New York is far greener than anyone expected.

Researchers carrying out a huge survey of New York City's trees found there are over 5 million 'forested natural areas' along with 666,000 street trees.

They say the study, the most comprehensive ever of New York's 'urban forest', could revolutionize urban planning.

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During the two-year inventory field biologists collected data from all of New York City's parks and natural areas. While 40 percent of the city is considered 'green space,' much of that includes parks, cemeteries, and back yards.

WHAT IS IN NEW YORK'S URBAN FORESTS? During the two-year inventory field biologists collected data from all of New York City's parks and natural areas. While 40 percent of the city is considered 'green space,' much of that includes parks, cemeteries, and back yards. About an eighth of this green space is considered forested natural areas. That accounts for over 10,000 acres of natural lands, a significant proportion for a densely populated city of 8.6 million people. Advertisement

'These findings confirm that native, healthy, and productive forests still exist in the nation's largest city, providing valuable ecosystem services and local recreational opportunities for millions of city-dwellers,' said Clara Pregitzer, a doctoral candidate at the Yale School of Forestry & Environmental Studies (F&ES) and lead author of the paper.

Teams spent two years collecting data in 53 designated forested natural areas, measuring the structure and composition in more than 1200 plots and measuring more than 40,000 individual trees.

Forested natural areas are essentially places that look and feel like 'the woods' or 'forests' as they are more traditionally known, the researchers said, as opposed to urban forest areas typified by street trees and park trees in in addition to natural areas.

Researchers found the city contains a variety of forests, due to the rich geologic history and proximity to water bodies in New York City — from the oak- and hickory-dominated forests along the terminal moraine that stretches from the southern end of Staten Island to the Bronx, to the maritime coastal forests, located at the confluence of the Hudson River and the Atlantic, where shrubby northern bayberries, black cherry, and sumac dominate.

Aerial view of parks in the Bronx, including Van Cortlandt Park. Researchers carrying out a huge survey of New York City 's trees found there are over 5 million 'forested natural areas' along with 666,000 street trees.

The team of researchers found that native species still comprise about 82 percent of New York City's forest stands.

While 40% of New York is considered 'green space', much of that includes parks, cemeteries and backyards.

Only about an eighth is forested natural areas, though this still represents a not inconsequential 4000-plus hectares amid the skyscrapers and 8.6 million people.

Most visitors think of New York's Parks, such as Central Park, pictured, as the only place to find trees. However,a new study found New York City has over 5 million 'forested natural areas' along with 666,000 street trees.

The researchers say the forest areas are key - and admit they were surprised by how many contained native trees.

'New York City has been managing these forests for more than 35 years but we've never fully known the different types, or quantified the structure and proportion of native species,' said.

Of the 57 unique forest types in the city, the researchers found 81 percent are native forest types that bear a closer resemblance to forests you might find in the Catskills or other rural parts of the state than the urban canopy described in those other recent assessments.

During the two-year inventory field biologists collected data from all of New York City's parks and natural areas.

While 40 percent of the city is considered 'green space,' much of that includes parks, cemeteries, and back yards.

About an eighth of this green space is considered forested natural areas.

That accounts for over 10,000 acres of natural lands, a significant proportion for a densely populated city.