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9 Ways Christmas Trees Are Reused After the Holidays

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Theo Wargo // Getty

You don’t need a calendar to tell you when the holidays have ended—just take a look outside to see if rows of skimpy, dried-out Christmas trees are lining the curb. Each year, roughly 33 million live Christmas trees are purchased in North America, many of which end up rotting in landfills once the new year arrives. But making our days merry and bright isn’t the only thing a felled evergreen is good for. Here are some ways Christmas trees continue to serve a purpose long after their decorations have been packed away.


The tree that’s erected in Manhattan’s Rockefeller Center each November is arguably the most iconic Christmas display there is. It’s also one of the largest, reaching up to 100 feet tall and often weighing more than 10 tons. That’s a lot of lumber, and luckily, Habitat for Humanity makes sure it’s put to good use. Every year since 2007, Rockefeller Center has donated its tree to Habit for Humanity International after taking it down on January 9. From there, the festive behemoth (usually a Norway Spruce) is divided into sections in the plaza before it's shipped to a mill in New Jersey for additional sawing. It’s eventually made into 2-by-4 and 2-by-6 beams used in construction projects around the country. Homes in Bridgeport, Connecticut, Morris, New Jersey, and Philadelphia all contain pieces of what was once the world’s most famous Christmas tree in their walls.


If you were to walk along the bottom of Lake Havasu between Arizona and California long enough, you’d eventually come across the site of a Christmas tree graveyard. What may be a creepy scene to holiday lovers is a lush utopia for fish—the branches of the spruces, firs, and pines provide a hiding place from predators and attract food for the fish to nibble on.

The 875-acre artificial reef resting on the lakebed consists of PVC pipe, cinder blocks, concrete sewer pipe, brush, and thousands of Christmas trees weighed down with sandbags. Decades of decomposed plant matter have built up a healthy layer of moss and algae around the non-degradable structures. This green coating attracts insects, which in turn attract fish looking for a snack. The end of the holiday season marks the introduction of 500 new trees to the reef, each of which will take about five or six years to break down completely.


Spend a day on the beach in summertime and Christmas trees will likely be far from your mind—but on at least one beach along the East Coast, there are thousands of abandoned conifers buried in the sand. That’s because Bradley Beach, New Jersey depends on recycled Christmas trees to build its sand dunes. Discarded trees are laid out on the beach and held in place between two parallel fences. Sand that blows in from shore gets caught in the branches, eventually packing into a full sand dune over the course of several seasons. Unlike piles that have been pushed together with bulldozers, sand dunes that are allowed to build naturally over time provide a more stable barrier against storm surges. When the time is right, the town plants dune grass to give the structures even more stability, with the vegetation's hairy roots anchoring trees in the sand.


An elephant plays with a Christmas tree at a zoo in Germany. Image credit: Odd Andersen // Getty Images

In the wild, many animals encounter plant life that changes with the seasons. The Oakland Zoo in California hopes to simulate this seasonal variety in captivity with annual Christmas tree donations. Each year, a local Christmas tree lot hands over whatever’s left of their inventory at the end of the season. The zoo’s residents are more than happy to take the trees that others didn’t want—zebras munch on the needles, squirrel monkeys swing from branch to branch, and otters play games of “smell and seek” with treats hidden in the trees by zookeepers. Oakland’s zoo isn’t the only one to take advantage of the surplus of trees at the end of year. The Staten Island Zoo, the North Georgia Zoo, the Linton Zoological Gardens in the UK all accept tree donations.


Christmas trees are a key tool in the fight to save Louisiana’s marshland. The state loses 25 to 35 miles of coastal wetlands a year to advancing ocean tides, and one thrifty way to prevent further damage is by building fences around the marsh’s perimeter. Since the Santa Saves the Marsh project began in 1986, over 1.5 million Christmas trees have been used for this purpose. Following the holiday season, bundles of timber collected from around the country are flown in via a helicopter on loan from the Army National Guard and dropped into the wetlands below. These trees are used to stuff pre-built wooden pens surrounding the bayou. Today, more than eight miles of Christmas tree fencing lines the vulnerable habitat, and it’s already proven valuable: When Hurricane Katrina hit Louisiana’s southern coast in 2005, the shoreline behind the barricade was better protected.


Christmas trees likely aren’t the alternative fuel source of the future, but that hasn’t stopped Burlington, Vermont from ringing every watt of energy they can get from their seasonal haul. The Joseph C. McNeil Wood and Yard Waste Depot collects hundreds of unwanted trees from households and Christmas tree lots at the end of each holiday season. That organic waste gets fed to a wood chipper, and part of the mulch that comes out is sent to the local power plant where it’s tossed into a boiler. The heat generated from the boiler evaporates water into steam that's used to power the turbine in the plant's generator. Each tree that's incinerated amounts to about 36 cents worth of energy for the town.

The Merry Mulch Project isn’t able to produce enough fuel to keep the plant running on 100-percent Christmas tree power (for that, the boiler would need to be fed the equivalent of 100 trees per second), but luckily, Burlington uses other renewable resources like wind and water to keep the city running throughout the year.


