Mayor Bill de Blasio celebrates planting of NYC's 1 millionth tree, praises predecessor Michael Bloomberg

New York City Mayor Bill de Blasio Friday celebrated the planting of the city's 1 millionth tree and his predecessor, Mayor Michael Bloomberg, who began the program.

"Today, we plant a tree that marks the completion of a great vision," de Blasio said at the Bronx event. "And the visionary stands to my right in the stylish yellow sweater," de Blasio continued, referring to the former mayor.

It was a rare joint appearance between the two men.

De Blasio was a harsh critic of Bloomberg during his years as public advocate and kept up attacks on his record after becoming mayor, especially on education and policing.

As of late, de Blasio has been hurting in the polls among constituencies that liked Bloomberg, such as white, middle-class voters.

De Blasio noted that some of his green initiatives build on those of Bloomberg.

The millionth tree, a lace bark elm, was planted at Joyce Kilmer Park, named after the World War I soldier who wrote the poem "Trees" before he was killed in action in 1918.

Bloomberg noted that the new trees have helped make the city's air the cleanest it has been in half a century.

The program, which hit its goal two years early with the planting of 1,017,634 trees, was one of the signature aims of Bloomberg's PlanNYC initiative, which he began eight years ago, to make the city sustainable.

Jesting that the podium seemed a little taller than he remembered, Bloomberg said: "Trees really do improve the air and our mental health, and improve real estate values."

De Blasio pledged: "We're not stopping; there will be 150,000 trees planted over the next three years to continue this tradition."