We begin our three-part wrap-up of this year-long series with our guide Marielle Anzelone, urban botanist and ecologist and the founder of NYC Wildflower Week.  Today, Robert Macfarlane, a fellow at the University of Cambridge and the author of several books, including Underland: A Deep Time Journey (W. W. Norton & Company, 2019), who shares his insights into how trees connect to each other, and the idea that each tree is a world to itself.

→For Friday's show, get creative about your tree and write a haiku* in honor of your tree -- or from the point of view of your tree -- or about the web of life that trees are part of.  Tweet your October tree pictures and your haikus to #BLTrees or email them to [email protected] with the subject line BLTrees Haiku. We'll read some on the air on Friday.

(*three lines of 5, 7, and 5 syllables, if you're following tradition)

Even in Brooklyn, my Pin Oak knows it's October. Trees have intelligence, as @RobGMacfarlane will share today, so my tree may also know that we are winding down our year long #BLTrees series this week with 3 special (and short) segments. Do tune in! 🍁 https://t.co/LLWJcUlGMw pic.twitter.com/gX4WfYNsq3

The last of the year long project - I think- #bltrees @nycbotanist the Japanese maple is starting to get fire orange 🔥- thank you @BrianLehrer and all the guests for this ride around the sun… pic.twitter.com/eckiCQa7cy

Tree and shadow.#bltrees pic.twitter.com/k47gJxhbO2

It’s the sky for me…perfect back ground to show of this oak #BLTrees pic.twitter.com/XHk2hgjzfB

Celebrating all stages of these fruits #BLTrees pic.twitter.com/AkiSzP6xkD