Science Friday - Top Science Stories Of 2022, Beavers, Christmas Tree Care. Dec 23, 2022, Part 1

Episode Date: December 23, 2022

A Look Back At The Top Science Stories of 2022 2022 was chock full of big science news. Scientists announced an important milestone toward the feasibility of nuclear fusion. Doctors transplanted a pig heart into a human for the very first time. And NASA returned to the moon with the successful launch of the Artemis I mission. Ira recaps the year in science news with Tim Revell, deputy United States editor of New Scientist, including what the James Webb Space telescope has taught us about our universe, the significance of ChatGPT on the future of artificial intelligence, the spread of Mpox, and more.   How The Humble Beaver Shaped A Continent The American beaver, Castor canadensis, nearly didn’t survive European colonialism in the United States. Prized for its dense, lustrous fur, and also sought after for the oil from its tail glands, the species was killed by the tens of thousands, year after year, until conservation efforts in the late 19th century turned the tide. In her new book, Beaverland: How One Weird Rodent Made America, author Leila Philipp tells that tale—and the ecological cost of this near-extermination. But she also has good news: beavers, and their skillful engineering of waterways, have the potential to ease the fire, drought and floods of a changing climate. She talks to Ira about the powerful footprint of the humble beaver. This book is the SciFri Book Club’s January 2023 pick. Find out more about our book club on this month’s main page.   In A New Hampshire Town, It’s Snowmobilers Vs. Beavers On a Saturday afternoon walk, Kelly Schofield and her husband turned a corner onto a road near their house in Bow. They sensed something was wrong with the beaver pond before they saw it. “You could smell it. It was pretty strong. And then when we got down to the pond where you could really see the pond, you could see it was gone,” she said.The pond was drained. Left behind was a huge tract of mud, and creatures trying to survive. Neighbors took videos of fish floundering as the water receded. Beavers are beloved by some and considered a nuisance by many. But Schofield and others who lived on the pond agreed: nature’s engineers made their property more valuable, and made their lives better. They took their kids down to the water to learn about frogs and turtles; watched ducks stop by as they migrated south. Read the rest at sciencefriday.com.   How Science Can Keep Your Christmas Tree Merry And Bright Nothing beats the smell of a live Christmas tree in your home, but how can you keep the needles on your tree and off your carpet? Rick Bates, professor of horticulture at Penn State University, offers tips for how to properly care for your Christmas tree this holiday season.   Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I am I. Rup Flato. Later in the hour, how the beaver literally shaped North America and why restoring beavers to more places could reduce the harms of global warming. Plus, with the holiday season in full gear, we're re-hearing one of our seasonal favorites. I'm talking about tips and tricks to keep your Christmas tree in tip-top shape. And please, whatever you do, don't put your fruit basket underneath your tree. We'll dig into the science of that to tell you why. First, I'll look back at the biggest science stories of 2022. Here are a few just to get us going.

Just last week, scientists announced an important milestone in the decades-long quest to harness nuclear fusion. Earlier this year, doctors transplanted a pig heart into a human for the very first time, and NASA made headway in returning to the moon with that successful launch and return of the Artemis I mission. And let us not forget the mesmerizing images of our. Cosmos sent back to Earth from the James Webb Space Telescope. Joining me now to recap the year in Science News is Tim Revel, Deputy U.S. editor at New Scientist based in New York. Welcome back.

Thanks for having me. There's lots of space news. Let's start with the JWST, the Web Space Telescope. And after many delays, it finally launched this year, the images have been, what, stunning? Do you have a favorite, Tim? Oh, absolutely, I've got a favorite. It was the pillars of creation image that it sent back, which if you remember, this was one of the most famous images from the Hubble Space Telescope, and JWST pointed in the same direction and took a photograph of it too. And I'm sure many people will have seen this image before.

It's like got these very tall towers of gas and dust, which is effectively a stellar nursery where stars are born. And in the Hubble Space Telescope image, they're quite opaque. you can't really see through them, but what JWST was able to do because it sees in a different wavelength of light was look through these pillars and see some of those very early stars forming behind it. I just think it's an incredible new take on an old image. It is a gorgeous image. It reminds me of movies now being reissued old movies in 4K. Yeah.

Beyond these images of planet stars and nebulas, what are some new discoveries coming from the telescope? Yeah, the new discoveries have been coming pretty quickly. It felt like such a long wait for JWST to go up and then a long wait for the first images to come out. But then just a few days after those first images, research has spotted within the JWST data, one of the oldest galaxies we've ever discovered. And that galaxy is from just 300 million years after the Big Bang. That's about 100 million years older than the previous record oldest galaxy that we'd seen. And then in December, JWST broke another record in finding the most distant galaxy ever confirmed.

