Real tree or artificial tree? This question confronts many people every December who don’t want to give up decorating their homes with the usual accoutrements of the holiday season, but who also want to be as friendly as possible to the environment. On the face of it, an artificial Christmas tree would seem to prevent natural fir trees from being removed from where they belong. In fact, at the end of the 19th century, deforestation caused by Christmas festivities led to the creation of the first artificial trees, made in Germany from goose feathers dyed green and attached to wire branches that were arranged around a wooden post.
Although nowadays the natural Christmas trees for sale usually come from a nursery, it is clear that felling a fir tree does bear an environmental cost, as living trees sequester carbon dioxide (CO2) and release oxygen, storing the carbon in the growth of their plant matter. But the impact is also undeniable in the case of artificial trees, now mostly manufactured in China from polyvinyl chloride (PVC). Although this is a recyclable plastic, the traditional use of lead as a stabilizer makes this material a source of pollution, particularly as the PVC ages and especially after nine years from its date of manufacture, according to one study. The PVC industry is replacing lead with other more environmentally friendly stabilizers, and in recent years China has encouraged the adoption of greener industrial processes.
The greatest supporters of artificial trees are found in the American Christmas Tree Association (ACTA), which brings together Christmas tree producers. A 2018 study commissioned by this organisation from the sustainability consultancy WAP concluded that “on a one-to-one comparison, one real Christmas tree generates fewer environmental impacts than one artificial tree.” The production and transport processes generate a greater impact in the case of the plastic tree. However, the report adds, these products are reused from one year to the next, and with a use of more than 4.7 years, an artificial tree produces a smaller ecological footprint than 4.7 real Christmas trees.
The experts also note that one should not get carried away by appearances; the production of natural trees also consumes fossil fuels through transport and machinery, to which is added the use of pesticides. One estimate suggested that driving 16 kilometres each way to buy a natural fir tree produces more carbon emissions than the amount of carbon stored in the tree, while even the international ocean transport of artificial trees is much more efficient.
However, the figures vary from study to study, partly due to the fact that the WAP and ACTA report did not take into account the large amount of carbon stored in the roots, which remains in the soil after a natural tree has been cut down. Other research by the Canadian consulting firm Ellipsos concluded that the impact of an artificial tree on climate change and resources is three times that of the natural fir tree for an average use of six years, and the figures are only reversed if the plastic one is reused for more than two decades. The global consulting firm Carbon Trust also significantly increased the time needed for reuse: an artificial tree must be reused for at least ten Christmases to keep its environmental impact below that of a natural one, concluded this entity, attributing two thirds of the carbon footprint of the artificial tree to the PVC and a quarter of it to the emissions resulting from its manufacture. The Carbon Trust estimated the carbon footprint of a two-metre artificial tree at 40 kilos of CO2.
But there is one common aspect on which the experts agree, namely that the total ecological impact of the life cycle of both types of tree is mainly influenced by their final destination. If a natural tree is burned, its carbon content is returned to the atmosphere in full, so there is no gain. Much worse is for the fir tree to end up in a landfill, since its decomposition causes all the carbon to be returned to the atmosphere in the form of methane, a greenhouse gas 21 times more powerful than CO2. For this reason, experts recommend that natural trees be recycled properly, chipping or composting them to produce mulch and thereby returning a good part of the carbon to the soil. Some researchers are also studying degradation processes of pine needles to convert them into useful compounds for industry, such as glucose, acetic acid and phenol. And of course, an optimal solution, if possible, would be to use a natural tree grown in a pot and reuse it year after year until finally replanting it in the soil.
The ecological footprint of Christmas is not limited to the tree. Consumption, large meals, special lighting and travel all increase our environmental impact this holiday season. To minimise the effect of our celebrations, the Carbon Trust publishes a series of recommendations, which are mostly self-evident: replace traditional lighting with LED lights, recycle, consume only what is necessary and do not prepare kilos of food that will end up in the rubbish. But some of the tips provided are less obvious. For example, it suggests cutting down on the use of glitter, a source of polluting micro-plastics. Buying gifts online avoids the emissions associated with a trip to the shopping centre and helps to better focus our consumption. Offering experiences and virtual or digital gifts eliminates not only tons of packaging, but also an accumulation of objects that in many cases end up in the rubbish, with an estimated environmental cost of 80 kilos of CO2 per person.
On the other hand, and given the need imposed by the COVID-19 pandemic to ventilate the spaces where family gatherings are held, dressing warmly is a greener alternative than wasting money on heating. And finally, not all foods that can be prepared at this time of year have the same environmental impact: plant-based foods are the most eco-friendly, and turkey has a smaller footprint than red meat. All of this is to help us continue to celebrate this holiday season for many years to come.