Do Christmas trees pump down CO2 from the atmosphere?

     Do Christmas Trees  pump down CO2 from the atmosphere?

I was very surprised when two Alaskan newspapers published articles about my geoengineering proposal a couple of weeks ago.  I was even more surprised when one of these papers published a second article on planetary geoengineering just a week later.

The second article, entitled "Alaska scientist advocates green system of carbon dioxide removal" featured an interview with Dan Mann, my colleague who is currently an Assistant Professor of Geography at the University of Alaska.  In the beginning of the article Prof. Mann dismissed geoengineering by saying "Geoengineering in arrogant and dangerous" and then went on to present his own "green" geoengineering concept.  The newspaper article reports that Prof. Mann owns a tree farm in New Zealand, and he travels back and forth from Alaska to New Zealand to oversee his tree farm.  Prof. Mann said that he had a carbon calculator that showed that his tree farm was removing CO2 from the atmosphere, and that his tree farm was an example of a "green" way to reduce CO2 in the atmosphere and mitigate greenhouse warming. 

Lets examine Dan Mann's green geoengineering idea a little bit more closely.  I'm going to call it the "CO2 Christmas Tree Pumpdown" idea, because one of Dan's fellow geography professors told me the main cash crop from Dan's tree farm in New Zealand is Christmas trees. 

Christmas trees, like all trees, soak up CO2 from the atmosphere while they are growing.  The typical Christmas tree is harvested when it is 4-12 years old.  Millions of Christmas trees then spend a couple of weeks decorating living rooms and standing guard over Christmas presents, and are subsequently discarded.   The unwanted Christmas trees typically wind up in landfills.  Once in the landfills the tree then decomposes.  As it decomposes all the CO2 that was stored in the cellulose of the tree is released back to the atmosphere.  Thus, while the Christmas trees do indeed pump down CO2 while they are growing, the net effect of Christmas tree growing operations on CO2 in the atmosphere is zero---i.e. all the carbon removed from the atmosphere when the Christmas tree was growing returns to the atmosphere when the decorations and tinsel are removed from the tree and it is hauled to the landfill and left to decompose.   

The CO2 Christmas tree pumpdown idea is definitely green and environmentally safe (not counting all the landfills buried in discarded Christmas trees each year), but unfortunately it doesn't actually accomplish anything in the way of reducing the amount of CO2 in the atmosphere, or mitigating the dangerous effects of future climate change that are predicted by the IPCC.