And that one formed within about 325 million years of the Big Bang and is somewhere in the region of about 30 billion light years away from Earth. And this is just the beginning. There's a lot more to come from JWST next year. And findings like these are really helping us to unpick how galaxies and in particular stars form in the universe. Amazing stuff. Speaking of first, something that sort of flew under the radar this year because of all these other firsts, the Chinese space station completed and fully crewed with three tachonauts. We didn't hear very much about that. Yeah, that was really exciting. I mean, they've been building it for a year or two, like in space. It consists of three modules. And over the last year or two, they've been tyco knots who've been helping put it together.

And one of the modules is living quarters. And then the other two are effectively laboratories to test stuff in space. space. And then in November, it was officially completed. And now for the foreseeable, there's going to be three Taekonauts living up there for about six months at a time. So swapping twice a year. And that will continue for at least the next 10 years. And let's see if we could round up our space news with that DART mission. NASA successfully tested this DART system or double asteroid redirect test, able to change the orbit of an asteroid. Sounds like the plot of a science fiction, movie. Oh, wait, it was. Okay. So what does that tell us? What does it mean for Earth's prospects should an asteroid actually come close to colliding with the Earth? Yeah, this was absolutely

outrageous that this happened, really. And so just to recap, the Dart mission was that NASA sent this spacecraft to an asteroid hundreds of thousands of miles away to see whether it could hit it, and then if it hit it, what would happen? And by the time Dart reached dimorphos, which is the name of this asteroid, it was traveling at 14,000 miles per hour, and it smashed so hard into dimorphus that an enormous plume of material shot off the asteroid surface, and corresponded to about two million pounds of dusty rocks sent out into space. But the thing we're most interested in was if it would affect dimorphus' orbit. Dymorphus, it orbits around a larger asteroid, and DART managed to tweak that orbit by about 32 minutes. And in the grand scheme of things,

that really is just a little nudge. But the idea is that if an object was barreling towards us on earth, a little nudge like this, far enough out from us would be enough to make it a miss rather than a hit. At least that's the plan. That is good news. Moving on to another topic in artificial intelligence. Now there's this new thing, an AI chat program called chatGBT. Why does it have so many people excited and maybe a little bit,

wary of this thing? Yeah, so chat GPT, it's an artificial intelligence, a chat bot built by the company OpenAI. And essentially, you can talk to it. And when it launched in November, it's publicly accessible so anyone can have a go. And you can ask it to do things. You can interact with it. And it just seems to be very good at a lot of things. So people have used it to find information. And people already talking about it as a potential Google killer, because it's so, good at retrieving information, but it can also write essays or computer code or even fiction. And it's really impressive a lot of the time, but then it also does somewhat worryingly seem to throw in misinformation periodically. So there's still a lot to be wary about with chat

CBT. So I'm not too worried yet about my job as a journalist and a writer. It's safe for now. Yeah, I think you're safe for now. We're going to talk a lot more about this in the new year and have some fun with it. I want to talk now about some new research that shook up the world of particle physics earlier this year. I'm talking about the W boson particle being heavier than we thought. Can you give us a quick refresher on what the W boson particle is and why this was such a big deal? Yeah, so this was really shocking when this happened. And the thing with the W boson is it's a fundamental particle and it sort of acts as a messenger for one of the main forces of nature called the weak nuclear force, which is responsible for a certain type of radioactivity.

But exactly what it does is by the by. The main thing is that it's absolutely integral to the standard model of particle physics, which is our best understanding of how the building blocks of the universe work. And so since the discovery of the W boson in the 1980s, physicists have been measuring it more and more accurately. And pretty much all of those measurements have agreed with each other until this one back in April from the collider detector at Fermilab in Illinois. And it was slightly different, but slightly different enough for it to be an issue in our understanding of the standard model. And so researchers,

they have performed a lot of checks to make sure it wasn't just a mistake, and their calculations suggest that the probability of it being a fluke is about one in 780 billion. And it's extraordinary, because it could overturn our understanding of physics, as we know it, at the moment, and hundreds of papers have been written trying to explain what is going on, including some that suggest new particles may exist that we were entirely unaware of. But either way, it's really exciting because we've known for a long time that there's something wrong with the standard model of particle physics. It can't explain gravity or dark matter. So this new finding might help reveal where we need to make improvements to make it better. Oh, Tim, details, details. You bring in the details all the time, especially in

