000 are street trees, maintained by the city. Hundreds of thousands more reside on federal and private property. A thousand such trees have been planted along the rolling green hills of a historic Catholic cemetery in Northeast Washington.

On a recent afternoon, arborists and tree-care workers unfurled hoses to water young saplings trying to survive their first full year in the ground. The sun was high and hot as workers perspiring in neon yellow shirts drove huge mounted tanks from tree to tree.

Mount Olivet Cemetery is one of the largest sites maintained by Casey Trees, a nonprofit that works with the city to restore and maintain the District’s canopy. It’s also a place where the city’s shift toward specific types of tree species is on full display.

White-flowering catalpa trees that were first found in forests throughout the Midwest dot the cemetery’s rolling knolls alongside needly bald cypress trees that hail from the Southeast and can grow in a wide range of swampy wet or dry, compact soil. Tough and fragrant Kentucky coffeetrees that can thrive in the face of drought and urban pollution live among showy tulip poplars and sturdy burr oaks.

Over the last several years, the District has relied on a team of about two dozen arborists to tend to its trees.

Their goal is a daunting one: a canopy cover of 40 percent citywide by 2032.

To achieve that, the city is pouring immense effort and attention into bolstering its street trees — those that line neighborhood sidewalks and medians.

If D.C. succeeds, it could help businesses and residents lower annual energy costs by more than $3.5 million and fortify the city against a changing and increasingly unstable climate, according to a report from the D.C. Department of Transportation. But to get there — and increase the canopy from the 37 percent cover it has been hovering around for the last five years — the District must plant more than 8,000 trees annually to outpace the loss of trees that are being removed or dying and to ensure significant enough survivability of new saplings.

To make it to maturity, saplings must survive threats big and small: Invasive vines that choke roots. Insects feeding on sap, stunting growth. Deer that assault them with their antlers. Hotter, drier summers that shorten a tree’s lifespan. Diseases and invasive parasites. Urban development and construction that can compact soil and hurt root health.

Meanwhile, budget cuts to programs aimed at aiding the city’s trees have undermined the District’s ambitious goal. The Trump administration this year froze tens of millions of dollars in funding to grants that sustain urban forestry efforts by nonprofits like Casey Trees.

Nick Smalley, the field manager at Casey Trees who oversees planting and maintenance efforts and deploys teams of arborists around the District, said his crews have shrunk. The nonprofit expects it will not be able to plant more than 5,000 trees in the upcoming season — just a little more than half of what it was able to put in the ground last year.

That means making shrewd decisions about resource allocation and what trees make sense to propagate, upkeep or remove.

“It’s hard because you really want to replace big trees with big trees that are going to do something,” Smalley said. “There’s so much beauty in a tree that is actually going to provide for the environment long-term.”

Prioritize, maintain and reduce

Tree turnover in the District is happening species by species, block by block.

The rate at which D.C.’s trees are changing is unnatural. That’s because of human intervention: The Urban Forestry Division sorts trees into three categories — prioritize, maintain and reduce — based on a wide range of factors, including which ones experts believe are most drought-tolerant, will live longest and will contribute the most to the city’s overall ecology.

“What we ask trees to do today is in some ways different than when L’Enfant designed the layout” of D.C., said Earl Eutsler, the District’s state forester, who oversees the planting and maintenance of city street trees. “Where people may have viewed trees as more of a decoration, we’re now saying we need trees to provide cooling, shade and we need them to reduce heat stress.”

In 2021, the city released a list of the 31 trees it aims to prioritize for planting. It included the overcup oak, a tree native to a more southern climate, primarily along the Atlantic and Gulf coastal plains.

“We tried to pick the trees that not only would do well in our climate but also the trees that would do well next to each other,” Eutsler said. “Our goal was to create a healthy, climate-tolerant forest.”

The Post’s analysis of which trees the city is prioritizing shows they have attributes that differ from trees that have long lived in D.C., like the sugar maple, which has been steadily declining in numbers and is slated for reduction over time. Some of the newer species D.C. is bringing in can tolerate longer stretches without rain and are more forgiving of their personal space being encroached upon.

One outlier in all of this: cherry blossoms, which are sensitive to temperature fluctuations, drought and other disturbances. (RIP, Stumpy.) Despite indicators that they will not do well in a changing climate, data shows these beloved trees are still getting the celebrity treatment and enough attention to keep their numbers strong.

All told, the District has removed more than 37,000 trees over the last five years. Some were sick. Others had reached the end of their natural healthy lives. Others were in the way of new construction projects and ongoing rapid development, much of which, data shows, is concentrated in D.C. neighborhoods most vulnerable to volatile climate shifts like extreme heat and flooding.

Several recent high-profile construction projects have thrust into the public sphere a debate over uprooting healthy, mature trees. The Washington Commanders’ return to Northeast Washington has threatened the fates of several dozen heritage trees — mature plants whose trunks measure at least 100 inches in circumference and are illegal to cut down without explicit permission from the mayor. The D.C. Council passed legislation that made it easier to chop down those trees, but in September, Commanders President Mark Clouse told the council that the NFL team intends “to protect as many of the Heritage Trees as possible.” There are an estimated 31 heritage trees on the stadium development site.

