Science·What on Earth?

Can't decide on a real vs. fake Christmas tree? Consider a 'living' tree

In this week's issue of our environment newsletter, we look at the benefits of a 'live' Christmas tree and how the U.S. Clean Air Act has helped birds across the continent.

Also: How the U.S. Clean Air Act has helped birds

White text against a semicircle made of lines and blue and green stripes
(Sködt McNalty/CBC)

Hello, Earthlings! This is our weekly newsletter on all things environmental, where we highlight trends and solutions that are moving us to a more sustainable world. (Sign up here to get it in your inbox every Thursday.)

This week:

  • Can't decide on a real vs. fake Christmas tree? Consider a 'living' tree
  • Is this the filling station of the future? 
  • How the U.S. Clean Air Act helped North American birds

Can't decide on a real vs. fake Christmas tree? Consider a 'living' tree

(Sean Gallup/Getty Images)

Real or fake Christmas tree? It's a tough choice, especially since both have environmental pros and cons. But there's a third option that few people consider: living (or potted) Christmas trees.

Stories like the one about the owl found in the Rockefeller Plaza Christmas tree can make some of us feel a little guilty about the impact real Christmas trees have on things like wildlife habitat.

With a living Christmas tree, which comes in a pot with roots intact, you can decorate and enjoy a real tree over the holidays and then afterward, plant it outside and actually create wildlife habitat that can last a long time.

"You're going to plant a tree that is going to be enjoyed for years to come," said Jamie Beckett, who's in charge of Christmas tree selection at Evergreen Garden Market in Toronto. The market generally sells a few potted trees each year and even offers workshops on how to care for them, but doesn't have any this year, partly because of a shortage.

Shirley Brennan, executive director of the Christmas Tree Farmers of Ontario, said there are people who want a Christmas tree but don't like the idea of cutting one down to decorate their house. Some have thought about planting a tree in their yard anyway, so why not do it this way?

"We see it more and more," Brennan said, adding that the idea is most popular among people in new housing subdivisions with little existing greenery.

Despite their benefits, living trees aren't for everyone. For one thing, a three-foot-tall living tree costs about the same as a six-foot-tall cut tree, although the former does of course last longer. And a key requirement is you need a place to plant it. (Donating it to a shared green space such as a park or grounds around a condo building may be an option).

Ensuring a live tree makes it through the holidays requires a bit of care and planning, Beckett and Brennan warn. Here are some of their tips:

  1. Know where you want to plant the tree before buying. Choose the species accordingly, as they grow to different sizes and tolerate different conditions. Often it also helps to dig the hole ahead of time, when the ground isn't frozen.

  2. Buy a larger tree if you can. These tend to survive better than smaller potted trees, but even the largest aren't that big, Beckett said. Potted trees generally top out at about three feet tall, as the root balls of larger trees are impractically large and heavy. 

  3. Have a sheltered, unheated space, such as a garage or porch, where the tree can transition between the outdoors and your heated home. Make sure it's not exposed to repeated freezing and thawing.

  4. Take good care of it. Make sure the root ball is moist but not too wet. Decorate the tree but make sure the lights aren't too hot and the decorations too heavy.

  5. Don't keep it indoors too long. Christmas Tree Farmers of Ontario recommends five days and definitely not more than 10 before moving it back to the garage or another outdoor shelter. Otherwise, the tree will get too used to the warm temperatures and won't survive being put back outside.

Brennan said the tree's survival improves if it spends less time indoors, and some customers have had good luck keeping and decorating their tree on the deck. She recommends planting the tree as soon as possible in the spring.

Beckett acknowledges that a living tree is trickier to care for than other kinds of Christmas trees, and may not always survive. But it's an opportunity to plant a tree that will always remind you of a happy Christmas past.

"I personally love the idea," he said. "I'd absolutely encourage somebody to try it."

— Emily Chung


Reader feedback

Next week's issue of What on Earth? will be the final one for 2020, a year quite unlike any other. With that in mind, we'd like to hear what changes you're making in your daily lives to reduce your environmental footprint. 
 
That could include anything from using less plastic or investing in renewable energy to resolving to buy fewer things or taking a more active role in conserving nature.

Write us at [email protected].

Old issues of What on Earth? are right here.

There's also a radio show! Later snowfalls, earlier melts and a Canadian Arctic that is warming three times the global average. As many of us escape to the outdoors for some pandemic relief, What on Earth host Laura Lynch asks: what will a Canadian winter mean in a warming climate? Listen on CBC Radio One on Sunday at 12:30 p.m., 1 p.m. in Newfoundland, or any time on podcast or CBC Listen.


The Big Picture: The filling station of the future?