physics. Let's move on and talk about this year seeing another pathogen spreading rapidly around the world this summer. I'm talking about M-pox, which until a few weeks ago was known as monkeypox. How did we go from an average of 400 cases a day in the U.S. at its peak to just a trickle of cases now. You hardly hear about it. Yeah, there was a really drastic change. It very quickly spiraled quickly. So back in May, there were only a few cases. And by the summer, it was, as you say, tens of thousands of cases globally. And thankfully, that has now really drastically changed. So the outbreak, it was spreading mostly among men who have sex with men through skin contact. And the CDC looked into this and they found that many men in the group as

awareness spread were reducing the number of sexual contacts that they had and taking greater precautions if they had symptoms. So that took it from what the World Health Organization declared as a public health emergency of international concern to what now is. really having a minimal impact across the U.S., but also the countries where it started spreading. Any public health lessons learned from the handling of this outbreak? Yeah, I think the big one is that behavior change matters when there's an outbreak. And what we saw here was that quick awareness campaigns and changing of behavior really drastically reduce the spread of Mpox. Let's move on to some really cool discoveries. This year, scientists found the endurance

Great story. The Lost Ship of Antarctic Explorer, Sir Ernest Shackleton from 1915. Let's review what's so special about that discovery. Yeah, absolutely incredible, probably the greatest ever undiscovered shipwreck. So at the bottom of the sea near Antarctica, under 10,000 feet of water is where they found the endurance. And it had been lying there for 107 years since it had been sort of crushed and penned in by sea ice and sank to the bottom of the sea. And what's just so, incredible is that it's sitting upright. Many of the timbers are still intact and the name endurance is still visible on the stern. And so it seems there's very little in the way of wood-consuming parasites in that part of the sea. And so it's just so incredibly well-preserved. That's really cool. I want to end on a simply amazing discovery in the plant world. And that's the world's largest plant. That's called Poseidon's ribbon weed. And it clones itself. Tell me more about that. Yeah, there's also an amazing discovery where in Western Australia's Shark Bay,

which is about 500 miles north of Perth, researchers were just looking at some of the plants there, and they took thousands of samples and suddenly found that thousands of them turned out to covers about a 70 square mile area, and it's grown to that size over about 4,500 years by just repeatedly cloning itself. Wow, that's got to be the largest clone ever, right? Yeah, it is. It's the largest known example of a clone in any environment on Earth. Wow. This plant has seen a lot in 4,500 years, Tim. Thank you for taking time to be with us today, and a happy holiday to you. Happy holiday to you too.

Tim Revel, Deputy U.S. editor at New Scientist based in New York City. We have to take a break, and when we come back, why restoring beavers to more parts of North America could reshape our waterways for the better, especially in the era of climate change? Stay with us. This is Science Friday. I'm Ira Flato. And now it's time to check in on the state of science. This is KERNO.

St. Louis Public Radio News. Iowa Public Radio News. Local science stories of national significance. Our story is a tale of rodents, betrayal, and the machinations of local bureaucracy. Bow, New Hampshire. It's a small town outside of Concord. Its residents enjoy a variety of outdoor activities like, ice skating, birdwatching, and snowmobiling. They would all come together at a local pond,

but beavers at the pond led to controversy and conflict with the town government. Joining me now to talk about this beaver brouhaha is Mara haplamazian, climate change reporter at New Hampshire Public Radio based in Concord. Welcome back to Science Friday. Thanks so much. Happy to be here. Nice to have you. Okay, beaver, pond, what could go wrong? So this pond is technically an impoundment. The beavers created it. They're the reason why people are able to ice skate on the pond. They make it possible for the fish to live there.

They're the reason the ducks can stop by as they migrate. But for this snowmobile club in town, their dam and the water in the pond were a problem. The snowmobilers built this bridge across one end of the pond right next to where the beaver dam is, near where the pond turns into a stream so they could access a snowmobiling route in the woods. and the snowmobiler said as the dam got bigger over time and the water level got harder to manage, it was threatening the bridge and interrupting their snowmobiling. So they put in this pipe meant to trick the beavers. Sometimes people call this kind of device a beaver deceiver. And that was meant to keep the water level down.

But the beavers ended up just plugging that up too. And the snowmobiler said they sort of ran out of options. So who came out on top in this story so far? Well, the snowmobile club got approval from the town government to trap the beavers. and remove what they called debris caused by the beavers. It was pretty unclear to most people what that meant, but the club ended up removing a lot of the dam itself and killing the beavers.

