The Right Path to a Million-Tree Urban Forest

This year’s Climate and Society class is out in the field (or lab or office) completing a summer internship or thesis. They’ll be documenting their experiences one blog post at a time. Read on to see what they’re up to.

The Nature Conservancy interns answer questions about tree species identification, and invasive pests and diseases. Credit: Manon Verchot/The Nature Conservancy

By Yue Qiu, C+S ’15

When most people think of forests, their mind immediately connects to pristine scenes of wilderness with undulating hills and valleys, highly dense tree coverage and wildlife roaming the woods. Efforts to preserve the wild forest can be dated back as early as 1891 in North America when the Shoshone National Forest in Wyoming became the first federally protected national forest. Today, there are a total of 154 protected forest areas in the U.S.

Street trees, on the other hand, are not quite the same as the ones in national forests. In recent years, the term “urban forest” has been coined to describe the public green space found in cities. Calling street trees “urban forest” at first seems to contradict every aspect of what people associate with the word “forest.” In New York, almost all urban trees are found outside of their natural settings, instead planted along streets, highways, neighborhood playgrounds and commercial developments, truncated by built infrastructure and limited by city ordinance.

When prompted with the question, “why is it important to have trees in a city?”, some might say it’s pretty to look at, fun to climb around or that no kids should grow up in ugly concrete jungle. For many, the value of having trees in an urban area is mostly landscape beautification.

But this is quickly changing. Study after study shows there are multiple benefits of urban trees, including improving air quality, decreasing asthma and obesity, reducing stormwater runoff, storing carbon and reducing energy expenditures among countless others. There is increasing traction to plant more trees and truly creating an urban forest.

In New York, MillionTreesNYC was put forward by then-Mayor Bloomberg in 2007 as one of the 132 PlaNYC initiatives, with a goal to plant 1 million new trees by 2017. Of that million, 220,000 will be street trees.

The initiative is a recognition of how urban trees are not just beautification tools, but also sinks to sequester carbon, mechanisms to conserve energy and tools to build communities. Since the program began in 2007, a total of 986,165 trees have been planted by partner organizations and volunteers, well on track to reach the goal before 2017.

Yet more is needed for a healthy urban forest in the city. Because of the limited resources, more effort has been put into planting trees than caring for trees. The enthusiasm of digging soil pits and securing root structures at planting also far outweighs the excitement — or the lack thereof — from routine check-ups that monitor the growth and health conditions of young trees in a challenging urban environment.

To answer this needs to assess and monitor the health of the urban forest, a collective of organizations including the National Forest Services, the City Department of Parks and Recreation and the Nature Conservancy have started to address this data void. This summer, I’m fortunate to be one of the three field supervisors to oversee the crucial field data collection for Urban Tree Health Monitoring program as part of the Healthy Trees, Healthy Cities initiative at the Nature Conservancy. This eight-week long program is set to not only record where new trees have been planted since the last comprehensive tree census in 2005 but also monitor the health of mature urban trees for the presence of non-native pests and signs of diseases.

Rachel Holmes, the Conservation Coordinator for the Urban Tree Health Monitoring program, said, “[we] can’t just keep planting more trees and not look after the ones that we’ve planted.”

She also suggested that mature trees can provide far more ecological and social benefits than their young counterparts and that it would be a misuse of resources if we succeeded in planting 1 million new trees but failed to detect the spread of pests and diseases that could potentially wipe out hundreds and thousands of trees in New York.