Developers, homeowners who put additions on their houses, and owners of buildings being converted for new uses may be forced to buy and plant trees along the street to aid in the effort to meet Mayor Bloomberg’s goal of planting 1 million new trees by 2030. Under a new proposal put forth by the Department of City Planning, these property owners and developers of new properties would have to purchase and plant at least one tree for every 25 feet of their property that runs alongside a street. Once planted, the trees would be maintained by the city. An organization that promotes the planting and preservation of trees in the city, Trees New York, estimates that it costs between $500 and $800 to purchase and plant a tree in the city. The city’s Department of Parks and Recreation plants trees for free upon request, but Trees New York states on its Web site that high demand means there can be a two-year wait.

The city’s proposal does not state whether property owners would be able to request a free tree from the city, nor does it say how long they would be given to meet the requirement, if approved. Trees already planted along the property would count toward the requirement.

A City Council member of Queens, Tony Avella, is promising to fight the proposal, saying he takes issue “with forcing a tree on a homeowner.” He said he is concerned that the city will not prune the trees on a regular basis.

“I think it’s a good goal, I just don’t think you should do it on the backs of homeowners,” he said. “There are people who have said the mayor has set an impossible goal.”

A former parks commissioner, Henry Stern, said the proposal is a wonderful idea, but he suggested the cost of purchasing new trees and planting them be shared by homeowners and the city.

“To see the city intervening, encouraging the planting of trees, is a great step,” he said. Trees “are the kings of the plant kingdom.”