Preface. Below are excerpts from a New York Times article about forests.
My book “Life After Fossil Fuels: A Reality Check on Alternative Energy” explains why the myriad ways we use fossil fuels can’t be electrified (or hydrogenized or anything else). Not even the electric grid can be 100% renewable.
Only biomass can do it all, obviously, since the 5,000 years of civilizations that preceded fossil fuels used biomass for energy as well as infrastructure. The least we could do for our descendants is to plant forests so they don’t freeze in the dark, can build homes, carts, and more and rebuild anew (and bury nuclear wastes).
Alice Friedemann www.energyskeptic.com author of 2021 Life After Fossil Fuels: A Reality Check on Alternative Energy best price here; 2015 When Trucks Stop Running: Energy and the Future of Transportation”, Barriers to Making Algal Biofuels, & “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Crazy Town, Collapse Chronicles, Derrick Jensen, Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity, XX2 report
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Jabr F (2020) The Social Life of Forests. Trees appear to communicate and cooperate through subterranean networks of fungi. What are they sharing with one another? New York Times.
When Europeans arrived on America’s shores in the 1600s, forests covered one billion acres of the future United States — close to half the total land area. Between 1850 and 1900, U.S. timber production surged to more than 35 billion board feet from five billion. By 1907, nearly a third of the original expanse of forest — more than 260 million acres — was gone. As of 2012, the United States had more than 760 million forested acres. The age, health and composition of America’s forests have changed significantly, however. Although forests now cover 80 percent of the Northeast, for example, less than 1 percent of its old-growth forest remains intact.
And though clearcutting is not as common as it once was, it is still practiced on about 40 percent of logged acres in the United States and 80 percent of them in Canada. In a thriving forest, a lush understory captures huge amounts of rainwater, and dense root networks enrich and stabilize the soil. Clearcutting removes these living sponges and disturbs the forest floor, increasing the chances of landslides and floods, stripping the soil of nutrients and potentially releasing stored carbon to the atmosphere. When sediment falls into nearby rivers and streams, it can kill fish and other aquatic creatures and pollute sources of drinking water. The abrupt felling of so many trees also harms and evicts countless species of birds, mammals, reptiles and insects.
Humans have relied on forests for food, medicine and building materials for many thousands of years. Forests have likewise provided sustenance and shelter for countless species over the eons. But they are important for more profound reasons too. Forests function as some of the planet’s vital organs. The colonization of land by plants between 425 and 600 million years ago, and the eventual spread of forests, helped create a breathable atmosphere with the high level of oxygen we continue to enjoy today. Forests suffuse the air with water vapor, fungal spores and chemical compounds that seed clouds, cooling Earth by reflecting sunlight and providing much-needed precipitation to inland areas that might otherwise dry out. Researchers estimate that, collectively, forests store somewhere between 400 and 1,200 gigatons of carbon, potentially exceeding the atmospheric pool.
Crucially, a majority of this carbon resides in forest soils, anchored by networks of symbiotic roots, fungi and microbes. Each year, the world’s forests capture more than 24 percent of global carbon emissions, but deforestation — by destroying and removing trees that would otherwise continue storing carbon — can substantially diminish that effect. When a mature forest is burned or clear-cut, the planet loses an invaluable ecosystem and one of its most effective systems of climate regulation. The razing of an old-growth forest is not just the destruction of magnificent individual trees — it’s the collapse of an ancient republic whose interspecies covenant of reciprocation and compromise is essential for the survival of Earth as we’ve known it.
By the time she was in grad school at Oregon State University, however, Simard, today 60-years-old and a professor of ecology at the University of British Columbia, understood that commercial clearcutting had largely superseded the sustainable logging practices of the past. Loggers were replacing diverse forests with homogeneous plantations, evenly spaced in upturned soil stripped of most underbrush. Without any competitors, the thinking went, the newly planted trees would thrive. Instead, they were frequently more vulnerable to disease and climatic stress than trees in old-growth forests. In particular, Simard noticed that up to 10 percent of newly planted Douglas fir were likely to get sick and die whenever nearby aspen, paper birch and cottonwood were removed. The reasons were unclear. The planted saplings had plenty of space, and they received more light and water than trees in old, dense forests. So why were they so frail?
