Scientists say that the ecological advantages and disadvantages of Christmas trees are not just limited to the environmental impact of real or plastic trees. So, what is the best Christmas choice to stay environmentally friendly?
Only 25-30 million real Christmas trees are sold annually in the United States, and approximately five million in the UK. Furthermore, real trees may be making a comeback among younger generations – a 2019 survey conducted in the US found that millennials are 82% more likely than baby boomers to buy a live tree.
However, the negative impact on the environment may not be as straightforward as once thought. These discussions often focus on the relative carbon footprint of real trees compared to plastic ones, but researchers say the discussion goes far beyond this aspect, notes BBC.
"I think there are many more shades than the simple black-and-white: 'Oh, we cut a tree and throw it away'," says Alexandra Kosiba, an expert in forest ecology at the University of Vermont Extension in the US.
After all, before being cut and displayed, a Christmas tree is cultivated - on land that could otherwise be used for different, better, or worse purposes. In Vermont, for example, Kosiba says, Christmas tree nurseries support the local economy and help maintain the rural landscape.
A Small Refuge for Biodiversity
The way we use land has become particularly important in the context of two pressing and deeply interconnected environmental crises: biodiversity loss and climate change. Forests represent an important part of this beneficial land use.
Trees are grown in nurseries for about 10 years before being harvested, meaning that for every tree cut down in a year, nine others remain standing.
Christmas trees are not included in the EU commitment to plant an additional three billion trees by 2030, as they are considered to have a relatively short life span.
Nevertheless, Christmas tree plantations can still provide a boost to biodiversity - and can provide a safe haven for nesting birds. Research shows this is especially true in areas where wildlife has declined as agriculture intensifies.
In a 2022 study in Germany, for example, researchers found that Christmas tree plantations could be important refuges for declining bird species such as the yellowhammer and corn bunting in intensive agricultural areas. Another study from 2018 in Sauerland, Germany, found that Christmas tree plantations are important refuges for woodlarks.
And a 2019 study in Belgium found that beetle diversity - including threatened species - was higher in Christmas tree nurseries than in corn plantations, but lower than in spruce plantations for timber, which are left to grow longer and use fewer fertilizers and pesticides than Christmas trees.
Similarly, in naturally wooded areas in the northeastern US, younger and more open forests, such as Christmas tree plantations, can provide a higher concentration of insects or plants, thereby better supporting birds and mammals at certain stages of their life cycle, says Andy Finton, director of landscape conservation at The Nature Conservancy, a US-based environmental non-profit organization.
Drawbacks of Christmas Tree Plantations
On the other hand, Christmas trees are usually treated with a lot of pesticides and particularly with fertilizers to keep them aesthetically pleasing, which has its own environmental impact, according to Paul Caplat, an ecologist at Queen's University Belfast in Northern Ireland.
A 2021 study led by Merle Streitberger from the University of Osnabrück in Germany found that organic Christmas tree nurseries have better habitat structure and plant species diversity than conventional ones and recommended a reduction in herbicide use.
Experts, however, say there is another unexpected advantage of planting Christmas trees - the fact that nursery land could be used for less ecological purposes. For example, areas near cities could find alternative uses such as parking, says Caplat.
Kosiba also notes that in rural areas of the northeastern US, where forests are often lost due to extensive development, Christmas tree nurseries can provide landowners with a significant diversified income. "This allows people to live in these places, manage and work on their land," she says.
In short, Finton explains, if a landowner has a viable Christmas tree nursery economically, they are encouraged to keep the land in "that natural, open state... and not to sell, for example, land that could be taken over by a shopping center or residential complex."
What About Carbon Emissions
Of course, there's also the carbon issue. Like any other tree, Christmas trees capture carbon as they grow. When cut down, they will start releasing that carbon.
"There is a continuous process of growth and removal of carbon from the atmosphere, which is a positive thing," says John Kazer, an expert in carbon footprint certification at Carbon Trust, a British environmental consultancy firm. However, as all the carbon absorbed by the tree will eventually be returned to the atmosphere after it dies, there is no overall carbon removal, he points out.
Additionally, the amount of carbon involved in the existence of a Christmas tree must be put into context. Carbon Trust estimates that a two-meter-tall Christmas tree burned after use emits only 3.5 kg of carbon dioxide equivalent - approximately 0.2% of the emissions from a round-trip flight from London to New York. A tree of the same size that ends up in a landfill has a carbon footprint of 16 kg of carbon dioxide - equivalent to 1% of that round-trip flight, or about two hamburgers.
How people dispose of Christmas trees after use is usually the most important aspect related to carbon emissions.
The worst-case scenario occurs when natural Christmas trees end up in landfills: the low oxygen conditions favor the release of a larger amount of carbon from the tree in the form of methane, rather than CO2.
Since methane is a greenhouse gas about 80 times more potent than CO2 over a 20-year period, a tree that ends up in a landfill emits about four to five times more carbon than one that does not, according to Carbon Trust data.
What Can We Do with Christmas Trees After Christmas
Ideally, if a tree is still alive and has roots, it will be replanted. If cut, a decent alternative is to chip it and turn it into compost. Meanwhile, if the tree is burned for energy, the carbon it contains will be emitted directly back into the atmosphere as carbon dioxide.
It is also worth checking if the place where the tree is purchased offers recycling services.
In addition to disposal, Christmas trees affect the climate due to the fertilizers used for their growth, which are manufactured from fossil fuels and produce nitrous oxide, another potent greenhouse gas. Forest management and exploitation also use fuel, as does transportation to their final destination.
There are, of course, a few options that can completely avoid waste. Some companies now offer tree rentals - allowing the borrowing of a potted tree for a few weeks at Christmas.
For those with space, another excellent option is to buy a potted Christmas tree, then keep it in the garden until the next year - maybe even plant it permanently once it becomes too large. "It's hard to imagine a better solution," says Finton, who recommends buying a local species that will thrive in the area where we live.
When Is a Plastic Tree Better
And then, of course, comes the question of whether it's better to simply get an artificial tree.
Plastic trees take hundreds of years to decompose in landfills, but they could generally have lower carbon emissions than buying multiple real trees if they are reused for a long enough time.
The Carbon Trust estimates the carbon footprint of plastic Christmas trees to be approximately seven to 20 times higher than that of a real tree, depending on factors such as whether the real tree ended up in a landfill or how far people traveled to pick it up.
If you have an artificial tree, the key is to reuse it for as many years as possible, says Kazar. "It takes a lot of effort to produce and transport these trees."
How Can We Have Real Trees and Protect the Environment
Therefore, natural Christmas trees may not be the ecological curse of the Holidays and can even offer some environmental benefits. However, we can still significantly improve their management. And a few simple things we can do:
- Producers can reduce or eliminate the fertilizers and pesticides used for their cultivation (including by accepting "less resistant" trees) and nurseries must obtain environmental certificates.
- Producers can also try to plant trees near cities, in places where alternative options for land use are ecologically poorer.
- Individually, we can consider using potted trees instead of cut ones, then planting them permanently.
- Also, we can prioritize buying local trees to reduce emissions from transportation. And most importantly, we can ensure that no Christmas tree ends up in a landfill, giving them another purpose.
T.D.