The Carbon Question is on everyone’s mind these days, due in no small part to Al Gore an the shockingly good An Inconvenient Truth and a steadily growing acknowledgement of the problems associated with global warming and it’s causes. This has been addressed as well in the architectural press, and the role that building occupies in the overall. Architects and advocates have responded with more green building in general, as well as more robust guidelines such as Architecture 2030 which continue to address the root cause (primarily energy use and materials production) and don’t significantly address landscape issues.

:: logo via Architecture 2030

Recently Slate featured a column titled The Greenest Tree (Jan 8. 2008), which asks the question, ‘Which tree species will do the most sequestering carbon?’ Or simply, which species aid us in doing our part to limit global warming in the landscape. While there are some simple recommendations, such as planting trees that are large, and deciduous, and focusing on those fast growing species (because they sequester more carbon more quickly due to size). The winner, due to a 2002 survey by NY Oasis, is the Tulip Tree (Liriodendron tulipifera) and the European Beech (Fagus sylvatica). The study delved into ecosystem valuation as well, by assessing a variety of factors such as size and type to provide a weighted compensatory value based on the tree.

::Liriodendron image via Floridata

Inevitably, the ability for plants to sequester carbon is fleeting, as they will release this carbon into the atmosphere when they die and begin to break down: From the same article in Slate:

“Yet even the hardiest native trees are doomed to die someday, and in doing so, spew their carbon back into the atmosphere. (That’s particularly bad news when the trees are killed as part of a timber company’s clear-cutting efforts, since no young trees are left behind to help mitigate the losses.) If you’re around to witness your trees’ twilight years, consider keeping the carbon in place by turning them into furniture or building lumber, rather than letting them go gently into that good night.”

::sustainable furnishings via The Joinery

At the very least, planting MORE of any type of trees have multiple benefits to the public, of which carbon sequestration is just one. A more focussed study from a landscape perspective, would be to provide additional date on how much more carbon sequestration is actually provided via the soil biomass. While planting trees and building, this reinforces the need for making soil conservation and erosion control measures to maintain soils during construction and farming operations paramount.