Philadelphia is a bit greener these days thanks to a city-led tree-planting push that's recently hit a major milestone.

Since the start of the Nutter Administration, 100,000 trees have taken root in public parks and private yards. Volunteers have planted 25,000 of them.

"We really wanted to depend on the citizens of this city to help us," said Michael DiBerardinis, deputy mayor for environmental and community resources.

To that end, the city has also been offering free trees through its TreePhilly program.

Launched last year by the city's department of Parks and Recreation, the program gives residents the opportunity to take home one or two trees to plant in their yards, including tulip trees and sweetbay magnolia trees.

The program, funded through a $75,000 annual grant from Wells Fargo handed out 4,000 trees during its inaugural year.

DiBerardinis said greener streets also provide a number of environmental and financial benefits.

"In terms of shade, it can actually decrease your heating bill if you have some mature trees providing tree cover to your house. In addition to that, it cleans the air and you don't want to underestimate it's role in sequestering carbon and helping out with climate change."

Mayor Nutter wants to have 300,000 new trees by 2015 as part of Greenworks Philadelphia, a sustainability effort aimed at making the city the greenest in the country.

The goal is part of a larger, longer-term effort to restore the city's tree canopy, which has taken a hit over the years as some trees have naturally died or been removed due to disease, among other things.

Nutter, DeBerardinis and other city officials will join residents tonight at the Marconi Plaza in South Philadelphia to celebrate the 100,000-tree mark.