Simard suspected that the answer was buried in the soil. Underground, trees and fungi form partnerships known as mycorrhizas: Threadlike fungi envelop and fuse with tree roots, helping them extract water and nutrients like phosphorus and nitrogen in exchange for some of the carbon-rich sugars the trees make through photosynthesis. Research had demonstrated that mycorrhizas also connected plants to one another and that these associations might be ecologically important, but most scientists had studied them in greenhouses and laboratories, not in the wild. For her doctoral thesis, Simard decided to investigate fungal links between Douglas fir and paper birch in the forests of British Columbia. Apart from her supervisor, she didn’t receive much encouragement from her mostly male peers. “The old foresters were like, Why don’t you just study growth and yield?” Simard told me. “I was more interested in how these plants interact. They thought it was all very girlie.”
Simard has studied webs of root and fungi in the Arctic, temperate and coastal forests of North America for nearly three decades. Her initial inklings about the importance of mycorrhizal networks were prescient, inspiring whole new lines of research that ultimately overturned longstanding misconceptions about forest ecosystems. By analyzing the DNA in root tips and tracing the movement of molecules through underground conduits, Simard has discovered that fungal threads link nearly every tree in a forest — even trees of different species. Carbon, water, nutrients, alarm signals and hormones can pass from tree to tree through these subterranean circuits. Resources tend to flow from the oldest and biggest trees to the youngest and smallest. Chemical alarm signals generated by one tree prepare nearby trees for danger. Seedlings severed from the forest’s underground lifelines are much more likely to die than their networked counterparts. And if a tree is on the brink of death, it sometimes bequeaths a substantial share of its carbon to its neighbors.
Although Simard’s peers were skeptical and sometimes even disparaging of her early work, they now generally regard her as one of the most rigorous and innovative scientists studying plant communication and behavior. David Janos, co-editor of the scientific journal Mycorrhiza, characterized her published research as “sophisticated, imaginative, cutting-edge.” Jason Hoeksema, a University of Mississippi biology professor who has studied mycorrhizal networks, agreed: “I think she has really pushed the field forward.” Some of Simard’s studies now feature in textbooks and are widely taught in graduate-level classes on forestry and ecology. She was also a key inspiration for a central character in Richard Powers’s 2019 Pulitzer Prize-winning novel, “The Overstory”: the visionary botanist Patricia Westerford. In May, Knopf will publish Simard’s own book, “Finding the Mother Tree,” a vivid and compelling memoir of her lifelong quest to prove that “the forest was more than just a collection of trees.”
Since Darwin, biologists have emphasized the perspective of the individual. They have stressed the perpetual contest among discrete species, the struggle of each organism to survive and reproduce within a given population and, underlying it all, the single-minded ambitions of selfish genes. Now and then, however, some scientists have advocated, sometimes controversially, for a greater focus on cooperation over self-interest and on the emergent properties of living systems rather than their units.
Before Simard and other ecologists revealed the extent and significance of mycorrhizal networks, foresters typically regarded trees as solitary individuals that competed for space and resources and were otherwise indifferent to one another. Simard and her peers have demonstrated that this framework is far too simplistic. An old-growth forest is neither an assemblage of stoic organisms tolerating one another’s presence nor a merciless battle royale: It’s a vast, ancient and intricate society. There is conflict in a forest, but there is also negotiation, reciprocity and perhaps even selflessness. The trees, understory plants, fungi and microbes in a forest are so thoroughly connected, communicative and codependent that some scientists have described them as superorganisms. Recent research suggests that mycorrhizal networks also perfuse prairies, grasslands, chaparral and Arctic tundra — essentially everywhere there is life on land. Together, these symbiotic partners knit Earth’s soils into nearly contiguous living networks of unfathomable scale and complexity. “I was taught that you have a tree, and it’s out there to find its own way,” Simard told me. “It’s not how a forest works, though.”
In some of her earliest and most famous experiments, Simard planted mixed groups of young Douglas fir and paper birch trees in forest plots and covered the trees with individual plastic bags. In each plot, she injected the bags surrounding one tree species with radioactive carbon dioxide and the bags covering the other species with a stable carbon isotope — a variant of carbon with an unusual number of neutrons. The trees absorbed the unique forms of carbon through their leaves. Later, she pulverized the trees and analyzed their chemistry to see if any carbon had passed from species to species underground. It had. In the summer, when the smaller Douglas fir trees were generally shaded, carbon mostly flowed from birch to fir. In the fall, when evergreen Douglas fir was still growing and deciduous birch was losing its leaves, the net flow reversed. As her earlier observations of failing Douglas fir had suggested, the two species appeared to depend on each other. No one had ever traced such a dynamic exchange of resources through mycorrhizal networks in the wild. In 1997, part of Simard’s thesis was published in the prestigious scientific journal Nature — a rare feat for someone so green. Nature featured her research on its cover with the title “The Wood-Wide Web,” a moniker that eventually proliferated through the pages of published studies and popular science writing alike.
