Tree farmer finds evidence of Wood Wide Web in Ohio

The term “Wood Wide Web” was unheard of until it appeared on the cover of the journal Nature in 1997. The phrase is used to compare underground networks of fungal fibers to the World Wide Web that powers the Internet.

The scientific community was intrigued by the idea that masses of intertwined fungi could transmit resources and allow trees to communicate. The concept continues to captivate the public’s imagination, especially after it appeared as a glowing, living network in the movie “Avatar.”

But now, almost 30 years later, there are still more questions than answers about what is going on underground. Some scientists are skeptical that fungi too small for the human eye to see can function like a powerful network, or purposely benefit trees and plants.

Two Ohio men, Jim Gresh and longtime forester and friend Ed Romano, say they see evidence of the Wood Wide Web in the six forested properties the Gresh family owns in the state. And they have numbers to back it up.

For instance, there is a remarkably high percentage of oak trees – 59% – in a 110-acre stand in Athens County. That’s almost six times the average percentage of oaks in Ohio forests, they say.

Another stand in Tuscarawas County not only has a high percentage of walnuts, but an abnormally fast growth rate among walnut trees growing close together in what foresters call “overstocked clusters.”

In both cases, Gresh and Romano credit the sharing of resources through fungal networks for these forest phenomena.

“The new fungal network theories fit our data and easily explain our most unexplainable observations,” Gresh said. “Fungal network impact is just common sense to us.”

EXPERIMENTS

It was a study by PhD student Suzanne Simard and her colleagues that made the cover of that 1997 edition of Nature. They exposed pairs of tree seedlings growing in a forest to radioactive CO2. After two years, they found that the carbon had passed from birch trees to fir trees, which had fungal networks beneath them, but not between birch and cedar trees, which had none.

The study seemed to go against the traditional forestry belief that trees compete for sun and other resources. It showed fir trees that were in the shade, and thus were unable to produce as much carbon from photosynthesis, received more carbon than fir trees that got some sun.

It seemed like carbon was “flowing downhill from where it was plentiful to where it was scarce,” biologist Merlin Sheldrake said of the study in his book “Entangled Life: How Fungi Make Our Worlds, Change Our Minds & Shape Our Future.”

REACTION

Simard, now an author and professor of forest ecology at the University of British Columbia, is a regular on the World Wide Web with articles, videos and TED talks that get millions of views. In a video called “How Trees Talk,” she says that fungal networks not only connect trees of the same species but other species as well.

Along with that of the Wood Wide Web, Simard’s concept of “mother trees” appeared in “Avatar.” These trees act as hubs in the forest and can be connected to hundreds of other trees, Simard says. These hub trees send out not only carbon but other resources to nurture their offspring and others. They even send out distress signals so other trees can build up defensive chemicals against threats like tree bark beetles.

“Through back-and-forth conversations, they increase the resilience of the whole community,” Simard explains in the video.

In an episode of PBS’s Green Planet called “The Fungi that Help Trees Talk,” Sir David Attenborough explains that fungi make up “a giant underground organism” whose filaments plug into the tips of tree roots. Trees not only send nutrients through the filaments but also chemicals and electrical signals, “allowing them to communicate with each other,” he said.

But the idea of trees talking makes some scientists say no way. A New York Times story published in 2022 begins: “(T)he theory of the wood-wide web is everywhere, and some scientists argue that it is overblown and unproven.” A headline on the Society of Environmental Journalists website asserts: ”Are Trees Talking Underground? For Scientists, It’s In Dispute.”

Skeptical scientists say that if there is transfer of elements between forest plants through fungal networks, it’s entirely passive, as in accidental.

“It doesn’t matter if it’s passive or purposeful,” Gresh said. “This mycorrhizal network is really important to the ecosystem.”

He and his wife, Heidi, manage their forested properties using the European method called close-to-nature forestry. They do sell timber, but clear-cutting and use of chemicals is forbidden. They aim for gentle harvests that protect the canopy and the soil, hoping to improve regeneration and biodiversity.

Retiring in 2015 after 33 years with the Timken Company, including six as president of its operations in China, Gresh didn’t take it easy. He served on several boards, including that of the Muskingum Watershed Conservancy District, and earned a degree in conservation ecology from Malone University.

He joined forestry associations in Ohio and Pennsylvania as well as conservation forestry groups in the United States, the United Kingdom and other parts of Europe. He continues to study conservation forestry and its benefits to migratory birds and other species.

He has also been learning conservation forestry from Romano, who marks the trees selected for harvest and supervises their removal, making sure damage to other trees and disturbance of the forest is minimal.

Gresh also employs young foresters who measure trees and record data using methods prescribed by the U. S. Forestry Service. That’s how he gets the numbers for percentages and growth rates.