And because the pond was created by the beavers, when the dam was gone, all the water drained out. So it was this kind of grisly scene. The neighbor said when they first saw the water drain, fish were sort of flopping around trying to survive. Plus, you know, they had to explain to their kids that there wouldn't be any ice skating this winter. You know, the day I was there,

it looked like just this huge mud pit. It was a flock of ducks that tried to land, but, you know, they seemed to realize the water was gone and they just turned around. So the neighbors really had no idea this would all happen. Was there fallout from this? Oh, yeah, there was a lot of pushback in the community Facebook group. You know, some of the neighbors of the pond actually organized. First, they went to this select board meeting to sort of air their grievances to town officials. They said the former pond had turned into this smelly mud hole. They had concerns about the impacts on wildlife. And some also said the whole situation set a dangerous precedent. You know, some people felt like the snowmobile club had asked for an inch,

taken a mile, and sort of faced no consequences. Fans of the beavers presented a plan to create a committee that would look for ways to restore the drained area back into a pond. And that group met for the first time in late November. I was at that meeting and the tensions were still really running high. Here's what happened when Mark Doobie, who manages the trails for the snowmobile club, tried to explain himself. And we weren't going to wait until it runs over the banks and takes out our bridge and takes out our trail again.

So you take our pond. We would have not. We wouldn't know folks, one person at a time, please. Because it's not a reasonable outcome. Wow, they had a frank exchange of views all right at that meeting. They did. You know, the tone softened a little bit as the night we're on and people sort of tried to figure out how they could work together and use the land. the way they all wanted to. And folks, you know, proposed solutions for rebuilding the beaver's work.

It's kind of funny. We hear people are complaining about beaver engineering, but people change the natural landscape all the time. I mean, was this something you were thinking about while reporting this? Totally. You know, I hear a lot of people talking about how beavers are a nuisance animal, but they're also super beloved, especially by people who benefit from the habitats they create. each of the groups in boat, you know, the neighbors who like the pond, the snowmobilers who wanted to change the landscape for their own benefit, and the beavers each have this deep relationship to that piece of land and that body of water. And it really made me think about how we see ourselves in relation to the natural world, you know, how we use it and change it to fit our needs and how changes to the landscape can be really meaningful for a wide variety of reasons. So has this been settled or what is the future of the pond now? Well, you know, some residents are really determined to restore it back into a pond, but to install a new dam or make other changes they'd need to get permission from the state.

And that could be a long shot. So their best bet might be to wait and hope another family of beavers moves back in. Thank you, Mara Hoplamazian, climate change reporter at New Hampshire Public Radio based in Concord. We've been talking about what happened when one town in New Hampshire lost its local beavers. But what happens when an entire continent loses the vast majority of this vital ecosystem engineer? That is, in fact, the story of North America after European colonization, and the loss of beavers and the effort to reintroduce them may shape what happens to our ecosystems for better or for worse under future climate change. Leila Philip is here with me to tell that story. She's the author of the new book, Beaverland,

how one weird rodent made America. Lila, your book is really a leave it to beaver story. Welcome to Science Friday. Thank you so much. I'm so glad to be here with you. Nice to have you. I know you start this book with your own local story about your local beavers and how they turned a wetland into a pond.

How dramatic was this change? It happened so fast. So I walked past this swampy area with my dog probably every day and just didn't really pay much attention to it. And then one day we walked past and it was just full of water. Beaver had cut down some trees and in very short order had swelled the water. And what's amazing about what beavers do is they'll come to a creek. In this case, the little area near my pond was just a little trickling creek.

And they swell it with a dam. And in this case, they stayed in that area because it was a low area. and they didn't need to move on. There was plenty of food. After they'd cut down enough trees to build the pond, they then fed on the aquatic vegetation there. After the beavers made this pond, what was incredible was the biodiversity that followed.

So so many animals, just bobcats and muskrat and mink and otters. It was just remarkable. And how much water do they store? After all, they are incredible engineers, as you say. I mean, that was the other thing that was incredible, and I leaned into in writing this book, because we know climate change is going to create far more devastating floods and fires, not to mention periods of extreme heat and drought. And beavers can help us deal with these problems because they bring water. So to go to your question, they'll go to a creek and they'll swell it out with water, and then they'll move down further and they'll swell it out again. So what was once a single thread of water looks from above like a line of almost beads on a chain.

And then the beavers will build canals into the woods on either side because they need them for transportation. And so the water has a lot of interaction with the land. If you get a flood, the water has a lot of places to go so that instead of ripping through the stream system, the water has a chance to settle down. And this is why it may seem counterintuitive to people, but beavers actually help with flooding. And science has actually been supporting this with study after study in recent years. And then around their ponds are these marshy areas that are wetlands. So a wetland, the water you can see is just the beginning. Because underneath, imagine this giant sponge you can't see.