In 2002, Simard secured her current professorship at the University of British Columbia, where she continued to study interactions among trees, understory plants and fungi. In collaboration with students and colleagues around the world, she made a series of remarkable discoveries. Mycorrhizal networks were abundant in North America’s forests. Most trees were generalists, forming symbioses with dozens to hundreds of fungal species. In one study of six Douglas fir stands measuring about 10,000 square feet each, almost all the trees were connected underground by no more than three degrees of separation; one especially large and old tree was linked to 47 other trees and projected to be connected to at least 250 more; and seedlings that had full access to the fungal network were 26 percent more likely to survive than those that did not.
Depending on the species involved, mycorrhizas supplied trees and other plants with up to 40 percent of the nitrogen they received from the environment and as much as 50 percent of the water they needed to survive. Below ground, trees traded between 10 and 40 percent of the carbon stored in their roots. When Douglas fir seedlings were stripped of their leaves and thus likely to die, they transferred stress signals and a substantial sum of carbon to nearby ponderosa pine, which subsequently accelerated their production of defensive enzymes. Simard also found that denuding a harvested forest of all trees, ferns, herbs and shrubs — a common forestry practice — did not always improve the survival and growth of newly planted trees. In some cases, it was harmful.
At this point other researchers have replicated most of Simard’s major findings. It’s now well accepted that resources travel among trees and other plants connected by mycorrhizal networks. Most ecologists also agree that the amount of carbon exchanged among trees is sufficient to benefit seedlings, as well as older trees that are injured, entirely shaded or severely stressed, but researchers still debate whether shuttled carbon makes a meaningful difference to healthy adult trees. On a more fundamental level, it remains unclear exactly why resources are exchanged among trees in the first place, especially when those trees are not closely related.
“Darwin’s theory of evolution by natural selection is obviously 19th-century capitalism writ large,” wrote the evolutionary biologist Richard Lewontin.
As Darwin well knew, however, ruthless competition was not the only way that organisms interacted. Ants and bees died to protect their colonies. Vampire bats regurgitated blood to prevent one another from starving. Vervet monkeys and prairie dogs cried out to warn their peers of predators, even when doing so put them at risk. At one point Darwin worried that such selflessness would be “fatal” to his theory. In subsequent centuries, as evolutionary biology and genetics matured, scientists converged on a resolution to this paradox: Behavior that appeared to be altruistic was often just another manifestation of selfish genes — a phenomenon known as kin selection. Members of tight-knit social groups typically share large portions of their DNA, so when one individual sacrifices for another, it is still indirectly spreading its own genes.
Kin selection cannot account for the apparent interspecies selflessness of trees, however — a practice that verges on socialism. Some scientists have proposed a familiar alternative explanation: Perhaps what appears to be generosity among trees is actually selfish manipulation by fungi. Descriptions of Simard’s work sometimes give the impression that mycorrhizal networks are inert conduits that exist primarily for the mutual benefit of trees, but the thousands of species of fungi that link trees are living creatures with their own drives and needs. If a plant relinquishes carbon to fungi on its roots, why would those fungi passively transmit the carbon to another plant rather than using it for their own purposes? Maybe they don’t. Perhaps the fungi exert some control: What looks like one tree donating food to another may be a result of fungi redistributing accumulated resources to promote themselves and their favorite partners.
“Where some scientists see a big cooperative collective, I see reciprocal exploitation,” said Toby Kiers, a professor of evolutionary biology at Vrije Universiteit Amsterdam. “Both parties may benefit, but they also constantly struggle to maximize their individual payoff.” Kiers is one of several scientists whose recent studies have found that plants and symbiotic fungi reward and punish each other with what are essentially trade deals and embargoes, and that mycorrhizal networks can increase conflict among plants. In some experiments, fungi have withheld nutrients from stingy plants and strategically diverted phosphorous to resource-poor areas where they can demand high fees from desperate plants.