EVIDENCE

On the Greshes’ Athens County property, there’s a smaller forest next to the 110-acre plot. Gresh says it appears that both areas were clear-cut in the late 1800s.

The smaller plot may have undergone stump removal as well because it was made into a pasture. It appears the pasture was abandoned 60 or 70 years ago, resulting in the young forest that is there today.

The larger plot was never used for pasture or anything else, so it’s had more than a century to regrow into forest. This older forest contains such a proliferation of mushrooms that Romano can only harvest a fraction of the chanterelles, morels and oyster mushrooms he loves to eat.

Mushrooms are the visible part of the underground fungal network. Biologists call them the “fruit” of fungi, like apples on a tree. Their job is to produce spores to then produce more fungi and more mushrooms.

“There’s probably six times the number of mushrooms than I’ve seen in any other forest,” said Romano, who’s been a forester for more than 50 years. “There has to be some kind of symbiotic relationship.”

Gresh says his forests, like the typical forests in Ohio, average between 7% and 20% oak trees. The smaller forest in Athens County is 10% oaks, right in the middle of that average range.

Yet the older forest, even though it’s right next door, is 59% oaks. And he believes a vibrant fungal network is the reason.

“In this forest, there’s a huge number of mushrooms and a phenomenal growth of oaks, almost 60% of all the trees,” he said. “We would consider this pretty compelling evidence that there is a Wood Wide Web.”

Meanwhile, on the Tuscarawas County property, there’s a huge – and obviously very old – tree they named the Grandmother Walnut. Gresh believes the area was clear-cut, perhaps for a pasture, leaving this majestic tree alone in the field. Unfortunately, it fell a few years ago in a storm.

But it left a legacy, Gresh said. Walnuts average only 1% of the trees in Ohio’s forests, which is about the same amount found on his other properties. However, the percentage of walnut trees in the stand around the Grandmother Walnut is around 10%.

And those walnuts have generated another strange statistic. Traditional timbering wisdom would say that trees growing close together are not able to get enough sunlight and nutrients and will grow very slowly. Yet the data shows more than 60% of the fastest-growing walnut trees on the property are in clusters, with some trees only four feet apart.

After doing soil tests and site comparisons, “we see no explanation for the faster growth in what appears to be a too-crowded and competitive environment,” Gresh said. Rather, this seems to be evidence of a mother tree using fungal networks to nourish its offspring, as Simard and other scientists describe.

AT RISK

Science has only recently acquired the technology to be able to detect and identify the tiny fungal organisms that make up the underground networks. Years ago, scientists said there may be 1.5 million species of fungi; now the estimate is 5 million. But even with the advent of genome sequencing, only 3% of those species have been identified, Gresh said.

“Fungi are now suggested to be the largest known living organisms on Earth,” he said. “One that was recently discovered in Oregon covers four square miles and is at least 2,400 years old. The new knowledge is impressive, but the infancy of the science is also humbling.”

Gresh and a growing number of people in the scientific community as well as the general public are worried about the Forestry Service’s “Early Successional Habitat Creation Project” and other programs like “The Young Forest Project.” Advocates of these programs say that logging, clear-cutting and controlled burning of some of the older forests gives young forests a chance to grow. This will benefit many bird and mammal species, including some that are in decline, they say.

Last year, seven biologists and ecologists published a paper saying these programs are based on too few studies and faulty data analysis. Instead of helping them, these programs will harm species by reducing connectivity and increasing isolation, not to mention their effects on biodiversity, the atmosphere and human health, they say. The title of the paper pretty much sums up their position: “Forest-clearing to create early-successional habitats: Questionable benefits, significant costs.”

Michael J. Kellett, executive director of the New England nonprofit RESTORE, The North Woods and the lead author of the paper, appears in a 2022 article in National Geographic, “Is clear-cutting U. S. forests good for wildlife?” Kellett is quoted as saying that “logging-for-wildlife programs” are “dealing in old science” and that the thinking behind them is “ecologically dangerous.”

In addition to agreeing with the scientists’ objections, Gresh worries that more logging and clear-cutting – especially if there is stump removal – will wreak havoc on the Wood Wide Web.

Simard, who ironically came from a family in the timbering business, would probably concur. In the video, she says that high-grade logging and clear-cut logging target mother trees because their wood is of higher value.

“Hub trees are not unlike rivets in an airplane,” she says. “You take out one or two and the plane still flies. But you take out one too many, and the whole system collapses.”

“Everything in God’s creation is interconnected, even things we can’t see,” Gresh said. “Our stewardship of the forests needs to be more caring and gentle to avoid harming these important connections.”