The notion that forest trees can "talk" to each other, share resources with their seedlings, and even protect them via a connective underground web of delicate fungal filaments has continuously piqued researchers' interest.
Do forest trees really 'talk'?
MICHAEL DANTAS/AFP via Getty Images
The concept has gained traction in popular media, even being raised in the popular Apple TV show Ted Lasso, and has been dubbed the "wood-wide web," but the science behind those ideas is unproven, according to University of Alberta expert Justine Karst, as per ScienceDaily.
Karst and two colleagues contest three popular claims about the capabilities of underground fungi known as common mycorrhizal networks, or CMNs, that connect roots of multiple plants underground in a peer-reviewed article published in Nature Ecology & Evolution that also shares their personal point of view.
Molds, yeast, and mushrooms are all examples of fungi.
They discovered that one of the claims, that CMNs are common in forests, is not supported by sufficient scientific evidence.
"With too few forests mapped," not enough is known about CMN structure and function in the field.
The second claim, that adult trees transfer resources, such as nutrients to seedlings via CMNs and that this increases survival and growth, was also found to be questionable.
A review of 26 studies, including one co-authored by Karst, found that while trees can transfer resources underground, CMNs do not always cause that flow, and seedlings typically do not benefit from CMN access.
Overall, their review found roughly equal evidence that connecting to a CMN would benefit or harm seedlings, with neutral effects being the most frequently reported.
According to Karst and her co-authors, the third claim, that adult trees preferentially send resources or "warning signals" of insect damage to young trees via CMNs, is not supported by a single peer-reviewed, published field study.
According to the researchers, exaggerated information can shape and distort the public narrative about CMNs, influencing how forests are managed.
Distorting science on CMNs in forests is a problem because sound science is essential for making forest management decisions.
Without additional evidence, it is premature to base forest practices and policies on CMNs.
In addition, failing to recognize misinformation can erode public trust in science.
Fungi, specifically mycorrhizal fungi, play an important role in the decomposition of organic matter, which provides plant roots with nutrients such as phosphorous and nitrogen, as per Stanford.
Fungi also provide water to plant roots in exchange for carbon, which they use to grow and expand their networks.
This exchange keeps excess carbon from entering the atmosphere, which is a useful mechanism for combating climate change.
Toby Kiers, executive director of the Society for the Protection of Underground Networks, describes these as "living nutrient highways that run beneath our feet" (SPUN).
The Amsterdam-based nonprofit, founded in late 2021, promote mycorrhizal fungi conservation through soil analysis and digital mapping.
According to Kiers, these fungi are linked to 90 percent of the world's plants.
This percentage also represents the estimated amount of undiscovered fungi on the planet.
Mycologist Nicholas Money, a biology professor at Miami University, believes SPUN faces challenges when analyzing samples, such as the large size of fungi and the large amounts of DNA within their cells, which can lead to errors.
"Identifying them doesn't really tell us much... about the importance of a particular fungus in that environment," he added.