So every one of these beaver damning complexes is like a giant invisible sponge storing water for times of drought. And we need that water, which is why beavers are so incredibly important to the health of, you know, the whole ecosystem. And you make that point in your book, that indigenous peoples of North America knew what you're telling me. They knew that beavers were crucial to the health of their ecosystem. they even forbade hunting of beavers, didn't they? That was one of the really interesting things that I learned when researching and writing this book. The indigenous peoples that lived throughout North America

understood the ecological value of the beavers. So the Algonquian peoples of the woodland areas of the Atlantic seaboard and up through the Great Lakes area had these wonderful stories of great beaver that are important teaching stories about beaver, and they had strict rules about how to hunt and harvest beavers. And out in the arid northern plains in places like Montana, the Blackfeet and other peoples out there actually had prohibitions against hunting the beaver

because they understood the value the beaver played in keeping water in the land. So this knowledge base is something that I think it's pretty interesting that our science now is almost catching up to. Geomorphologists, eco-hydrologists, wildlife managers are all beginning to really understand and study the value of the beaver as what is called a keystone species. So you're talking about how the country was filled with beaver. And then in the book, it talks about how European settlers came in and, totally disrupted the ecosystem. Yeah, I mean, I think colonization was environmentally devastating on many respects, but the fur trade, which wiped out the beaver, geomorphologists now talk about that as the great drying, because basically what happened was the river systems very quickly

became degraded without beavers in them. So in what are called paleo rivers or rivers before colonization, You don't have single channel rivers that we see today that run along one thread. Instead, you would have multi-threaded, braided creeks and streams that were messy and multi-threaded and would overspill, contract, and then recede with the rhythm of the seasons. And so they were, imagine them as arteries or veins of water that were pulsing life into the land. that's a river system that is working at peak hydraulic function. So when the beavers were taken out and no longer able to maintain the river systems, you had really huge impact.

At the height of the beaver trade, these animals were slaughtered by the tens of thousands every year. How did we get it together to protect beavers after this massive kill-off? Did we realize their value? Well, that's what's so kind of amazing and fantastic about this story is that, well, we didn't understand yet their value to us as environmental restoration partners, which we do understand now, but smart policies at the right time in the early 1900s brought beavers back. It's part of this kind of counterintuitive North American wildlife program that we had, was fantastically successful, and in a counterintuitive way,

it was actually based on bringing wildlife back for hunting and trapping. So at that time, the idea was to return wildlife as a hunting and trapping resource. But thank goodness the beaver were returned, they rebounded, and now we understand that a live beaver is much more valuable than a pelt. This is Science Friday from WNYC Studios. but still we just heard a story from New Hampshire where the public was pushing back against having a beaver pond

because it got in the way of their snowmobiles and took their recreation away. So there is still there is push and pull, is there not? Yes, there's always going to be human wildlife conflict because we live where the wildlife have always been. But I have to say, stories like that really give me pause because there are now very sophisticated methods for controlling beavers with non-lethal methods and flow devices and pond levelers. The places where I have seen those fail, often they have been jerry-rigged solutions that towns have done, you know, the highway department has just put maybe some wire over the culvert.

Of course, beavers can just stick, you know, stuff wire and block the culvert right back up. So I think it really behooves a town or a community to explore in a really full way, non-lethal methods, before they do things like start breaking the dam, because breaking a dam is just often a very unproductive way of managing beavers. Either you drive the beavers away and you have no more pond anymore, so you lose all that biodiversity and the beautiful pond, and the beavers go somewhere else to create a problem for someone else if habitat is limited, or the beavers may die because if it's November and they can't have shelter in time, they'll be, you know, winter is coming. This is such an interesting book. I learned so much from your book.

Who knew that a million years ago, beaver were as big as bears? Wow. Yeah. Yeah, isn't that amazing? I mean, they've been on the continent for something like 37 million years. And I like to imagine beaverland. I mean, imagine North America when there were 400 million fever living on it. And so much water pulsing through the land and the great boreal forests. No wonder there was a tremendous research. source of wildlife that sprang up throughout the continent. Well, I want to ask you one last question about that. About 400 million beaver, you talk about that with climate change and the future challenges we're going to face, how will beaver help us face those challenges? It has been shown in study after study that beaver wetlands hold nine times more water than areas without

beavers. So imagine if in the coming times of drought, you have these big sponges of water in the land. That's going to help everything. Out west, there are now the U.S. Fish and Wildlife Service just funded a study looking not just can beavers help prevent wildfires, but how many beavers wear? So in other words, harnessing beaver wetlands to use this kind of speed bumps for wildfires. And in flooding, out in Milwaukee, there's a study that was done in 2021. I write about this in the book where they're looking at the watershed of the Milwaukee River, and they've estimated that if they put in literally 4,500, I think it's 63 beaver, they can create water storage for 1.7 trillion gallons of water.