Several of the ecologists I interviewed agreed that regardless of why and how resources and chemical signals move among the various members of a forest’s symbiotic webs, the result is still the same: What one tree produces can feed, inform or rejuvenate another. Such reciprocity does not necessitate universal harmony, but it does undermine the dogma of individualism and temper the view of competition as the primary engine of evolution.
The most radical interpretation of Simard’s findings is that a forest behaves “as though it’s a single organism,” as she says in her TED Talk. Some researchers have proposed that cooperation within or among species can evolve if it helps one population outcompete another — an altruistic forest community outlasting a selfish one, for example. The theory remains unpopular with most biologists, who regard natural selection above the level of the individual to be evolutionarily unstable and exceedingly rare. Recently, however, inspired by research on microbiomes, some scientists have argued that the traditional concept of an individual organism needs rethinking and that multicellular creatures and their symbiotic microbes should be regarded as cohesive units of natural selection. Even if the same exact set of microbial associates is not passed vertically from generation to generation, the functional relationships between an animal or plant species and its entourage of microorganisms persist — much like the mycorrhizal networks in an old-growth forest. Humans are not the only species that inherits the infrastructure of past communities.
When a seed germinates in an old-growth forest, it immediately taps into an extensive underground community of interspecies partnerships. Uniform plantations of young trees planted after a clear-cut are bereft of ancient roots and their symbiotic fungi. The trees in these surrogate forests are much more vulnerable to disease and death because, despite one another’s company, they have been orphaned. Simard thinks that retaining some mother trees, which have the most robust and diverse mycorrhizal networks, will substantially improve the health and survival of future seedlings — both those planted by foresters and those that germinate on their own.
Since at least the late 1800s, North American foresters have devised and tested dozens of alternatives to standard clearcutting: strip cutting (removing only narrow bands of trees), shelterwood cutting (a multistage process that allows desirable seedlings to establish before most overstory trees are harvested) and the seed-tree method (leaving behind some adult trees to provide future seed), to name a few. These approaches are used throughout Canada and the United States for a variety of ecological reasons, often for the sake of wildlife, but mycorrhizal networks have rarely if ever factored into the reasoning.
Ryan told me about the 230,000-acre Menominee Forest in northeastern Wisconsin, which has been sustainably harvested for more than 150 years. Sustainability, the Menominee believe, means “thinking in terms of whole systems, with all their interconnections, consequences and feedback loops.” They maintain a large, old and diverse growing stock, prioritizing the removal of low-quality and ailing trees over more vigorous ones and allowing trees to age 200 years or more — so they become what Simard might call grandmothers. Ecology, not economics, guides the management of the Menominee Forest, but it is still highly profitable. Since 1854, more than 2.3 billion board feet have been harvested — nearly twice the volume of the entire forest — yet there is now more standing timber than when logging began. “To many, our forest may seem pristine and untouched,” the Menominee wrote in one report. “In reality, it is one of the most intensively managed tracts of forest in the Lake States.”
Diverse microbial communities inhabit our bodies, modulating our immune systems and helping us digest certain foods. The energy-producing organelles in our cells known as mitochondria were once free-swimming bacteria that were subsumed early in the evolution of multicellular life. Through a process called horizontal gene transfer, fungi, plants and animals — including humans — have continuously exchanged DNA with bacteria and viruses. From its skin, fur or bark right down to its genome, any multicellular creature is an amalgam of other life-forms. Wherever living things emerge, they find one another, mingle and meld.
Five hundred million years ago, as both plants and fungi continued oozing out of the sea and onto land, they encountered wide expanses of barren rock and impoverished soil. Plants could spin sunlight into sugar for energy, but they had trouble extracting mineral nutrients from the earth. Fungi were in the opposite predicament. Had they remained separate, their early attempts at colonization might have faltered or failed. Instead, these two castaways — members of entirely different kingdoms of life — formed an intimate partnership. Together they spread across the continents, transformed rock into rich soil and filled the atmosphere with oxygen.
Eventually, different types of plants and fungi evolved more specialized symbioses. Forests expanded and diversified, both above- and below ground. What one tree produced was no longer confined to itself and its symbiotic partners. Shuttled through buried networks of root and fungus, the water, food and information in a forest began traveling greater distances and in more complex patterns than ever before. Over the eons, through the compounded effects of symbiosis and coevolution, forests developed a kind of circulatory system. Trees and fungi were once small, unacquainted ocean expats, still slick with seawater, searching for new opportunities. Together, they became a collective life form of unprecedented might and magnanimity.