In Rock Creek Park, which is federally owned and managed by the National Park Service, a controversial $25 million plan to renovate the Rock Creek Park Golf Course will involve axing at least 1,000 mature trees — though the federal government and its partner, nonprofit National Links Trust, have pledged to plant three new trees for every healthy, native tree removed.

These high-profile cases will contribute to an overall loss of more than 2,000 trees annually. But even the District’s routine removals disproportionately affect certain species more than others, data shows.

Maples — specifically sugar maples and Norway maples — are declining rapidly: more than 46 percent over the last 15 years, The Post found. Other species, including pin oaks and American elms, have also seen their numbers drop by more than 12 percent since 2010.

The reasons these trees are being cut vary.

Norway maples, for example, are hardy and resistant to many of the challenges of growing in a city, but, experts say, they’re also an invasive plant that outcompetes native trees and can overtake an area. Sugar maples, on the other hand, are native to the region, but generally do better in cooler, more consistent weather.

Trees being promoted citywide, such as cherrybark oaks, willow oaks and sugarberries, are more common in climate zones in the southern and central regions of the country, according to data from the U.S. Department of Agriculture. Trees on the District’s “prioritize” list are also taller, live longer and are more resistant to periods of drought, heat and erratic weather shifts.

The average height of trees that the city wants to promote is about 90 feet tall at full maturity. Currently, the average height of the District’s street trees is about 70 feet tall.

“We’ve found that our weather is becoming more like the Midwest,” Eutsler said. “Even though the amount of rain we received each year is about the same, we’ve noticed that there are longer stretches of weeks and months where the city doesn’t get any rain compared to 10 years ago.”

Imagine a city like St. Louis.

Or Kansas City.

That, Eutsler said, could be predictive of what D.C. may eventually look like.

Changing one tree species for another may not seem like a big shift on its face, but losing trees that have, in some cases, existed in the District for centuries may have wide-ranging and hard-to-predict impacts on insects, animals and even people.

Some naturalists in the region resist the notion that humans should get involved in tree migration, the natural process by which trees slowly move to new regions over the course of centuries, or, in some cases, millennia. Critics argue that it may expedite change that other flora and fauna are not yet ready for — and that nature has its own way of adapting to a shifting climate.

Alonso Abugattas, who runs the Capital Naturalist blog and social media pages, said his “biggest worry” is that as humans begin to filter out whole species of trees, “we’ll lose everything else that depends on those trees.”

“Mother Nature changes on her own,” Abugattas said. “Slowly. But still, I just don’t think we need to assist in that.”

Others, like naturalist Choukas-Bradley, have applauded the proactive efforts the District is taking to get ahead of climatological shifts, saying that D.C. has long been a “shining example of a tree-filled city.”

“Trees make us happier and healthier. They cool the air, they delight us with their beauty through all seasons, they shade our streets, they grace our parks, and I’m so glad that cities are increasingly recognizing the importance of urban trees,” she said. “That is something that Washington, D.C., has never forgotten.”

One of the more obvious ways people may begin to notice tree changes is in the District’s colorful display of fall foliage. Typically, D.C.’s trees take on a wide range of autumnal hues: reds and oranges, purples and yellows.

But the trees being prioritized trend toward gold in the fall — a phenomenon that city officials said is unintentional. Red- and purple-leafed trees will, according to The Post’s data analysis, become increasingly rare.

In the last 15 years, the number of trees that turn red in the fall has declined from 35 percent in 2010 to just about 27 percent today. In that same period, the portion of trees that go gold as the seasons change has increased from 50 to 55 percent. Trees like the willow oak, which does better in warmer climates, and the ginkgo tree, which adapts well to urban settings, have helped drive this shift.

Changes like this to the environment in which people live may affect Washingtonians in unanticipated ways.

“There’s this phenomenon called phenology anxiety that has to do with the timing of things in nature — when birds migrate, when trees leaf out, when they flower, all the things that run according to a natural cycle,” Choukas-Bradley said. “Climate change is affecting all of that already. And when we plant new trees or lose certain types of trees, that may change how seasons look and feel. And when things get out of whack, that can make people anxious.”

A tree grows in Cleveland Park

While the District on the whole is prioritizing trees that will grow tall and live long, there are many factors that weigh into each planting decision.

Often, arborists choose particular trees with an eye toward density and distance from other plants. Other times, they evaluate sun exposure versus shade created by surrounding trees or structures.

Sometimes, people pick trees because, well, they’re pretty.

The towering maple that once grew in front of Hester’s house has since been replaced by a flowering dogwood tree.

The sapling is small and spindly with branches that stretch upward toward the sky.

Hester watched its leaves droop during spates of drought in the midsummer’s heat. Some discolored in the sun. Though the tree was planted on city land, Hester said he felt protective of the plant. He watered it, checked up on it, made sure the dirt around it stayed packed and moist.

The tree, which promises pink blossoms in the spring, will look nothing like its predecessor.

Flowering dogwoods are small and showy. Even the tallest among them tops out around 45 feet, on the low end for a maple. They live, even in the most ideal conditions, about 50 years.

Still, to get there, it needs to survive: through the frost of winter, amid year-round traffic along the busy road. And, eventually, the many unknowns that lie ahead in a changing, warming world.