CORRECTION: The first paragraph of this story has been updated to reflect the fact that paid foresters, not volunteers, plant almost all of the trees in this initiative.
Baltimore City is not known for its lush greenery, but urban foresters at the Baltimore Tree Trust hope to change that, one tree at a time.
Every fall and spring, members of Baltimore Tree Trust plant trees in city neighborhoods — and it’s part of the state’s effort to combat climate change. The greenery is supposed to increase tree canopy, enhance neighborhoods and cool the city’s urban heat islands.
“Houses come and go, people have come and gone, but the trees are still there and they are indicators that Baltimore is still growing,” said Bryant Smith, CEO of Baltimore Tree Trust.
The effort is part of Maryland’s goal to plant more than 5 million native trees across the state by the end of 2031. The state committed to the mass tree planting initiative after passing the Tree Solutions Now Act in 2021.
The 5 Million Trees Initiative is a collaborative effort involving state agencies, community programs and volunteers across Maryland. More than 1.5 million trees have already been planted as part of the initiative, according to a fiscal 2025 report.
Through photosynthesis, trees remove carbon dioxide — a leading greenhouse gas — from the atmosphere. The trees planted through this program could, once they mature in a few years, remove 30,000 metric tons of carbon dioxide from the atmosphere annually. The commitment will support Maryland’s goal to cut 2006 carbon emissions levels by 60% by 2031.
The benefits
A central goal of the 5 million trees initiative is to increase healthy forest cover across the state, according to Ashley Triplett-Peltzman, the associate director of policy and planning at the Maryland Forest Service.
Mass tree plantings can help improve the state’s wildlife habitats, air quality and biodiversity, which can benefit natural landmarks in the state such as the Chesapeake Bay, she explained.
Triplett-Peltzman said tree planting mitigates climate change because trees capture and store carbon dioxide in their trunks and roots in a process called carbon sequestration.
The Tree Solutions Now Act will help serve Maryland’s larger Climate Solutions Now Act passed in 2022. As part of that legislation, Maryland aims to achieve net-zero greenhouse gas emissions statewide by 2045.
Another byproduct of the tree planting effort is increased community engagement across the state, Triplett-Peltzman said.
“When we’re working with some of these groups that have gotten funding, we’re engaging volunteers and we’re also engaging students,” she said. “We’re using the tree planting to increase environmental literacy and environmental stewardship.”
Serving underserved areas
The state requires at least 10% of trees be planted in underserved urban areas – city neighborhoods that have limited exposure to trees. The initiative’s fiscal 2025 report said more than 86,500 have been planted in these communities under the program, which is paid for by state funds and local grants.
Underserved areas are determined by income levels, unemployment levels and a history of redlining or housing discrimination, according to Lianna Gomori-Ruben, a senior program officer at the Chesapeake Bay Trust.
The trust is the central organization tasked with overseeing tree plantings in underserved urban areas, which it achieves through its grant program. According to Gomori-Ruben, the trust has already made roughly 150 awards to plant more than 100,000 trees.
One of the biggest benefits of planting trees in urban areas is reducing a city’s urban heat island effect, which occurs when a city experiences much higher temperatures than nearby rural areas. This happens because buildings, roads and concrete absorb and then re-emit the sun’s heat. Tree plantings in cities can cool surrounding areas, sometimes as much as 10 degrees, Gomori-Ruben said.
But tree plantings also create economic benefits. People have to be hired to plant and maintain trees, she said.
“We know that cities that have trees have higher real estate values,” Gomori-Ruben said. “So when you have trees in your community, your housing property goes up as well.”
Gomori-Ruben said most of Baltimore City — which has a history of redlining, or racial discrimination in housing finance — is eligible for funds through the trust’s program.
Smith, the CEO of the Baltimore Tree Trust, pointed out the tree plantings have made a stark difference in the city’s communities. The trust has planted trees in places such as lawns, grass strips, parks and schools.
Abandoned buildings with lots of concrete are now turning into streets lined with trees, said Smith, who was born and raised in Baltimore.
“I’ve definitely seen the benefits and the major impacts of the work that’s been done in urban forestry city, but also other indicators that the work’s not done and we have to continue to focus,” Smith said.
‘It’s a partial solution’
Maintaining the trees planted is just as important as putting them in the ground, according to Triplett-Peltzman at the Maryland Forest Service.
“There’s just such a history of going to a place, planting trees and leaving,” Triplett-Peltzman said. “And then the survival rates for these trees is historically really low.”
She added that other factors such as deer and invasive plant species can impact the survival rates of seedlings.
About 30% of new trees planted are likely to die within the first few years of planting, according to University of Maryland geographical sciences professor George Hurtt, who conducts research for the 5 million trees initiative.
As a result, the state aims to plant more to make up for the trees that are likely to die, Hurtt said.
Hurtt also said all trees planted must be native to Maryland, since non-native tree species may invasively outgrow other trees.
Maryland is expected to plant more than 4.5 million trees by 2031 based on the average survivorship of trees committed under state and federally funded programs, according to a 2024 progress report for the initiative.
Despite the benefits of tree planting initiatives, Hurtt added other things must be done to combat climate change. Since fossil fuel emissions warm the planet more than anything else, more efforts need to be made to switch to renewable energy sources, he explained.
“It can’t solve the entire problem,” Hurtt said of the tree planting initiative. “It’s a partial solution.”
Frances Marie Panday, a data analyst at the Maryland Department of Environment, said even though the carbon benefit of trees might not be realized until they mature 10 years down the line, it doesn’t mean the state can’t start mitigating the impacts of climate change now.
“Tree planting is just one level we use to get us closer to that goal,” she said. “We recognize that we can’t rely on low-hanging fruit to address that.”
Nationwide comparisons
Across the U.S., several other states have committed to mass tree planting initiatives, including Wisconsin and New York.
Maryland is unique in its approach to a mass tree planting initiative because it is the first state in the nation to utilize a remote-sensing methodology to quantify the carbon benefits of trees, according to Panday.
Researchers for the 5 million tree initiative use high-resolution satellite data and artificial intelligence modeling to confirm the locations of the plantings. They also detect the amount of carbon stored in each tree.
“That’s one of the ways that we are leading the charge on utilizing our natural and working lands, as we want to make sure that the forest carbon sequestration benefits of trees are captured in our greenhouse gas inventory,” Panday said.
Maryland’s commitment is unique because the 5 million tree initiative is codified in state policy, according to Tanner Haid, the senior director of urban forestry field delivery at American Forests. The statewide commitment gives the initiative authority, accountability and funding, he explained.
Maryland’s Tree Solutions Now Act not only represents a statewide commitment, but makes the initiative an interagency effort, according to Haid. The Department of Agriculture, the Department of Environment, the Department of Natural Resources and the Chesapeake Bay Trust team up to lead the initiative.
“The goal is bringing people together,” he said. “That’s what makes what Maryland is doing, and some others, special because it’s like this cumulative approach of all of them working together towards it.”
Gary Allen, president of the Maryland Forestry Foundation, pointed out that Maryland’s efforts should be viewed as a collaboration with other states, rather than a competition.
The U.S. has a history of losing forest cover due to urban development, Allen explained. He said that in the early 1980s and 1990s, Maryland lost more than 1,000 acres each month because of development.
Although the state has cut that number down to fewer than 200 acres a month, Allen said the 5 million tree initiative is still essential in bringing back the state’s forest canopy.
“The highest benefit of a piece of property is not always to have it paved over and a building put on it,” Allen said. “Sometimes the best thing that can be done with it … is to actually preserve and protect the natural cover on that land.”