Vegetation means accumulation of organic matter through the consumption of CO2 from the atmosphere. Christmas trees are particularly good at that. They absorb and store CO2 in their life processes during which CO2 is being transformed into carbon, which in turn is bound in stems, branches, needles and in the soil. During one year, a ready-for-sale Christmas tree takes up approx. 4 kg of CO2. During the entire 10-year life cycle of a Christmas tree, the tree accumulates a total of 18 kg of CO2. This implies that 3.3 tons of carbon or 12.2 tons of CO2 are absorbed annually per hectare planted with Christmas trees. This volume corresponds to the total accumulation of CO2 in Danish forests.
The explanation is that Christmas trees are planted with a narrow spacing and are fast growing trees - up to 2 cm of added height per day - and they carry several generations of needles. When Christmas trees are harvested, needles, branches and large amounts of roots are left behind which are slowly becoming part of the soil's carbon pool. The slow process is an advantage, because it increases the accumulation of carbon in the soil. At the same time, the soil preparation in connection with Christmas tree production is gentle, since the preparation only takes place every tenth year and "scratches" in the surface of the soil. This results in a more undisturbed carbon storage compared to that of other agricultural production.
The large storage is underpinned by insignificant fertilization, which is the reason why the trees are growing fast and accumulate a large volume of CO2.
When after Christmas, the trees are used for burning instead of oil, coal and gas, fossil fuels are replaced. Thus, Christmas trees refrain from harming the atmosphere with fossil CO2 thus delivering a positive contribution to the CO2-balance. Ideally, Christmas trees sold in Denmark can be used for heating purposes in more than 2,000 households annually. However, Christmas trees are most commonly disposed of via recycle centres, and this results in composting thus resulting in accumulated carbon once again being released, when the compost is used in local parks and private gardens.
