If you asked me a few years about the trees in my backyard, I would have said, “Yes, there are trees.”
That would have been the end of it.
But now, after a few years of being more involved at Leaf & Limb and paying more attention, I can tell you that my red maple is doing just fine despite the Yellow Bellied Sapsuckers neatly dotting holes around the trunk. The willow oaks that line the street are dying, but stable. Tulip poplars and their camouflaged flowers shade the southwest side of my house. And I’m grateful that the mulberry tree at the edge of my property is far enough away that I don’t end up with a pink polka-dotted car during early summer.
And trees are not just important within my idyllic backyard. They are essential everywhere. Not only do they clean the air and filter rainwater runoff, they also make communities healthier, boost economies, and conserve energy.
I witnessed the benefits of trees in Manhattan with my family a few weeks ago. The New York streets become rank in the sweltering summer heat, the pavement seemingly creating an outdoor convection oven. While pockets of mature trees exist, struggling saplings in concrete boxes is the norm. Central Park is a refuge, but I was taken aback by how much a recent addition had improved the cityscape.
The Highline is a city park built along an abandoned railroad track on the West Side of Manhattan. Above the hustle and bustle of Chelsea, there are gardens and public art and, most importantly, trees. We walked from 30th street to the Chelsea Markets on a particularly hot day that I expected would keep away other visitors. Much to my surprise, the Highline was full of tourists taking photos, business people having lunch meetings, and families eating ice cream on benches.
The trees transform the space.
The design of the space is gorgeous, but without the dense rows of trees, the Highline would hardly be different from the hot, sticky streets below. The air felt cleaner and at least 10 degrees cooler on the Highline. The adjacent luxury apartments were selling at a premium. People were active on what would otherwise have been an uncomfortably hot day.
Urban trees are critical to the health, safety, and economy of communities. According to a report from the University of Washington, the “estimated total annual air pollution removal (of ozone, particulate matter, NO2, SO2, and carbon monoxide) by urban trees across 55 U.S. cities is 711,000 metric tons, representing $3.8 billion in public value.” That amount of air pollution being removed in just these 55 cities is equivalent to the weight of almost 4,000 blue whales!
Beyond producing oxygen and cleaning the air, trees also improve soil and water quality. According to the Alliance for Community Trees (ACT), “trees help remediate soil at landfills by absorbing, transforming and containing a number of contaminates.” ACT also states that “Urban forest can reduce annual stormwater runoff by 2–7 percent, and a mature tree can store 50 to 100 gallons of water during large storms.” This means that trees can help prevent devastating flooding. They also act as filters for storm water runoff, reducing the number of pollutants that reach streams and, eventually, our drinking water.
Trees also provide innumerable health benefits.
Communities that have more trees and green space show a lower incidence of childhood asthma. Children with ADD demonstrate fewer attention deficit symptoms when they play in green spaces. Individuals that live in neighborhoods with more access to parks report having lower BMI and less anxiety and stress. They also report getting sick less often.
But perhaps the most critical task that trees face right now is slowing down the impact of climate change by reducing temperatures and storing carbon. In urban settings, trees can reduce the air temperature by 10 to 20 degrees, which reduces ozone levels and improves air quality. Carbon sequestration may be a tongue twister, but it’s just a fancy word for removing carbon dioxide, a harmful greenhouse gas, from the atmosphere. Removal of CO2 from the atmosphere is vital to reducing global temperatures, and trees are uniquely suited for that task. According to ACT, “Individual urban trees contain about four times more carbon than individual trees in forests.”
As heroic as the carbon sequestration of individual urban trees is, these trees cannot fight climate change alone. However, a concerted, world-wide effort to plant trees on a massive scale could make a huge difference.
Trees can slow down or stop the impact of climate change.
Recently, the Crowther Lab of ETH Zurich published a study in the journal Science that shows how many trees need to be planted to slow down or stop the impact of climate change. They identified roughly 2.2 billion acres of non-agricultural land in Russia, the United States, Canada, Australia, Brazil, and China. If all of those areas were reforested, the mature trees “could store two thirds of the 300 billion tonnes [sic] of carbon that has been released into the atmosphere as a result of human activity since the Industrial Revolution.”
Let me say that again: reforesting ONLY non-arable land could recapture 66% of the carbon that has been released into the atmosphere over the last 200 years.
Harmful greenhouses gases would be removed from the atmosphere, global temperatures would be lowered, and we wouldn’t have to face the devastating outcomes of environmental change. Trees are our greatest technology.
But rather than the world gaining forested land, land is being deforested at an alarming rate. According to the World Wildlife Federation, “We’re losing 18.7 million acres of forests annually, equivalent to 27 soccer fields every minute.”
We need to act now so that we can continue to enjoy all of the benefits that trees provide.
So what can you do? Here’s my challenge: you don’t have to plant 2.2 billion acres of trees or even one acre. Instead, go outside and find one tree. It can be one you see on your way to work or to your kid’s school or one right outside your back door. Just pick one. Then learn three things about it: is it a wildlife habitat? What kind of flowers does it produce in the spring? What species of tree is it?
Becoming familiar with your trees and paying attention to them is the first step in becoming an advocate. Who knows where the knowledge you gain from this attention and curiosity will take you.
I’d love to hear what you learned about your trees or, more broadly, what you plan to do to protect trees in your neighborhood. As always, healthy trees, happy people.