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.   The Sweet Song Of The Largest Tree On Earth For this story, we’re taking a trip to south central Utah and into the Fishlake National Forest to visit the largest tree on earth, an aspen named Pando. The strange thing about Pando is that it doesn’t really look like the world’s biggest tree. It has rolling hills with thousands of tall, lean aspens swaying in the wind. But Pando is there, hiding in plain sight. All those tree trunks you see aren’t actually individual trees. Technically, they’re branches, and that’s because Pando is one massive tree—sprawling more than 100 acres, with 47,000 branches growing from it. There is a lot to learn about Pando, and our guests turned to sound to understand the tree better. Together, they created an “acoustic portrait” to hear all the snaps, splinters, and scuttles that happen in and around the tree. Ira talks with Jeff Rice, a sound artist and co-founder of the Acoustic Atlas at the Montana State University Library, and Lance Oditt, executive director of the non-profit Friends of Pando, which is dedicated to preserving the tree.   This $7 Violin May Be $7... But How Does It Sound? Stringed instruments can be a joy to the ears and the eyes. They’re handcrafted, made of beautiful wood, and the very best ones are centuries old, worth hundreds of thousands of dollars, or sometimes even millions. But there’s a new violin in the works—one that’s 3D-printed. It costs just a few bucks to print, making it an affordable and accessible option for young learners and classrooms. Dr. Mary-Elizabeth Brown is a concert violinist and the founder and director of the AVIVA Young Artists Program in Montreal, Quebec, and she’s been tinkering with the design of 3D-printed violins for years. She talks with Ira about the science behind violins, the design process, and how she manages to turn $7 worth of plastic into a beautiful sounding instrument.   To stay updated on all-things-science, sign up for Science Friday's newsletters. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.