Don’t Stress About What Kind of Christmas Tree to Buy, but Reuse Artificial Trees and Compost Natural Ones
By Bert Cregg
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.
Cutting the 2018 Capitol Christmas Tree in Oregon's Willamette National Forest for delivery by truck to the National Mall in Washington, DC. USFS / Pacific Northwest
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.
Dan Cassens: Starting Your Own Christmas Tree Farm youtu.be
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 U.S., whereas purchasing artificial trees principally supports manufacturers in China.
Going Head to Head
Recently the American Christmas Tree Association, which represents artificial tree manufacturers, commissioned a life cycle assessment comparing real and artificial Christmas trees. The analysis considered environmental aspects of sustainability, but did not examine social or economic impacts.
The report concluded that the environmental "break-even" point between a real Christmas tree and an artificial tree was 4.7 years. In other words, consumers would need to keep artificial trees for five years to offset the environmental impact of purchasing a real tree each year.
One major shortcoming of this analysis was that it ignored the contribution of tree roots—which farmers typically leave in the ground after harvest—to soil carbon storage. This omission could have a significant impact on the break-even analysis, given that increasing soil organic matter by just one percent can sequester 11,600 pounds of carbon per acre.
Keep Smyrna Beautiful is hosting "Bring One For The Chipper", the annual Christmas tree recycling program on 1/5/19… https://t.co/CrjXkVI8Y6— Keep Smyrna Beautiful (@Keep Smyrna Beautiful)1544454099.0
Reuse or Recycle Your Tree
Consumers can't affect how farmers grow their live trees or how manufacturers produce artificial versions, but they can control what happens after Christmas to the trees they purchase. For artificial trees, that means reusing them as many times as possible. For natural trees, it means recycling them.
This is essential to optimize the carbon footprint of a real tree. Grinding used Christmas trees and using them for mulch returns organic matter to the soil, and can contribute to building soil carbon. Many public works departments across the United States routinely collect and chip used Christmas trees after the holidays. If local tree recycling is not available, trees can be chipped and added to compost piles. They also can be placed in backyards or ponds to provide bird or fish habitat.
In contrast, if a used tree is tossed into a bonfire, all of its carbon content is immediately returned to the air as carbon dioxide. This also applies to culled trees on tree farms. And if used trees are placed in landfills, their carbon content will ultimately return to atmosphere as methane because of the way materials buried in landfills break down. Methane is a greenhouse gas 21 times more potent than carbon dioxide over a century, so this is the most environmentally harmful way to dispose of a used tree.
All kinds of factors influence choices about Christmas trees, from fresh trees' scent to family traditions, travel plans and the desire to support farmers or buy locally. Regardless of your choice, the key to relieving environmental angst is planning to reuse or recycle your tree. Then you can focus on gifts to put under it.
Reposted with permission from our media associate The Conversation.
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By Harry Kretchmer
By 2030, almost a third of all the energy consumed in the European Union must come from renewable sources, according to binding targets agreed in 2018. Sweden is helping lead the way.
Sweden is a world leader in renewable energy consumption. Swedish Institute/World Bank
Naturally Warm<p>54% of Sweden's power comes from renewables, and is helped by its geography. With plenty of moving water and 63% forest cover, it's no surprise the <a href="https://sweden.se/nature/energy-use-in-sweden/#" target="_blank">two largest renewable power sources</a> are hydropower and biomass. And that biomass is helping support a local energy boom.</p><p>Heating is a key use of energy in a cold country like Sweden. In recent decades, as fuel oil taxes have increased, the country's power companies have turned to renewables, like biomass, to fuel local 'district heating' plants.</p><p>In Sweden these trace their <a href="https://www.sciencedirect.com/science/article/pii/S0360544217304140#fig3" target="_blank">origins back to 1948</a>, when a power station's excess heat was first used to heat nearby buildings: steam is <a href="https://www.sciencedirect.com/topics/engineering/district-heating-system" target="_blank">forced along a network of pipes</a> to wherever it's needed. Today, there are around 500 district heating systems across the country, from major cities to small villages, providing heat to homes and businesses.</p><p>District heating used to be fueled mainly from the <a href="https://www.sciencedirect.com/science/article/pii/S0360544217304140" target="_blank">by-products of power plants</a>, waste-to-energy plants and industrial processes. These days, however, Sweden is bringing more renewable sources into the mix. And as a result of competition, this localized form of power is now the country's<a href="https://www.sciencedirect.com/science/article/pii/S0360544217304140#fig3" target="_blank" rel="noopener noreferrer"> home-heating market leader.</a></p>
Sweden is using smart grids to turn buildings into energy producers. Huang et al/Elsevier
Energy ‘Prosumers’<p>But Sweden doesn't stop at village-level heating solutions. Its new breed of energy-generation takes hyper-local to the next level.</p><p>One example is in the city of Ludivika where 1970s flats <a href="https://www.buildup.eu/sites/default/files/content/transforming-a-residential-building-cluster-into-electricity-prosumers-in-sweden.pdf" target="_blank">have recently been retrofitted with the latest smart energy technology</a>.</p><p>48 family apartments spread across 3 buildings have been given photovoltaic solar panels, thermal energy storage and heat pump systems. A micro energy grid connects it all, and helps charge electric cars overnight.</p><p>The result is a cluster of 'prosumer' buildings, producing rather than consuming enough power for 77% of residents' needs. With <a href="http://www.diva-portal.org/smash/get/diva2:1232060/FULLTEXT01.pdf" target="_blank" rel="noopener noreferrer">high levels of smart meter usage</a>, it's a model that looks set to spread across Sweden.</p>
<div id="d7bf9" class="rm-shortcode" data-rm-shortcode-id="8757b138d5570bec9d6aad18074a429a"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1273556364263071744" data-partner="rebelmouse"><div style="margin:1em 0">Read more about Western Harbour and book a visit: https://t.co/ujSmVs9rNK 🏡🌳🌊 https://t.co/C5PuPziqIM</div> — Smart City Sweden (@Smart City Sweden)<a href="https://twitter.com/SmartCitySweden/statuses/1273556364263071744">1592474473.0</a></blockquote></div>
Scaling Up<p>A recent development by E.ON in Hyllie, a district on the outskirts of Malmö, southern Sweden, <a href="https://www.eonenergy.com/blog/2019/February/sweden-smart-city" target="_blank">has scaled up the smart grid principle</a>. Energy generation comes from local wind, solar, biomass and waste sources.</p><p>Smart grids then balance the power, react to the weather, deploying extra power when it's colder or putting excess into battery storage when it's warm. The system is not only more efficient, but bills have fallen.</p><p>Smart energy developments like those in Hyllie, Ludivika, and renewable-driven district heating, offer a radical alternative to the centralized energy systems many countries rely on today.</p><p>The EU's leaders have a challenge: how to generate 32% of energy from renewables by 2030. Sweden offers a vision of how technology and local solutions can turn a goal into a reality.</p>
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