From time to time, I have given some thought to the idea of trees as pollution suckers – their ability to sap pollution from the air and store it. I have also thought about what would be better at absorbing carbon dioxide (CO2) – a tree or plant (shrub). In that department, I believe trees win hands down, but, that would, of course, depend on the tree and shrub. Added to all of this, I’ve written about a type of tree, Megaflora, that I understand is a pretty good sponge when it comes to helping de-pollute air and more.
Now, as far as pollution-reducing devices go, trees might not rank among those at the top – that is, the best performers. But, they can and do help. In the book: Walkable City: How Downtown Can Save America, One Step at a Time, author and city planner Jeff Speck devotes a whole section to trees. Speck points out a number of ways trees planted along neighborhood streets and/or on residential property and which provide shade can lessen the reliance on home cooling systems, for example, compared to areas devoid of shade trees, which can reduce energy costs and that, in turn, can lower demand on the electric grid and, therefore, can result in energy-created emissions being produced being less. In fact, cited by Speck in Walkable City is a passage from the U.S. Department of Agriculture via its Forest Service Pamphlet #FS-363 effectively stating that one healthy tree has the same cooling effect as 10 air conditioners the size of a room, running all day long.1 Imagine the amount of energy that could be saved if shade trees took the place of home cooling systems.
Elaborating on this Speck remarked that a neighborhood devoid of tree shading has an air-conditioning requirement of between 35 percent (on the high end) and 15 percent (on the low end) more than a neighborhood that is properly shaded.2 He notes also that trees, as CO2 absorbers, when located nearby roadways, capture 10 times more motor-vehicle-emitted carbon dioxide than trees located farther away.3
It would follow then that in places where air pollution is problematic, planting more of the types of trees that are effective at removing pollution from the atmosphere would make sense.
So, I must admit that if I was tasked with whether to put in a lawn or a landscaped yard with a goodly proportion of trees, I would opt for the latter, especially if the trees themselves were effective at sinking carbon and other pollutants from the air. This accompanied by an abundance of hearty drought-tolerant ground cover that is good at soil control to minimize or prevent both soil erosion and water run-off.
Oh, and another benefit of having trees and ground cover, as a lawn-mower owner, I’d be hard-pressed to then find a use for it. Should such a mower be internal-combustion powered, by not using such, air would be further helped.
For more on trees’ benefits, look here.
- Jeff Speck, Walkable City: How Downtown Can Save America, One Step at a Time, 2012, p. 226.
- Ibid, p. 227.