With Christmas fast approaching, what better way to keep the conversation going at Christmas dinner than some strange and interesting facts? To count down the days until Santa arrives check in here to find your daily science facts. 1st December Christmas Tree at NYC Rockefeller Centre Each year, 25 to 30 million trees are sold in the US alone making it a once-a-year billion dollar industry. But what affect does this have on our environment? On average, each tree will absorb 22kg of CO₂ per year so, as fir trees generally grow for 7-10 years, your Christmas tree will have absorbed 154kg of CO₂ in it's life time. That makes the total amount of CO₂ absorbed by the US Christmas industry 4.62 billion kilograms of CO₂! It's not all good news though. Whatever amount of CO₂ a tree has absorbed in it's lifetime is released back into the environment once its been chopped down and starts to decay. Therefore, to make use of all that carbon, compost your old tree and use its nutri