And that is water storage valued at $3.3 billion annually. And I think we should think about beavers like millions of highly trained engineers out there, ready to work for us for free, instead of instinctively thinking of them as nuisance pests. And I think if we can change that paradigm, we'll be a lot better off. Unfortunately, Lila, we have run out of time. I want to thank you for taking time to be with us today. Thank you so much for having me. Lila Philip, author of Beaverland, How One Weird Rodent Made America.

And good news, bookworms, members of the sci-fi book club will be reading Beaverland together this January. You can find everything you need to get started, including upcoming events, a short excerpt to read, and a giveaway to win a free book. It's all on our website, sciencefriiday.com slash beaverland. That's science friday.com slash beaverland. We have to take a break, and when we come back, science tips to keep your Christmas tree merry and bright this holiday season. This is Science Friday. I'm I Refleto. You know, over the years, we've looked into the science behind many of our holiday favorites,

including Christmas trees. And one of the most fascinating facts that I learned is that there are certain gifts that should not be going under the tree. If you have a large bowl of fruit, will it give off ethylene? Yeah, of course. Don't keep your fruits close to your trees. Seriously, keep the fruit. Honestly, yeah.

Yeah, keep a, if you get a fruit basket for Christmas, Exactly. Don't put it under the tree. Get the fruit basket away from under the tree. Get away. Yeah, that's correct, actually. And there you have it. That's from a conversation I had in 2010 with Raj Lada, founding director of the Christmas Tree Research Center at Dalhousie University in Nova Scotia, Canada.

So if you want to keep your Christmas tree to last through Christmas and even the new year, keep that fruit basket away from your tree. Okay, now that you've moved your fruit basket, what else can you do to keep your Christmas tree healthy and your home relatively needle-free? Here's another interview from 2012, full of tips and tricks to keep your tree looking just as good as the day you brought it home. I spoke with Rick Bates, Professor of Horticulture and the Department of Plant Science at Penn State University and University Park, Pennsylvania. Welcome to the program. Good afternoon, Ira. Thanks for having me.

Is there a specific species that makes a good Christmas tree, one better than the others? There are. If you look at kind of everything that's out there on the market, you're going to see spruce, you'll see pine, you'll see Douglas fir, and then what we call true fur. And the true fur tend to be kind of like the Cadillac of the Christmas tree species. In the east, Frasier fur tends to be the species of choice. In the western U.S., a lot of people really like noble fur. So it's a fir tree? Yeah, it's a fur as opposed to a pine or a spruce.

Do you know how to ask the sea, you know, if you're getting the real fur tree or not? Well, usually a retailer, even somebody at a big box store, for instance, usually could tell you the difference. Certainly the true fur, the needles tend to be soft. You can run your hand over a branch and they'll be nice and flexible and soft. When we think of Christmas tree aroma, we're often thinking about furs, whether we know it or not, balsam fur or con-color fur, tend to be really aromatic. The spruce tend to have kind of a spiny or prickly needle. So if you grab hold of, let's say, a Colorado spruce, you're going to know it. The pines, for instance, white pine, tends to have a real thin, long, fine.

needle, real soft, real fine texture. When we were researching this, Rick, we found that there's a whole bunch of researching Christmas trees, a lot of it going on. Why is that? Well, there is. It's a big industry. If you look at how many Christmas trees we consume as a nation, the U.S. uses about 30 million plus or minus a year.

Europe, Western Europe, particularly, they're closer to 50 million. So it's a billion dollar a year plus industry. There are a lot of Christmas tree farmers across the country, probably in the neighborhood of 15 to 20,000 producers of Christmas trees. So it's a big industry. Rick, let's get into some of the do's and don'ts of a Christmas tree. For example, when is the best time to buy the tree? Well, usually sometime after Thanksgiving is when the Christmas tree sales season starts to heat up.

