The proof is on display when you climb Morris Road SE in Anacostia, or stand on Boulder Bridge in Rock Creek Park, or sit back against one of the Capitol Columns in the National Arboretum.
As if you needed proof. The richly woven autumn fabric of gold and orange and red and bronze drapes the urban landscape. You don't have to journey to the Shenandoah Valley to see trees do their amazing annual pigment tricks. Just stick around home.
Leaf colors are reaching crescendo in the District about now, and the peak should continue for a week or so, according to horticulturists. There is debate over how much dye the summer drought drained from the show. The hues "just won't have the oomph they usually do," said Robert DeFeo, chief horticulturist in the region for the National Park Service.
But Kevin Conrad, a horticulturist at the National Arboretum, said so far he hasn't noticed much difference from previous autumns. And Ranger Alyssa "Aly" Baltrus in Rock Creek Park observes that after the drought, rainfall and favorable temperatures have allowed the leaves to make a "comeback."
As for the maples exploding in red and orange fireballs on 16th Street NW, they appear to have forgotten the drought entirely.
Washington is a well-treed city. And inside every tree is a frustrated post-Impressionist artist struggling to break free. They use the palette of Van Gogh, with the possible exception of midnight blue.
Conrad leads the way to one of his favorite fall views--an array of 22 sandstone Corinthian columns that once stood at the East Portico of the Capitol. The columns now stand in the middle of a field at the arboretum, where visitors have a 360-degree panorama of surrounding woodland.
There's the deep scarlet of the black gum, the orange and yellow of the beech, the yellow and red of the maple, the straw gold of the hickory, the red and maroon of the dogwood, the hanging red flame of the sassafras, the yellow burst at the top of the straight and tall tulip poplar.
The oak, as usual, is an underachieving colorist. Its leaves go from green to tan to dead. But some types of oaks in some circumstances dare surprising improvisations in copper and maroon.
Conrad is a connoisseur who sees past the showiness of the leaves to how they work with the other hues and the spaces of the woods. Take the American beech, he said. It has exquisite pale gray bark. As the golden flakes drift and pile at the foot of the tree, more and more of the bark is exposed, until all the gold is gone and, "Poof! You've got a silhouette of a gray tree."
He also makes the case for the evergreens. Most people dismiss them as boring suit-wearing party poopers in fall. But Conrad savors the contrast they establish with their more frilly deciduous neighbors.
And he appreciates how some evergreen species lose their older needles now. The needles turn gold on the green branches before falling to weave a carpet of gold on the forest floor.
For another view, leave the columns and step down a trail into the woods. With the afternoon sun suffusing the dripping yellow of a bottlebrush buckeye, or the still-green of a deep-forest beech, it's like standing inside a paper lantern.
Even the exotic and tiny bonsai tree sports little daubs of autumn makeup. The arboretum's Bonsai Fall Foliage Show continues daily from 10 a.m. to 3:30 p.m. through Sunday.
Tree art owes a lot to biochemistry. The green of a leaf is from chlorophyll, a molecule that acts like a cloaking device, masking the other colors that are present all along. Chlorophyll helps the leaf make sugar from sunlight, a process known as photosynthesis. Chlorophyll can't absorb green light, which gets reflected and becomes the color of the leaf you see.
In preparation for winter, the leaf stops making chlorophyll, allowing the colors of other molecules present in the leaf to show through--the basic yellows, oranges and reds, plus all the coppers, umbers and plums in between.
Around the city, maples and dogwoods are the most reliably gaudy street trees. There's a brilliant burnt-orange maple to greet Virginia commuters after they cross the Roosevelt Bridge.
The Mall's treescape is somewhat monotonous because of the uniform planting of elms. But Constitution Gardens has a variety of blazing species, as do the fringes of the Ellipse. The cherry trees around the Tidal Basin last week were a soft rusty red, like scouring brushes, as crisply apt for this season as their pink cloud disguise is for spring.
At the Capitol, many of the trees had barely begun to turn, except for the pale yellow Eastern black walnut planted at the corner of Independence and First streets SW in memory of J. Sterling Morton, founder of Arbor Day.
In Anacostia Park, a drive north from the 11th Street Bridge provides a clear view of the puffs of color clustered on the opposite shore, uninterrupted for more than a mile.
Turn around and pull onto Martin Luther King Jr. Boulevard, then left onto Morris Road SE. From the hilltop grounds of Our Lady of Perpetual Help Church, the big picture of autumn Washington is spread before you, rolling toward downtown. Earth tones lap at the cold white marble of the federal buildings.
Rock Creek Park is denoted on maps with a thick green swath--inaccurately so at this time of year. A trip down Beach Drive would require most of a box of crayons to convey. But pick a weekend day when there are no cars, and linger on Boulder Bridge--the bridge of big stones that carries Beach over the creek--and look at the colors cascading down to the water.
Farther north, above Military Road, Ranger Baltrus leads the way onto a section of the Western Ridge Trail. She points out the ferns, turning a sandy color; the low shrubs, with leaves going yellow or red and sometimes with colorful fall berries; the vines shooting up red; the hues of the smaller trees and the tall trees that date back to just after the Civil War.
"All the different layers of the forest are changing," she said.
Deeper in the forest, the autumn colors come more slowly. Looking down a wooded slope, you see the green lower vegetation, the straight soaring black trunks and the sun filtering down through a gold and green canopy.
"Fall is probably the most beautiful of all the seasons," Baltrus said. "It's not what people think of when they think of Washington, D.C."
CAPTION: A jogger passes the Tidal Basin, which reflects the variegated colors of the fall foliage. Autumn has painted the city various shades of red and gold.
CAPTION: The Washington Monument, top, is framed with fall colors when viewed from the FDR Memorial. Above, warm weather and a vivid tapestry of colors draw people to Rock Creek Park, where some young men, left, play Frisbee under a dazzling canopy.