I attended a conference in Half Moon Bay, California last week and drove by several picturesque tree farms and pumpkin patches. This immediately made me think I should take my six year-old daughter to cut our own tree this year.
But before I establish a new holiday tradition, I thought I better research whether cutting our own tree is better environmentally than buying a tree from a local store, or even buying an artificial tree.
The way we assess decisions like this at GoodGuide is through a method called “Life Cycle Assessment” (LCA). LCA is a tool for analyzing the full impacts of a product across the different stages of its “life cycle” – from growing a crop or extracting raw materials, to manufacturing the product, to transportation, to using the product, to final disposal. It is often surprising to learn where the biggest environmental impacts are along a product’s life cycle, and to see which products ultimately are greener.
So which is greener: natural or artificial trees?
Most people reading this blog probably assume the answer is obvious: natural is more natural!
But after that truism, things get more complicated. Natural trees can sequester carbon. But they also require land, water, fertilizers, and pesticides. Artificial trees can be used for years and years. But they are usually made from polyvinyl chloride (PVC) treated with potentially toxic flame retardants, and shipped from China.
Not surprisingly the American Christmas Tree Association – the trade association for the artificial tree industry – released a study in 2008 claiming that artificial trees are better for the environment than natural trees if you use them for over 10 years.
The ACTA study seemed largely unconcerned with the potential environmental and health impacts of manufacturing polyvinyl chloride, or the potential dioxin emissions if the PVC is burned at the end of its life.
A more recent, and more independent, Life Cycle Assessment conducted by a Canadian consulting firm – Ellipsos – came to very different conclusions. The 50 page report, with 4 appendices, and peer review comments, comes down on the side of natural trees.
When compared on an annual basis, the artificial tree, which has a life span of six years, has three times more impacts on climate change and resource depletion than the natural tree. It is roughly equivalent in terms of human health impacts, but almost four times better on ecosystem quality compared to the natural tree. The natural tree contributes to significantly less carbon dioxide emission (39%) than the artificial tree. Nevertheless, because the impacts of the artificial tree occur at the production stage, and since it can be reused multiple times, if the artificial tree were kept longer, it would become a better solution than the natural tree. It would take, however, approximately 20 years before the artificial tree would become a better solution regarding climate change.”
One interesting finding that both studies agreed on was that:
the most significant contribution to global warming came from fossil fuel consumption in transportation of real Christmas trees from tree farms and lots to consumer homes. The study also indicated that driving out to a tree farm and cutting down a tree is the worst environmental choice you can make when buying a Christmas tree and that it’s substantially better for the environment to buy a tree from a local retailer rather than to drive out to a farm, due to the incremental fossil fuel consumed.”
The bottom line: it is definitely not a good idea for me to drive to the mountains to cut down my own tree. The emissions from my car will swamp the other environmental impacts of the tree.
So my conclusion is that if I can’t convince my household to go for a living, potted tree – that unfortunately doesn’t look anything like a Christmas tree – we will likely purchase a farm-raised tree from a local store.