By Robert McDonald, Lead Scientist for Global Cities, The Nature Conservancy

Would you spend $8 per year to see your community reduce rates of obesity, heart disease, anxiety, and asthma? Still not convinced? What if that investment also reduced energy costs and increased property values?

Urban trees can transform city neighborhoods, contributing to a wide range of public health gains, and investing an additional $8 per person, on average, in planting and maintaining urban trees could have a significant impact. Yet across the United States, cities are losing about 4 million trees per year.

The humble street tree is an ecological powerhouse. Study after study has shown multiple benefits to people and society. Trees and other green spaces in cities can help manage runoff during rainstorms. They can help clean and cool the air, reducing harmful air pollutants and air temperatures on city streets. They lend beauty to our communities and significantly increase property values. And time spent in natural environments has demonstrated mental health benefits.

A new white paper written by me and my colleagues at The Nature Conservancy, along with The Trust for Public Land and Analysis Group, raises the concern that a combination of reduced budgets and the ravages of drought, storms and pest infestations takes a toll on urban trees, and without investment, cities are losing all the benefits that trees provide.

Our paper finds that meeting the funding gap for urban forests would cost only $8 per resident per year. The report, titled Funding Trees for Health also finds that a significant percentage of that cost could be offset by the public health gains that city trees provide.

Recent research focused on major US cities found that urban trees could account for $25 million in annual savings related to healthcare costs and lost work days from air pollution alone.

Every year, between 3 and 4 million people around the world die as a result of air pollution and its lifelong impacts on human health, and urban trees that a serve as pollution barriers and even filter the air are a cost-effective solution. Granted, the situation varies greatly in different cities across the world. Nevertheless, our analysis demonstrates that a green urban future is not an impossible dream, but is quite affordable in most places, if policymakers and others commit to making this critical investment.

The full paper offers several specific examples of innovative public-sector partnership and private sector investments that highlight the full societal value of urban trees. However, municipal leaders in communities of all sizes can begin to address significant health challenges by thinking creatively about the role of nature in cities and towns:

  • Establish codes to set minimum open space or maximum building lot coverage ratios for new development.
  • Implement policies to incentivize private tree planting.
  • Break down municipal silos to facilitate various departments – such as public health and environmental agencies – to collaborate.
  • Link funding for trees and parks to health goals and objectives.
  • Invest time and effort in educating the public about the tangible public health benefits and economic impact of trees.

All cities, big or small, can begin exploring ways to create links between the health sector and urban forestry agencies. The key is connecting public health outcomes to urban trees. Communication and coordination between a city’s parks, forestry and public health departments can reveal new sources of funding for tree planting and maintenance. Working together, the health sector and the urban forestry sector can achieve a healthier, more verdant world.

To learn more, download The Nature Conservancy’s in-depth analysis at

Dr. Robert McDonald is Lead Scientist for the Global Cities program at The Nature Conservancy. He researches the impact and dependencies of cities on the natural world, and helps direct the science behind much of the Conservancy’s urban conservation work. He holds a PhD in Ecology from Duke University and has published more than 50 peer-reviewed publications, and a recent book, entitled Conservation for Cities.

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