On Monday, a service station opened in Braintree, Essex, in southeast England, that represents a shift in the history of automobiles. That's because the station (pictured below) is geared toward electric vehicles — it features 36 rapid chargers that can top up a battery with a 320-kilometre range in about 20 minutes. Charging costs 24 pence (about 40 cents Cdn) per kilowatt-hour of energy, which for a car like the Tesla Model 3 or Nissan Leaf would mean about $24 for a full tank. The concept was developed by Gridserve and Hitachi Capital UK, and is the first of 100 stations the companies are planning to roll out across Britain in the coming years. At this particular station, the electricity is generated from an array of solar panels on the roof of the station as well as a network of solar farms, and is balanced by a six megawatt-hour battery on the premises to make sure there is always power available to commuters.

(Gridserve)

Hot and bothered: Provocative ideas from around the web

  • The New York Times Magazine recently ran this cover story exploring new research about forests — namely, that trees communicate with each other and help each other thrive. The person largely responsible for this insight: a Canadian ecologist named Suzanne Simard.

  • Canadian banks are still investing big money in the Keystone XL pipeline, despite a pledge from U.S. president-elect Joe Biden that he will block the project. A new report from the Rainforest Action Network says five Canadian banks (BMO, TD, RBC, CIBC and Scotiabank) are spending a total of $35 billion on the project, with BMO leading the way with $20.3 billion. BMO recently announced it would swap its oil and gas investments in the U.S. for Canadian assets.

  • Electronic waste in the U.S. is on the decline, according to new research from Yale University. Researchers found that the total mass of e-waste produced by Americans has decreased since 2015, mainly because of the phasing out of certain bulky TVs and monitors for sleeker devices. The drop in e-waste is also attributed to the fact that many devices are now "convergent" — meaning tasks that would have once required multiple devices can now often be facilitated with just one.

How the U.S. Clean Air Act helped North American birds

(Gerrit Vyn)

Ozone can be both good and bad — in the atmosphere, it protects us from harmful UV radiation, but at ground level, it can contribute to thick smog that endangers humans as well as birds. 

Regulating it is a win for both vertebrate classes.

A new study published in Proceedings of the National Academy of Sciences says that improved air quality under policies like those in the U.S. Clean Air Act may have saved as many as 1.5 billion birds. 

Researchers from Cornell University and the University of Oregon used crowd-sourced data to track changes in bird abundance, air quality and regulation for 3,214 U.S. counties between 2002 and 2016. They found that small migratory birds such as sparrows, warblers and finches — which make up 86 per cent of all North American landbirds — are the most vulnerable to ground-level ozone pollution, which occurs when pollutants from cars and power plants, for example, react with sunlight. 

The Clean Air Act was signed into law in 1963, but amendments in 1970 created national ambient air quality standards that put limits on pollutants like ozone, lead, carbon monoxide and nitrogen dioxide, among others. By reducing pollutants through the Act, the U.S. avoided more than 160,000 premature deaths in 2010 alone, according to a peer-reviewed study by the U.S. Environmental Protection Agency.

The new study is the first evidence that shows the continental-level impacts of air pollution on birds and how much they benefit from clean air policies, said Amanda Rodewald, a co-author of the study and senior director of the Center for Avian Population Studies at the Cornell Lab of Ornithology. 

"The birds in the United States that could be impacted are going to include those that are migrating to and from Canada, and also birds that are wintering in Central or South America and the Caribbean," said Rodewald.

These borderless birds are important seed dispersers and pest controllers. They're especially vulnerable to air pollution because they have high oxygen requirements for flight and because of the way they breathe. Birds don't inhale and exhale like humans but rather have a continuous air flow that increases their exposure to pollutants. 

Here in Canada, Canadian Ambient Air Quality Standards (CAAQS) are set by a council of environment ministers from federal, provincial and territorial governments to keep pollutants at bay. Since ground-level ozone isn't emitted but formed by a chemical reaction between sunlight and nitrogen oxides or other volatile organic compounds, it requires the regulation of multiple pollutants.

Without regulation, ground-level ozone can wreak havoc on entire ecosystems. 

"[Some] plant species experience slower growth and become more sensitive to pests and severe weather in the presence of higher ozone levels," said Jill Baumgartner, associate professor in McGill University's department of epidemiology, biostatistics and occupational health. 

"Effects on individual species can impact the larger ecosystem by changing species diversity, habitat for wildlife and water or nutrient cycles."

Studies have shown that climate change could lead to higher levels of ozone pollution and poor air days — days when ground-level ozone is damaging to human health. And poor air days for humans means poor air days for birds. 

That's why Rodewald, who is based in New York state, said agreements involving Canada, the United States and Mexico — such as the Migratory Bird Treaty Act — are important in keeping North America's bird populations healthy. 

"The U.S., not surprisingly, has been rolling back these protections," said Rodewald. "We're not being a good partner with our neighbours in terms of protecting our shared bird communities, and there are consequences of those reductions." 

— Jade Prévost-Manuel


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Editor: Andre Mayer | Logo design: Sködt McNalty

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