It kind of depends on what your estimation is of how long you want to leave the tree up. You know, I normally go out and get a tree the weekend after Thanksgiving and I procrastinate and taking it down. And so it sometimes doesn't come down until after the first of the year. So it may be five or six weeks. So you don't want to push the envelope or you might end up with more needles on the floor. So, you know, generally four to six weeks ought to be. ought to be the limit. So if you're, let's say, you know, choosing a species that maybe doesn't have the best needle retention, let's say a white pine or a scotch pine, maybe you want to wait until

the first of December in that first week of December or the second week of December, you may not want to try to leave it on display for quite as long. Let's talk about a live tree. We've had a number of tweets. And Nathan Ryder, Flouvo, they want to know, first, Should I dig up an expense tree to plant after the holidays? How can I make sure it lives? How do I keep the tree alive and replanted after Christmas? What are the do's and don'ts for a live tree? Those are all good questions, and it tends to be a little bit more complicated, you know, than the face value of the question.

We have a lot of trouble keeping live trees alive when we transplant them back outside in the landscape after Christmas. And probably the best way to go about it, rather than actually digging up a tree and hauling it inside, would be to go to a local garden center or some of the retailers that are now offering this kind of product, like a containerized conifer, maybe a little bit smaller than a six to seven foot tree, but they're out there and they're becoming more common. Start with that kind of product. And then rather than planning it outside directly after the display period, after, you know, the first of the year, keeping it inside, something like an unheated garage. The light doesn't matter so much as just not exposing it to the real cold temperatures, especially here in the northeast after you've had it on display. Do you water the roof, if you have it in your garage, do you water the root ball at all? You know, because it's a cooler environment and it's not exposed to the wind, it doesn't use a lot of water. So rather than maybe a once a week watering, just check it frequently, maybe once a week,

but I bet you only have to water it once every couple of weeks. It's not going to use a lot of water. And then just as soon as the ground becomes workable in the spring, that might be March for some parts of the country, maybe April. That's when you want to go out and actually plant it. If you do that, I think your chances of that tree surviving in the landscape are going to be a lot better than if you just dig something up from a farm or from your yard, drag it inside, and then replant it. The other thing to keep in mind is that the longer you keep that kind of live tree inside on display in a warm living room, the worse your chances are going to be for that plant living once you plant it back outside. So you want to kind of limit the amount of time to maybe a week to 10 days inside on display versus a cut Christmas tree. You know, that's going to be recycled after the display period anyway.

So you can leave it inside until it actually starts to shed needles. But for this live product that you want back out in your yard, you know, try to limit the amount of time that you're going to have it inside. That's some shock it goes through. It's going to go from that warm to the cold. Yeah, exactly. Yeah. Let's go to Bonnie in North Little Rock, Arkansas. Hi, Bonnie. I'm just wondering about what variety of tree is least likely to cause allergy problem. I've had some trouble over the past three years when the tree comes in the house,

and I'm thinking about an artificial tree. It'd be the first one I've ever had. So I love a live tree. Yeah. That's a good question, and I hope you kind of stick with it and continue using a live tree. I don't know that there are really big differences between species in terms of allergies that we know about. There are some environmental factors that I think can lend to a tree maybe having the spores or the mold that might cause a problem. If you have a period of time when the tree's been harvested that's wet, or particularly if it's warm and moist. And they're in Arkansas, you may have some November temperatures and conditions where it's relatively warm, there's a lot

of moisture around. Often when a Christmas tree producer or retailer has a cut tree, they will bail it, which means they'll wrap it in twine, bundle it up so that it stores better. That kind of traps some of that moisture inside. So something like opening that tree up, before you bring it inside, especially if it's been on display at a retail outlet under those kind of warm, moist conditions. That can help. Let it dry out. Should you cut it, put a fresh cut where the old one is? Well, that's going to help in terms of the longevity and the quality of the tree inside. It may not do much in terms of allergies or spores.

The other thing is a lot of choose-and-cut farms in the better retailers, they're probably going to shake the tree before you buy it. So they'll put it basically on a device that simply vibrates the tree, and that knocks out any kind of loose needles or dead needles that may be up in the tree. And that gets rid of a lot of the debris, a lot of the structures like the dead needles where, you know, there might be a spore or something on that needle, and that can kind of clean the tree up. So that can help. Under most conditions, people generally don't have much of a reaction. Bonnie, thanks for calling. Good luck for you. Okay, thank you. Let's go to Stan in Tallahassee.

Hi, Stan. Hey, I had a question. We have a, and I was wondering. Yeah, what affects how long your tree will live? Maybe you can throw in that question. I asked about cutting it when you get it home. Will that affect how long it lives? It does.

