The Decider: Christmas Trees
Real vs. artificial: Which option is better for the planet?
If Christmas trees are at the center of your holiday decorations, you might be deciding between a real or artificial tree. But is either one actually better for the environment? We know you hate to hear this, but it’s complicated. Let’s break it down.
Grown vs. manufactured
Artificial Christmas trees are made mainly with steel and two types of plastic, polyvinyl chloride (PVC) and polypropylene, according to a 2018 life cycle analysis (LCA) by WAP Sustainability Consulting, a firm specializing in LCAs and carbon management for businesses. The American Christmas Tree Association (ACTA), which represents artificial tree manufacturers, commissioned the study.
Mining iron ore and making steel from it, and extracting and refining petroleum to make plastic, both lead to air and water pollution. Then comes the energy-intensive process of making and assembling the tree. Per the 2018 study, manufacturing consumes 247 megajoules of non-renewable energy — enough to power the average American home for 2.4 days. It also releases sulfur dioxide and nitrous oxides, gases that pollute and acidify the air, and has a carbon footprint equivalent to 7 kilograms of coal burned.
On the other hand, in North America, real Christmas trees are crops, explains Shirley Brennan, executive director of the Canadian Christmas Tree Growers Association. This means the trees are grown to be cut down and do not contribute to deforestation.
Tim O’Connor, executive director of the National Christmas Tree Association (NCTA), a US association representing Christmas tree growers, says over email that real trees “stabilize soil, protect water supplies and provide refuge for wildlife.” Because every tree cut is typically replaced by one to three others, these benefits are not threatened by yearly harvesting. The carbon footprint of this stage is negative, saving the equivalent of 4.5 kg of coal from being burned.
That said, the 2018 LCA concluded cultivating Christmas trees involves significant non-renewable energy use. Over the roughly 10 years it takes to produce a tree, gas-powered vehicles and tools (like chainsaws) are used for planting, maintenance, and harvesting. Even so, the non-renewable energy used amounts to a third of that required to produce an artificial tree.
At the same time, growers use pesticides—which contribute to water acidification and pollution—and fertilizers, which cause nitrous oxide emissions. To minimize these impacts, look for farms with sustainable practices or certifications. For example, SERF-certified Christmas tree farms in Oregon meet environmental and worker-health standards. Organic Christmas trees are another option.
The transportation dilemma
According to the 2018 study, the average artificial tree sold in North America is imported from China. But Manasa Kovvali Rao, a sustainability data manager and researcher at WAP Sustainability, explains that bulk transportation is very efficient. Since the overall impact is divided by all the items in cargo, the portion of impact allocated to a single tree in a ship or truck is minimal.
Of course, being shipped from China and then transported by truck to retailers means artificial trees have higher transport emissions than real trees, which North American consumers can buy locally. Using the 2018 study numbers, transportation emissions are equivalent to 1.2 versus 0.9 kg of coal burned for artificial and real trees respectively.
But real trees necessitate yearly transport, whereas artificial trees are transported once and kept an average of 10 years, according to Jami Warner, executive director of ACTA. This amounts to about 9 kg of coal burned over a decade for an annual real tree — 7.5 times that of an artificial tree.
Emissions aside, transporting artificial trees is more environmentally harmful. Cargo ships use diesel combustion engines and bunker fuel, a highly polluting byproduct of oil refinement. These burnt fuels are released into the air and water as the ship moves, contributing to smog, ocean acidification, and eutrophication (the excessive mineral enrichment of water).
Decking the halls
While in the home, the impact of either tree is negligible. Real trees need to be watered, but the 2018 LCA estimates only 62 liters are needed over an 18-day Christmas season — that’s like flushing a toilet that meets the minimum standards of the US Environmental Protection Agency (EPA) 10.3 times.
The end of the road
A major shortcoming of the 2018 LCA is that it does not account for the environmental impact of plastic waste. Kovvali Rao from WAP explains that the programs to measure it are still being developed. Nevertheless, disposing of plastic trees is detrimental to the environment, given it takes them hundreds of years to biodegrade.
For real Christmas trees, let’s focus on the most common disposal options: landfill, composting, and repurposing. If your local landfill is equipped to capture energy, methane released during decomposition will be captured and returned to the grid as energy. In other landfills, however, methane will go into the atmosphere, exacerbating global warming. Only about 75 facilities in the US capture energy and many in Canada don’t either, so avoid throwing your tree away if possible.
Repurposing or composting a real tree is the greenest disposal option. Part of the carbon dioxide and methane trees sequester is released during composting, but it’s only about 50%, claims a 2010 LCA by consulting firm PE Americas (also commissioned by ACTA). The other 50% “remains sequestered in the biomass,” the study states. According to the US EPA, compost can multiply soil’s ability to store organic carbon, so the environmental benefits go beyond saving a single tree from landfill.
Cities and towns throughout North America have programs that compost Christmas trees or chip them into mulch for public parks and gardens. The New York Times identified other programs that use old Christmas trees to protect beaches from erosion and create habitats for fish in lakes. Repurposed trees emit uncaptured gases as they decompose, but they give nutrients to soil, unlike landfilled trees.
And the winner Is…
All things considered, real trees are greener, provided they don’t travel too far from the farm to your home, and your community has a repurposing or composting scheme.
If these options aren’t available, you can purchase an artificial tree and use it for many years. The 2018 study identified a five-year break-even point for all environmental factors measured. However, a 2009 LCA by Montreal consulting firm Ellipsos concludes you’d need to keep an artificial tree for 20 years to break even in terms of carbon footprint. Given that plastic won’t disappear for hundreds of years, if at all, it’s probably better to err on the side of the 2009 study.
Real or artificial, the overall environmental impact of Christmas trees is minimal. The total carbon footprint of an artificial tree per the 2018 study equals 0.004 cars used for a year. The numbers are even smaller for real trees.
Kurt Rosenstrater, an associate professor at Iowa University’s Department of Agriculture and Biosystems Engineering who specializes in LCAs, believes people should also take other factors, like affordability, tradition, and supporting the local economy, into account. Given this, choose the tree that’s best for you, then keep it for as long as possible or repurpose it.
Print Issue: Winter 2021
Print Title: Christmas Contest: Evergreen vs. Plastic