Sally Brown
BioCycle February 2012, Vol. 53, No. 2, p. 52

Some families can trace their bloodlines back to the Mayflower. I trace mine back to the J line. The J, formerly the QJ, is the line on the New York City subway system that goes from Jamaica, Queens, through East New York, Bedford Stuyvesant and Williamsburg in Brooklyn before finally ending up in Manhattan, near City Hall. My grandfather was a conductor on the then Broadway Brooklyn local. Dukey, the family dog would check the clock and run down the block to greet him and carry his newspaper on the walk back home from the train to their house.
As a teenager, I started taking the J train to school in Manhattan. I knew it was only safe to take it during rush hours, going with the traffic. Looking out of the window as the train went past most of those Brooklyn neighborhoods (it is all above ground in Brooklyn and Queens) was a vision of urban blight. It looked like pictures of the war zones from WWII; maybe not as famous as the South Bronx, but not a whole lot different. Just before the train crossed over into Manhattan, we went through Williamsburg, a really terrifying neighborhood. I would look out of the window in horror that people actually had to live there. For those of you who know Williamsburg now, I am not kidding.
Today, you can take the J train any time of day or night. If you get off in Williamsburg, you can find trendy bars, restaurants and shops on every corner, as well as a two bedroom condo for just under $900,000. And if you take the train further east into Brooklyn, instead of rubble you’ll see trees and restored homes. When you look up these properties on real estate websites, in addition to pictures of the remodeled kitchens, you will find a “walkability” score.
Coming with the current real estate crisis, we are seeing a change in trends. More and more people are moving back into cities, where they can take public transit, walk to a restaurant, and not have to worry about mowing their quarter acre lots. But the cities that they want to live in are not just concrete jungles. In addition to good theater, people want open space and green space. They want access to trails and trees. They also want a sense of community, not of isolation.
This trend is very good for the environment. Living in a high density area is generally much better for the environment than living spread out in cul de sacs. This is true for many reasons. Having recently done some calculations, I’ll give you one example.

Running the Numbers

In November 2010, BioCycle had a cover story written by Andrew Trlica about soil carbon accumulation in restored mine sites. Andrew is a former graduate student of mine and he and I are just polishing up the article from his thesis to submit to a journal. In addition to quantifying soil carbon storage, Andrew did a life cycle assessment of greenhouse gas emissions from one hectare of disturbed land. He modeled what would be emitted or sequestered from that one hectare (1 ha) if it were a) restored to forest, b) restored it to forest with biosolids, or c) if a few homes were built on it. He located this hectare in the Pacific Northwest, about 60 km east of Seattle. This is in fact where the Weyerhaeuser Company developed about 500 hectares of forestland into lots of houses.
Andrew’s homes were hypothetical; on that 1 ha he had about 3.9 of them, each about 243 m2 in size. He looked at emissions associated with building and maintaining the homes for 30 years. For infrastructure, he only considered road construction and maintenance. Emissions from all of those residents driving to work every day were not considered, and drive they would. No chance of a J train being constructed anywhere near this 1 ha. One article I read suggested that traffic-related emissions from low density (here 19 homes per ha) would be 4 times higher in comparison to high density (a 15 story condo in Toronto).
Well it turns out, no surprise, that restoring disturbed land to forest in the Northwest sequesters carbon. Counting soil carbon and tree biomass, in 30 years just under 300 tons of CO2 would be stored in that one hectare. If some biosolids were added to make the trees grow faster (compost is also an excellent option here, as are numerous other organic residuals), that would increase to 475 tons of CO2 —a result of both increased soil carbon storage and bigger trees.
Conversely, opting for those “view lots,” restoring only half of the hectare to trees and building 3.9 homes on the rest, the outcome is very different. Those 3.9 value meal homes (no where near in size to some of the McMansions built in the last decade), along with the roads required to get to them, end up emitting over 2,800 tons of CO2 in 30 years. If you want to be proactive and construct energy efficient structures, you can bring that down a bunch, to 1,250 tons.
Other benefits are tied to restoring the land to trees. In his thesis, Andrew quantified how much rainfall would be soaked back into the soil instead of landing on asphalt (200 million liters over that same 30 year period). He calculated how much revenue that hectare would bring in (based on annual tourist dollars in the county and fraction of tourists surveyed who said that hiking was one reason that they visited the area). That came to $30,000. Numbers like these make that $900,000 condo in Williamsburg look like a good deal.
In upcoming columns, I’ll talk more about trends in the U.S. on where people want to live. There is a lot to discuss about how urban, suburban and rural will fit together in the future. In the mean time, on your next trip to New York, take a ride on the J. The A train is not the only one worth singing about.
Sally Brown — Research Associate Professor at the University of Washington in Seattle — authors this regular column. Email Dr. Brown at slb@u.washington.edu.