Script preview: Street Trees

I'm trying to hustle and release this video on Thursday! Hope you enjoy.

Street Trees

I live in Sacramento, and when I moved here I learned two things quickly. First, Sacramento summers are hot. Like really hot. Many days are over 100 degrees. The second thing I learned is that Sacramento is livable, even with those high temperatures, thanks to its extensive tree canopy. The trees provide shade that makes me feel about 10-15 degrees cooler, and without them I probably would’ve moved a long time ago. Shade is just one of the many many benefits trees provide in urban areas, and I’m going to count down my favorites, as well talk about what it takes to maintain a verdant urban forest.

Let’s start the countdown at number 5. Trees are so valuable that they can help raise property values. One study found that having mature street trees in front of a home increased its value by 3 to 15 percent. Portland, Oregon’s street trees contribute a whopping $1.1 billion to the value of homes in the city. Homes with street trees sell faster, too. 

Because of the incredible economic benefit street trees provide, it is critical that cities make concerted efforts to plan them in lower income neighborhoods. This relatively inexpensive step could help homeowners build wealth through their property. And, of course, those residents would reap all of the other benefits of street trees on this list, including number four…

Shade. You’d think that since I started this video on the topic of shade, that I would rate it higher. But there are so many benefits associated with street trees that I had to slot it in at number four. Shade doesn’t just mean cooler humans, it means cooler buildings too. Strategically-placed trees can shade windows and buildings, reducing the need for air conditioning. Planting a tree that shades the west side of your house can reduce your energy bills by 12 percent in 15 years. A young tree can cool the city like ten room-sized air conditioners operating 20 hours a day.

Shade can make sunny cities like Sacramento bearable for vampires like me, and sometimes I will choose which side of the street to walk on based which side has the most shade. So what’s next on my list?

Safety! Safety is certainly more important than shade. But how do trees make streets safer, you ask? They do this in a couple of ways. First, people drive more slowly on tree-lined streets than streets without trees because the trees give the impression streets are narrower than they are. I have a video on this topic if you want to learn more. Speed is the biggest factor in the severity of a collision with pedestrians and cyclists. A decrease in speed of even a few miles per hour can dramatically improve the chances a pedestrian would survive a crash with a car. Here in Sacramento, this street slows down cars by putting trees right in the middle of the road, kind of like natural traffic calming. And urban streets with tree-lined medians, like this one, are also safer than streets without them. Trees also make streets safer is by creating a buffer between moving traffic and the sidewalk. Trees can intercept runaway vehicles before they hit someone on the sidewalk. 

So street trees can save a life, but street trees also give us life, by producing oxygen. It’s my number 2 favorite benefit. Two medium-sized trees can supply enough oxygen for one person for a year. Even more than that, trees sequester the gas most responsible for global warming: carbon dioxide. They also clean the air by absorbing particulates in the air, such as dirt and dust as well as harmful pollutants coming out of car tailpipes. 

You might think, that’s great, but that’s true of every tree, not just street trees. And you’d be right, but street trees absorb 9 times more pollutants than trees farther away, so proximity is important. You can literally breathe easier when street trees are present, too, as a study found that neighborhoods with street trees have lower incidents of asthma among residents.

Okay, so it’s going to be hard to top oxygen, a life giving element, in this list of street tree benefits. And this is just my subjective list. But the number 1 most important benefit of street trees is beauty. This channel is called “City Beautiful” after all. Humans are a social species, and I believe we benefit from living near each other, like in a city. But our love of nature is undeniable. We love trees and green in a deep way. Streets with trees look so much better than streets without them. Street trees create a pleasing “tunnel” effect, both across the roadway itself, as well as along the sidewalks. One of my all time favorite planning books is Great Streets, by Allan Jacobs. In it, he says:

“Given a limited budget, the most effective expenditure of funds to improve a street would probably be trees. […] Moreover, for many people trees are the most important single characteristic of a good street.” p. 293.

Street trees make us happier. If you want a nice street, add trees. That’s the long and short of it. 

I should mention that it’s not as simple as sticking a tree in the ground. I want to take a moment to appreciate the work our cities urban foresters do to ensure a healthy urban forest. For one thing, it’s important to choose trees that are appropriate for the climate, soil, and setting. Palm trees work in Sacramento, but not in Milwaukee. 

It’s also critical to plant a variety of trees. Unfortunately, we learned that lesson the hard way. In the first part of the 20th century, many cities planted elms as street trees, some almost exclusively. It made sense, as they created that perfect “tunnel” effect I just talked about. You won’t see many elms lining streets anymore, as 75 percent were wiped out after dutch elm disease swept through North America. Many streets and cities were left with few street trees at all. Here in Sacramento we have been relatively lucky. There are still about 8,000 elms left, but we had 19,000 in the 1970s. 

For similar reasons, it’s also important to have streets lined with young, middle aged, and old trees. A consistent canopy definitely looks great, but the truth is trees get old and die. If all the trees are planted at the same time, there’s a good chance they’ll all die around the same time too, leaving a street without its trees. And I hope this video has shown that a street without trees is not a good street at all. You don’t have to go out and hug a tree, the next time you’re out for a walk, thank a tree for making it safer and more pleasant.