District's volunteer tree keepers battle nature and neighbors to help city grow its canopy The dulcet affirmation delivered by Cooke isn't just some quirk for her home garden. Cooke is a tree keeper, entrusted to watch and water - and maybe talk - to one of thousands of new trees planted across the District. The arboreal army, with more than 1,000 volunteers, is the first line of defense in a city program to obscure the District's skies with tree tops. And the dead of summer is the biggest battle season. The air is thick, and the soil is dry. Fragile young trees need water, lest they perish, which would suit some neighbors just fine. A few houses down on 18th Street SE, Elizabeth Miles fumed about the tree planting. "The last time I had a tree, the roots got all in my water line ," Miles, 72, said. Now some man came and put up a new tree. I don't want it! I tried calling tree-one-one, I mean 3-1-1, and they couldn't do anything. Cooke, who has loved nature since she was a little girl, tried to explain the worth of trees - their aesthetic beauty and how they help boost property values - to neighbors. She talked to her neighbors as sweetly as she would to Marie. Yes, the tree has a name. "They think I'm a little weird," said Cooke, laughing. Tree cover has recently emerged as not just an environmental indicator but an economic one, with poorer places usually having less shade. Citing the many benefits of trees, the District is aiming to have 40 percent of the city covered in a tree canopy by 2035. The goal has led to a blitz of saplings seen throughout the city. About $1.6 million in mostly federal funding was spent on planting more than 7,000 trees last year. Efforts were concentrated east of the Anacostia River and other neighborhoods where there isn't much shade. Planters haven't always been welcomed, said John P. Thomas, the city's supervisory arborist. Neighbors are concerned that trees will mean leaves to rake and bird droppings to wipe off cars, or a shadowy area perfect for drug deals. "We've been yelled at and told to get off the property, but we only use city property,"" Thomas said. Some people have called their councilman. Some people have said they are bringing out a shotgun. We say, "We're just planting trees." " Three years ago, the city created the adoption program to improve man-nature relations. It was cheap. The alternative was contracting a company to bring out a truck and water every new tree, driving up the project's costs and its carbon footprint. So city officials advertised the Canopy Keeper program on billboards outside liquor stores. They hired youths to fan out across neighborhoods with young trees, wrapping on cards that say "adopt me" and bar codes that can be scanned with a smartphone for information.