WE'RE HARDLY out of the car in a blighted block of southern Baltimore when faces appear at windows and doorways. Three strangers, one scribbling notes, heading for a back alley - something's up.
The truth is stranger than the neighbors might believe. Marion Bedingfield, a city forester and big-tree guru of Baltimore, has brought us here to appreciate the full and glorious potential of a weed.
When you're responsible for about a half-million trees, it's hard to have one favorite, "but I can tell you we're all proud of this bad boy," Bedingfield says, pushing through junk and mattresses that clog the alleyway.
And behold, mid-alley, from a cratered, eroded back yard, rises the city and state champion ailanthus. As big around as three people, hands linked, could reach, it soars three stories high and shades, it seems, half the block.
Don't get close, Bedingfield warns. The landlord's not friendly. Bedingfield had to confirm its championship measurements on the sly while trimming some limbs encroaching on adjacent rooftops.
Tree of heaven is the ailanthus' common name. But land managers call it tree of hell, a weedy, normally scraggly, invasive species with soft, stinky wood and scant wildlife value. It's virtually the only thing that will flourish in the poor soil and dim sunlight of dense city neighborhoods.
So it's fitting that here, on this mean block, something stately and world class can flower. In fact, the ailanthus is one of about 20 state champion trees within the city's borders.
Bedingfield, a 25-year veteran of the city Forestry Division, has published a register since 1989 that catalogs Baltimore's finest, most unusual and historically significant trees. He also gives, by appointment, usually for groups, a three-hour tour of the city's surprisingly diverse treescape.
So much emphasis around the bay is put on the immense values of forests for cleansing air and water, one forgets the sheer beauty and artistry individual trees can achieve when freed, in parks and street medians, from the forest's stern competition for sunlight.
"Every tree has a story," Bedingfield says. There's the Al Capone weeping cherry, for example. On the 33rd Street side of Union Memorial Hospital, with a spread of 42 feet, in blossom it's one of Baltimore's great spring exuberances.
During 1939 and 1940, the gangster Capone frequented the city for syphilis treatments. He was denied admission by Johns Hopkins. In appreciation to Union Memorial for admitting him, Capone donated money and the cherry tree.
Druid Hill Park, third-oldest urban park in the nation, is a staple of Bedingfield's tour. There's a black gum, 66 feet high, spreading 88 feet in great, dark, twisty arches. In fall it has some of the most intense red color to be seen in any tree, Bedingfield says. And in winter, only the dying American elm, victim of a blight, more elegantly frames patches of blue sky among its limbs than the old gum.
Just off Druid Lake Drive in the park is the city's biggest paulownia, about 16 feet around. In Japan, it is tradition to plant one when a daughter is born, and when she marries, to make a wedding chest of the wood, which takes a fine, high polish.
Paulownia seeds were used as "popcorn" to pack merchandise for shipping, the forester says, which accounts for the paulownia's showy, purple-blossomed presence along roads and railways.
By the entrance to the zoo stands a grove of sturdy swamp white oaks, the first memorial planted in the United States honoring World War I vets. They are 81 years old and have many centuries left in them.
The swamp oak is not much for fall color, but when a breeze flutters their leaves, turning the silvery undersides to and fro, they are a summer show to equal quaking aspens in the Rockies.
Also in the park is what Bedingfield calls "the most drawn and painted tree in the city," a mammoth Osage orange.
One of the few North American trees with wood heavier than water, the Osage orange was prime material for the bows of Native Americans. In the Midwest it's known as bois d'arc (bow wood).
To do the city's notable trees justice would take days - and all four seasons. There's the 110-foot-tall bald cypress in the 700 block of E. Northern Parkway, and the massive copper beech, nearly 15 feet around and 104 feet high on private property in the 100 block of Castlewood Road.
Also the huge gingko biloba in the 700 block of Evesham Road, a tree that can live six centuries or more. The gingko is known these days more for an extract held to boost memory, but no one could forget the rich, buttery gold it turns in autumn.
Despite its success as a city street tree - Redwood Street and the 500 block of N. Calvert St. are good examples - "a gingko is the only tree we'll cut down while its still living," Bedingfield says.
That's because females - you can't tell the sex until they mature after about 17 years - drop fruit that smells like vomit.
Other lessons peculiar to urban forestry, Bedingfield says, include: "Never, never plant black walnuts or fruit trees next to a school." The fruits and nuts readily become "alley apples," ammunition for fights.
For information about city tree tours or to order a list of Baltimore's notable trees, call the city's Forestry Division at 410-396-6108.