How many trees does it take to green a football championship? It depends. If you're organizing a the largest sporting event for a country, but that country is rather thinly populated, you might decide 25,000.
What if you're organizing an extravaganza for a large country heavily populated with energy intensive fans? How many? About 100,000? Your event will attract 300 times as many veiwers as the other country's. Maybe you should plant more than 7 million trees. Well, the NFL settled on 9,000.
Why does the Canadian Football League need so many trees to offset an estimated 300 tonnes of carbon generated during the Grey Cup, and the Super Bowl need so few trees for its 350 tonnes of emissions? (Better yet: why is the Grey Cup generating almost as many emissions as the Super Bowl?)
Are the NFL's trees, which it is planting in Arizona (see map), more efficient? To be honest, the NFL's ponderosa pines are probably less up to the task of capturing carbon than the CFL's spruces. So shouldn't the NFL need more trees, not fewer?
The truth is, generating carbon offsets from forestry projects is pretty complicated stuff. Take the following equation, for example. It comes from the
Guidelines for National Greenhouse Gas Inventories from the United Nation's Intergovernmental Panel on Climate Change. It's really quite a simple formula for determing the amount of carbon captured by a tree (apologies if this isn't aligned. I actually can't tell):
IPCC For the hypothetical country,
GW = 4.0 tonnes d.m.
ha-1 yr-1 (Table 4.12); and
R = 0.40 tonne d.m. (tonne d.m.)-1 for
above-ground biomass <50 gtotal =" 4.0" cf =" 0.47">● 5.6 tonnes d.m. ha-1 yr-1 ● 0.47 tonne C (tonne d.m.)-1
= 2,632 tonnes C
yr-1
Complicating things, the NFL plans for most of its trees to die -- they're being planted in an area that was burned recently, after all.
The CFL isn't actually planting 25,000 trees. It's buying offsets from zerofootprint.net, which bought them from a reforestation project in Maple Ridge, British Columbia. Judging from the
voluntary carbon standards , which recommends long lag times to determine if trees actually grow to maturity, neither of these plantations should be generating offsets for some time.
No one doubts forests can store carbon in vast quanities. Only a crank would suggest otherwise.
In recent decades, the researchers say the area burned each year by wildfire has doubled, annual harvest rates have increased somewhat, and rates of carbon uptake by aging (Canadian) forests have slowed. In extreme fire years, such as 1995, 1998, 2002, 2003, and 2004, the carbon dioxide released as the forests burned accounted for up to 45% of Canada's total greenhouse gas emissions, dwarfing emissions from big industrial sources. In other years the forest still absorbs more carbon than it releases.
Who were these tree-hating researchers?
The Canadian Forest Service. Sigh.
