Everyone likes trees.
It’s why the richest neighborhoods in your city are covered in trees. And why it was a tragedy when Detroit lost nearly all of its elm trees. Tree love is universal. Sadly though, tree cover is on the decline in the majority of American cities.
A recent paper published by researchers estimated that urban tree cover is decreasing up to 1 percent over a 5-year period. This finding roughly translates to a loss of 36 million trees per year. However, we are also losing millions in health benefits every year just from this decline in tree cover.
Hearing this was particularly shocking to me. I wanted to learn more about city trees, their value, and how they are being affected. Why do I care about trees? Well, they play a big role in the health of a city and climate change.
Whether you realize it or not, trees play a critical role in our lives. They look nice, yes. But they actually modify the environment and pack health benefits. They absorb rain, which reduces stormwater and flooding. They help remove air pollution, which is obviously bad for you. They also keep your neighborhood cooler through something called evapotranspiration and reduce your electricity bills just from the shade they provide.
The full list of tree benefits is a lot longer and includes: moderating air temperature, avoiding emissions, saving building energy use, carbon sequestration, carbon storage, improving human comfort, removing pollution, transpiration, reducing UV radiation, aesthetics or property value, providing forest products, biodiversity, nutrients cycling, wildlife habitats, avoiding run-off, reducing flooding, intercepting rainfall, and improving water quality (Source).
What does this mean? Well there are an estimated 5.5 billion trees in American urban areas. Researchers estimate these trees save $5.4 billion in energy usage, $5.4 billion from air pollution removal, $4.8 billion in carbon sequestration, and another $2.7 billion in pollutant emissions (Source). That’s a calm amount of $18.3 billion in savings provided by just these city trees every year.
Of course, there are benefits to trees that can’t be quantified. Trees have a certain amount of cultural, psychological, and supportive benefits that can’t be fully appreciated. Trees obviously provide a lot of value by just being trees.
We are losing a portion of these benefits each year. This decline in tree cover means we are losing $96 million in savings each year. The loss of trees is tragic, but it also means we are sacrificing our own health and our own wallets. We are losing millions of dollars worth of trees each year and we are losing a big part of our city landscape. We need to do something, but let’s try to figure out what is going on.
About 80% of Americans live in urban areas today and those areas will continue to grow. City growth plays a big role in displacing trees. Cities are not static islands of populations but are always growing and changing.
What I didn’t know is that cities experience growth through periods of expansion, adding more land to its area, and densification, compacting more people within its limits. As a city expands, it will clear more land for residents and businesses. As more people squeeze into a city, trees and other green space will be further pushed out.
Worldwide, the percentage of people living in urban areas will increase from 50% in 2010 to nearly 70% by 2050. This will result in even more expansion and densification within urbanised areas. As a result, more trees will be cut down and removed.
Of course, this works both ways. Cities can regrow green space in parts that are neglected or as people move out. It is why parts of Detroit actually saw an increase in vegetation from 1975 to 1992 (Source). Cities also do shrink sometimes and will actually regrow more green space. However, most urban areas in the United States are growing.
It is a hard life for city trees. They have to overcome a mixture of social and environmental factors. Trees are often hurt by social effects, like mistreatment or neglect. Cars and trucks often break off or damage parts of trees. On top of that, heatwaves and harsh climates make it harder to grow in cities. Natural disasters and climate changes also play a role in their destruction. Thousands of trees were destroyed in Houston after Hurricane Harvey. Diseases like the Dutch Elm Disease wiped out thousands of trees in Detroit. All these effects lead into a battle for regrowing trees in our cities.
The competition for the city budget is fierce. Planting and managing urban trees requires sufficient funding from the city, which isn’t always prioritized. This has an impact on the health of the city trees. Neglection leads to hazardous, dead trees, which isn’t good.
Investing in urban forestry programs is in the community’s best interest. For every dollar spent on tree planting and care, cities see an average of $2.25 returned to their residents.
What We Need
It doesn’t have to be this way. We could increase the tree coverage in our cities if we tried. Researchers estimate that large cities have room to plant 18% more trees on average. We need to get better and smarter in our city planning.
Better monitoring and analysis tools — We need better tools and systems for monitoring and assessing our American urban forests. We need to work with forestry programs to integrate well-funded restoration measures.
Better green-space policies — We need better policies for planning and incorporating green-space in our growing cities. This means more collaboration between urban forestry leaders and city planners.
Better public standards for planning —We need to set better standards for natural green space requirements throughout our cities.
Public participation — We need more community involvement in the care and planning on green space to meet residential needs. There needs to be more buy-in from residents and active participation in growing the green space available to them.
Million Tree Initiative — A series of ongoing environmental projects to increase the number of urban trees in Los Angeles, Denver, New York, London, Ontario, and Shanghai.
Urban Forest Inventory and Analysis — A program to provide a comprehensive inventory of major urban forests by the U.S. Forest Service.
Green City, Clean Waters — Philadelphia’s plan to reduce stormwater pollution by up to 85 percent through the use of green infrastructure.
Seattle’s Urban Forest Stewardship Plan — Seattle’s program of neighborhood contribution to management of urban forests.
New York’s Stewardship Program — A program that teaches volunteers how to independently take care of parks, natural areas, and street trees.
We have a decision to make. Trees can continue to decline in our cities. Climate change and urbanization will increasingly push out the trees from our cities. This would mean sicker populations, barren landscapes, higher pollution and higher electricity bills.
Or we can decide to do something about it. Efforts to plant more trees in our cities have been successfully so far. In New York, the city’s One Million Trees initiative was completed two years earlier than expected and people turned up throughout the city volunteering to plant trees. This will be good for both our health and our wallets.
Go outside and plant more trees. Find a volunteer event near you and contribute.
Here is a good place for volunteers to look for these cities: New York, Los Angeles, Chicago, Houston, Phoenix, Philadelphia, San Antonio, San Diego, Dallas, San Jose, Austin, Jacksonville, San Francisco, Columbus.