Environmentally conscious consumers often ask me whether a real Christmas tree or an artificial one is the more sustainable choice. As a horticulture and forestry researcher, I know this question is also a concern for the Christmas tree industry, which is wary of losing market share to artificial trees.
And they have good reason: Of the 48.5 million Christmas trees Americans purchased in 2017, 45 percent were artificial, and that share is growing. Many factors can influence this choice, but the bottom line is that both real and artificial Christmas trees have negligible environmental impacts. Which option “wins” in terms of carbon footprint depends entirely on assumptions about how long consumers would keep an artificial tree versus how far they would drive each year to purchase a real tree.
FROM SEEDLING TO WOOD CHIPPER
Many consumers believe real Christmas trees are harvested from wild forest stands and that this process contributes to deforestation. In fact, the vast majority of Christmas trees are grown on farms for that express purpose.
To estimate the total impact of something like a Christmas tree, researchers use a method called life cycle assessment to develop a “cradle to grave” accounting of inputs and outputs required to produce, use and dispose of it. For natural Christmas trees, this covers everything from planting seedlings to harvesting the trees and disposing of them, including equipment use, fertilizer and pesticide applications, and water consumption for irrigation.
Life cycle assessments often will also estimate a system’s carbon footprint. Fuel use is the biggest source of greenhouse gas emissions in Christmas tree production. Using 1 gallon of gas or diesel to power a tractor or delivery truck releases 20 to 22 pounds (9 to 10 kilograms) of carbon dioxide into the atmosphere.
On the positive side, Christmas trees absorb and store carbon from the atmosphere as they grow, which helps to offset emissions from operations. Carbon represents about 50 percent of the dry weight of the wood in a tree at harvest. According to recent estimates, Christmas tree-sized conifers store roughly 20 pounds of carbon dioxide in their above-ground tissue and likely store similar amounts below ground in their roots.
However, using 1 gallon of gasoline produces about the same amount of carbon dioxide, so if a family drives 10 miles each way to get their real tree, they likely have already offset the carbon sequestered by the tree. Buying a tree closer to home or at a tree lot along your daily commute can reduce or eliminate this impact.
And natural trees have other impacts. In 2009, Scientific American specifically called out the Christmas tree industry for greenwashing, because growers’ press releases touted carbon uptake from Christmas tree plantations while ignoring pesticide use and carbon dioxide emissions from plantation management, harvesting and shipping.
IS SYNTHETIC BETTER?
Artificial trees have a different set of impacts. Although many people think shipping trees from factories in China takes a lot of energy, ocean shipping is actually very efficient. The largest energy use in artificial trees is in manufacturing.
Producing the polyvinyl chloride and metals that are used to make artificial trees generates greenhouse gas emissions and other pollutants. China is working to reduce pollution from its chemical industry, but this may drive up the prices of those materials and the goods made from them.
Moreover, to consider sustainability from a broader perspective, production of real Christmas trees supports local communities and economies in the United States, whereas purchasing artificial trees principally supports manufacturers in China.
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Source: Urban Faith