The best way to look at it, I think, is it's a, a combination of genetics and environment. And the genetics are based in the tree. So there'll be some tree-to-tree differences and some differences between these species that we've talked about. But then the other big factor are the environmental conditions that the trees exposed to. And really what we're talking about are the environmental factors that relate to water, to hydration of the tree and to how quickly the environmental factors around that tree pull water out of the tree. And so the key is, if you want to control the environment, is to try to keep the tree as hydrated as you can during the entire display period. And so that would start with, like you mentioned, a fresh half-inch or inch cut on the base of the tree if you don't know how long it's been since the tree was harvested.

That's going to open up the xylem vessels to take in water. It's going to open the tree up to absorb water. And trees actually can drink a lot of water, especially when they're freshly cut. So it's not uncommon for a tree to absorb a gallon or more a day. A gallon a day. A gallon a day. A good rule of thumb is about a quarter water per inch of stem diameter per day. And this goes down kind of over the lifespan of the tree when it's inside.

But initially, that could be a lot of water. What about those plant packets they put inside? Does help keep the tree alive? The research that we have to date don't really indicate that there's much benefit from. that. You'd be better off concentrating your efforts on things like making sure you've got a proper reservoir of water, something that holds at least a gallon, keeping fresh water in there. Like your caller's question suggests maybe keeping it out of the sun, out of drafts, away from heat, heater vent, something like that, can tend to dry the tree out. So what you're really trying to do

or modify or reduce all those factors that would suck moisture out of the tree. And that's going to probably do more than anything else to extend the life of the tree on display. One question for you about, you know, we're looking forward at, what's the best way to dispose of your tree once the holiday is over? When the holidays are over, and, you know, I don't know if you're like me, I tend to push the envelope and I don't really take the tree outside until I kind of start to see needles dropping and it clearly is on its way out. Most municipalities now have a good recycling program where they will turn that Christmas tree into mulch just like they would branches or leaves in the

autumn. So they'll take the tree and they'll put it into that composting waste stream and turn it into something useful that the municipality then often either gives away or cells in the form of mulch. So it's a great way to recycle. And actually, if you get on the website, realchristreys.org, you often can actually find a recycling program in your municipality. This is Science Friday from WNYC Studios. If you're just joining us, we're revisiting a conversation about the science of Christmas tree care with Rick Bates, Professor of Horticulture at Penn State University. I heard that You have a novel or have come up with a novel method of disposal of Christmas tree that we wouldn't have thought of or expected in a lake. Is that correct?

Yeah. If you're out in the country or around a reservoir or farm pond or farm lake, some people will take the Christmas tree and actually toss it into the lake and it actually provides some habitat for small fish. Well, they allow you to do that? Well, you probably want to ask first. A number of years ago lived next to a farm that had a couple of farm ponds. And the farmer was happy to have the Christmas trees in the lake because there was a pretty healthy bass population and bluegill population. So it's a good practice.

Not everybody can do that if you're in an urban area. But certainly that or recycling the tree is a real good solution. It really is a renewable resource. So we grow the trees and turning them into mulch after the season is a good way to dispose of them. And what about the temperature of the water? You say we need a gallon jug to put it in, to keep it filled with a gallon. Does it help to make it hotter water than, you know, than average temperature? It really doesn't matter.

Cold water is fine. What does matter is the fresh cut on the base of the tree. If it's been, you know, a day or so since that tree's been harvested, putting the fresh cut, opens up those pores that are going to draw in the water. And if the water's cold or hot, it doesn't matter so much as having a fresh cut and no sap covering that base of the trunk. So that's the most important thing then. Enough water, give it a fresh cut, and have a merry Christmas.

Yeah, and enjoying the tree. And, you know, those things like keeping it maybe out of the sunlight, out of drafts, away from heater vents. But then checking the reservoir routinely, because I find that commonly, people are surprised just with how much water the tree uses, especially in that first week. So keeping an eye on that Christmas tree stand reservoir. And keep the fruit baskets away from it. Thank you very much, Rick.

Okay, thank you. Rick Bates, Professor of Horticulture in the Department of Plant Science at Penn State University. And that about wraps up our holiday hour. Here's Sandy Roberts with some of the folks who helped make this show happen. Thanks, Ira. Nehima Ahmed is our manager of impact strategy. Beth Rami is our controller. Jordan Smudjik and Jason Rosenberg are our grants managers.

Melissa Mayors is our office manager. And I'm Sandy Roberts, education program manager. Thanks for listening. Thank you, Sandy. BJ Leatherman compose our theme music. And of course, if you missed any part of this program, or you'd like to hear it again. Subscribe to our podcasts or ask your smart speaker to play

Science Friday. We'd love to hear from you. Email us the old-fashioned way, SciFri at ScienceFriday.com. Have a great holiday weekend. I'm Ira Flato.