Radiolab – "From Tree to Shining Tree"

Date: July 30, 2016 | Hosts: Jad Abumrad & Robert Krulwich
Main Guests: Dr. Suzanne Simard (Forestry Professor, UBC), Jennifer Frazer (Science Writer)

Episode Overview

This episode delves into the secretive, astonishing underground world of trees and fungi—exploring the so-called "Wood Wide Web." Hosts Jad and Robert, joined by experts, uncover how forests are vast communities of interlinked organisms that trade food, messages, and even defend each other. Through captivating storytelling and illuminating analogies, the episode overturns assumptions about forests as mere collections of competing trees, revealing extraordinary cooperation beneath the soil.

Key Discussion Points and Insights

1. Childhood Curiosity and the Discovery of Roots

• Suzanne Simard’s Origin Story: Suzanne, a forestry professor, recalls her childhood exploring the British Columbia rainforest, literally tasting the forest floor ([02:52]).
• Pivotal Incident: A family dog, Jiggs, falls into an outhouse, prompting the family to dig him out and expose a mat of intertwined roots—Simard’s first encounter with the complexity beneath the forest ([05:20]).
  • Quote:

  “Jigs had provided this incredible window for me, ... how many different colors they were, how many different shapes there were, that they were so intertwined, as abundant as what was going on above ground. It was magic for me.”
  —Suzanne Simard ([05:58])

2. The Underground Connections – Early Research

• Industrial Forestry and Unexpected Observations:
  • Simard notices that Douglas fir trees grow healthier alongside birch; removing birch led to fir decline ([07:28]).
  • Hypothesis: There is some form of underground cooperation.
• Radioisotope Experiment:
  • Trees (fir, birch, cedar) are labeled with radioactive gas to track how “food” moves.
  • Discovery: Trees share resources underground, with one tree connected to up to 47 others ([09:00]–[10:03]).
  • Quote:

  “It’s just this incredible communications network that... people had no idea about in the past because we didn’t know how to look.”
  —Suzanne Simard ([10:14])

3. The "Wood Wide Web" Explained

• Science Writer Jennifer Frazer introduces the memorable term “Wood Wide Web” for this network ([10:51]).
• Is it Just Roots? No, it’s more than that—a third organism is involved.

4. Meet the Real Connectors: Fungi

• Field Trip to the Bronx Botanical Garden:
  • Hosts and experts look for and find fine, white fungal threads—the real networkers ([13:01]–[13:10]).
  • Physical Scale: Up to 7 miles of fungal “threading” in a pinch of dirt ([13:39]).
• Fungi are Not Plants:
  • Biological Category: Fungi are more closely related to animals than plants ([13:54]).
  • Ancient Origins: Fossils show fungi-plant association going back 400 million years ([14:31]).

5. How the System Operates: Mutualism, Mining, and Murder

• Mutual Support System:
  • Fungi access minerals/water in the soil and swap them for sugar (carbon) produced by trees ([15:31]–[19:16]).
  • Quote:

  “The fungi need sugar to build their bodies the same way that we use our food to build our bodies.”
  —Jennifer Frazer ([18:15])

• How Fungi Acquire Minerals:
  • Mining: Secreting acids to bore tunnels into rocks and extract mineral nutrients (nitrogen, phosphorus, etc.) ([24:03]–[24:51]).
  • Hunting: Some fungi trap and kill tiny soil dwellers (springtails) to absorb their nitrogen ([25:25]–[26:55]).
    • Gruesome Image: Springtails found with fungus threads growing inside them—still alive ([26:36]).
  • Fishing: Fungi transport nutrients from decomposing fish (like salmon left by bears) into trees, making up to 75% of the nitrogen in some trees ([27:54]–[28:33]).

6. The Economy of the Forest: Scale and Reciprocity

• Sugar Trade Scale: A tree may send 20–80% of its sugar into the underground network to feed fungi ([29:00]–[29:14]).
• The “Bank Account” Model:
  • Trees bank resources in fungi and retrieve them when needed—resources flow back and forth ([29:46]–[30:10]).
  • Warning System: Trees send alert chemicals through the fungal network if they’re attacked or under environmental stress ([30:16]–[31:05]).
    • Quote:

    “If a tree’s injured, it’ll cry out in a kind of chemical way... and warn neighboring trees or seedlings.”
    —Suzanne Simard ([30:25])

7. Adaptation, Resilience, and Intelligence?

• Resource Redistribution in Stress:
  • Dying trees may move their carbon to better-adapted, often different, trees—boosting forest survival ([31:27]–[32:53]).
  • Quote:

  “There’s an intelligence there that’s beyond just the species.”
  —Suzanne Simard ([33:08])

• Plant Intelligence Controversy:
  • Simard, when asked, recognizes the parallel to brains or nervous systems, though mainstream science remains cautious ([33:43]–[34:06]).
  • Quote:

  “Physically, when we look at the belowground structure, it looks so much like a brain... there are so many parallels.”
  —Suzanne Simard ([33:43])

8. The Forest as a Superorganism

• Jennifer Frazer likens the forest to a superorganism, like a honeybee colony.
  • “It’s almost as if the forest is acting as an organism itself.” ([34:06])

Notable Quotes & Memorable Moments

• “Jigs had provided this incredible window for me... it was magic for me.”
  —Suzanne Simard ([05:58])

• On fungal mining:

  “They secrete acid and these acids come out and they start to dissolve the rock. It’s like they’re drilling and the fungus actually builds a tunnel inside the rock and... can mine them.”
  —Jennifer Frazer ([24:37])

• “Springtail murder” revelation:

  “[The] fungus ate them. In the little springtail bodies, there were little tubes growing inside them... [still alive].”
  —Jennifer Frazer ([26:36])

• “Salmon in tree rings” discovery:

  “The fungi... drink the salmon carcass down and then send it off to the tree, and the tree has evidence of its salmon consumption.”
  —Robert Krulwich ([27:54])

• Underground chemical warnings and cooperation:

  “So you can see this is like a game of telephone. One tree goes, 'Oh,' and the next one goes, 'Oh,' ... and then they do stuff.”
  —Robert Krulwich ([30:48])

Timestamps for Important Segments

• Intro and Setting Up the Forest Scene – [01:59]–[02:52]
• Simard’s Origin Story (Jiggs, Roots, and Wonder) – [02:52]–[06:19]
• Clearcutting and the First Suspicion of Networked Forests – [06:31]–[08:13]
• Radioactive Gas Experiment & Discovery of Underground Network – [08:13]–[10:14]
• Introduction of the “Wood Wide Web” – [10:51]–[11:53]
• Bronx Botanical Garden: Discovering Fungi – [11:53]–[13:39]
• Fungal Mutualism, Mining, and Predation – [15:31]–[27:07]
• Resource Banking, Warning Signals, “Intelligence” – [29:46]–[33:08]
• Forest as Superorganism Discussion, Plant Intelligence – [34:06]–[35:30]

Tone and Language

The tone throughout is playful, curious, and slightly irreverent—hallmarks of Radiolab's storytelling style. Interviewees speak with wonder and awe, and technical details are broken down with vivid analogies and humor.

Takeaway

"From Tree to Shining Tree" reimagines forests as communities shaped by secret partnerships, cunning resource deals, and something that feels awfully like social intelligence. Far from being lonely, rival giants, trees are participants in a bustling, collaborative "internet" mediated by ancient fungi—a Wood Wide Web that supports, warns, and adapts for the good of the whole forest.

If you've never before marveled at the ground beneath your feet, this episode leaves you with a brand new respect for the unseen alliances and dramas beneath the forest floor.