It’s hard to go for a hike through Dunbar Cave State Park in Tennessee without trampling on ghosts of Christmas past—all of the mulch used to cushion their trails is made from old Christmas trees. A thousand trees are mulched by the park as part of their annual Trees to Trails program and laid along pathways by volunteers. According to the National Christmas Tree Association, Friends of Dunbar Cave board member David Boen said they stick to Christmas trees exclusively because “by definition they don't have any invasive species or seeds.” In addition to making them easier to walk on, mulch also protects trails from damaging water run-off.


Since 2012, artist Michael Neff has installed a seasonal art project in New York City. “The Suspended Forest” started with a handful of forgotten Christmas trees hung illegally beneath an overpass in Williamsburg. The most recent iteration included 40 floating trees harvested from sidewalks and tree lots after Christmas. They were on display in a warehouse in Queens through the month of January (this time around, Neff had actually received permission to put them there). He hopes to keep bringing the exhibit back to New York and potentially re-imagine it for different cities in the future.


If a Christmas tree doesn’t end up hanging in a warehouse, decomposing on a lakebed, or providing festive scenery for a landfill, it’s most likely turned into mulch. Plenty of towns pulverize their discarded Christmas trees for use in parks and public spaces, but San Diego does something a little different with theirs. For decades the Miramar Greenery has invited city residents to pick up free mulch and compost for use on private property. After dropping off unwanted trees at locations around town or dumping them on the curb, families can visit the Greenery later in the year to collect the mulch they helped contribute to. In a single year, the recycling program can make mulch out of nearly 1000 trees, making the city’s Christmas trees the gifts that keep on giving.

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The Roomba's Creator Invented an Underwater Vacuum That Sucks Up Invasive Lionfish
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Invasive fish can be a major issue for waterways, since they can devastate native species and take a toll on environmental diversity. The red shiner, for instance, is a hardy fish that can survive basically anywhere, and in the process, outcompete and kill native fish species. Invasive species can travel far and wide, hopping across continents with human help (whether on purpose or by accident).

Colin Angle, who co-founded iRobot, the company that invented the Roomba, has an answer. It’s kind of like a robot vacuum, but for invasive fish, according to Fast Company. The Guardian, developed by Angle’s nonprofit Robots in Service of the Environment, is an underwater robot designed to stun lionfish, suck them up, and bring them to the surface.

Lionfish, native to the Indo-Pacific, are considered an invasive species in the Atlantic and the Caribbean, where they have few predators and huge appetites for both crustaceans and other fish. The fish can eat up to 20 other fish in half an hour, lay up to 40,000 eggs every few days, and live up to 30 years, making them a formidable foe for environmentalists. They may have been introduced in the mid-1980s by personal aquarium owners in Florida releasing pets that got too big for their tanks.

As part of the effort to rid Atlantic waterways of lionfish, the U.S. government has tried to encourage people to catch and eat them. If other species can be overfished, couldn’t lionfish?

The Guardian isn’t the only robot with a mission to eradicate invasive fish. Queensland University of Technology’s COTSbot is designed to kill crown of thorns starfish in the Great Barrier Reef. Unlike COTSbot, though, The Guardian isn’t autonomous. Someone above the water has to control it remotely, directing it toward fish to suck up using a camera feed.

That’s by design, though. The idea is that like the Roomba, the Guardian will be affordable enough for fishermen to use so they can hunt the fish and sell them in restaurants. (One unit currently costs about $1000.) The Guardian's ability to reach depths of up to 400 feet will aid fishermen in waters and reefs that can't be easily accessed.

Each Guardian can bring up about 10 live lionfish at a time. And while one robot cannot eradicate lionfish from the ocean alone, a huge number of them could make a dent.

The Guardian is currently in testing in Bermuda.

[h/t Fast Company]

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Climate Change Could Resurrect the Dust Bowl
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Three Lions / Stringer / Getty Images

The billowing dust storms we know from black-and-white photos of the Great Depression could become a reality for future generations, scientists warn. As Gizmodo reports, climate change is grooming the southwest and central Great Plains for a new version of the Dust Bowl that plagued the region in the 1930s.

After gathering 12 years of satellite data (2003–2015), researchers at Princeton University and NOAA's Geophysical Fluid Dynamics Laboratory predict that dust clouds will increase in parts of the U.S. in the latter half of this century. As they lay out in their study in Scientific Reports, prolonged drought and barren landscapes caused by deforestation are set to create the perfect conditions for the same type of storms that drove people from the Great Plains nine decades ago. At its worst, this phenomenon could be deadly; when they're not breathing in dust, residents in the affected areas could be exposed to dangerous pathogens and chemicals carried by air currents.

Dust storms occur when winds stir up dirt particles into dark, massive clouds. During the so-called Dirty Thirties, soil loosened by over-tilling was a major contributor to the dust that enveloped land. Even with more sustainable farming practices, dry summers could create the same arid, dusty landscapes required for a repeat of the Dust Bowl.

While there's still much research to be done on the subject, the study authors hope their findings will get people thinking about how to prepare for the consequences. "Our specific projections may provide an early warning on erosion control, and help improve risk management and resource planning," co-author Bing Pu said in a Princeton University press statement.

That seems like an improvement over ideas for fighting the Dust Bowl that were proposed in the 1930s, which included paving over the Great Plains and bombing the sky. Fortunately, we still have a few decades to come up with better strategies this time around.

[h/t Gizmodo]


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