Pastor Elbert Street noticed a small crack in the wall behind the pulpit at Grace Christian Baptist Church.
It widened. Then a branch appeared. A cluster of leaves unfurled.
That was when Street realized that something was growing between the walls of his East Baltimore church: an 8-foot-tall tree.
The 79-year-old pastor and others took the wall apart, hacked down the tree and hauled away bags of branches and roots. The tree came back. They cut it down again. And then again.
A contractor estimated it would cost $5,000 to remove the tree and fix the walls — money the church didn't have.
Now, three years later, leafy branches jut from the bricks at the rear of the church. The inner wall, covered in a fresh layer of plaster, remains unbroken. At least for now.
"It's only a matter of time before it returns," Street said.
They appear in long-vacant buildings and carefully tended structures. Seeds dispersed by wind and birds take root, needing only water, sun and a pinch of soil. The trees are reminders that Baltimore was once a forest, and, if the trees had their way, would become one again.
At least 13 grow from buildings in a four-block area on the west side of downtown. Among them are a pair of broad-leafed paulownia trees that lean from second-floor windows in vacant buildings in the 400 block of N. Howard St. Large and verdant, they appear almost to be mocking the scrawny saplings growing in sidewalk wells.
Nearby, on Tyson Street, a trunk muscles through bricks on the ground floor of an abandoned building. More trees poke from upper windows like nosy neighbors.
Smaller trees appear on some of the city's finest buildings. One is perched on an upper balcony of the Clarence M. Mitchell Jr. Courthouse. Another sits high on a balcony of the Belvedere in Mount Vernon.
The trees usually belong to two invasive species, the paulownia and ailanthus. They push apart walls, twist metal beams, and, in time, destroy foundations.
Julie Day, the city housing department's deputy commissioner of land resources, said trees growing in vacant properties can pose serious risks for adjacent buildings.
The roots can grow directly into brick and cause flooding by damaging gutters. They can even dislodge the foundations of houses, she said. Workers will remove trees in city-owned buildings if they trigger complaints, she said, although the city does not keep track of the number it has removed.
Removal costs have ranged from $800 to $3,500. A home with a large tree growing in it will usually need to be gutted, Day said.
Despite their destructive nature, they can also create shade, homes for birds, and, in the eyes of some, beauty.
One such tree presides over the back lot of the Current Galleryon the west side of downtown.
It shades the lot during the day, and, at night, Christmas lights twinkle in its leaves.
"If we didn't have a tree back there, it would be like a gross parking lot," said Monique Crabb, a co-director of the gallery.
Martin Kasey, the coffee director at Station North's Canteen cafe, mourns the tree that grew between the bricks of his nearby apartment. The tree shaded his apartment's back porch before it was cut down.
"It provided this sense of enclosure, as well as the shade and the green," Kasey said.
Frank Fantauzzi, a professor of architectural design at the Maryland Institute College of Art, said the errant trees are a reminder of the ephemerality of buildings and nature's desire to create more life.
"There is a back and forth between architecture and nature whether we like it or not," he said. "When the building begins to fail, nature begins to take over."
For most, the invasive trees are at best a nuisance.
Several grow from the top floors of three buildings near the corner of Charles Street and North Avenue.
"So many people walking by say, 'Look, there's a tree growing out of that building,'" said Kevin Brown, who owns the Station North Arts Cafe, which is on the bottom floor of one of the buildings.
Brown said the trees have been growing in buildings on the block since he leased the space for his business in 2005. Now they have grown rangy. Brown hopes to buy the building and remove the trees.
"I just want them gone," he said.
Paulownia and ailanthus trees once received a very different reception in this country.
Both were used to make medicines in their native China, according to Arnoldia, the magazine of Harvard University's Arnold Arboretum.
Europeans, impressed by the species' rapid growth, began shipping them to Europe and North America in the late 1700s and early 1800s.
Paulownia, which has broad, heart-shaped leaves, was named for a Dutch princess, leading to the nickname "Princess Tree." Ailanthus has spindly leaves that grow in symmetric rows along its branches. It is called the "Tree of Heaven" because of its rapid ascension to the sky.
In the 1800s, both species were planted in fine estates. But soon they were choking out other varieties of trees. By the early 1900s, gardeners no longer prized the two species. But they had taken root, especially in urban areas.
The "Tree of Heaven" inspired the title of the 1943 novel "A Tree Grows in Brooklyn." Author Betty Smith described it as a tree that "liked poor people."
"It grew in boarded-up lots and out of neglected rubbish heaps and it was the only tree that grew out of cement," she wrote.
The U.S. Department of Agriculture considers both trees invasive species. Once they send down roots, they are very difficult to remove.
But some buildings can still be salvaged after trees take hold.
The long-vacant former Centre Theater on North Avenue contained three trees when Jubilee Baltimore Inc. began renovating it two years ago. The first phase of the project, which will eventually house a joint film program between MICA and the Johns Hopkins University, is slated to be complete in the spring.
"You really felt like Indiana Jones breaking into a temple," said Jubilee's president, Charles Duff.
The trees grew in a stairwell, their trunks slanted as they reached for the light, Duff said. Workers made several attempts to remove the trees before finally killing them with herbicide.
"The life force was pretty strong," he said.
Street, the pastor of Grace Baptist, is well aware of the tenacity of a tree. He is hoping someone will come forward to help remove the one that grows in his church.
The red-cushioned chairs are arranged in precise lines before the pulpit. Brass chandeliers gleam. But chaos waits in the wall.
Street can still point out the spot, a few feet to the left of the gold cross, where the tree split the plaster.
The tree is one of many problems plaguing Street's church, which is in the former Park Theater, near Johns Hopkins Hospital.
Vandals stole a sign from the front of the church. The congregation has shrunk as former members have moved away. Street often stays up at night worrying about finances, and the congregation doesn't have the thousands of dollars it would take to permanently remove the tree.
"We believe in miracles, so we're looking for a miracle here," he said. "We've been looking for a miracle for a long time."